diff --git a/app/src/main/java/com/gatecontrol/android/mail/MailLogic.kt b/app/src/main/java/com/gatecontrol/android/mail/MailLogic.kt
index 3bdd18d1..9a4f2fae 100644
--- a/app/src/main/java/com/gatecontrol/android/mail/MailLogic.kt
+++ b/app/src/main/java/com/gatecontrol/android/mail/MailLogic.kt
@@ -74,6 +74,51 @@ object MailLogic {
     /** Whether a mail still belongs to the list it is in after [action] (archive, delete, junk, move take it away). */
     fun leavesList(action: String): Boolean = action in setOf(SWIPE_ARCHIVE, SWIPE_DELETE, "junk", "move", "tab")
 
+    // ─── the menu: an account's folders ─────────────────────────────
+
+    /**
+     * Whether the menu shows [accountId]'s folders: as the person folded it this session ([folds]), else open for the
+     * account of the [box] shown.
+     */
+    fun foldOpen(folds: Map<Long, Boolean>, accountId: Long, box: Box): Boolean = folds[accountId] ?: (box.accountId == accountId)
+
+    /** [folds] after a tap on the account (its folders open or close; the menu stays). */
+    fun toggleFold(folds: Map<Long, Boolean>, accountId: Long, box: Box): Map<Long, Boolean> =
+        folds + (accountId to !foldOpen(folds, accountId, box))
+
+    // ─── a conversation ─────────────────────────────────────────────
+
+    /**
+     * A conversation (`GET threads/<id>`) around the open mail [currentId]: the mails before it and those after it,
+     * each oldest first (the newest at the bottom, as in Outlook). Without the open mail in it, all count as before.
+     */
+    fun conversation(items: List<MMessage>, currentId: Long): Pair<List<MMessage>, List<MMessage>> {
+        val sorted = items.distinctBy { it.id }.sortedWith(compareBy({ it.summary.date }, { it.id }))
+        val at = sorted.indexOfFirst { it.id == currentId }
+        if (at < 0) return sorted to emptyList()
+        return sorted.subList(0, at) to sorted.subList(at + 1, sorted.size)
+    }
+
+    /** The senders of a conversation for its line ("Anna, Tim"), each once, at most [max]. */
+    fun participants(items: List<MSummary>, max: Int = 3): List<String> =
+        items.map { it.from }.distinctBy { it.email.lowercase() }.map { it.label }.filter { it.isNotBlank() }.take(max)
+
+    // ─── a sender ───────────────────────────────────────────────────
+
+    /** `GET search` for the mails of [email] in the account [accountId] (all accounts without one). */
+    fun senderQuery(email: String, accountId: Long?, cursor: String? = null): Map<String, String> = buildMap {
+        put("from", email.trim().lowercase())
+        put("box", accountId?.toString() ?: BOX_ALL)
+        cursor?.let { put("cursor", it) }
+    }
+
+    /** The server's `from` matches a part of the address: only the mails of exactly [email] stay. */
+    fun fromSender(items: List<MSummary>, email: String): List<MSummary> = items.filter { it.from.email.trim().equals(email.trim(), ignoreCase = true) }
+
+    /** The name of [email] in the person's contacts (`contacts?q=`, a `person` hit), null when there is none. */
+    fun contactOf(contacts: List<MContact>, email: String): MContact? =
+        contacts.firstOrNull { it.source == MContact.SOURCE_PERSON && it.email.trim().equals(email.trim(), ignoreCase = true) && !it.name.isNullOrBlank() }
+
     // ─── swipes ─────────────────────────────────────────────────────
 
     const val SWIPE_ARCHIVE = MSettings.SWIPE_ARCHIVE
@@ -311,21 +356,50 @@ object MailLogic {
         return parseRecipients(addr).addresses.firstOrNull()
     }
 
+    /** The page's margin (CSS px) around the mail. */
+    const val PAGE_PADDING = 12
+
+    /** Below this a mail is not made any smaller to fit (pinching still zooms in). */
+    const val MIN_ZOOM = 0.25
+
+    /** How often a page is laid out again to fit (each time only smaller, so it always ends). */
+    const val FIT_ROUNDS = 3
+
     /**
      * The page the WebView shows: the mail's (already cleaned) HTML with a strict content policy (no scripts, no
-     * frames, pictures only from the app's own address) and a width that fits the phone.
+     * frames, pictures only from the app's own address) and a width that fits the phone: pictures, tables, long
+     * links and preformatted text stay inside the screen. What is still wider (a newsletter's table of a fixed 600 px)
+     * is made smaller as a whole with [zoom] (CSS `zoom` on the mail, as mail apps do), measured from outside by
+     * [fitZoom] — the page itself never runs a script. Pinching still zooms in.
      */
-    fun page(html: String, dark: Boolean = false): String {
+    fun page(html: String, dark: Boolean = false, zoom: Double = 1.0): String {
         val csp = "default-src 'none'; img-src $BASE_URL data:; style-src 'unsafe-inline'; font-src data:; " +
             "script-src 'none'; frame-src 'none'; form-action 'none'; base-uri 'none'"
         val colors = if (dark) "color-scheme: light;" else ""
+        val z = zoom.coerceIn(MIN_ZOOM, 1.0)
+        val fit = if (z < 1.0) "#gc-fit{zoom:${String.format(java.util.Locale.ROOT, "%.3f", z)}}" else ""
         return "<!doctype html><html><head><meta charset=\"utf-8\">" +
             "<meta http-equiv=\"Content-Security-Policy\" content=\"$csp\">" +
             "<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">" +
-            "<style>html,body{margin:0;padding:0;$colors}body{padding:12px;font-family:sans-serif;font-size:15px;line-height:1.5;" +
+            "<style>html,body{margin:0;padding:0;$colors}body{padding:${PAGE_PADDING}px;font-family:sans-serif;font-size:15px;line-height:1.5;" +
             "word-wrap:break-word;overflow-wrap:anywhere;background:#FFFFFF;color:#1A1D22}" +
-            "img{max-width:100%;height:auto}table{max-width:100%}pre{white-space:pre-wrap}</style></head><body>" +
-            html + "</body></html>"
+            "img{max-width:100%;height:auto}table{max-width:100%}td,th{overflow-wrap:anywhere}" +
+            "a{overflow-wrap:anywhere;word-break:break-word}pre{white-space:pre-wrap;overflow-wrap:anywhere}$fit</style></head><body>" +
+            "<div id=\"gc-fit\">" + html + "</div></body></html>"
+    }
+
+    /**
+     * The [page]'s zoom so the mail fits without scrolling sideways, from what the WebView measured: [viewCss] its
+     * width and [contentCss] the width of what it shows (both in CSS px, the content at the [current] zoom). Null
+     * when it fits already (1 px of rounding allowed) or would not get smaller; never below [MIN_ZOOM].
+     */
+    fun fitZoom(viewCss: Double, contentCss: Double, current: Double = 1.0): Double? {
+        if (viewCss <= 2 * PAGE_PADDING || contentCss <= viewCss + 1.0 || current <= MIN_ZOOM) return null
+        // the mail at zoom 1 (the margin on the left is not zoomed; one on the right may count or not)
+        val mail = (contentCss - PAGE_PADDING) / current
+        val zoom = ((viewCss - 2 * PAGE_PADDING) / mail).coerceIn(MIN_ZOOM, 1.0)
+        val rounded = kotlin.math.floor(zoom * 1000) / 1000
+        return rounded.takeIf { it < current - 0.001 }
     }
 
     // ─── the body of a draft ────────────────────────────────────────
diff --git a/app/src/main/java/com/gatecontrol/android/mail/MailModels.kt b/app/src/main/java/com/gatecontrol/android/mail/MailModels.kt
index 38b78037..29980096 100644
--- a/app/src/main/java/com/gatecontrol/android/mail/MailModels.kt
+++ b/app/src/main/java/com/gatecontrol/android/mail/MailModels.kt
@@ -320,7 +320,13 @@ data class MOutboxItem(
     val error: String?,
 )
 
-data class MContact(val name: String?, val email: String, val source: String)
+data class MContact(val name: String?, val email: String, val source: String) {
+    companion object {
+        /** A contact of the person (the coming contacts plugin); `recent`: someone written with lately. */
+        const val SOURCE_PERSON = "person"
+        const val SOURCE_RECENT = "recent"
+    }
+}
 
 /** "Zum Ablegen": an attachment the AI was not sure about. */
 data class MFilingItem(
diff --git a/app/src/main/java/com/gatecontrol/android/mail/MailRepository.kt b/app/src/main/java/com/gatecontrol/android/mail/MailRepository.kt
index 35a03de3..3276ee81 100644
--- a/app/src/main/java/com/gatecontrol/android/mail/MailRepository.kt
+++ b/app/src/main/java/com/gatecontrol/android/mail/MailRepository.kt
@@ -28,6 +28,7 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.drop
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import timber.log.Timber
 import javax.inject.Inject
@@ -63,6 +64,15 @@ class MailRepository @Inject constructor(
     private val _undo = MutableStateFlow<MUndo?>(null)
     val undo: StateFlow<MUndo?> = _undo.asStateFlow()
 
+    /** The menu's folded accounts (account id → folders shown), kept while the app runs. */
+    private val _folds = MutableStateFlow<Map<Long, Boolean>>(emptyMap())
+    val folds: StateFlow<Map<Long, Boolean>> = _folds.asStateFlow()
+
+    /** A tap on an account in the menu: its folders open or close ([MailLogic.toggleFold]). */
+    fun toggleFold(accountId: Long, box: MailLogic.Box) {
+        _folds.update { MailLogic.toggleFold(it, accountId, box) }
+    }
+
     @Volatile private var meAt = 0L
     private var refreshJob: Job? = null
 
diff --git a/app/src/main/java/com/gatecontrol/android/navigation/MailNavigation.kt b/app/src/main/java/com/gatecontrol/android/navigation/MailNavigation.kt
index 7b28104b..9ef61f6b 100644
--- a/app/src/main/java/com/gatecontrol/android/navigation/MailNavigation.kt
+++ b/app/src/main/java/com/gatecontrol/android/navigation/MailNavigation.kt
@@ -16,6 +16,8 @@ import com.gatecontrol.android.ui.mail.MailOutboxScreen
 import com.gatecontrol.android.ui.mail.MailReadNav
 import com.gatecontrol.android.ui.mail.MailReadScreen
 import com.gatecontrol.android.ui.mail.MailSearchScreen
+import com.gatecontrol.android.ui.mail.MailSenderNav
+import com.gatecontrol.android.ui.mail.MailSenderScreen
 import com.gatecontrol.android.ui.mail.MailSettingsScreen
 
