From d8c9aaa66aea3636d99f90ff181d2a6c508884ef Mon Sep 17 00:00:00 2001
From: Linus Rath <139418639+rathlinus@users.noreply.github.com>
Date: Sun, 16 Aug 2026 21:54:52 +0200
Subject: [PATCH] feat: add setting to render plain-text emails in normal or
 monospace font #830

---
 components/email/email-viewer.tsx             |  3 ++-
 components/email/thread-conversation-view.tsx |  3 ++-
 components/settings/reading-settings.tsx      | 14 ++++++++++++++
 components/settings/settings-app.tsx          |  3 ++-
 locales/ar/common.json                        |  6 ++++++
 locales/ca/common.json                        |  6 ++++++
 locales/cs/common.json                        |  6 ++++++
 locales/da/common.json                        |  6 ++++++
 locales/de/common.json                        |  6 ++++++
 locales/en/common.json                        |  6 ++++++
 locales/es/common.json                        |  6 ++++++
 locales/fa/common.json                        |  6 ++++++
 locales/fr/common.json                        |  6 ++++++
 locales/he/common.json                        |  6 ++++++
 locales/hu/common.json                        |  6 ++++++
 locales/it/common.json                        |  6 ++++++
 locales/ja/common.json                        |  6 ++++++
 locales/ko/common.json                        |  6 ++++++
 locales/lv/common.json                        |  6 ++++++
 locales/mn/common.json                        | 11 ++++++++++-
 locales/nl/common.json                        |  6 ++++++
 locales/pl/common.json                        |  6 ++++++
 locales/pt/common.json                        |  6 ++++++
 locales/ro/common.json                        |  6 ++++++
 locales/ru/common.json                        |  6 ++++++
 locales/sk/common.json                        |  6 ++++++
 locales/tr/common.json                        |  6 ++++++
 locales/uk/common.json                        |  6 ++++++
 locales/zh/common.json                        |  6 ++++++
 stores/settings-store.ts                      |  6 ++++++
 30 files changed, 180 insertions(+), 4 deletions(-)

diff --git a/components/email/email-viewer.tsx b/components/email/email-viewer.tsx
index a72135ac9..9d28f1389 100644
--- a/components/email/email-viewer.tsx
+++ b/components/email/email-viewer.tsx
@@ -662,6 +662,7 @@ export function EmailViewer({
   const tWelcome = useTranslations('welcome');
   const externalContentPolicy = useSettingsStore((state) => state.externalContentPolicy);
   const messageSpacing = useSettingsStore((state) => state.messageSpacing);
+  const plainTextFont = useSettingsStore((state) => state.plainTextFont);
   const mailAttachmentAction = useSettingsStore((state) => state.mailAttachmentAction);
   const attachmentPosition = useSettingsStore((state) => state.attachmentPosition);
   const addTrustedSender = useSettingsStore((state) => state.addTrustedSender);
@@ -5024,7 +5025,7 @@ export function EmailViewer({
                 className="email-content-text text-foreground"
                 dangerouslySetInnerHTML={{ __html: sanitizePlainTextRenderedHtml(effectiveEmailContent.html) }}
                 style={{
-                  fontFamily: 'ui-monospace, "SF Mono", Consolas, monospace',
+                  ...(plainTextFont === 'mono' && { fontFamily: 'ui-monospace, "SF Mono", Consolas, monospace' }),
                   fontSize: '14px',
                   lineHeight: '1.6',
                   wordBreak: 'break-word',
diff --git a/components/email/thread-conversation-view.tsx b/components/email/thread-conversation-view.tsx
