feat(themes): colour families with light/dark, follow system, corners, frames, accent

- Fjord (new), Polarized Hell and Suri Hell complete the families
  Klassik, Fjord, Terrakotta, Polarized, Suri
- settings: family table, follow-system, corners, button frames and an own
  accent colour (per device); compact quick picker in the user menus
- code colours in index.css are fallbacks only

chore(release): v0.14.0

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,6 +6,16 @@ Das Format folgt [Keep a Changelog](https://keepachangelog.com/de/1.1.0/), die V
 
 ## [Unreleased]
 
+## [0.14.0] - 2026-10-30
+
+### Added
+- Themes als Farbfamilien mit je einer hellen und dunklen Variante: Klassik, **Fjord** (neu, Gletscherblau / Nachtblau), Terrakotta, Polarized (neu: **Polarized Hell**), Suri (neu: **Suri Hell**).
+- Darstellung in den Kontoeinstellungen: Tabelle Familie × Hell/Dunkel, „Hell oder dunkel: Wie System“ (wechselt innerhalb der Familie mit dem Gerät), Ecken (Wie Theme / Rund / Eckig), Rahmen an Knöpfen (mit / ohne) und eine eigene Akzentfarbe (Vorschläge oder frei wählbar). Alles gilt pro Gerät.
+- Benutzermenü und Handy-Profil: kompakte Schnellwahl mit einem Farbpunkt pro Familie und Hell / Dunkel / Wie System; eigene Themes darunter.
+
+### Changed
+- Code-Farben aus `index.css` sind nur noch Rückfallwerte; die Code-Farben eines Themes gewinnen immer.
+
 ## [0.13.0] - 2026-10-30
 
 ### Added
@@ -324,7 +334,8 @@ Das Format folgt [Keep a Changelog](https://keepachangelog.com/de/1.1.0/), die V
 - Geteilte Listen (Einkaufs-, Pack- und Checklisten) mit `#Kategorie`-Gruppierung, Mengenangaben und Echtzeit-Abhaken.
 - Benutzer-, Gruppen- und Admin-Verwaltung (Ersteinrichtungs-Assistent, Einladungscodes, Profilbilder, persönliche API-Keys & Webhook-Ingest `/api/v1/webhooks/ingest`, JSON-Datenexport) sowie CSS-Theme-Engine mit 4 Themes (`Dark`, `Light`, `High Contrast`, `Soft`) und PWA-Unterstützung.
 
-[Unreleased]: https://git.dsit.me/sandrodach/MindSift/compare/v0.13.0...dev
+[Unreleased]: https://git.dsit.me/sandrodach/MindSift/compare/v0.14.0...dev
+[0.14.0]: https://git.dsit.me/sandrodach/MindSift/compare/v0.13.0...v0.14.0
 [0.13.0]: https://git.dsit.me/sandrodach/MindSift/compare/v0.12.2...v0.13.0
 [0.12.2]: https://git.dsit.me/sandrodach/MindSift/compare/v0.12.1...v0.12.2
 [0.12.1]: https://git.dsit.me/sandrodach/MindSift/compare/v0.12.0...v0.12.1

Doku/theming.md

@@ -82,6 +82,11 @@ Jede Theme-Datei gliedert sich in sechs exakt definierte Bereiche:
 | `light` | [`theme-light.css`](../frontend/src/themes/theme-light.css) | Daylight Clean White / Minimalistisch | Modern dezent (`4px` Cards, `4px` Buttons) |
 | `terracotta` | [`theme-terracotta.css`](../frontend/src/themes/theme-terracotta.css) | Warmes Cremepapier, Tinte, Terrakotta-Akzent, eigene Code-Farben in Erdtönen | Weich (`12px`) |
 | `terracotta-night` | [`theme-terracotta-night.css`](../frontend/src/themes/theme-terracotta-night.css) | Espresso-Braun, Creme-Schrift, glühender Terrakotta-Akzent | Weich (`12px`) |
+| `fjord` / `fjord-night` | [`theme-fjord.css`](../frontend/src/themes/theme-fjord.css), [`theme-fjord-night.css`](../frontend/src/themes/theme-fjord-night.css) | Kühles Papier und Gletscherblau / Nachtblau | Weich (`12px`) |
+| `polarized-light` | [`theme-polarized-light.css`](../frontend/src/themes/theme-polarized-light.css) | Helles Gegenstück zu Polarized: Mintweiß, Petrol | Eckig (`0px`) |
+| `suri-light` | [`theme-suri-light.css`](../frontend/src/themes/theme-suri-light.css) | Helles Gegenstück zu Suri: Lavendel, Pflaume | Weich (`10px`) |
+
+Die eingebauten Themes sind in Farbfamilien mit je einer hellen und dunklen Variante gruppiert (`THEME_FAMILIES` in [`theme.ts`](../frontend/src/lib/theme.ts)). Pro Gerät lassen sich unter Darstellung zusätzlich einstellen: Hell/Dunkel „Wie System“ (wechselt innerhalb der Familie), Ecken (`data-corners="round|square"` überschreibt die `--radius-*`-Werte), Rahmen an Knöpfen (`data-button-borders="off"`) und eine eigene Akzentfarbe (setzt `--accent-*` direkt am Wurzelelement). Code-Farben in `index.css` sind nur Rückfallwerte (`:where(...)`), die `--code-*`-Werte eines Themes gewinnen immer.
 | `polarized` | [`theme-polarized.css`](../frontend/src/themes/theme-polarized.css) | Tiefdunkles Obsidian mit elektrischem Grün/Türkis | Streng eckig (`0px` Cards, `2px` Buttons) |
 | `suri` | [`theme-suri.css`](../frontend/src/themes/theme-suri.css) | Warmes Mitternachts-Pflaume mit samtiger Orchidee | Weich gerundet (`10px` Cards, `6px` Buttons) |
 | *Template* | [`theme-template.css`](../frontend/src/themes/theme-template.css) | Vollständig dokumentierte Kopiervorlage | Frei anpassbar |