 /** Mail's ways between its screens (the tab, a page beside Start and the routes on top share them). */
@@ -71,6 +73,18 @@ internal fun NavGraphBuilder.mailRoutes(
                     compose = { mode, reply -> if (id != null) go(Screen.MailCompose.create(ref = id, mode = mode, reply = reply)) },
                     mailTo = { to -> go(Screen.MailCompose.create(to = to)) },
                     open = { other -> navController.navigate(Screen.MailMessage.create(other)) },
+                    sender = { email, name, account -> go(Screen.MailSender.create(email, name, account)) },
+                ),
+            )
+        }
+    }
+    composable(Screen.MailSender.route, arguments = listOf(optional(Screen.MailSender.ARG_EMAIL), optional(Screen.MailSender.ARG_NAME), optional(Screen.MailSender.ARG_ACCOUNT))) {
+        GcContentWidth {
+            MailSenderScreen(
+                MailSenderNav(
+                    back = back,
+                    write = { to, account -> go(Screen.MailCompose.create(account = account, to = to)) },
+                    open = { id -> navController.navigate(Screen.MailMessage.create(id)) },
                 ),
             )
         }
diff --git a/app/src/main/java/com/gatecontrol/android/navigation/Screen.kt b/app/src/main/java/com/gatecontrol/android/navigation/Screen.kt
index 17ffac74..ce817ac6 100644
--- a/app/src/main/java/com/gatecontrol/android/navigation/Screen.kt
+++ b/app/src/main/java/com/gatecontrol/android/navigation/Screen.kt
@@ -160,6 +160,17 @@ sealed class Screen(val route: String) {
         }
     }
     data object MailSearch : Screen("mail/search")
+    /** A sender's page: their mails in the account `account`. */
+    data object MailSender : Screen("mail/sender?email={email}&name={name}&account={account}") {
+        const val ARG_EMAIL = "email"
+        const val ARG_NAME = "name"
+        const val ARG_ACCOUNT = "account"
+        fun create(email: String, name: String? = null, account: Long? = null): String {
+            fun enc(v: String) = java.net.URLEncoder.encode(v, "UTF-8").replace("+", "%20")
+            val args = listOfNotNull("email=" + enc(email), name?.takeIf { it.isNotBlank() }?.let { "name=" + enc(it.take(200)) }, account?.let { "account=$it" })
+            return "mail/sender?" + args.joinToString("&")
+        }
+    }
     /** "Zum Ablegen": attachments the AI was not sure about. */
     data object MailFiling : Screen("mail/filing")
     /** "Konto hinzufügen"; `account` = sign in to that Microsoft account again. */
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailComponents.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailComponents.kt
index 65252464..20f5e0b4 100644
--- a/app/src/main/java/com/gatecontrol/android/ui/mail/MailComponents.kt
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailComponents.kt
@@ -235,9 +235,9 @@ internal fun FileBadge(name: String, mime: String, size: Int = 40) {
 
 /** The round avatar with the sender's initials in the account's color. */
 @Composable
-internal fun SenderAvatar(name: String?, email: String, color: Color) {
-    Box(Modifier.size(40.dp).clip(CircleShape).background(color), contentAlignment = Alignment.Center) {
-        Text(MailLogic.initials(name, email), color = Color(0xFF0D1015), fontWeight = FontWeight.Bold, fontSize = 14.sp)
+internal fun SenderAvatar(name: String?, email: String, color: Color, size: Dp = 40.dp) {
+    Box(Modifier.size(size).clip(CircleShape).background(color), contentAlignment = Alignment.Center) {
+        Text(MailLogic.initials(name, email), color = Color(0xFF0D1015), fontWeight = FontWeight.Bold, fontSize = (size.value * 0.35f).sp)
     }
 }
 
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeScreen.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeScreen.kt
index 94c5e5ec..0740eb47 100644
--- a/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeScreen.kt
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeScreen.kt
@@ -58,6 +58,7 @@ import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.semantics.contentDescription
 import androidx.compose.ui.semantics.heading
 import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.semantics.stateDescription
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -114,6 +115,7 @@ fun MailHomeScreen(nav: MailNav, viewModel: MailHomeViewModel = hiltViewModel())
     val undo by viewModel.undo.collectAsStateWithLifecycle()
     val message by viewModel.message.collectAsStateWithLifecycle()
     val reopen by viewModel.reopen.collectAsStateWithLifecycle()
+    val folds by viewModel.folds.collectAsStateWithLifecycle()
     val context = mailContext()
     val scope = rememberCoroutineScope()
     val drawer = rememberDrawerState(DrawerValue.Closed)
@@ -165,6 +167,8 @@ fun MailHomeScreen(nav: MailNav, viewModel: MailHomeViewModel = hiltViewModel())
                     box = box,
                     filing = filing,
                     outbox = outbox,
+                    folds = folds,
+                    onFold = viewModel::toggleFold,
                     onBox = { close(); viewModel.selectBox(it) },
                     onFiling = { close(); nav.filing() },
                     onOutbox = { close(); nav.outbox() },
@@ -573,8 +577,9 @@ internal object MailFolders {
 
 /**
  * The menu (mockup "Seitenmenü"): "Mail", "Alle Posteingänge", "Zum Ablegen" (with Drive), "Postausgang" (when
- * something waits), the accounts — the chosen one with its folders — and below "Konto hinzufügen" and the settings.
- * Calendar and resources come later (phase 2/3).
+ * something waits), the accounts with their folders and below "Konto hinzufügen" and the settings. A tap on an
+ * account opens or closes its folders (the menu stays, [folds] keeps it for the session); picking its "Posteingang"
+ * or a folder closes the menu. Calendar and resources come later (phase 2/3).
  */
 @Composable
 private fun MailDrawer(
@@ -583,6 +588,8 @@ private fun MailDrawer(
     box: MailLogic.Box,
     filing: Int,
     outbox: Int,
+    folds: Map<Long, Boolean>,
+    onFold: (Long) -> Unit,
     onBox: (MailLogic.Box) -> Unit,
     onFiling: () -> Unit,
     onOutbox: () -> Unit,
@@ -611,31 +618,26 @@ private fun MailDrawer(
                 item(key = "accounts") { DrawerLabel(stringResource(R.string.mail_accounts)) }
             }
             accounts.forEach { a ->
+                val open = MailLogic.foldOpen(folds, a.id, box)
                 item(key = "a${a.id}") {
-                    DrawerAccount(a, me?.unreadByAccount?.get(a.id) ?: 0, on = box.accountId == a.id && box.folderId == null) {
-                        onBox(MailLogic.Box(a.id))
-                    }
+                    DrawerAccount(a, me?.unreadByAccount?.get(a.id) ?: 0, on = !open && box.accountId == a.id, open = open) { onFold(a.id) }
                 }
-                if (box.accountId == a.id) {
+                if (open) {
                     val list = MailFolders.ordered(folders[a.id].orEmpty())
+                    // the account's inbox is always there (also before its folders came)
+                    if (list.none { it.role == MFolder.ROLE_INBOX }) {
+                        item(key = "i${a.id}") {
+                            DrawerFolder(stringResource(R.string.mail_inbox), 0, on = box.accountId == a.id && box.folderId == null) { onBox(MailLogic.Box(a.id)) }
+                        }
+                    }
                     list.forEach { f ->
                         item(key = "f${f.id}") {
-                            val label = MailFolders.label(f)
-                            Row(
-                                Modifier
-                                    .fillMaxWidth()
-                                    .heightIn(min = 40.dp)
-                                    .clip(RoundedCornerShape(12.dp))
-                                    .background(if (box.folderId == f.id) extra.accentBg else Color.Transparent)
-                                    .selectable(selected = box.folderId == f.id, role = Role.Tab) {
-                                        onBox(MailLogic.Box(a.id, f.id.takeIf { f.role != MFolder.ROLE_INBOX }))
-                                    }
-                                    .padding(start = 58.dp, end = 12.dp),
-                                verticalAlignment = Alignment.CenterVertically,
-                            ) {
-                                Text(label, style = MaterialTheme.typography.bodyMedium, color = if (box.folderId == f.id) extra.accentText else MaterialTheme.colorScheme.onSurface, modifier = Modifier.weight(1f), maxLines = 1, overflow = TextOverflow.Ellipsis)
-                                if (f.unread > 0) Text(f.unread.toString(), style = MaterialTheme.typography.labelMedium, color = extra.muted, fontWeight = FontWeight.Bold)
-                            }
+                            val inbox = f.role == MFolder.ROLE_INBOX
+                            DrawerFolder(
+                                MailFolders.label(f),
+                                f.unread,
+                                on = if (inbox) box.accountId == a.id && box.folderId == null else box.folderId == f.id,
+                            ) { onBox(MailLogic.Box(a.id, f.id.takeIf { !inbox })) }
                         }
                     }
                 }
@@ -692,24 +694,49 @@ private fun DrawerItem(icon: androidx.compose.ui.graphics.vector.ImageVector?, l
     }
 }
 