index 9b339cdca..26de3e08d 100644
--- a/components/email/thread-conversation-view.tsx
+++ b/components/email/thread-conversation-view.tsx
@@ -240,6 +240,7 @@ function EmailCard({
   const mailAttachmentAction = useSettingsStore((state) => state.mailAttachmentAction);
   const hideInlineImageAttachments = useSettingsStore((state) => state.hideInlineImageAttachments);
   const emailAlwaysLightMode = useSettingsStore((state) => state.emailAlwaysLightMode);
+  const plainTextFont = useSettingsStore((state) => state.plainTextFont);
   const sender = email.from?.[0];
   const isUnread = !email.keywords?.$seen;
   const isStarred = email.keywords?.$flagged;
@@ -616,7 +617,7 @@ function EmailCard({
                   "[&_table]:border-collapse [&_td]:p-2 [&_th]:p-2",
                   "[&_img]:max-w-full [&_img]:h-auto"
                 )}
-                style={{ whiteSpace: 'pre-wrap', fontFamily: 'ui-monospace, "SF Mono", Consolas, monospace', fontSize: '13px' }}
+                style={{ whiteSpace: 'pre-wrap', ...(plainTextFont === 'mono' && { fontFamily: 'ui-monospace, "SF Mono", Consolas, monospace' }), fontSize: '13px' }}
                 dangerouslySetInnerHTML={{ __html: sanitizePlainTextRenderedHtml(emailContent.html) }}
               />
             )}
diff --git a/components/settings/reading-settings.tsx b/components/settings/reading-settings.tsx
index 8ce27ab5f..0c959e0d1 100644
--- a/components/settings/reading-settings.tsx
+++ b/components/settings/reading-settings.tsx
@@ -36,6 +36,7 @@ export function ReadingSettings() {
     hideInlineImageAttachments,
     attachmentImagePreviewsEnabled,
     messageSpacing,
+    plainTextFont,
     updateSetting,
   } = useSettingsStore();
 
@@ -130,6 +131,19 @@ export function ReadingSettings() {
       </SettingItem>
       )}
 
+      {!isSettingHidden('plainTextFont') && (
+      <SettingItem label={t('plain_text_font.label')} description={t('plain_text_font.description')} locked={isSettingLocked('plainTextFont')}>
+        <Select
+          value={plainTextFont}
+          onChange={(value) => updateSetting('plainTextFont', value as typeof plainTextFont)}
+          options={[
+            { value: 'mono', label: t('plain_text_font.mono') },
+            { value: 'sans', label: t('plain_text_font.sans') },
+          ]}
+        />
+      </SettingItem>
+      )}
+
       {!isSettingHidden('deleteAction') && (
       <SettingItem label={t('delete_action.label')} description={t('delete_action.description')} locked={isSettingLocked('deleteAction')}>
         <div className="flex flex-col gap-2">
diff --git a/components/settings/settings-app.tsx b/components/settings/settings-app.tsx
index f3f527fdc..3bcb64c15 100644
--- a/components/settings/settings-app.tsx
+++ b/components/settings/settings-app.tsx
@@ -207,6 +207,7 @@ const tabSearchPaths: Record<Tab, string[]> = {
     'settings.email_behavior.hide_inline_image_attachments',
     'settings.email_behavior.hover_actions',
     'settings.email_behavior.permanently_delete_junk',
+    'settings.email_behavior.plain_text_font',
     'settings.email_behavior.show_preview',
   ],
   composing: [
@@ -250,7 +251,7 @@ const tabKeywords: Record<Tab, string> = {
   notifications: 'sound alert push badge',
   appearance: 'theme dark light font size accent color animation density',
   layout: 'toolbar sidebar account switcher unified mailbox icons rail',
-  reading: 'mark read preview thread conversation archive delete attachment open',