README.md

@@ -100,7 +100,7 @@ Technik dahinter: [Doku/modules/collaboration.md](Doku/modules/collaboration.md)
 * Geführte Ersteinrichtung, Rollen *Admin* und *Mitglied*, Einladungscodes, optional offene Registrierung.
 * Gruppen mit Gruppen-Admins für Freigaben.
 * Admin-Bereich: Benutzer, Einladungen, Instanzname, SMTP, Freigabe-Modus.
-* Sechs Themes (Dark, Light, Terrakotta, Terrakotta Nacht, Polarized, Suri) plus Theme-Manager für eigene CSS-Themes, installierbar als PWA. Die App startet auch ohne Netz mit dem zuletzt geladenen Stand; offline erfasste Gedanken und abgehakte Aufgaben oder Listeneinträge werden nachgereicht, sobald die Verbindung wieder da ist.
+* Fünf Farbfamilien mit je einer hellen und dunklen Variante (Klassik, Fjord, Terrakotta, Polarized, Suri), Hell/Dunkel auf Wunsch wie das System, eigene Akzentfarbe, Ecken rund oder eckig, Knöpfe mit oder ohne Rahmen plus Theme-Manager für eigene CSS-Themes, installierbar als PWA. Die App startet auch ohne Netz mit dem zuletzt geladenen Stand; offline erfasste Gedanken und abgehakte Aufgaben oder Listeneinträge werden nachgereicht, sobald die Verbindung wieder da ist.
 
 ### 🔌 Integrationen
 

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mindsift-frontend",
-  "version": "0.13.0",
+  "version": "0.14.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mindsift-frontend",
-      "version": "0.13.0",
+      "version": "0.14.0",
       "license": "Unlicense",
       "dependencies": {
         "@fontsource-variable/inter": "5.3.0",

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "mindsift-frontend",
   "private": true,
-  "version": "0.13.0",
+  "version": "0.14.0",
   "license": "Unlicense",
   "type": "module",
   "scripts": {

frontend/src/App.tsx

@@ -42,6 +42,7 @@ import {
   AVAILABLE_THEMES,
   customThemeOption,
   initThemeOnBoot,
+  watchSystemScheme,
   isCustomThemeId,
   setActiveTheme as applyTheme,
   ThemeId,
@@ -66,6 +67,7 @@ import { MobileHeaderMenu } from './components/MobileHeaderMenu';
 import { UserAvatar } from './components/UserAvatar';
 import { CommandPalette } from './components/CommandPalette';
 import { AppFooter } from './components/AppFooter';
+import { ThemeQuickPicker } from './components/ThemeQuickPicker';
 import { AboutModal } from './components/AboutModal';
 import { consumePendingShares, formatSharedThought } from './lib/shareTarget';
 import { APP_VERSION } from './version';
@@ -442,6 +444,9 @@ export const App: React.FC = () => {
     setActiveThemeState(isCustomThemeId(themeId) && css === undefined ? 'dark' : themeId);
   };
 
+  // "Wie System": the theme follows the system's light/dark switch while the app is open
+  useEffect(() => watchSystemScheme(setActiveThemeState), []);
+
   const handleChangeTheme = (themeId: ThemeId) => {
     triggerHaptic(10);
     activateTheme(themeId, customThemes);
@@ -979,26 +984,7 @@ export const App: React.FC = () => {
                     <Palette className="w-3 h-3 text-accent" />
                     <span>Design-Theme</span>
                   </span>
-                  <div className="grid grid-cols-2 gap-1">
+                  <ThemeQuickPicker activeTheme={activeTheme} themes={allThemes} onChange={handleChangeTheme} />
-                    {allThemes.map((t) => (
-                      <button
-                        key={t.id}
-                        type="button"
-                        onClick={() => handleChangeTheme(t.id)}
-                        className={`h-7 px-2 text-[11px] font-medium border rounded-btn flex items-center gap-1.5 transition-colors ${
-                          activeTheme === t.id
-                            ? 'bg-panel-elevated border-accent text-main font-semibold'
-                            : 'bg-canvas border-border text-muted hover:text-main'
-                        }`}
-                      >
-                        <span
-                          className="w-2.5 h-2.5 border border-strong flex-shrink-0"
-                          style={{ backgroundColor: t.previewBg }}
-                        />
-                        <span className="truncate">{t.name.replace('MindSift ', '').split(' ')[0]}</span>
-                      </button>
-                    ))}
-                  </div>
                 </div>
 
                 {/* Menu Items */}
@@ -1560,26 +1546,7 @@ export const App: React.FC = () => {
                 <Palette className="w-3.5 h-3.5 text-accent" />
                 <span>Design-Theme</span>
               </span>
-              <div className="grid grid-cols-2 gap-2">
+              <ThemeQuickPicker activeTheme={activeTheme} themes={allThemes} onChange={handleChangeTheme} touch />
-                {allThemes.map((t) => (
-                  <button
-                    key={t.id}
-                    type="button"
-                    onClick={() => handleChangeTheme(t.id)}
-                    className={`h-9 px-2.5 text-xs font-medium border rounded-btn flex items-center gap-2 transition-colors cursor-pointer ${
-                      activeTheme === t.id
-                        ? 'bg-panel-elevated border-accent text-main font-semibold'
-                        : 'bg-canvas border-border text-muted hover:text-main'
-                    }`}
-                  >
-                    <span
-                      className="w-3 h-3 border border-strong flex-shrink-0 rounded-full"
-                      style={{ backgroundColor: t.previewBg }}
-                    />
-                    <span className="truncate">{t.name.replace('MindSift ', '')}</span>
-                  </button>
-                ))}
-              </div>
             </div>
 