-/** An account in the menu (like the Outlook app): its picture or the provider's mark, the name, the address below. */
+/** A folder of an account in the menu (indented below it). */
 @Composable
-private fun DrawerAccount(a: MAccount, count: Int, on: Boolean, onClick: () -> Unit) {
+private fun DrawerFolder(label: String, unread: Int, on: Boolean, onClick: () -> Unit) {
     val extra = GateControlTheme.extraColors
     Row(
         Modifier
             .fillMaxWidth()
-            .heightIn(min = 56.dp)
+            .heightIn(min = 40.dp)
             .clip(RoundedCornerShape(12.dp))
             .background(if (on) extra.accentBg else Color.Transparent)
             .selectable(selected = on, role = Role.Tab, onClick = onClick)
-            .padding(horizontal = 12.dp, vertical = 6.dp),
+            .padding(start = 58.dp, end = 12.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Text(label, style = MaterialTheme.typography.bodyMedium, color = if (on) extra.accentText else MaterialTheme.colorScheme.onSurface, modifier = Modifier.weight(1f), maxLines = 1, overflow = TextOverflow.Ellipsis)
+        if (unread > 0) Text(unread.toString(), style = MaterialTheme.typography.labelMedium, color = extra.muted, fontWeight = FontWeight.Bold)
+    }
+}
+
+/**
+ * An account in the menu (like the Outlook app): its picture or the provider's mark, the name, the address below and
+ * the arrow; a tap opens or closes its folders.
+ */
+@Composable
+private fun DrawerAccount(a: MAccount, count: Int, on: Boolean, open: Boolean, onClick: () -> Unit) {
+    val extra = GateControlTheme.extraColors
+    val state = stringResource(if (open) R.string.mail_folders_shown else R.string.mail_folders_hidden)
+    Row(
+        Modifier
+            .fillMaxWidth()
+            .heightIn(min = 56.dp)
+            .clip(RoundedCornerShape(12.dp))
+            .background(if (on) extra.accentBg else Color.Transparent)
+            .clickable(role = Role.Button, onClickLabel = stringResource(if (open) R.string.mail_folders_hide else R.string.mail_folders_show), onClick = onClick)
+            .semantics { stateDescription = state }
+            .padding(start = 12.dp, end = 6.dp, top = 6.dp, bottom = 6.dp),
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = Arrangement.spacedBy(12.dp),
     ) {
         MailAccountAvatar(a, size = 34.dp, ring = if (on) extra.accentBg else MaterialTheme.colorScheme.surface)
         MailAccountText(a, Modifier.weight(1f), color = if (on) extra.accentText else MaterialTheme.colorScheme.onSurface, bold = on)
         if (count > 0) Text(count.toString(), style = MaterialTheme.typography.labelMedium, fontWeight = FontWeight.Bold, color = extra.muted)
+        Icon(if (open) GcIcons.ChevronUp else GcIcons.ChevronDown, contentDescription = null, tint = extra.muted, modifier = Modifier.size(18.dp))
     }
 }
 
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeViewModel.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeViewModel.kt
index 504fef92..8421f9df 100644
--- a/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeViewModel.kt
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailHomeViewModel.kt
@@ -53,6 +53,8 @@ class MailHomeViewModel @Inject constructor(
     val meError: StateFlow<String?> = repository.meError
     val folders: StateFlow<Map<Long, List<MFolder>>> = repository.folders
     val undo: StateFlow<MUndo?> = repository.undo
+    /** The menu's folded accounts ([MailLogic.foldOpen]). */
+    val folds: StateFlow<Map<Long, Boolean>> = repository.folds
 
     private val _box = MutableStateFlow(MailLogic.Box(saved.get<Long>(KEY_ACCOUNT)?.takeIf { it > 0 }, saved.get<Long>(KEY_FOLDER)?.takeIf { it > 0 }))
     val box: StateFlow<MailLogic.Box> = _box.asStateFlow()
@@ -107,6 +109,9 @@ class MailHomeViewModel @Inject constructor(
         }
     }
 
+    /** A tap on an account in the menu: its folders open or close, the menu stays. */
+    fun toggleFold(accountId: Long) = repository.toggleFold(accountId, _box.value)
+
     fun selectBox(box: MailLogic.Box) {
         if (box == _box.value) return
         _box.value = box
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailHtmlView.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailHtmlView.kt
index 5206b200..ca67e5b4 100644
--- a/app/src/main/java/com/gatecontrol/android/ui/mail/MailHtmlView.kt
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailHtmlView.kt
@@ -1,6 +1,7 @@
 package com.gatecontrol.android.ui.mail
 
 import android.annotation.SuppressLint
+import android.content.Context
 import android.graphics.Color
 import android.view.ViewGroup
 import android.webkit.WebResourceRequest
@@ -13,6 +14,7 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableDoubleStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.ui.Modifier
@@ -28,7 +30,11 @@ import java.io.ByteArrayInputStream
  * file or content access, no forms, storage or windows; the page's requests are answered by the app — the plugin's
  * pictures (`img/<token>`, `cid/<mail>/<attachment>`) loaded with the app's own sign-in through [loader], everything
  * else answered empty, so the mail never reaches the network by itself. A tap on a link leaves the app ([onLink]).
- * Shown on a light sheet: mails are made for one.
+ * Shown on a light sheet: mails are made for one (the app has no dark rendering of mails).
+ *
+ * Wide mails (a newsletter's table of a fixed width) fit the screen: the page keeps pictures and tables inside it,
+ * and what is still wider is measured from outside (the WebView's content width, no script) and laid out again
+ * smaller ([MailLogic.fitZoom], at most [MailLogic.FIT_ROUNDS] times). Pinching still zooms in.
  */
 @SuppressLint("SetJavaScriptEnabled")
 @Composable
@@ -42,12 +48,15 @@ internal fun MailHtmlView(
 ) {
     val load = rememberUpdatedState(loader)
     val link = rememberUpdatedState(onLink)
-    val page = remember(html) { MailLogic.page(html) }
+    // the zoom that makes the mail fit (1 until measured), and how often it was laid out again
+    val zoom = remember(html) { mutableDoubleStateOf(1.0) }
+    val rounds = remember(html) { intArrayOf(0) }
+    val page = remember(html, zoom.doubleValue) { MailLogic.page(html, zoom = zoom.doubleValue) }
     Box(modifier.fillMaxWidth().clip(RoundedCornerShape(16.dp)).background(androidx.compose.ui.graphics.Color.White)) {
         AndroidView(
             modifier = Modifier.fillMaxWidth(),
             factory = { ctx ->
-                WebView(ctx).apply {
+                MailWebView(ctx).apply {
                     layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
                     setBackgroundColor(Color.WHITE)
                     isVerticalScrollBarEnabled = false
@@ -81,9 +90,18 @@ internal fun MailHtmlView(
                             val path = MailLogic.interceptPath(url)
                             if (path != null && request.method.equals("GET", ignoreCase = true)) {
                                 val got = runCatching { runBlocking { load.value(path) } }.getOrNull()
-                                if (got != null) return WebResourceResponse(got.second, null, ByteArrayInputStream(got.first))
+                                // never kept by the WebView: a picture refused while blocked comes once "Bilder laden" allowed it
+                            if (got != null) return WebResourceResponse(got.second, null, 200, "OK", NO_STORE, ByteArrayInputStream(got.first))
                             }
-                            return WebResourceResponse("text/plain", "utf-8", 404, "Not Found", emptyMap(), ByteArrayInputStream(ByteArray(0)))
+                            return WebResourceResponse("text/plain", "utf-8", 404, "Not Found", NO_STORE, ByteArrayInputStream(ByteArray(0)))
+                        }
+
+                        override fun onPageFinished(view: WebView, url: String?) {
+                            (view as? MailWebView)?.measureSoon()
+                        }
+
+                        override fun onScaleChanged(view: WebView, oldScale: Float, newScale: Float) {
+                            (view as? MailWebView)?.scaleNow = newScale
                         }
 
                         override fun shouldOverrideUrlLoading(view: WebView, request: WebResourceRequest): Boolean {
@@ -96,6 +114,13 @@ internal fun MailHtmlView(
             },
             onRelease = { web -> web.destroy() },
             update = { web ->
+                web.onWide = { viewCss, contentCss ->
+                    val next = MailLogic.fitZoom(viewCss, contentCss, zoom.doubleValue)
+                    if (next != null && rounds[0] < MailLogic.FIT_ROUNDS) {
+                        rounds[0]++
+                        zoom.doubleValue = next
+                    }
+                }
                 val key = page to round
                 if (web.tag != key) {
                     web.tag = key
@@ -105,3 +130,39 @@ internal fun MailHtmlView(
         )
     }
 }
+
+/** Answers of the page's requests are never kept by the WebView. */
+private val NO_STORE = mapOf("Cache-Control" to "no-store")
+
+/**
+ * The mail's WebView, which can tell how wide its content is ([onWide], in CSS px): after the page loaded and whenever
+ * its size changes (pictures came).
+ */
+private class MailWebView(context: Context) : WebView(context) {
+    /** The page's scale now (the WebView's pixels per CSS px times the pinch). */
+    var scaleNow: Float = context.resources.displayMetrics.density
+    var onWide: ((viewCss: Double, contentCss: Double) -> Unit)? = null
+    private val measure = Runnable { measureNow() }
+
+    fun measureSoon() {
+        removeCallbacks(measure)
+        postDelayed(measure, MEASURE_DELAY_MS)
+    }
+
+    private fun measureNow() {
+        // the page is laid out device-wide (viewport width=device-width); the content's width at the scale now (pinched
+        // or not) in CSS px
+        val density = resources.displayMetrics.density
+        if (width <= 0 || scaleNow <= 0f) return
+        onWide?.invoke(width / density.toDouble(), computeHorizontalScrollRange() / scaleNow.toDouble())
+    }
+
+    override fun onSizeChanged(w: Int, h: Int, ow: Int, oh: Int) {
+        super.onSizeChanged(w, h, ow, oh)
+        measureSoon()
+    }
+
+    private companion object {
+        const val MEASURE_DELAY_MS = 150L
+    }
+}
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadScreen.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadScreen.kt
index 26838ee3..96f0c037 100644
--- a/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadScreen.kt
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadScreen.kt
@@ -44,6 +44,7 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.semantics.heading
 import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.semantics.stateDescription
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -72,12 +73,15 @@ data class MailReadNav(
     val mailTo: (String) -> Unit,
     /** Another mail of the conversation. */
     val open: (Long) -> Unit,
+    /** The sender's page (their mails in the account [accountId]). */
+    val sender: (email: String, name: String?, accountId: Long) -> Unit = { _, _, _ -> },
 )
 