+  reading: 'mark read preview thread conversation archive delete attachment open monospace mono font plain text',
   composing: 'editor signature plain text reply forward draft compose',
   downloads: 'download filename template eml attachment save export',
   identities: 'from address signature email',
diff --git a/locales/ar/common.json b/locales/ar/common.json
index 4f9a4d4cc..cafdec391 100644
--- a/locales/ar/common.json
+++ b/locales/ar/common.json
@@ -1195,6 +1195,12 @@
         "always": "إضافة تباعد دائمًا",
         "edge": "من الحافة إلى الحافة"
       },
+      "plain_text_font": {
+        "label": "خط النص العادي",
+        "description": "الخط المستخدم لرسائل النص العادي",
+        "mono": "أحادي المسافة",
+        "sans": "عادي (مثل التطبيق)"
+      },
       "archive_mode": {
         "label": "الأرشفة في",
         "description": "كيفية تنظيم الرسائل عند الأرشفة",
diff --git a/locales/ca/common.json b/locales/ca/common.json
index 0404ea5db..20347af39 100644
--- a/locales/ca/common.json
+++ b/locales/ca/common.json
@@ -1195,6 +1195,12 @@
         "always": "Afegeix sempre espaiat",
         "edge": "De vora a vora"
       },
+      "plain_text_font": {
+        "label": "Tipus de lletra del text pla",
+        "description": "Tipus de lletra per als correus de text pla",
+        "mono": "Monoespaiada",
+        "sans": "Normal (igual que l'aplicació)"
+      },
       "archive_mode": {
         "label": "Arxiva a",
         "description": "Com organitzar els correus en arxivar-los",
diff --git a/locales/cs/common.json b/locales/cs/common.json
index 669df5d29..f74898572 100644
--- a/locales/cs/common.json
+++ b/locales/cs/common.json
@@ -1192,6 +1192,12 @@
         "always": "Vždy přidat odsazení",
         "edge": "Od okraje k okraji"
       },
+      "plain_text_font": {
+        "label": "Písmo prostého textu",
+        "description": "Písmo použité pro e-maily v prostém textu",
+        "mono": "Neproporcionální",
+        "sans": "Normální (stejné jako aplikace)"
+      },
       "archive_mode": {
         "label": "Archivovat do",
         "description": "Jak organizovat e-maily při archivaci",
diff --git a/locales/da/common.json b/locales/da/common.json
index fbd92a31a..346ca1915 100644
--- a/locales/da/common.json
+++ b/locales/da/common.json
@@ -1195,6 +1195,12 @@
         "always": "Tilføj altid afstand",
         "edge": "Kant til kant"
       },
+      "plain_text_font": {
+        "label": "Skrifttype til ren tekst",
+        "description": "Skrifttype til e-mails i ren tekst",
+        "mono": "Monospace",
+        "sans": "Normal (samme som appen)"
+      },
       "archive_mode": {
         "label": "Arkivér i",
         "description": "Hvordan e-mails organiseres ved arkivering",
diff --git a/locales/de/common.json b/locales/de/common.json
index a5b1b8f7c..3d7dd5e9b 100644
--- a/locales/de/common.json
+++ b/locales/de/common.json
@@ -1192,6 +1192,12 @@
         "always": "Immer Abstand hinzufügen",
         "edge": "Randlos"
       },
+      "plain_text_font": {
+        "label": "Schriftart für Nur-Text",
+        "description": "Schriftart für Nur-Text-E-Mails",
+        "mono": "Monospace",
+        "sans": "Normal (wie die App)"
+      },
       "archive_mode": {
         "label": "Nachrichten archivieren in",
         "description": "Wie E-Mails beim Archivieren organisiert werden",
diff --git a/locales/en/common.json b/locales/en/common.json
index 1e19e50fd..0a48db76b 100644
--- a/locales/en/common.json
+++ b/locales/en/common.json
@@ -1195,6 +1195,12 @@
         "always": "Always add spacing",