             {/* Menu Items */}

frontend/src/components/ThemeQuickPicker.tsx

@@ -0,0 +1,113 @@
+import React from 'react';
+import { Monitor, Moon, Sun } from 'lucide-react';
+import {
+  AVAILABLE_THEMES,
+  getFollowSystem,
+  resolveTheme,
+  setFollowSystem,
+  THEME_FAMILIES,
+  ThemeId,
+  ThemeOption,
+} from '../lib/theme';
+
+interface ThemeQuickPickerProps {
+  activeTheme: ThemeId;
+  /** All themes including the user's own (shown as small chips) */
+  themes: ThemeOption[];
+  onChange: (id: ThemeId) => void;
+  /** Bigger touch targets in the phone sheet */
+  touch?: boolean;
+}
+
+// Compact switcher for the user menu: one dot per colour family plus light/dark; own themes below
+export const ThemeQuickPicker: React.FC<ThemeQuickPickerProps> = ({ activeTheme, themes, onChange, touch = false }) => {
+  const active = AVAILABLE_THEMES.find((t) => t.id === activeTheme);
+  const mode = active?.mode ?? 'dark';
+  const customThemes = themes.filter((t) => t.isCustom);
+  const dot = touch ? 'w-9 h-9' : 'w-7 h-7';
+  const followSystem = getFollowSystem();
+  const pick = (id: ThemeId) => onChange(resolveTheme(id));
+
+  return (
+    <div className="space-y-2">
+      <div className="flex items-center justify-between gap-2">
+        <div className="flex items-center gap-1.5" role="radiogroup" aria-label="Farbfamilie">
+          {THEME_FAMILIES.map((f) => {
+            const preview = AVAILABLE_THEMES.find((t) => t.id === (mode === 'light' ? f.light : f.dark));
+            const selected = active?.family === f.id;
+            return (
+              <button
+                key={f.id}
+                type="button"
+                role="radio"
+                aria-checked={selected}
+                onClick={() => pick(mode === 'light' ? f.light : f.dark)}
+                title={f.name}
+                className={`${dot} rounded-full flex items-center justify-center transition-transform active:scale-95 cursor-pointer ${
+                  selected ? 'ring-2 ring-accent ring-offset-2 ring-offset-panel' : 'hover:scale-105'
+                }`}
+                style={{ backgroundColor: preview?.previewBg }}
+              >
+                <span className="w-3 h-3 rounded-full" style={{ backgroundColor: preview?.previewAccent }} />
+              </button>
+            );
+          })}
+        </div>
+        <div className="flex items-center rounded-full bg-panel-elevated p-0.5" role="radiogroup" aria-label="Hell oder dunkel">
+          {(['light', 'dark', 'auto'] as const).map((m) => {
+            const family = active?.family ? THEME_FAMILIES.find((f) => f.id === active.family) : undefined;
+            const selected = m === 'auto' ? followSystem : !followSystem && !!active && mode === m;
+            const disabled = !family;
+            return (
+              <button
+                key={m}
+                type="button"
+                role="radio"
+                aria-checked={selected}
+                disabled={disabled}
+                onClick={() => {
+                  if (!family) return;
+                  setFollowSystem(m === 'auto');
+                  onChange(m === 'auto' ? resolveTheme(family.dark) : family[m]);
+                }}
+                title={m === 'light' ? 'Hell' : m === 'dark' ? 'Dunkel' : 'Wie System'}
+                aria-label={m === 'light' ? 'Hell' : m === 'dark' ? 'Dunkel' : 'Wie System'}
+                className={`${touch ? 'h-9 w-9' : 'h-7 w-7'} rounded-full flex items-center justify-center transition-colors cursor-pointer disabled:opacity-40 disabled:cursor-not-allowed ${
+                  selected ? 'bg-panel text-accent shadow-sm' : 'text-muted hover:text-main'
+                }`}
+              >
+                {m === 'light' ? (
+                  <Sun className="w-3.5 h-3.5" />
+                ) : m === 'dark' ? (
+                  <Moon className="w-3.5 h-3.5" />
+                ) : (
+                  <Monitor className="w-3.5 h-3.5" />
+                )}
+              </button>
+            );
+          })}
+        </div>
+      </div>
+      {customThemes.length > 0 && (
+        <div className="flex flex-wrap gap-1">
+          {customThemes.map((t) => (
+            <button
+              key={t.id}
+              type="button"
+              onClick={() => {
+                setFollowSystem(false);
+                onChange(t.id);
+              }}
+              className={`h-7 px-2 rounded-full text-[11px] flex items-center gap-1.5 border transition-colors cursor-pointer ${
+                activeTheme === t.id ? 'border-accent text-main' : 'border-border text-muted hover:text-main'
+              }`}
+            >
+              <span className="w-2.5 h-2.5 rounded-full" style={{ backgroundColor: t.previewAccent }} />
+              <span className="truncate max-w-[8rem]">{t.name}</span>
+            </button>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+};

frontend/src/features/settings/UserSettingsView.tsx

@@ -23,7 +23,24 @@ import { ServerBackupsCard } from './ServerBackupsCard';
 import { saveBlob } from '../../lib/download';
 import { api, clearToken, triggerHaptic } from '../../lib/api';
 import { passwordProblem } from '../../lib/password';
-import { customThemeId, ThemeId, ThemeOption } from '../../lib/theme';
+import {
+  AVAILABLE_THEMES,
+  CornerStyle,
+  customThemeId,
+  getCornerStyle,
+  setCornerStyle,
+  getFollowSystem,
+  setFollowSystem,
+  resolveTheme,
+  getButtonBorders,
+  setButtonBorders,
+  ButtonBorders,
+  getAccentColor,
+  setAccentColor,
+  THEME_FAMILIES,
+  ThemeId,
+  ThemeOption,
+} from '../../lib/theme';
 import themeTemplateCss from '../../themes/theme-template.css?raw';
 import { UserAvatar, resizeImageToDataUrl } from '../../components/UserAvatar';
 import { LegalLinks } from '../../components/LegalLinks';
@@ -158,6 +175,10 @@ export const UserSettingsView: React.FC<UserSettingsViewProps> = ({
   const [demoMode, setDemoMode] = useState(false);
   const linkPreviewsOn = useLinkPreviewsEnabled();
   const [journalOn, setJournalOn] = useState(isJournalEnabled);
+  const [corners, setCorners] = useState<CornerStyle>(getCornerStyle);
+  const [followSystem, setFollowSystemState] = useState(getFollowSystem);
+  const [buttonBorders, setButtonBordersState] = useState<ButtonBorders>(getButtonBorders);
+  const [accent, setAccent] = useState<string | null>(getAccentColor);
   useEffect(() => {
     api
       .getAuthStatus()
@@ -920,8 +941,205 @@ export const UserSettingsView: React.FC<UserSettingsViewProps> = ({
                 />
               </div>
 