 /**
- * A mail (mockup "Mail lesen mit KI und Anhang nach Drive"): archive, delete and more on top; subject, sender and
- * account; the AI bar ("Kurz gesagt", to-dos as chips); the attachments with Drive's suggestion; "Bilder laden";
- * the body; the earlier mails of the conversation; answer suggestions, "Antworten" and "Weiterleiten" below.
+ * A mail (mockup "Mail lesen mit KI und Anhang nach Drive"): archive, delete and more on top; subject, the
+ * conversation ("Unterhaltung · n Mails": a tap shows all its mails, oldest first, each unfolding), sender (a tap
+ * opens the sender's page) and account; the AI bar ("Kurz gesagt", to-dos as chips); the attachments with Drive's
+ * suggestion; "Bilder laden"; the body; answer suggestions, "Antworten" and "Weiterleiten" below.
  */
 @Composable
 fun MailReadScreen(nav: MailReadNav, viewModel: MailReadViewModel = hiltViewModel()) {
@@ -152,11 +156,35 @@ fun MailReadScreen(nav: MailReadNav, viewModel: MailReadViewModel = hiltViewMode
                     Modifier.weight(1f).verticalScroll(rememberScrollState()).padding(horizontal = 16.dp).padding(bottom = 16.dp),
                     verticalArrangement = Arrangement.spacedBy(12.dp),
                 ) {
-                    Header(m, account?.label, accountColor(account))
+                    Subject(m)
+                    // the conversation: its line, and once tapped the mails before this one (oldest first)
+                    val (older, newer) = remember(state.conversation, m.id) { MailLogic.conversation(state.conversation, m.id) }
+                    val thread = me?.settings?.threads != false && m.summary.threadId != null && m.summary.threadCount > 1
+                    val threadMail: @Composable (MMessage) -> Unit = { t ->
+                        ThreadMail(
+                            t,
+                            color = accountColor(me?.account(t.summary.accountId)),
+                            unfolded = t.id in state.threadUnfolded,
+                            onFold = { viewModel.toggleThreadMail(t.id) },
+                            onOpen = { nav.open(t.id) },
+                            loader = viewModel::picture,
+                            onLink = onLink,
+                        )
+                    }
+                    if (thread) {
+                        ThreadLine(
+                            count = maxOf(m.summary.threadCount, state.conversation.size),
+                            names = MailLogic.participants(state.conversation.map { it.summary }.ifEmpty { listOf(m.summary) }),
+                            open = state.threadOpen,
+                            loading = state.threadLoading,
+                            onToggle = viewModel::toggleThread,
+                        )
+                        if (state.threadOpen) older.forEach { threadMail(it) }
+                    }
+                    SenderLine(m, account?.label, accountColor(account), onSender = { nav.sender(m.summary.from.email, m.summary.from.name, m.summary.accountId) })
                     if (state.offline) {
                         GcBanner(tone = GcTone.Neutral, icon = GcIcons.Wifi) { Text(stringResource(R.string.mail_offline_copy), style = MaterialTheme.typography.bodySmall) }
                     }
-                    if (state.thread.isNotEmpty()) ThreadBox(state.thread, nav.open)
                     AiCard(state.ai, me, onRetry = { viewModel.runAi(force = true) }, onFamily = viewModel::todoToFamily, onCalendar = { todo ->
                         addToCalendar(context, todo, todo.text)
                     })
@@ -223,6 +251,8 @@ fun MailReadScreen(nav: MailReadNav, viewModel: MailReadViewModel = hiltViewMode
                             )
                         }
                     }
+                    // the mails after this one (the newest at the bottom)
+                    if (thread && state.threadOpen) newer.forEach { threadMail(it) }
                 }
                 BottomBar(
                     replies = (state.ai as? MailAiState.Ready)?.ai?.replies.orEmpty(),
@@ -254,28 +284,46 @@ fun MailReadScreen(nav: MailReadNav, viewModel: MailReadViewModel = hiltViewMode
 }
 
 @Composable
-private fun Header(m: MMessage, accountLabel: String?, color: androidx.compose.ui.graphics.Color) {
+private fun Subject(m: MMessage) {
+    Text(
+        m.summary.subject.ifEmpty { stringResource(R.string.mail_no_subject) },
+        style = MaterialTheme.typography.headlineSmall,
+        modifier = Modifier.semantics { heading() },
+    )
+}
+
+/** The sender (a tap: their page), the account and the time (a tap: the details). */
+@Composable
+private fun SenderLine(m: MMessage, accountLabel: String?, color: androidx.compose.ui.graphics.Color, onSender: () -> Unit) {
     val extra = GateControlTheme.extraColors
     var details by remember { mutableStateOf(false) }
     Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
-        Text(
-            m.summary.subject.ifEmpty { stringResource(R.string.mail_no_subject) },
-            style = MaterialTheme.typography.headlineSmall,
-            modifier = Modifier.semantics { heading() },
-        )
-        Row(
-            Modifier.clickable(role = Role.Button, onClickLabel = stringResource(R.string.mail_details)) { details = !details },
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(8.dp),
-        ) {
-            MailDot(color)
-            Text(m.summary.from.label.ifEmpty { stringResource(R.string.mail_unknown_sender) }, style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold, maxLines = 1, overflow = TextOverflow.Ellipsis, modifier = Modifier.weight(1f, fill = false))
-            Text(
-                listOfNotNull(accountLabel?.let { stringResource(R.string.mail_to_account, it) }, mailTime(m.summary.date)).joinToString(" · "),
-                style = MaterialTheme.typography.bodySmall,
-                color = extra.muted,
-                maxLines = 1,
-            )
+        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            Row(
+                Modifier
+                    .weight(1f, fill = false)
+                    .heightIn(min = 32.dp)
+                    .clip(RoundedCornerShape(8.dp))
+                    .clickable(role = Role.Button, onClickLabel = stringResource(R.string.mail_sender_show), onClick = onSender),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                MailDot(color)
+                Text(m.summary.from.label.ifEmpty { stringResource(R.string.mail_unknown_sender) }, style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold, maxLines = 1, overflow = TextOverflow.Ellipsis)
+            }
+            Row(
+                Modifier.heightIn(min = 32.dp).clickable(role = Role.Button, onClickLabel = stringResource(R.string.mail_details)) { details = !details },
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(4.dp),
+            ) {
+                Text(
+                    listOfNotNull(accountLabel?.let { stringResource(R.string.mail_to_account, it) }, mailTime(m.summary.date)).joinToString(" · "),
+                    style = MaterialTheme.typography.bodySmall,
+                    color = extra.muted,
+                    maxLines = 1,
+                )
+                Icon(if (details) GcIcons.ChevronUp else GcIcons.ChevronDown, contentDescription = null, tint = extra.muted, modifier = Modifier.size(14.dp))
+            }
         }
         if (details) {
             SelectionContainer {
@@ -301,25 +349,99 @@ private fun DetailLine(label: String, list: List<MAddress>) {
     )
 }
 