         "edge": "Edge to edge"
       },
+      "plain_text_font": {
+        "label": "Plain Text Font",
+        "description": "Font used for plain text emails",
+        "mono": "Monospace",
+        "sans": "Normal (same as the app)"
+      },
       "archive_mode": {
         "label": "Archive in",
         "description": "How to organize emails when archiving",
diff --git a/locales/es/common.json b/locales/es/common.json
index 89dde6f3c..a1b27cc83 100644
--- a/locales/es/common.json
+++ b/locales/es/common.json
@@ -1192,6 +1192,12 @@
         "always": "Añadir espaciado siempre",
         "edge": "De borde a borde"
       },
+      "plain_text_font": {
+        "label": "Fuente de texto sin formato",
+        "description": "Fuente utilizada para los correos de texto sin formato",
+        "mono": "Monoespaciada",
+        "sans": "Normal (igual que la aplicación)"
+      },
       "archive_mode": {
         "label": "Archivar en",
         "description": "Cómo organizar los correos al archivar",
diff --git a/locales/fa/common.json b/locales/fa/common.json
index c53b454ab..1fbfa9b64 100644
--- a/locales/fa/common.json
+++ b/locales/fa/common.json
@@ -1195,6 +1195,12 @@
         "always": "همیشه فاصله اضافه شود",
         "edge": "لبه به لبه"
       },
+      "plain_text_font": {
+        "label": "قلم متن ساده",
+        "description": "قلم مورد استفاده برای ایمیل‌های متن ساده",
+        "mono": "تک‌عرض",
+        "sans": "معمولی (مانند برنامه)"
+      },
       "archive_mode": {
         "label": "بایگانی در",
         "description": "سازمان‌دهی بایگانی",
diff --git a/locales/fr/common.json b/locales/fr/common.json
index 10e304168..45d758518 100644
--- a/locales/fr/common.json
+++ b/locales/fr/common.json
@@ -1192,6 +1192,12 @@
         "always": "Toujours ajouter un espacement",
         "edge": "Bord à bord"
       },
+      "plain_text_font": {
+        "label": "Police du texte brut",
+        "description": "Police utilisée pour les e-mails en texte brut",
+        "mono": "À chasse fixe",
+        "sans": "Normale (comme l'application)"
+      },
       "archive_mode": {
         "label": "Archiver dans",
         "description": "Comment organiser les emails lors de l'archivage",
diff --git a/locales/he/common.json b/locales/he/common.json
index 03ddeafd9..6b2fb02f3 100644
--- a/locales/he/common.json
+++ b/locales/he/common.json
@@ -1146,6 +1146,12 @@
         "always": "תמיד להוסיף מרווח",
         "edge": "מקצה לקצה"
       },
+      "plain_text_font": {
+        "label": "גופן טקסט פשוט",
+        "description": "הגופן המשמש להודעות בטקסט פשוט",
+        "mono": "ברוחב קבוע",
+        "sans": "רגיל (כמו היישום)"
+      },
       "archive_mode": {
         "label": "ארכיון ב",
         "description": "כיצד לארגן מיילים בעת אחסון בארכיון",
diff --git a/locales/hu/common.json b/locales/hu/common.json
index 1e0a70879..54c87d498 100644
--- a/locales/hu/common.json
+++ b/locales/hu/common.json
@@ -1195,6 +1195,12 @@
         "always": "Mindig legyen térköz",
         "edge": "Széltől szélig"
       },
+      "plain_text_font": {
+        "label": "Egyszerű szöveg betűtípusa",
+        "description": "Az egyszerű szöveges e-mailekhez használt betűtípus",
+        "mono": "Rögzített szélességű",
+        "sans": "Normál (mint az alkalmazás)"
+      },
       "archive_mode": {
         "label": "Archiválás helye",
         "description": "Hogyan rendezze az e-maileket archiváláskor",
diff --git a/locales/it/common.json b/locales/it/common.json