+              {/* Colour families: left light, right dark */}
+              <div className="space-y-2">
+                <div className="grid grid-cols-[1fr_minmax(0,9rem)_minmax(0,9rem)] sm:grid-cols-[1fr_12rem_12rem] items-center gap-2 px-1 text-[11px] font-semibold uppercase tracking-wider text-faint">
+                  <span>Theme</span>
+                  <span className="text-center">Hell</span>
+                  <span className="text-center">Dunkel</span>
+                </div>
+                {THEME_FAMILIES.map((f) => (
+                  <div
+                    key={f.id}
+                    className="grid grid-cols-[1fr_minmax(0,9rem)_minmax(0,9rem)] sm:grid-cols-[1fr_12rem_12rem] items-center gap-2 p-2 rounded-card bg-canvas"
+                  >
+                    <div className="min-w-0 px-1">
+                      <p className="font-semibold text-main text-sm truncate">{f.name}</p>
+                      <p className="text-[11px] text-muted truncate">{f.subtitle}</p>
+                    </div>
+                    {[f.light, f.dark].map((id) => {
+                      const t = AVAILABLE_THEMES.find((x) => x.id === id)!;
+                      const selected = activeTheme === id;
+                      return (
+                        <button
+                          key={id}
+                          type="button"
+                          onClick={() => onThemeChange(resolveTheme(id))}
+                          aria-pressed={selected}
+                          title={t.name}
+                          className={`h-14 rounded-card p-2 flex flex-col justify-between text-left transition-all cursor-pointer ${
+                            selected ? 'ring-2 ring-accent' : 'hover:scale-[1.02]'
+                          }`}
+                          style={{ backgroundColor: t.previewBg, border: '1px solid rgba(127,127,127,0.25)' }}
+                        >
+                          <span className="flex items-center gap-1">
+                            <span className="w-6 h-2.5 rounded-full" style={{ backgroundColor: t.previewPanel }} />
+                            <span className="w-2.5 h-2.5 rounded-full" style={{ backgroundColor: t.previewAccent }} />
+                          </span>
+                          <span className="text-[11px] font-semibold truncate" style={{ color: t.previewText }}>
+                            {selected ? '✓ Aktiv' : t.mode === 'light' ? 'Hell' : 'Dunkel'}
+                          </span>
+                        </button>
+                      );
+                    })}
+                  </div>
+                ))}
+              </div>
+
+              {/* Corners for every theme (per device) */}
+              <div className="p-3.5 rounded-card border border-border bg-canvas flex flex-wrap items-center justify-between gap-3">
+                <div className="text-xs">
+                  <p className="font-semibold text-main">Ecken</p>
+                  <p className="text-[11px] text-faint">Abgerundet oder eckig – unabhängig vom Theme. Gilt für dieses Gerät.</p>
+                </div>
+                <div className="flex items-center bg-panel-elevated rounded-btn p-0.5 text-xs" role="radiogroup" aria-label="Ecken">
+                  {(
+                    [
+                      ['theme', 'Wie Theme'],
+                      ['round', 'Rund'],
+                      ['square', 'Eckig'],
+                    ] as [CornerStyle, string][]
+                  ).map(([value, label]) => (
+                    <button
+                      key={value}
+                      type="button"
+                      role="radio"
+                      aria-checked={corners === value}
+                      onClick={() => {
+                        setCornerStyle(value);
+                        setCorners(value);
+                      }}
+                      className={`h-9 sm:h-7 px-3 rounded-btn transition-colors cursor-pointer ${
+                        corners === value ? 'bg-panel text-main font-semibold shadow-sm' : 'text-muted hover:text-main'
+                      }`}
+                    >
+                      {label}
+                    </button>
+                  ))}
+                </div>
+              </div>
+
+              {/* Light/dark: fixed, or following the system inside the family */}
+              <div className="p-3.5 rounded-card border border-border bg-canvas flex flex-wrap items-center justify-between gap-3">
+                <div className="text-xs">
+                  <p className="font-semibold text-main">Hell oder dunkel</p>
+                  <p className="text-[11px] text-faint">„Wie System“ wechselt innerhalb der Farbfamilie mit dem Hell-/Dunkelmodus des Geräts.</p>
+                </div>
+                <div className="flex items-center bg-panel-elevated rounded-btn p-0.5 text-xs" role="radiogroup" aria-label="Hell oder dunkel">
+                  {(
+                    [
+                      [false, 'Selbst wählen'],
+                      [true, 'Wie System'],
+                    ] as [boolean, string][]
+                  ).map(([value, label]) => (
+                    <button
+                      key={label}
+                      type="button"
+                      role="radio"
+                      aria-checked={followSystem === value}
+                      onClick={() => {
+                        setFollowSystem(value);
+                        setFollowSystemState(value);
+                        if (value) onThemeChange(resolveTheme(activeTheme));
+                      }}
+                      className={`h-9 sm:h-7 px-3 rounded-btn transition-colors cursor-pointer ${
+                        followSystem === value ? 'bg-panel text-main font-semibold shadow-sm' : 'text-muted hover:text-main'
+                      }`}
+                    >
+                      {label}
+                    </button>
+                  ))}
+                </div>
+              </div>
+
+              {/* Frames around buttons */}
+              <div className="p-3.5 rounded-card border border-border bg-canvas flex flex-wrap items-center justify-between gap-3">
+                <div className="text-xs">
+                  <p className="font-semibold text-main">Rahmen an Knöpfen</p>
+                  <p className="text-[11px] text-faint">Ohne Rahmen sind Knöpfe nur leicht hinterlegt. Gilt für dieses Gerät.</p>
+                </div>
+                <div className="flex items-center bg-panel-elevated rounded-btn p-0.5 text-xs" role="radiogroup" aria-label="Rahmen an Knöpfen">
+                  {(
+                    [
+                      ['on', 'Mit Rahmen'],
+                      ['off', 'Ohne Rahmen'],
+                    ] as [ButtonBorders, string][]
+                  ).map(([value, label]) => (
+                    <button
+                      key={value}
+                      type="button"
+                      role="radio"
+                      aria-checked={buttonBorders === value}
+                      onClick={() => {
+                        setButtonBorders(value);
+                        setButtonBordersState(value);
+                      }}
+                      className={`h-9 sm:h-7 px-3 rounded-btn transition-colors cursor-pointer ${
+                        buttonBorders === value ? 'bg-panel text-main font-semibold shadow-sm' : 'text-muted hover:text-main'
+                      }`}
+                    >
+                      {label}
+                    </button>
+                  ))}
+                </div>
+              </div>
+
+              {/* Own accent colour on top of the theme */}
+              <div className="p-3.5 rounded-card border border-border bg-canvas space-y-2.5">
+                <div className="flex flex-wrap items-center justify-between gap-2 text-xs">
+                  <div>
+                    <p className="font-semibold text-main">Akzentfarbe</p>
+                    <p className="text-[11px] text-faint">Ersetzt die Akzentfarbe des Themes (Knöpfe, Links, Markierungen). Gilt für dieses Gerät.</p>
+                  </div>
+                  {accent && (
+                    <button
+                      type="button"
+                      onClick={() => {
+                        setAccentColor(null);
+                        setAccent(null);
+                      }}
+                      className="btn-action h-9 sm:h-7 px-2.5 text-xs"
+                    >
+                      Wie Theme
+                    </button>
+                  )}
+                </div>
+                <div className="flex flex-wrap items-center gap-2">
+                  {['#2563eb', '#0f766e', '#16a34a', '#ca8a04', '#c2410c', '#dc2626', '#db2777', '#8e44c9', '#475569'].map((c) => (
+                    <button
+                      key={c}
+                      type="button"
+                      onClick={() => {
+                        setAccentColor(c);
+                        setAccent(c);
+                      }}
+                      title={c}
+                      aria-label={`Akzentfarbe ${c}`}
+                      className={`w-9 h-9 sm:w-7 sm:h-7 rounded-full transition-transform hover:scale-110 cursor-pointer ${
+                        accent === c ? 'ring-2 ring-offset-2 ring-offset-canvas ring-main' : ''
+                      }`}
+                      style={{ backgroundColor: c }}
+                    />
+                  ))}
+                  <label className="flex items-center gap-1.5 text-[11px] text-muted cursor-pointer">
+                    <input
+                      type="color"
+                      value={accent || '#2563eb'}
+                      onChange={(e) => {
+                        setAccentColor(e.target.value);
+                        setAccent(e.target.value);
+                      }}
+                      className="w-9 h-9 sm:w-7 sm:h-7 rounded-full border border-border bg-transparent p-0 cursor-pointer"
+                      aria-label="Eigene Akzentfarbe wählen"
+                    />
+                    Eigene
+                  </label>
+                </div>
+              </div>
+
+              {themes.some((t) => t.isCustom) && <p className="font-semibold text-main text-sm pt-1">Eigene Themes</p>}
               <div className="grid grid-cols-1 sm:grid-cols-2 gap-3">
-                {themes.map((t) => {
+                {themes.filter((t) => t.isCustom).map((t) => {
                   const isSelected = activeTheme === t.id;
                   const custom = customThemes.find((c) => customThemeId(c) === t.id);
                   return (