-/** The earlier mails of the conversation (tap: open one). */
+/** "Unterhaltung · n Mails" with its senders: a tap shows all its mails (or folds them again). */
 @Composable
-private fun ThreadBox(thread: List<MSummary>, onOpen: (Long) -> Unit) {
+private fun ThreadLine(count: Int, names: List<String>, open: Boolean, loading: Boolean, onToggle: () -> Unit) {
     val extra = GateControlTheme.extraColors
+    val state = stringResource(if (open) R.string.mail_thread_shown else R.string.mail_thread_hidden)
+    Row(
+        Modifier
+            .fillMaxWidth()
+            .heightIn(min = 48.dp)
+            .clip(RoundedCornerShape(18.dp))
+            .background(MaterialTheme.colorScheme.surface)
+            .clickable(role = Role.Button, onClickLabel = stringResource(if (open) R.string.mail_thread_hide else R.string.mail_thread_show), onClick = onToggle)
+            .semantics { stateDescription = state }
+            .padding(horizontal = 14.dp, vertical = 8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(10.dp),
+    ) {
+        Column(Modifier.weight(1f), verticalArrangement = Arrangement.spacedBy(2.dp)) {
+            Text(pluralStringResource(R.plurals.mail_thread, count, count), style = MaterialTheme.typography.labelMedium, color = extra.muted)
+            if (names.isNotEmpty()) {
+                Text(names.joinToString(", "), style = MaterialTheme.typography.bodyMedium, fontWeight = FontWeight.Medium, maxLines = 1, overflow = TextOverflow.Ellipsis)
+            }
+        }
+        if (loading) CircularProgressIndicator(Modifier.size(16.dp), strokeWidth = 2.dp)
+        Icon(if (open) GcIcons.ChevronUp else GcIcons.ChevronDown, contentDescription = null, tint = extra.muted, modifier = Modifier.size(18.dp))
+    }
+}
+
+/**
+ * Another mail of the conversation: sender, time and preview; a tap unfolds it (its body, "Mail öffnen" for the
+ * attachments and answering).
+ */
+@Composable
+private fun ThreadMail(
+    t: MMessage,
+    color: androidx.compose.ui.graphics.Color,
+    unfolded: Boolean,
+    onFold: () -> Unit,
+    onOpen: () -> Unit,
+    loader: suspend (String) -> Pair<ByteArray, String>?,
+    onLink: (String) -> Unit,
+) {
+    val extra = GateControlTheme.extraColors
+    val s = t.summary
+    val state = stringResource(if (unfolded) R.string.mail_thread_shown else R.string.mail_thread_hidden)
     Column(Modifier.fillMaxWidth().clip(RoundedCornerShape(18.dp)).background(MaterialTheme.colorScheme.surface)) {
-        Text(
-            pluralStringResource(R.plurals.mail_thread, thread.size + 1, thread.size + 1),
-            style = MaterialTheme.typography.labelMedium,
-            color = extra.muted,
-            modifier = Modifier.padding(start = 14.dp, top = 10.dp, bottom = 4.dp),
-        )
-        thread.forEach { t ->
-            Row(
-                Modifier.fillMaxWidth().heightIn(min = 44.dp).clickable { onOpen(t.id) }.padding(horizontal = 14.dp, vertical = 6.dp),
-                verticalAlignment = Alignment.CenterVertically,
-                horizontalArrangement = Arrangement.spacedBy(10.dp),
-            ) {
-                Text(t.from.label, style = MaterialTheme.typography.bodyMedium, fontWeight = if (t.unread) FontWeight.Bold else FontWeight.Medium, maxLines = 1, overflow = TextOverflow.Ellipsis, modifier = Modifier.weight(1f))
-                Text(mailTime(t.date), style = MaterialTheme.typography.bodySmall, color = extra.muted)
+        Row(
+            Modifier
+                .fillMaxWidth()
+                .heightIn(min = 56.dp)
+                .clickable(role = Role.Button, onClick = onFold)
+                .semantics { stateDescription = state }
+                .padding(horizontal = 14.dp, vertical = 10.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(10.dp),
+        ) {
+            SenderAvatar(s.from.name, s.from.email, color, size = 32.dp)
+            Column(Modifier.weight(1f), verticalArrangement = Arrangement.spacedBy(2.dp)) {
+                Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                    Text(
+                        s.from.label.ifEmpty { stringResource(R.string.mail_unknown_sender) },
+                        style = MaterialTheme.typography.bodyMedium,
+                        fontWeight = if (s.unread) FontWeight.Bold else FontWeight.SemiBold,
+                        maxLines = 1,
+                        overflow = TextOverflow.Ellipsis,
+                        modifier = Modifier.weight(1f),
+                    )
+                    Text(mailTime(s.date), style = MaterialTheme.typography.bodySmall, color = extra.muted)
+                }
+                if (!unfolded) {
+                    val preview = s.snippet.ifBlank { s.subject }
+                    if (preview.isNotBlank()) Text(preview, style = MaterialTheme.typography.bodySmall, color = extra.muted, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+            }
+        }
+        if (unfolded) {
+            Column(Modifier.fillMaxWidth().padding(start = 8.dp, end = 8.dp, bottom = 8.dp), verticalArrangement = Arrangement.spacedBy(4.dp)) {
+                val html = t.html
+                if (html != null) {
+                    val page = remember(html, t.attachments) { MailLogic.rewriteCid(html, t.id, t.attachments) }
+                    MailHtmlView(page, loader = loader, onLink = onLink)
+                } else {
+                    SelectionContainer {
+                        Text(t.text.orEmpty(), style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.85f), modifier = Modifier.padding(horizontal = 6.dp))
+                    }
+                }
+                Row(verticalAlignment = Alignment.CenterVertically) {
+                    if (t.imagesBlocked || t.attachments.any { !it.inline }) {
+                        Icon(if (t.imagesBlocked) GcIcons.Photo else GcIcons.Paperclip, contentDescription = null, tint = extra.muted, modifier = Modifier.padding(start = 6.dp).size(14.dp))
+                    }
+                    Spacer(Modifier.weight(1f))
+                    TextButton(onClick = onOpen) { Text(stringResource(R.string.mail_thread_open)) }
+                }
             }
         }
     }
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadViewModel.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadViewModel.kt
index 48484112..6bf7c961 100644
--- a/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadViewModel.kt
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailReadViewModel.kt
@@ -61,8 +61,13 @@ data class MailReadState(
     val loading: Boolean = true,
     val offline: Boolean = false,
     val error: String? = null,
-    /** The other mails of the conversation, oldest first. */
-    val thread: List<MSummary> = emptyList(),
+    /** The mails of the conversation (`GET threads/<id>`, this one among them), oldest first; empty until loaded. */
+    val conversation: List<MMessage> = emptyList(),
+    /** "Unterhaltung · n Mails" was tapped: all its mails show, the open one unfolded. */
+    val threadOpen: Boolean = false,
+    val threadLoading: Boolean = false,
+    /** The other mails of the conversation unfolded. */
+    val threadUnfolded: Set<Long> = emptySet(),
     val attachments: List<MailAttachmentUi> = emptyList(),
     val ai: MailAiState = MailAiState.Off,
     val imagesBusy: Boolean = false,
@@ -200,10 +205,7 @@ class MailReadViewModel @Inject constructor(
         val me = repository.me.value ?: repository.refresh().valueOrNull()
         val account = me?.account(m.summary.accountId)
         // the conversation (when the person groups by conversation)
-        val threadId = m.summary.threadId
-        if (me?.settings?.threads != false && threadId != null && m.summary.threadCount > 1) {
-            api.thread(threadId).valueOrNull()?.let { items -> _state.update { it.copy(thread = items.map { t -> t.summary }.filter { t -> t.id != m.id }) } }
-        }
+        if (me?.settings?.threads != false && hasThread(m)) loadThread()
         // the AI bar: only where the server offers AI and the account allows it
         if (me?.has(MMe.FEATURE_AI) == true && account?.ai != false) {
             if (_state.value.ai !is MailAiState.Ready) _state.update { it.copy(ai = MailAiState.Loading) }
@@ -222,6 +224,35 @@ class MailReadViewModel @Inject constructor(
         }
     }
 
+    private fun hasThread(m: MMessage): Boolean = m.summary.threadId != null && m.summary.threadCount > 1
+
+    /** The conversation's mails (`GET threads/<id>`, oldest first). */
+    private suspend fun loadThread() {
+        val threadId = _state.value.message?.summary?.threadId ?: return
+        if (_state.value.threadLoading) return
+        _state.update { it.copy(threadLoading = true) }
+        val r = api.thread(threadId)
+        _state.update { s ->
+            when (r) {
+                is MResult.Ok -> s.copy(conversation = r.value, threadLoading = false)
+                else -> s.copy(threadLoading = false)
+            }
+        }
+        if (r !is MResult.Ok && _state.value.threadOpen) _event.value = MailReadEvent.Toast(mailText(context, MailHomeViewModel.code(r)))
+    }
+
+    /** A tap on "Unterhaltung · n Mails": all mails of the conversation show (loaded now when not yet), or fold again. */
+    fun toggleThread() {
+        val open = !_state.value.threadOpen
+        _state.update { it.copy(threadOpen = open) }
+        if (open && _state.value.conversation.isEmpty()) viewModelScope.launch { loadThread() }
+    }
+
+    /** Another mail of the conversation unfolded or folded. */
+    fun toggleThreadMail(id: Long) {
+        _state.update { s -> s.copy(threadUnfolded = if (id in s.threadUnfolded) s.threadUnfolded - id else s.threadUnfolded + id) }
+    }
+
     private fun aiError(r: MResult<*>): MailAiState = when ((r as? MResult.Failed)?.code) {
         "ai_off" -> MailAiState.Off
         else -> MailAiState.Error(MailHomeViewModel.code(r))
@@ -258,6 +289,8 @@ class MailReadViewModel @Inject constructor(
                 is MResult.Ok -> {
                     show(r.value.first, loading = false)
                     cache.putMessage(r.value.second)
+                    // the HTML is the same as before (its pictures' addresses do not change): the page loads them now
+                    imagesAllowed(sender)
                 }
                 else -> _event.value = MailReadEvent.Toast(mailText(context, MailHomeViewModel.code(r)))
             }
@@ -449,6 +482,16 @@ class MailReadViewModel @Inject constructor(
         }
     }
 