index 5e2e2bd9a..b7657a14f 100644
--- a/locales/it/common.json
+++ b/locales/it/common.json
@@ -1192,6 +1192,12 @@
         "always": "Aggiungi sempre spaziatura",
         "edge": "Da bordo a bordo"
       },
+      "plain_text_font": {
+        "label": "Carattere del testo semplice",
+        "description": "Carattere usato per le email in testo semplice",
+        "mono": "Monospazio",
+        "sans": "Normale (come l'app)"
+      },
       "archive_mode": {
         "label": "Archivia in",
         "description": "Come organizzare le email durante l'archiviazione",
diff --git a/locales/ja/common.json b/locales/ja/common.json
index be8d0c988..e8b71f97f 100644
--- a/locales/ja/common.json
+++ b/locales/ja/common.json
@@ -1192,6 +1192,12 @@
         "always": "常に余白を追加",
         "edge": "余白なし"
       },
+      "plain_text_font": {
+        "label": "プレーンテキストのフォント",
+        "description": "プレーンテキストメールに使用するフォント",
+        "mono": "等幅",
+        "sans": "標準（アプリと同じ）"
+      },
       "archive_mode": {
         "label": "アーカイブ先",
         "description": "アーカイブ時のメール整理方法",
diff --git a/locales/ko/common.json b/locales/ko/common.json
index 106c40659..95ca78f43 100644
--- a/locales/ko/common.json
+++ b/locales/ko/common.json
@@ -1192,6 +1192,12 @@
         "always": "항상 여백 추가",
         "edge": "가장자리까지 채우기"
       },
+      "plain_text_font": {
+        "label": "일반 텍스트 글꼴",
+        "description": "일반 텍스트 이메일에 사용되는 글꼴",
+        "mono": "고정폭",
+        "sans": "기본(앱과 동일)"
+      },
       "archive_mode": {
         "label": "보관 방식",
         "description": "메일을 보관할 때 어떻게 분류할지 설정해요",
diff --git a/locales/lv/common.json b/locales/lv/common.json
index 8b0026571..3d396ce4f 100644
--- a/locales/lv/common.json
+++ b/locales/lv/common.json
@@ -1192,6 +1192,12 @@
         "always": "Vienmēr pievienot atstarpi",
         "edge": "No malas līdz malai"
       },
+      "plain_text_font": {
+        "label": "Vienkārša teksta fonts",
+        "description": "Fonts vienkārša teksta e-pastiem",
+        "mono": "Vienplatuma",
+        "sans": "Parasts (tāpat kā lietotnē)"
+      },
       "archive_mode": {
         "label": "Arhivēt mapē",
         "description": "Kā organizēt vēstules arhivējot",
diff --git a/locales/mn/common.json b/locales/mn/common.json
index 3fd6a5c54..43a51083c 100644
--- a/locales/mn/common.json
+++ b/locales/mn/common.json
@@ -855,7 +855,10 @@
     "zh": "简体中文",
     "fa": "فارسی",
     "farsi": "فارسی",
-    "switch_to_farsi": "Фарси хэл рүү шилжих"
+    "switch_to_farsi": "Фарси хэл рүү шилжих",
+    "mn": "Монгол",
+    "mongolian": "Монгол",
+    "switch_to_mongolian": "Монгол хэл рүү шилжих"
   },
   "settings": {
     "title": "Тохиргоо",
@@ -1192,6 +1195,12 @@
         "always": "Үргэлж хоорондын зайг нэмэх",
         "edge": "Ирмэгээс ирмэг хүртэл"
       },
+      "plain_text_font": {
+        "label": "Энгийн текстийн фонт",
+        "description": "Энгийн текстэн имэйлд ашиглах фонт",
+        "mono": "Тогтмол өргөнтэй",
+        "sans": "Энгийн (апптай ижил)"
+      },
       "archive_mode": {
         "label": "Архив",
         "description": "Архивлахдаа имэйлийг хэрхэн зохион байгуулах вэ",
diff --git a/locales/nl/common.json b/locales/nl/common.json
index 4372b6df4..0ab37400b 100644
--- a/locales/nl/common.json
+++ b/locales/nl/common.json
@@ -1192,6 +1192,12 @@
         "always": "Altijd ruimte toevoegen",
         "edge": "Rand tot rand"
       },
+      "plain_text_font": {
+        "label": "Lettertype voor platte tekst",
+        "description": "Lettertype voor e-mails in platte tekst",