frontend/src/features/workspace/WorkspaceView.tsx

@@ -1362,7 +1362,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
             type="button"
             disabled={subView !== 'editor'}
             onClick={subView === 'editor' ? toggleSidebar : undefined}
-            className={`hidden sm:inline-flex h-8 w-8 items-center justify-center rounded-btn border transition-colors ${
+            className={`chip-btn hidden sm:inline-flex h-8 w-8 items-center justify-center rounded-btn border transition-colors ${
               subView !== 'editor'
                 ? 'opacity-35 bg-canvas border-border text-faint cursor-not-allowed pointer-events-none'
                 : isSidebarCollapsed
@@ -1394,7 +1394,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
           <button
             type="button"
             onClick={() => setSubView('editor')}
-            className={`h-8 px-2 sm:px-3 text-xs font-medium border rounded-btn transition-colors flex items-center justify-center gap-1.5 cursor-pointer min-w-0 ${
+            className={`chip-btn h-8 px-2 sm:px-3 text-xs font-medium border rounded-btn transition-colors flex items-center justify-center gap-1.5 cursor-pointer min-w-0 ${
               subView === 'editor'
                 ? 'bg-panel border-accent text-main'
                 : 'bg-canvas border-border text-muted hover:text-main'
@@ -1410,7 +1410,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
               setSubView('todos');
               setMobileShowDetail(true);
             }}
-            className={`h-8 px-2 sm:px-3 text-xs font-medium border rounded-btn transition-colors flex items-center justify-center gap-1.5 cursor-pointer min-w-0 ${
+            className={`chip-btn h-8 px-2 sm:px-3 text-xs font-medium border rounded-btn transition-colors flex items-center justify-center gap-1.5 cursor-pointer min-w-0 ${
               subView === 'todos'
                 ? 'bg-panel border-accent text-main'
                 : 'bg-canvas border-border text-muted hover:text-main'
@@ -1429,7 +1429,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
               setSubView('tags');
               setMobileShowDetail(true);
             }}
-            className={`h-8 px-2 sm:px-3 text-xs font-medium border rounded-btn transition-colors flex items-center justify-center gap-1.5 cursor-pointer min-w-0 ${
+            className={`chip-btn h-8 px-2 sm:px-3 text-xs font-medium border rounded-btn transition-colors flex items-center justify-center gap-1.5 cursor-pointer min-w-0 ${
               subView === 'tags' || subView === 'tag_detail'
                 ? 'bg-panel border-accent text-main'
                 : 'bg-canvas border-border text-muted hover:text-main'

frontend/src/index.css

@@ -15,6 +15,10 @@
 @import './themes/theme-terracotta-night.css';
 @import './themes/theme-polarized.css';
 @import './themes/theme-suri.css';
+@import './themes/theme-fjord.css';
+@import './themes/theme-fjord-night.css';
+@import './themes/theme-polarized-light.css';
+@import './themes/theme-suri-light.css';
 