+    /**
+     * The pictures were allowed (`POST messages/<id>/images`): those the page was refused are asked for again — none of
+     * them is kept (a refusal never is, and the WebView keeps no answer); always for the [sender]: the conversation's
+     * mails come again with theirs.
+     */
+    private fun imagesAllowed(sender: Boolean) {
+        reloadPictures()
+        if (sender && _state.value.conversation.isNotEmpty()) viewModelScope.launch { loadThread() }
+    }
+
     /** The page asks for its pictures again (those it has come from [pictures]). */
     private fun reloadPictures(fromTimer: Boolean = false) {
         if (!fromTimer) synchronized(this) {
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailSenderScreen.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailSenderScreen.kt
new file mode 100644
index 00000000..13d0e1d5
--- /dev/null
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailSenderScreen.kt
@@ -0,0 +1,136 @@
+package com.gatecontrol.android.ui.mail
+
+import android.content.ClipData
+import android.content.ClipboardManager
+import android.content.Context
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.text.selection.SelectionContainer
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.heading
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.gatecontrol.android.R
+import com.gatecontrol.android.mail.MContact
+import com.gatecontrol.android.ui.components.GcIcons
+import com.gatecontrol.android.ui.components.GcOutlineButton
+import com.gatecontrol.android.ui.components.GcPrimaryButton
+import com.gatecontrol.android.ui.components.GcSubpageBar
+import com.gatecontrol.android.ui.theme.GateControlTheme
+
+/** Where the sender's page leads. */
+data class MailSenderNav(
+    val back: () -> Unit,
+    /** A new mail to [to] from the account [accountId]. */
+    val write: (to: String, accountId: Long?) -> Unit,
+    val open: (Long) -> Unit,
+)
+
+/**
+ * A sender (a tap on the sender of a mail): avatar or initials, name and address, "Mail schreiben" and "Adresse
+ * kopieren"; below all their mails in the account, page by page.
+ */
+@Composable
+fun MailSenderScreen(nav: MailSenderNav, viewModel: MailSenderViewModel = hiltViewModel()) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    val me by viewModel.me.collectAsStateWithLifecycle()
+    val context = mailContext()
+    val extra = GateControlTheme.extraColors
+    val account = me?.account(state.accountId)
+    Column(Modifier.fillMaxSize()) {
+        GcSubpageBar(title = stringResource(R.string.mail_sender_title), onBack = nav.back, backDescription = stringResource(R.string.mail_back))
+        LazyColumn(Modifier.weight(1f)) {
+            item(key = "head") {
+                Column(
+                    Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 12.dp),
+                    horizontalAlignment = Alignment.CenterHorizontally,
+                    verticalArrangement = Arrangement.spacedBy(6.dp),
+                ) {
+                    SenderAvatar(state.label.takeIf { it != state.email }, state.email, accountColor(account), size = 72.dp)
+                    Text(
+                        state.label,
+                        style = MaterialTheme.typography.headlineSmall,
+                        textAlign = TextAlign.Center,
+                        modifier = Modifier.padding(top = 6.dp).semantics { heading() },
+                    )
+                    if (state.label != state.email) {
+                        SelectionContainer { Text(state.email, style = MaterialTheme.typography.bodyMedium, color = extra.muted, textAlign = TextAlign.Center) }
+                    }
+                    SenderContact(state.contact)
+                    Row(Modifier.padding(top = 10.dp), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                        GcPrimaryButton(
+                            stringResource(R.string.mail_sender_write),
+                            onClick = { nav.write(state.email, state.accountId) },
+                            modifier = Modifier.weight(1f),
+                            icon = MailIcons.Pen,
+                            minHeight = 44.dp,
+                        )
+                        GcOutlineButton(
+                            stringResource(R.string.mail_sender_copy),
+                            onClick = {
+                                copy(context, state.email)
+                                toast(context, context.getString(R.string.mail_sender_copied))
+                            },
+                            modifier = Modifier.weight(1f),
+                            icon = GcIcons.Copy,
+                            minHeight = 44.dp,
+                        )
+                    }
+                }
+            }
+            item(key = "label") {
+                Text(
+                    if (account != null) stringResource(R.string.mail_sender_mails_in, account.label) else stringResource(R.string.mail_sender_mails),
+                    style = MaterialTheme.typography.labelMedium,
+                    color = extra.muted,
+                    modifier = Modifier.padding(start = 16.dp, end = 16.dp, top = 12.dp, bottom = 4.dp).semantics { heading() },
+                )
+            }
+            items(state.items, key = { it.id }) { item ->
+                MailRow(item = item, account = me?.account(item.accountId), onClick = { nav.open(item.id) }, onLongClick = { nav.open(item.id) })
+                MailDivider()
+            }
+            when {
+                state.loading -> item(key = "busy") {
+                    Row(Modifier.fillMaxWidth().padding(16.dp), horizontalArrangement = Arrangement.Center) { CircularProgressIndicator(Modifier.size(24.dp)) }
+                }
+                state.error != null && state.items.isEmpty() -> item(key = "error") { ErrorBox(mailText(context, state.error), onRetry = viewModel::load) }
+                state.items.isEmpty() -> item(key = "none") { ErrorBox(stringResource(R.string.mail_sender_none), onRetry = null) }
+                state.next != null -> item(key = "more") { TextButton(onClick = viewModel::more, modifier = Modifier.padding(16.dp)) { Text(stringResource(R.string.mail_more_results)) } }
+            }
+        }
+    }
+}
+
+/**
+ * What the person's contacts know about the sender. For now only that they are one (the name above comes from
+ * there); the coming contacts plugin fills this place (phone, company, …) — no contacts are kept by Mail itself.
+ */
+@Composable
+private fun SenderContact(contact: MContact?) {
+    if (contact == null) return
+    Text(stringResource(R.string.mail_sender_in_contacts), style = MaterialTheme.typography.bodySmall, color = GateControlTheme.extraColors.accentText)
+}
+
+private fun copy(context: Context, text: String) {
+    val cm = context.getSystemService(Context.CLIPBOARD_SERVICE) as? ClipboardManager ?: return
+    runCatching { cm.setPrimaryClip(ClipData.newPlainText("Mail", text)) }
+}
diff --git a/app/src/main/java/com/gatecontrol/android/ui/mail/MailSenderViewModel.kt b/app/src/main/java/com/gatecontrol/android/ui/mail/MailSenderViewModel.kt
new file mode 100644
index 00000000..19d8c025
--- /dev/null
+++ b/app/src/main/java/com/gatecontrol/android/ui/mail/MailSenderViewModel.kt
@@ -0,0 +1,98 @@
+package com.gatecontrol.android.ui.mail
+
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.gatecontrol.android.mail.MContact
+import com.gatecontrol.android.mail.MMe
+import com.gatecontrol.android.mail.MResult
+import com.gatecontrol.android.mail.MSummary
+import com.gatecontrol.android.mail.MailLogic
+import com.gatecontrol.android.mail.MailRepository
+import com.gatecontrol.android.navigation.Screen
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+data class MailSenderState(
+    val email: String = "",
+    /** The name the mail gave. */
+    val name: String? = null,
+    val accountId: Long? = null,
+    /**
+     * The sender in the person's contacts (`contacts?q=`, a `person` hit), null without one. The place for what the
+     * coming contacts plugin knows about them; for now only its name is shown.
+     */
+    val contact: MContact? = null,
+    /** Their mails in the account, newest first. */
+    val items: List<MSummary> = emptyList(),
+    val next: String? = null,
+    val loading: Boolean = true,
+    val error: String? = null,
+) {
+    /** The name shown: from the contacts first, else from the mail. */
+    val label: String get() = contact?.name?.takeIf { it.isNotBlank() } ?: name?.takeIf { it.isNotBlank() } ?: email
+}
+
+/** A sender's page: who it is (the contacts' name when there is one) and their mails in the account (`GET search?from=`). */
+@HiltViewModel
+class MailSenderViewModel @Inject constructor(
+    private val repository: MailRepository,
+    saved: SavedStateHandle,
+) : ViewModel() {
+
+    private val api = repository.api
+    val me: StateFlow<MMe?> = repository.me
+
+    private val _state = MutableStateFlow(
+        MailSenderState(
+            email = saved.get<String>(Screen.MailSender.ARG_EMAIL)?.trim().orEmpty(),
+            name = saved.get<String>(Screen.MailSender.ARG_NAME)?.trim()?.takeIf { it.isNotEmpty() },
+            accountId = saved.get<String>(Screen.MailSender.ARG_ACCOUNT)?.toLongOrNull()?.takeIf { it > 0 },
+        ),
+    )
+    val state: StateFlow<MailSenderState> = _state.asStateFlow()
+
+    init {
+        load()
+    }
+
+    /** The first page of their mails and their contact. */
+    fun load() {
+        val s = _state.value
+        if (!MailLogic.isEmail(s.email)) {
+            _state.update { it.copy(loading = false, error = "not_found") }
+            return
+        }
+        _state.update { it.copy(loading = true, error = null) }
+        viewModelScope.launch {
+            api.contacts(s.email).valueOrNull()?.let { list -> _state.update { it.copy(contact = MailLogic.contactOf(list, s.email)) } }
+        }
+        viewModelScope.launch {
+            when (val r = api.search(MailLogic.senderQuery(s.email, s.accountId))) {
+                is MResult.Ok -> _state.update { it.copy(items = MailLogic.fromSender(r.value.items, s.email), next = r.value.next, loading = false, error = null) }
+                else -> _state.update { it.copy(loading = false, error = MailHomeViewModel.code(r)) }
+            }
+        }
+    }
+
+    /** The next page (the cursor of the last one). */
+    fun more() {
+        val s = _state.value
+        val next = s.next ?: return
+        if (s.loading) return
+        _state.update { it.copy(loading = true) }
+        viewModelScope.launch {
+            when (val r = api.search(MailLogic.senderQuery(s.email, s.accountId, next))) {
+                is MResult.Ok -> _state.update {
+                    it.copy(items = MailLogic.merge(it.items, MailLogic.fromSender(r.value.items, s.email)), next = r.value.next, loading = false)
+                }
+                else -> _state.update { it.copy(loading = false, error = MailHomeViewModel.code(r)) }
+            }
+        }
+    }
+}
diff --git a/app/src/main/res/values-de/strings_mail.xml b/app/src/main/res/values-de/strings_mail.xml
index 5776c1d5..ab0c63c4 100644