+        "mono": "Monospace",
+        "sans": "Normaal (zoals de app)"
+      },
       "archive_mode": {
         "label": "Archiveren in",
         "description": "Hoe e-mails bij archivering worden georganiseerd",
diff --git a/locales/pl/common.json b/locales/pl/common.json
index 5485c3790..2f17cd8f1 100644
--- a/locales/pl/common.json
+++ b/locales/pl/common.json
@@ -1192,6 +1192,12 @@
         "always": "Zawsze dodawaj odstępy",
         "edge": "Od krawędzi do krawędzi"
       },
+      "plain_text_font": {
+        "label": "Czcionka zwykłego tekstu",
+        "description": "Czcionka używana dla wiadomości w zwykłym tekście",
+        "mono": "O stałej szerokości",
+        "sans": "Normalna (jak aplikacja)"
+      },
       "archive_mode": {
         "label": "Archiwizuj w",
         "description": "Jak organizować wiadomości e-mail podczas archiwizacji",
diff --git a/locales/pt/common.json b/locales/pt/common.json
index 5b12ef775..fe85d7688 100644
--- a/locales/pt/common.json
+++ b/locales/pt/common.json
@@ -1192,6 +1192,12 @@
         "always": "Sempre adicionar espaçamento",
         "edge": "De borda a borda"
       },
+      "plain_text_font": {
+        "label": "Fonte de texto simples",
+        "description": "Fonte usada para e-mails de texto simples",
+        "mono": "Monoespaçada",
+        "sans": "Normal (igual ao aplicativo)"
+      },
       "archive_mode": {
         "label": "Arquivar em",
         "description": "Como organizar os e-mails ao arquivar",
diff --git a/locales/ro/common.json b/locales/ro/common.json
index 5769072b6..35a3a7d10 100644
--- a/locales/ro/common.json
+++ b/locales/ro/common.json
@@ -1195,6 +1195,12 @@
         "always": "Adaugă întotdeauna spațiere",
         "edge": "Din margine în margine"
       },
+      "plain_text_font": {
+        "label": "Font pentru text simplu",
+        "description": "Fontul folosit pentru e-mailurile în text simplu",
+        "mono": "Monospațiat",
+        "sans": "Normal (la fel ca aplicația)"
+      },
       "archive_mode": {
         "label": "Arhivați în",
         "description": "Cum să organizați e-mailurile atunci când le arhivați",
diff --git a/locales/ru/common.json b/locales/ru/common.json
index 2db38fb33..2744be9d2 100644
--- a/locales/ru/common.json
+++ b/locales/ru/common.json
@@ -1192,6 +1192,12 @@
         "always": "Всегда добавлять отступы",
         "edge": "От края до края"
       },
+      "plain_text_font": {
+        "label": "Шрифт обычного текста",
+        "description": "Шрифт для писем в обычном тексте",
+        "mono": "Моноширинный",
+        "sans": "Обычный (как в приложении)"
+      },
       "archive_mode": {
         "label": "Архивировать в",
         "description": "Как организовывать письма при архивировании",
diff --git a/locales/sk/common.json b/locales/sk/common.json
index 63cb88fe3..568c172e8 100644
--- a/locales/sk/common.json
+++ b/locales/sk/common.json
@@ -1195,6 +1195,12 @@
         "always": "Vždy pridať odsadenie",
         "edge": "Od okraja po okraj"
       },
+      "plain_text_font": {
+        "label": "Písmo obyčajného textu",
+        "description": "Písmo použité pre e-maily v obyčajnom texte",
+        "mono": "Neproporcionálne",
+        "sans": "Normálne (rovnaké ako aplikácia)"
+      },
       "archive_mode": {
         "label": "Archivovať do",
         "description": "Ako organizovať e-maily pri archivácii",
diff --git a/locales/tr/common.json b/locales/tr/common.json
index 4371161fe..da03838a8 100644
--- a/locales/tr/common.json