 @tailwind base;
 @tailwind components;
@@ -413,8 +417,9 @@ body {
     color: var(--text-main);
   }
 
-  /* Prism Syntax Highlighting Tokens (VS Code Dark+ / Light+ via Theme Variables) */
+  /* Prism Syntax Highlighting Tokens (VS Code Dark+ / Light+ via Theme Variables).
-  :root {
+     Fallbacks only (:where has no specificity): a theme's own --code-* values always win. */
+  :where(:root) {
     --code-keyword: #569cd6;
     --code-string: #ce9178;
     --code-number: #b5cea8;
@@ -426,8 +431,7 @@ body {
     --code-variable: #9cdcfe;
   }
 
-  :root:not(.dark):not([data-theme="terracotta"]),
+  :where(:root:not(.dark)) {
-  :root[data-theme="light"] {
     --code-keyword: #0000ff;
     --code-string: #a31515;
     --code-number: #098658;
@@ -603,3 +607,33 @@ fieldset:disabled :is(button, input, select, textarea) {
     animation: none !important;
   }
 }
+
+/* Corner switch (Darstellung): overrides the theme's radii on every theme */
+:root[data-corners='square'] {
+  --radius-card: 0px !important;
+  --radius-btn: 2px !important;
+  --radius-input: 2px !important;
+  --radius-checkbox: 0px !important;
+}
+:root[data-corners='round'] {
+  --radius-card: 12px !important;
+  --radius-btn: 8px !important;
+  --radius-input: 8px !important;
+  --radius-checkbox: 4px !important;
+}
+
+/* Button frames switch (Darstellung): without frames, regular buttons are a soft tint instead */
+:root[data-button-borders='off'] :is(.btn-action, .btn-icon, .btn-secondary, .tab-btn, .chip-btn) {
+  border-color: transparent !important;
+}
+:root[data-button-borders='off'] :is(.btn-action, .btn-icon, .btn-secondary, .chip-btn):not(:disabled) {
+  background-color: color-mix(in srgb, var(--text-main) 6%, transparent);
+}
+:root[data-button-borders='off'] :is(.btn-action, .btn-icon, .btn-secondary, .chip-btn):not(:disabled):hover {
+  background-color: color-mix(in srgb, var(--text-main) 11%, transparent);
+}
+/* … the selected tab keeps a visible accent tint */
+:root[data-button-borders='off'] .chip-btn.border-accent {
+  background-color: var(--accent-dim) !important;
+  color: var(--accent-primary);
+}

frontend/src/lib/__tests__/theme.test.ts

@@ -1,5 +1,19 @@
 import { describe, it, expect, beforeEach } from 'vitest';
-import { setActiveTheme, initThemeOnBoot, customThemeOption, getActiveTheme } from '../theme';
+import {
+  setActiveTheme,
+  initThemeOnBoot,
+  customThemeOption,
+  getActiveTheme,
+  themeCounterpart,
+  setCornerStyle,
+  getCornerStyle,
+  THEME_FAMILIES,
+  AVAILABLE_THEMES,
+  setFollowSystem,
+  resolveTheme,
+  setAccentColor,
+  setButtonBorders,
+} from '../theme';
 
 const lightCss = `:root[data-theme="papier"] { --bg-app: #fafafa; --accent-primary: #15803d; --radius-card: 8px; }`;
 
@@ -83,3 +97,62 @@ describe('built-in themes', () => {
     expect(document.documentElement.classList.contains('dark')).toBe(true);
   });
 });
+
+describe('theme families and corners', () => {
+  beforeEach(() => localStorage.clear());
+
+  it('pairs every family with an existing light and dark theme', () => {
+    for (const f of THEME_FAMILIES) {
+      expect(AVAILABLE_THEMES.find((t) => t.id === f.light)?.mode).toBe('light');
+      expect(AVAILABLE_THEMES.find((t) => t.id === f.dark)?.mode).toBe('dark');
+    }
+    expect(themeCounterpart('fjord')).toBe('fjord-night');
+    expect(themeCounterpart('polarized')).toBe('polarized-light');
+    expect(themeCounterpart('custom:x')).toBeNull();
+  });
+
+  it('forces round or square corners and keeps the choice', () => {
+    setCornerStyle('square');
+    expect(document.documentElement.getAttribute('data-corners')).toBe('square');
+    expect(getCornerStyle()).toBe('square');
+    setCornerStyle('theme');
+    expect(document.documentElement.hasAttribute('data-corners')).toBe(false);
+    expect(getCornerStyle()).toBe('theme');
+  });
+});
+
+describe('follow system, accent and button frames', () => {
+  beforeEach(() => localStorage.clear());
+
+  it('picks the family variant that matches the system when following it', () => {
+    const original = window.matchMedia;
+    window.matchMedia = ((q: string) => ({ matches: q.includes('dark'), media: q, addEventListener() {}, removeEventListener() {} })) as unknown as typeof window.matchMedia;
+    try {
+      expect(resolveTheme('fjord')).toBe('fjord');
+      setFollowSystem(true);
+      expect(resolveTheme('fjord')).toBe('fjord-night');
+      expect(resolveTheme('suri-light')).toBe('suri');
+      expect(resolveTheme('custom:x')).toBe('custom:x');
+    } finally {
+      window.matchMedia = original;
+    }
+  });
+
+  it('sets the accent variables and removes them again', () => {
+    setActiveTheme('dark');
+    setAccentColor('#c2410c');
+    const style = document.documentElement.style;
+    expect(style.getPropertyValue('--accent-primary')).toBe('#c2410c');
+    expect(style.getPropertyValue('--text-on-accent')).toBe('#ffffff');
+    expect(style.getPropertyValue('--accent-dim')).toBe('rgba(194, 65, 12, 0.16)');
+    setAccentColor(null);
+    expect(style.getPropertyValue('--accent-primary')).toBe('');
+  });
+
+  it('switches button frames off and on', () => {
+    setButtonBorders('off');
+    expect(document.documentElement.getAttribute('data-button-borders')).toBe('off');
+    setButtonBorders('on');
+    expect(document.documentElement.hasAttribute('data-button-borders')).toBe(false);
+  });
+});

frontend/src/lib/theme.ts

@@ -15,8 +15,28 @@ export interface ThemeOption {
   previewText: string;
   isRounded: boolean;
   isCustom?: boolean;
+  /** Built-in themes come in families with a light and a dark variant */
+  family?: string;
+  mode?: 'light' | 'dark';
 }
 