--- a/app/src/main/res/values-de/strings_mail.xml
+++ b/app/src/main/res/values-de/strings_mail.xml
@@ -238,6 +238,25 @@
     <string name="mail_err_exists">Dieses Konto gibt es schon.</string>
     <string name="mail_err_links_disabled">Drive-Links sind ausgeschaltet.</string>
     <string name="mail_err_failed">Das hat nicht geklappt.</string>
+    <!-- reader: the menu's folders, the conversation, the sender's page -->
+    <string name="mail_folders_show">Ordner zeigen</string>
+    <string name="mail_folders_hide">Ordner ausblenden</string>
+    <string name="mail_folders_shown">Ordner aufgeklappt</string>
+    <string name="mail_folders_hidden">Ordner zugeklappt</string>
+    <string name="mail_thread_show">Alle Mails der Unterhaltung zeigen</string>
+    <string name="mail_thread_hide">Unterhaltung zuklappen</string>
+    <string name="mail_thread_shown">Aufgeklappt</string>
+    <string name="mail_thread_hidden">Zugeklappt</string>
+    <string name="mail_thread_open">Mail öffnen</string>
+    <string name="mail_sender_show">Absender zeigen</string>
+    <string name="mail_sender_title">Absender</string>
+    <string name="mail_sender_write">Mail schreiben</string>
+    <string name="mail_sender_copy">Adresse kopieren</string>
+    <string name="mail_sender_copied">Adresse kopiert</string>
+    <string name="mail_sender_mails">Mails von diesem Absender</string>
+    <string name="mail_sender_mails_in">Mails von diesem Absender in %1$s</string>
+    <string name="mail_sender_none">Noch keine Mails von diesem Absender.</string>
+    <string name="mail_sender_in_contacts">In deinen Kontakten</string>
     <plurals name="mail_thread">
         <item quantity="one">Unterhaltung · %d Mail</item>
         <item quantity="other">Unterhaltung · %d Mails</item>
diff --git a/app/src/main/res/values/strings_mail.xml b/app/src/main/res/values/strings_mail.xml
index 3f293026..1f20b20d 100644
--- a/app/src/main/res/values/strings_mail.xml
+++ b/app/src/main/res/values/strings_mail.xml
@@ -238,6 +238,25 @@
     <string name="mail_err_exists">This account exists already.</string>
     <string name="mail_err_links_disabled">Drive links are switched off.</string>
     <string name="mail_err_failed">That did not work.</string>
+    <!-- reader: the menu's folders, the conversation, the sender's page -->
+    <string name="mail_folders_show">Show folders</string>
+    <string name="mail_folders_hide">Hide folders</string>
+    <string name="mail_folders_shown">Folders shown</string>
+    <string name="mail_folders_hidden">Folders hidden</string>
+    <string name="mail_thread_show">Show all mails of the conversation</string>
+    <string name="mail_thread_hide">Hide the conversation</string>
+    <string name="mail_thread_shown">Unfolded</string>
+    <string name="mail_thread_hidden">Folded</string>
+    <string name="mail_thread_open">Open mail</string>
+    <string name="mail_sender_show">Show sender</string>
+    <string name="mail_sender_title">Sender</string>
+    <string name="mail_sender_write">Write mail</string>
+    <string name="mail_sender_copy">Copy address</string>
+    <string name="mail_sender_copied">Address copied</string>
+    <string name="mail_sender_mails">Mails from this sender</string>
+    <string name="mail_sender_mails_in">Mails from this sender in %1$s</string>
+    <string name="mail_sender_none">No mails from this sender yet.</string>
+    <string name="mail_sender_in_contacts">In your contacts</string>
     <plurals name="mail_thread">
         <item quantity="one">Conversation · %d mail</item>
         <item quantity="other">Conversation · %d mails</item>
diff --git a/app/src/test/java/com/gatecontrol/android/mail/MailReaderUxTest.kt b/app/src/test/java/com/gatecontrol/android/mail/MailReaderUxTest.kt
new file mode 100644
index 00000000..f4f512c0
--- /dev/null
+++ b/app/src/test/java/com/gatecontrol/android/mail/MailReaderUxTest.kt
@@ -0,0 +1,124 @@
+package com.gatecontrol.android.mail
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+
+/** The reader's rules: a wide mail fits, the menu's folded accounts, a conversation, a sender's mails. */
+class MailReaderUxTest {
+
+    private fun s(id: Long, date: Long, from: String = "a@b.de", name: String? = "Anna") = MSummary(
+        id = id, accountId = 1, folderId = null, threadId = 9, threadCount = 3, from = MAddress(name, from), to = emptyList(),
+        subject = "s$id", snippet = "", date = date, unread = false, flagged = false, answered = false, hasAttachments = false,
+        tab = MSummary.TAB_RELEVANT, savedToDrive = false, aiSummary = null,
+    )
+
+    private fun m(id: Long, date: Long, from: String = "a@b.de", name: String? = "Anna") =
+        MMessage(s(id, date, from, name), emptyList(), emptyList(), emptyList(), "<p>$id</p>", null, false, 0, emptyList(), null)
+
+    // ─── a wide mail fits ───────────────────────────────────────────
+
+    @Test
+    fun `the page keeps pictures, tables, links and pre inside and wraps the mail for the zoom`() {
+        val page = MailLogic.page("<table width=\"600\"><tr><td>x</td></tr></table>")
+        assertTrue(page.contains("name=\"viewport\" content=\"width=device-width, initial-scale=1\""), "device wide, pinching allowed")
+        assertFalse(page.contains("user-scalable"), "pinching stays allowed")
+        assertTrue(page.contains("img{max-width:100%;height:auto}"))
+        assertTrue(page.contains("table{max-width:100%}"))
+        assertTrue(page.contains("pre{white-space:pre-wrap"))
+        assertTrue(page.contains("a{overflow-wrap:anywhere"))
+        assertTrue(page.contains("<div id=\"gc-fit\"><table width=\"600\">"))
+        assertFalse(page.contains("zoom:"), "not zoomed until measured")
+        assertTrue(page.contains("script-src 'none'"), "the mail never runs a script")
+    }
+
+    @Test
+    fun `a measured zoom goes into the page, never below the minimum`() {
+        assertTrue(MailLogic.page("<p>x</p>", zoom = 0.6).contains("#gc-fit{zoom:0.600}"))
+        assertTrue(MailLogic.page("<p>x</p>", zoom = 0.05).contains("#gc-fit{zoom:0.250}"))
+        assertFalse(MailLogic.page("<p>x</p>", zoom = 1.4).contains("zoom:"))
+    }
+
+    @Test
+    fun `fitZoom - a 600 px newsletter on a 360 px phone is made smaller, a fitting mail is not`() {
+        // 360 wide, the mail's table 600 + the left margin
+        val z = MailLogic.fitZoom(360.0, 612.0)!!
+        assertEquals((360.0 - 24) / 600, z, 0.002)
+        // laid out at that zoom it fits: no further round
+        assertNull(MailLogic.fitZoom(360.0, 12 + 600 * z + 12))
+        // fits already (1 px of rounding)
+        assertNull(MailLogic.fitZoom(360.0, 360.0))
+        assertNull(MailLogic.fitZoom(360.0, 361.0))
+        // measured again at a zoom: the next is computed from the mail at zoom 1
+        val again = MailLogic.fitZoom(360.0, 12 + 600 * 0.8, current = 0.8)!!
+        assertEquals((360.0 - 24) / 600, again, 0.002)
+        // never below the minimum, never larger than now
+        assertEquals(MailLogic.MIN_ZOOM, MailLogic.fitZoom(360.0, 5000.0)!!, 0.0001)
+        assertNull(MailLogic.fitZoom(360.0, 5000.0, current = MailLogic.MIN_ZOOM))
+        assertNull(MailLogic.fitZoom(0.0, 600.0))
+    }
+
+    // ─── the menu: folded accounts ──────────────────────────────────
+
+    @Test
+    fun `an account's folders - open for the account shown until folded, then as the person left them`() {
+        val box = MailLogic.Box(3)
+        assertTrue(MailLogic.foldOpen(emptyMap(), 3, box), "the shown account starts open")
+        assertFalse(MailLogic.foldOpen(emptyMap(), 4, box))
+        // the open one closes again (it could not before)
+        val closed = MailLogic.toggleFold(emptyMap(), 3, box)
+        assertFalse(MailLogic.foldOpen(closed, 3, box))
+        val other = MailLogic.toggleFold(closed, 4, box)
+        assertTrue(MailLogic.foldOpen(other, 4, box))
+        assertFalse(MailLogic.foldOpen(other, 3, box), "each account keeps its own")
+        // picking another box later keeps what the person chose
+        assertFalse(MailLogic.foldOpen(other, 3, MailLogic.Box(3, 11)))
+        assertTrue(MailLogic.foldOpen(MailLogic.toggleFold(other, 3, box), 3, box))
+    }
+
+    // ─── a conversation ─────────────────────────────────────────────
+
+    @Test
+    fun `a conversation around the open mail - older above, newer below, each oldest first`() {
+        val items = listOf(m(3, 300), m(1, 100), m(2, 200), m(4, 400))
+        val (older, newer) = MailLogic.conversation(items, 2)
+        assertEquals(listOf(1L), older.map { it.id })
+        assertEquals(listOf(3L, 4L), newer.map { it.id })
+        // the newest open: all others above
+        assertEquals(listOf(1L, 2L, 3L) to emptyList<Long>(), MailLogic.conversation(items, 4).let { (a, b) -> a.map { it.id } to b.map { it.id } })
+        // not in it: all above
+        assertEquals(4, MailLogic.conversation(items, 99).first.size)
+        // the same date: by id
+        assertEquals(listOf(5L, 6L), MailLogic.conversation(listOf(m(6, 100), m(5, 100)), 0).first.map { it.id })
+    }
+
+    @Test
+    fun `a conversation's senders, each once`() {
+        val list = listOf(s(1, 1, "a@b.de", "Anna"), s(2, 2, "tim@b.de", "Tim"), s(3, 3, "A@B.de", "Anna B."), s(4, 4, "x@y.de", null))
+        assertEquals(listOf("Anna", "Tim", "x@y.de"), MailLogic.participants(list))
+        assertEquals(listOf("Anna"), MailLogic.participants(list, max = 1))
+    }
+
+    // ─── a sender ───────────────────────────────────────────────────
+
+    @Test
+    fun `a sender's mails - the search in the account, page by page, exactly that address`() {
+        assertEquals(mapOf("from" to "anna@b.de", "box" to "3"), MailLogic.senderQuery(" Anna@b.de ", 3))
+        assertEquals(mapOf("from" to "anna@b.de", "box" to "all", "cursor" to "c-1"), MailLogic.senderQuery("anna@b.de", null, "c-1"))
+        val items = listOf(s(1, 1, "anna@b.de"), s(2, 2, "hanna@b.de"), s(3, 3, "ANNA@b.de"))
+        assertEquals(listOf(1L, 3L), MailLogic.fromSender(items, "anna@b.de").map { it.id })
+    }
+
+    @Test
+    fun `a sender's name from the contacts - only a person's`() {
+        val contacts = listOf(
+            MContact("Anna Recent", "anna@b.de", MContact.SOURCE_RECENT),
+            MContact("Anna Müller", "Anna@B.de", MContact.SOURCE_PERSON),
+        )
+        assertEquals("Anna Müller", MailLogic.contactOf(contacts, "anna@b.de")?.name)
+        assertNull(MailLogic.contactOf(contacts.take(1), "anna@b.de"), "someone written with lately is no contact")
+        assertNull(MailLogic.contactOf(listOf(MContact(null, "anna@b.de", MContact.SOURCE_PERSON)), "anna@b.de"), "without a name")
+    }
+}
diff --git a/app/src/test/java/com/gatecontrol/android/navigation/MainTabsTest.kt b/app/src/test/java/com/gatecontrol/android/navigation/MainTabsTest.kt
index fcf50598..c34a6887 100644
--- a/app/src/test/java/com/gatecontrol/android/navigation/MainTabsTest.kt
+++ b/app/src/test/java/com/gatecontrol/android/navigation/MainTabsTest.kt
@@ -201,5 +201,7 @@ class MainTabsTest {
         assertEquals("mail/accounts/add", Screen.MailAddAccount.create())
         assertEquals("mail/accounts/add?account=3", Screen.MailAddAccount.create(3))