+++ b/locales/tr/common.json
@@ -1192,6 +1192,12 @@
         "always": "Her zaman boşluk ekle",
         "edge": "Kenardan kenara"
       },
+      "plain_text_font": {
+        "label": "Düz metin yazı tipi",
+        "description": "Düz metin e-postalar için kullanılan yazı tipi",
+        "mono": "Eş aralıklı",
+        "sans": "Normal (uygulamayla aynı)"
+      },
       "archive_mode": {
         "label": "Arşivle",
         "description": "Arşivlerken e-postaların nasıl düzenleneceği",
diff --git a/locales/uk/common.json b/locales/uk/common.json
index ef7ccb506..4793092d7 100644
--- a/locales/uk/common.json
+++ b/locales/uk/common.json
@@ -1192,6 +1192,12 @@
         "always": "Завжди додавати відступи",
         "edge": "Від краю до краю"
       },
+      "plain_text_font": {
+        "label": "Шрифт звичайного тексту",
+        "description": "Шрифт для листів у звичайному тексті",
+        "mono": "Моноширинний",
+        "sans": "Звичайний (як у застосунку)"
+      },
       "archive_mode": {
         "label": "Архівувати в",
         "description": "Як упорядкувати листи під час архівування",
diff --git a/locales/zh/common.json b/locales/zh/common.json
index 14e66d82d..10cae8dca 100644
--- a/locales/zh/common.json
+++ b/locales/zh/common.json
@@ -1192,6 +1192,12 @@
         "always": "始终添加边距",
         "edge": "无边距"
       },
+      "plain_text_font": {
+        "label": "纯文本字体",
+        "description": "用于纯文本邮件的字体",
+        "mono": "等宽",
+        "sans": "普通（与应用相同）"
+      },
       "archive_mode": {
         "label": "归档方式",
         "description": "归档时如何组织邮件",
diff --git a/stores/settings-store.ts b/stores/settings-store.ts
index 953d17262..d0f9c008a 100644
--- a/stores/settings-store.ts
+++ b/stores/settings-store.ts
@@ -128,6 +128,9 @@ export type MailLayout = 'split' | 'focus' | 'horizontal';
  * - 'edge'  : never add one (render edge-to-edge)
  */
 export type MessageSpacing = 'auto' | 'always' | 'edge';
+
+/** Font used to render text/plain email bodies. */
+export type PlainTextFont = 'mono' | 'sans';
 export type CalendarHoverPreview = 'off' | 'instant' | 'delay-500ms' | 'delay-1s' | 'delay-2s';
 export type SendDelaySeconds = 0 | 10 | 30 | 60;
 export type ProtocolOpenMode = 'active-session' | 'new-tab';
@@ -313,6 +316,7 @@ interface SettingsState {
   emailsPerPage: number;
   externalContentPolicy: ExternalContentPolicy;
   messageSpacing: MessageSpacing; // Gutter around the message body in the reader
+  plainTextFont: PlainTextFont; // Font for text/plain email bodies in the reader
   mailAttachmentAction: MailAttachmentAction;
   attachmentPosition: AttachmentPosition;
   emailAlwaysLightMode: boolean; // Always render email content in light mode
@@ -541,6 +545,7 @@ const DEFAULT_SETTINGS = {
   emailsPerPage: 50,
   externalContentPolicy: 'ask' as ExternalContentPolicy,
   messageSpacing: 'auto' as MessageSpacing,
+  plainTextFont: 'mono' as PlainTextFont,
   mailAttachmentAction: 'preview' as MailAttachmentAction,
   attachmentPosition: 'beside-sender' as AttachmentPosition,
   emailAlwaysLightMode: false,
@@ -759,6 +764,7 @@ export const useSettingsStore = create<SettingsState>()(
           emailsPerPage: state.emailsPerPage,
           externalContentPolicy: state.externalContentPolicy,
           messageSpacing: state.messageSpacing,
+          plainTextFont: state.plainTextFont,
           mailAttachmentAction: state.mailAttachmentAction,
           attachmentPosition: state.attachmentPosition,
           archiveMode: state.archiveMode,