+export interface ThemeFamily {
+  id: string;
+  name: string;
+  subtitle: string;
+  light: ThemeId;
+  dark: ThemeId;
+}
+
+// Left light, right dark – the settings and the quick switcher show them in this order
+export const THEME_FAMILIES: ThemeFamily[] = [
+  { id: 'classic', name: 'Klassik', subtitle: 'Neutral mit Blau, eckig', light: 'light', dark: 'dark' },
+  { id: 'fjord', name: 'Fjord', subtitle: 'Kühles Papier, Gletscherblau', light: 'fjord', dark: 'fjord-night' },
+  { id: 'terracotta', name: 'Terrakotta', subtitle: 'Warmes Papier, gebrannte Erde', light: 'terracotta', dark: 'terracotta-night' },
+  { id: 'polarized', name: 'Polarized', subtitle: 'Petrol und Türkis, eckig', light: 'polarized-light', dark: 'polarized' },
+  { id: 'suri', name: 'Suri', subtitle: 'Lavendel, Pflaume, Orchidee', light: 'suri-light', dark: 'suri' },
+];
+
 export const THEME_STORAGE_KEY = 'mindsift_active_theme';
 // CSS of the active custom theme, so it applies on boot before the API answers (no flash)
 const CUSTOM_CSS_CACHE_KEY = 'mindsift_custom_theme_css';
@@ -90,7 +110,176 @@ export const AVAILABLE_THEMES: ThemeOption[] = [
     previewText: '#fbf7ff',
     isRounded: true,
   },
-];
+  {
+    id: 'fjord',
+    name: 'Fjord (Gletscherblau)',
+    subtitle: 'Kühles Papier, Tintenblau & Fjordblau (12px)',
+    file: 'src/themes/theme-fjord.css',
+    previewBg: '#e9eef5',
+    previewPanel: '#f7f9fc',
+    previewAccent: '#2b6cb0',
+    previewText: '#14202e',
+    isRounded: true,
+  },
+  {
+    id: 'fjord-night',
+    name: 'Fjord Nacht (Tiefsee)',
+    subtitle: 'Nachtblau, Mondlicht & leuchtendes Gletscherblau (12px)',
+    file: 'src/themes/theme-fjord-night.css',
+    previewBg: '#0e1621',
+    previewPanel: '#152131',
+    previewAccent: '#5b9bdf',
+    previewText: '#e6eef8',
+    isRounded: true,
+  },
+  {
+    id: 'polarized-light',
+    name: 'Polarized Hell (Lagune)',
+    subtitle: 'Kreidiges Mintweiß mit tiefem Petrol (0px)',
+    file: 'src/themes/theme-polarized-light.css',
+    previewBg: '#e6f0ef',
+    previewPanel: '#f6fbfa',
+    previewAccent: '#0f766e',
+    previewText: '#0f2422',
+    isRounded: false,
+  },
+  {
+    id: 'suri-light',
+    name: 'Suri Hell (Lavendel)',
+    subtitle: 'Lavendelpapier, Pflaume & Orchidee (10px)',
+    file: 'src/themes/theme-suri-light.css',
+    previewBg: '#efe9f4',
+    previewPanel: '#fbf8fd',
+    previewAccent: '#8e44c9',
+    previewText: '#23182e',
+    isRounded: true,
+  },
+].map((t) => {
+  const family = THEME_FAMILIES.find((f) => f.light === t.id || f.dark === t.id);
+  return family ? { ...t, family: family.id, mode: family.light === t.id ? ('light' as const) : ('dark' as const) } : t;
+});
+
+/** The same family in the other mode (light ↔ dark); custom themes have none */
+export function themeCounterpart(id: ThemeId): ThemeId | null {
+  const f = THEME_FAMILIES.find((x) => x.light === id || x.dark === id);
+  if (!f) return null;
+  return f.light === id ? f.dark : f.light;
+}
+
+// Light/dark follows the system inside the chosen family (per device)
+const FOLLOW_SYSTEM_KEY = 'mindsift_theme_follow_system';
+
+export function getFollowSystem(): boolean {
+  return load(FOLLOW_SYSTEM_KEY) === '1';
+}
+
+export function setFollowSystem(on: boolean): void {
+  store(FOLLOW_SYSTEM_KEY, on ? '1' : null);
+}
+
+function systemPrefersDark(): boolean {
+  return typeof window !== 'undefined' && !!window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;
+}
+
+/** With "follow system": the family's variant that matches the system; otherwise the theme itself */
+export function resolveTheme(id: ThemeId): ThemeId {
+  if (!getFollowSystem()) return id;
+  const f = THEME_FAMILIES.find((x) => x.light === id || x.dark === id);
+  if (!f) return id;
+  return systemPrefersDark() ? f.dark : f.light;
+}
+
+/** Switches the theme when the system changes between light and dark; returns the unsubscribe */
+export function watchSystemScheme(onChange: (id: ThemeId) => void): () => void {
+  if (typeof window === 'undefined' || !window.matchMedia) return () => {};
+  const mq = window.matchMedia('(prefers-color-scheme: dark)');
+  const handler = () => {
+    if (!getFollowSystem()) return;
+    const next = resolveTheme(getActiveTheme());
+    if (next !== getActiveTheme()) {
+      setActiveTheme(next);
+      onChange(next);
+    }
+  };
+  mq.addEventListener('change', handler);
+  return () => mq.removeEventListener('change', handler);
+}
+
+// Buttons with or without frames (per device): "off" removes the border of the regular buttons
+export type ButtonBorders = 'on' | 'off';
+const BUTTON_BORDERS_KEY = 'mindsift_button_borders';
+
+export function getButtonBorders(): ButtonBorders {
+  return load(BUTTON_BORDERS_KEY) === 'off' ? 'off' : 'on';
+}
+
+export function setButtonBorders(value: ButtonBorders): void {
+  store(BUTTON_BORDERS_KEY, value === 'off' ? 'off' : null);
+  applyButtonBorders(value);
+}
+
+function applyButtonBorders(value: ButtonBorders): void {
+  if (typeof document === 'undefined') return;
+  if (value === 'off') document.documentElement.setAttribute('data-button-borders', 'off');
+  else document.documentElement.removeAttribute('data-button-borders');
+}
+
+// Own accent colour on top of any theme (per device); null = the theme's accent
+const ACCENT_KEY = 'mindsift_accent';
+const ACCENT_VARS = ['--accent-primary', '--accent-hover', '--accent-dim', '--accent-border', '--text-on-accent'];
+
+export function getAccentColor(): string | null {
+  const v = load(ACCENT_KEY);
+  return v && /^#[0-9a-f]{6}$/i.test(v) ? v : null;
+}
+
+export function setAccentColor(hex: string | null): void {
+  store(ACCENT_KEY, hex);
+  applyAccent(hex);
+}
+
+function hexToRgb(hex: string): [number, number, number] {
+  return [1, 3, 5].map((i) => parseInt(hex.slice(i, i + 2), 16)) as [number, number, number];
+}
+
+function applyAccent(hex: string | null): void {
+  if (typeof document === 'undefined') return;
+  const style = document.documentElement.style;
+  if (!hex) {
+    ACCENT_VARS.forEach((v) => style.removeProperty(v));
+    return;
+  }
+  const [r, g, b] = hexToRgb(hex);
+  // Hover goes towards the text colour: darker on light themes, lighter on dark ones
+  const dark = document.documentElement.classList.contains('dark');
+  const mix = (c: number) => Math.round(dark ? c + (255 - c) * 0.2 : c * 0.82);
+  const toHex = (c: number) => c.toString(16).padStart(2, '0');
+  style.setProperty('--accent-primary', hex);
+  style.setProperty('--accent-hover', `#${toHex(mix(r))}${toHex(mix(g))}${toHex(mix(b))}`);
+  style.setProperty('--accent-dim', `rgba(${r}, ${g}, ${b}, ${dark ? 0.16 : 0.1})`);
+  style.setProperty('--accent-border', `rgba(${r}, ${g}, ${b}, 0.38)`);
+  style.setProperty('--text-on-accent', 0.2126 * r + 0.7152 * g + 0.0722 * b > 160 ? '#111111' : '#ffffff');
+}
+
+// Corners: follow the theme, or force round / square for every theme (per device)
+export type CornerStyle = 'theme' | 'round' | 'square';
+const CORNERS_STORAGE_KEY = 'mindsift_corners';
+
+export function getCornerStyle(): CornerStyle {
+  const v = load(CORNERS_STORAGE_KEY);
+  return v === 'round' || v === 'square' ? v : 'theme';
+}
+
+export function setCornerStyle(style: CornerStyle): void {
+  store(CORNERS_STORAGE_KEY, style === 'theme' ? null : style);
+  applyCorners(style);
+}
+
+function applyCorners(style: CornerStyle): void {
+  if (typeof document === 'undefined') return;
+  if (style === 'theme') document.documentElement.removeAttribute('data-corners');
+  else document.documentElement.setAttribute('data-corners', style);
+}
 