         assertEquals("mail/accounts/3", Screen.MailAccount.create(3))
+        assertEquals("mail/sender?email=a%40b.de&name=Anna%20M%C3%BCller&account=3", Screen.MailSender.create("a@b.de", "Anna Müller", 3))
+        assertEquals("mail/sender?email=a%40b.de", Screen.MailSender.create("a@b.de", " ", null))
     }
 }
diff --git a/app/src/test/java/com/gatecontrol/android/ui/mail/MailReaderViewModelsTest.kt b/app/src/test/java/com/gatecontrol/android/ui/mail/MailReaderViewModelsTest.kt
new file mode 100644
index 00000000..dd3bb4ad
--- /dev/null
+++ b/app/src/test/java/com/gatecontrol/android/ui/mail/MailReaderViewModelsTest.kt
@@ -0,0 +1,235 @@
+package com.gatecontrol.android.ui.mail
+
+import android.content.Context
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.gatecontrol.android.mail.MAddress
+import com.gatecontrol.android.mail.MChanged
+import com.gatecontrol.android.mail.MContact
+import com.gatecontrol.android.mail.MLimits
+import com.gatecontrol.android.mail.MMe
+import com.gatecontrol.android.mail.MMessage
+import com.gatecontrol.android.mail.MMicrosoft
+import com.gatecontrol.android.mail.MPicture
+import com.gatecontrol.android.mail.MResult
+import com.gatecontrol.android.mail.MSearchPage
+import com.gatecontrol.android.mail.MSettings
+import com.gatecontrol.android.mail.MSummary
+import com.gatecontrol.android.mail.MailApi
+import com.gatecontrol.android.mail.MailCache
+import com.gatecontrol.android.mail.MailRepository
+import com.gatecontrol.android.navigation.Screen
+import com.google.gson.JsonObject
+import io.mockk.coEvery
+import io.mockk.coVerify
+import io.mockk.every
+import io.mockk.mockk
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.cancelAndJoin
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+
+/** The reading screen after "Bilder laden" and with its conversation; the sender's page. */
+@OptIn(ExperimentalCoroutinesApi::class)
+class MailReaderViewModelsTest {
+
+    private val api: MailApi = mockk(relaxed = true)
+    private val cache: MailCache = mockk(relaxed = true)
+    private val repository: MailRepository = mockk(relaxed = true)
+    private val context: Context = mockk(relaxed = true)
+    private val me = MutableStateFlow<MMe?>(null)
+    private val viewModels = mutableListOf<ViewModel>()
+
+    private fun summary(id: Long, date: Long = id * 100, from: String = "news@ionos.de", threadCount: Int = 1, unread: Boolean = false) = MSummary(
+        id = id, accountId = 1, folderId = 5, threadId = if (threadCount > 1) 77 else null, threadCount = threadCount,
+        from = MAddress("IONOS", from), to = emptyList(), subject = "s$id", snippet = "snip $id", date = date, unread = unread,
+        flagged = false, answered = false, hasAttachments = false, tab = MSummary.TAB_RELEVANT, savedToDrive = false, aiSummary = null,
+    )
+
+    private fun message(id: Long, blocked: Boolean = false, threadCount: Int = 1) = MMessage(
+        summary(id, threadCount = threadCount), emptyList(), emptyList(), emptyList(),
+        "<table width=\"600\"><tr><td><img src=\"img/$id.0.sig\"></td></tr></table>", "text", blocked, 0, emptyList(), null,
+    )
+
+    private fun me(threads: Boolean = true) = MMe(
+        features = setOf(MMe.FEATURE_MAIL, MMe.FEATURE_IMAGES), limits = MLimits(5, 0, 0, 12),
+        microsoft = MMicrosoft(null, "https://login.microsoftonline.com/common", emptyList()), accounts = emptyList(),
+        unreadAll = 0, unreadByAccount = emptyMap(), settings = MSettings.DEFAULT.copy(threads = threads),
+    )
+
+    @BeforeEach
+    fun setUp() {
+        Dispatchers.setMain(Dispatchers.Unconfined)
+        every { repository.api } returns api
+        every { repository.cache } returns cache
+        every { repository.me } returns me
+        every { repository.folders } returns MutableStateFlow(emptyMap())
+        every { repository.changed } returns MutableSharedFlow<MChanged>()
+        coEvery { cache.message(any()) } returns null
+        every { context.getString(any()) } returns "text"
+    }
+
+    @AfterEach
+    fun tearDown() {
+        runBlocking { viewModels.forEach { it.viewModelScope.coroutineContext[Job]!!.cancelAndJoin() } }
+        Dispatchers.resetMain()
+    }
+
+    private fun reader(id: Long): MailReadViewModel =
+        MailReadViewModel(context, repository, SavedStateHandle(mapOf(Screen.MailMessage.ARG_ID to id.toString()))).also { viewModels += it }
+
+    // ─── "Bilder laden" ─────────────────────────────────────────────
+
+    @Test
+    fun `after Bilder laden the returned mail is shown and the page loads its pictures again at once`() {
+        me.value = me()
+        coEvery { api.message(1) } returns MResult.Ok(message(1, blocked = true) to JsonObject())
+        coEvery { api.allowImages(1, false) } returns MResult.Ok(message(1, blocked = false) to JsonObject())
+        val vm = reader(1)
+        val before = vm.state.value
+        assertTrue(before.message!!.imagesBlocked)
+
+        vm.allowImages(sender = false)
+
+        val after = vm.state.value
+        assertFalse(after.message!!.imagesBlocked, "the server's answer is the state")
+        assertFalse(after.imagesBusy)
+        // the same HTML as before (the pictures' addresses do not change): only a new round makes the WebView load again
+        assertEquals(before.message!!.html, after.message!!.html)
+        assertEquals(before.pictureRound + 1, after.pictureRound)
+        coVerify { cache.putMessage(any(), any()) }
+    }
+
+    @Test
+    fun `a picture refused while blocked is not kept - it is asked for again after Bilder laden`() {
+        me.value = me()
+        coEvery { api.message(1) } returns MResult.Ok(message(1, blocked = true) to JsonObject())
+        coEvery { api.picture("img/1.0.sig") } returnsMany listOf(MPicture.None, MPicture.Got(byteArrayOf(1, 2), "image/png"))
+        val vm = reader(1)
+        assertNull(runBlocking { vm.picture("img/1.0.sig") })
+        assertEquals("image/png", runBlocking { vm.picture("img/1.0.sig") }!!.second)
+        coVerify(exactly = 2) { api.picture("img/1.0.sig") }
+    }
+
+    @Test
+    fun `Bilder laden refused - a toast, the mail stays as it was`() {
+        me.value = me()
+        coEvery { api.message(1) } returns MResult.Ok(message(1, blocked = true) to JsonObject())
+        coEvery { api.allowImages(1, true) } returns MResult.Failed("images_off", 409)
+        val vm = reader(1)
+        vm.allowImages(sender = true)
+        assertTrue(vm.state.value.message!!.imagesBlocked)
+        assertEquals(0, vm.state.value.pictureRound)
+        assertTrue(vm.event.value is MailReadEvent.Toast)
+    }
+
+    // ─── the conversation ───────────────────────────────────────────
+
+    @Test
+    fun `the conversation loads with the mail, oldest first, and opens on a tap`() {
+        me.value = me(threads = true)
+        coEvery { api.message(2) } returns MResult.Ok(message(2, threadCount = 3) to JsonObject())
+        coEvery { api.thread(77) } returns MResult.Ok(listOf(message(1, threadCount = 3), message(2, threadCount = 3), message(3, threadCount = 3)))
+        val vm = reader(2)
+        assertEquals(listOf(1L, 2L, 3L), vm.state.value.conversation.map { it.id })
+        assertFalse(vm.state.value.threadOpen, "folded until tapped")
+
+        vm.toggleThread()
+        assertTrue(vm.state.value.threadOpen)
+        vm.toggleThreadMail(1)
+        assertEquals(setOf(1L), vm.state.value.threadUnfolded)
+        vm.toggleThreadMail(1)
+        assertTrue(vm.state.value.threadUnfolded.isEmpty())
+        vm.toggleThread()
+        assertFalse(vm.state.value.threadOpen)
+        coVerify(exactly = 1) { api.thread(77) }
+    }
+
+    @Test
+    fun `without grouping the conversation loads only when tapped`() {
+        me.value = me(threads = false)
+        coEvery { api.message(2) } returns MResult.Ok(message(2, threadCount = 2) to JsonObject())
+        coEvery { api.thread(77) } returns MResult.Ok(listOf(message(1, threadCount = 2), message(2, threadCount = 2)))
+        val vm = reader(2)
+        assertTrue(vm.state.value.conversation.isEmpty())
+        coVerify(exactly = 0) { api.thread(any()) }
+        vm.toggleThread()
+        assertEquals(listOf(1L, 2L), vm.state.value.conversation.map { it.id })
+        assertFalse(vm.state.value.threadLoading)
+    }
+
+    @Test
+    fun `a single mail has no conversation to load`() {
+        me.value = me()
+        coEvery { api.message(2) } returns MResult.Ok(message(2) to JsonObject())
+        val vm = reader(2)
+        vm.toggleThread()
+        coVerify(exactly = 0) { api.thread(any()) }
+    }
+
+    // ─── the sender's page ──────────────────────────────────────────
+
+    private fun sender(email: String = "news@ionos.de", name: String? = "IONOS", account: Long? = 1): MailSenderViewModel =
+        MailSenderViewModel(
+            repository,
+            SavedStateHandle(
+                mapOfNotNull(
+                    Screen.MailSender.ARG_EMAIL to email,
+                    Screen.MailSender.ARG_NAME to name,
+                    Screen.MailSender.ARG_ACCOUNT to account?.toString(),
+                ),
+            ),
+        ).also { viewModels += it }
+
+    private fun mapOfNotNull(vararg pairs: Pair<String, String?>): Map<String, Any?> = pairs.filter { it.second != null }.toMap()
+
+    @Test
+    fun `the sender's mails in the account, page by page, with the contact's name`() {
+        coEvery { api.contacts("news@ionos.de") } returns MResult.Ok(listOf(MContact("IONOS Kundenservice", "news@ionos.de", MContact.SOURCE_PERSON)))
+        coEvery { api.search(mapOf("from" to "news@ionos.de", "box" to "1")) } returns
+            MResult.Ok(MSearchPage(listOf(summary(9), summary(8, from = "othernews@ionos.de")), "c-8", false))
+        coEvery { api.search(mapOf("from" to "news@ionos.de", "box" to "1", "cursor" to "c-8")) } returns
+            MResult.Ok(MSearchPage(listOf(summary(7), summary(9)), null, false))
+        val vm = sender()
+        val s = vm.state.value
+        assertEquals("IONOS Kundenservice", s.label, "the contacts' name first")
+        assertEquals(listOf(9L), s.items.map { it.id }, "exactly this address")
+        assertEquals("c-8", s.next)
+        assertFalse(s.loading)
+
+        vm.more()
+        assertEquals(listOf(9L, 7L), vm.state.value.items.map { it.id })
+        assertNull(vm.state.value.next)
+        vm.more()
+        coVerify(exactly = 2) { api.search(any()) }
+    }
+
+    @Test
+    fun `without a contact the mail's name, without that the address`() {
+        coEvery { api.contacts(any()) } returns MResult.Ok(listOf(MContact("Recent", "news@ionos.de", MContact.SOURCE_RECENT)))
+        coEvery { api.search(any()) } returns MResult.Ok(MSearchPage(emptyList(), null, false))
+        assertEquals("IONOS", sender().state.value.label)
+        assertEquals("news@ionos.de", sender(name = null).state.value.label)
+        assertNull(sender().state.value.contact)
+    }
+
+    @Test
+    fun `no address - nothing is asked`() {
+        val vm = sender(email = "kein-mail")
+        assertEquals("not_found", vm.state.value.error)
+        coVerify(exactly = 0) { api.search(any()) }
+    }
+}