 export const isCustomThemeId = (id: ThemeId) => id.startsWith(CUSTOM_THEME_PREFIX);
 export const customThemeId = (t: UserTheme): ThemeId => CUSTOM_THEME_PREFIX + t.id;
@@ -157,6 +346,7 @@ function applyToDocument(themeId: ThemeId, customCss: string | null): void {
       ? isLightColor(readCssVar(customCss, 'bg-app'))
       : isLightColor(AVAILABLE_THEMES.find((t) => t.id === themeId)?.previewBg);
   root.classList.toggle('dark', !light);
+  applyAccent(getAccentColor());
   syncThemeColorMeta();
 }
 
@@ -209,7 +399,11 @@ export function setActiveTheme(themeId: ThemeId, customCss?: string): void {
 }
 
 export function initThemeOnBoot(): ThemeId {
-  const active = getActiveTheme();
+  applyCorners(getCornerStyle());
+  applyButtonBorders(getButtonBorders());
+  const saved = getActiveTheme();
+  const active = resolveTheme(saved);
+  if (active !== saved) store(THEME_STORAGE_KEY, active);
   applyToDocument(active, isCustomThemeId(active) ? load(CUSTOM_CSS_CACHE_KEY) : null);
   return active;
 }

frontend/src/themes/theme-fjord-night.css

@@ -0,0 +1,69 @@
+/* ==========================================================================
+   MINDSIFT THEME: FJORD NACHT (Tiefsee & Mondlicht)
+   Das dunkle Gegenstück zu Fjord: tiefes Nachtblau statt Schwarz,
+   mondhelle Schrift, leuchtendes Gletscherblau, weiche Ecken.
+   ========================================================================== */
+
+:root[data-theme="fjord-night"] {
+  /* --- 1. AKZENTFARBE (Leuchtendes Gletscherblau) --- */
+  --accent-primary: #5b9bdf;
+  --accent-hover: #7db2ea;
+  --accent-dim: rgba(91, 155, 223, 0.16);
+  --accent-border: rgba(91, 155, 223, 0.40);
+  --text-on-accent: #0b1622;
+
+  /* --- 2. OBERFLÄCHEN & HINTERGRÜNDE (Tiefsee) --- */
+  --bg-app: #0e1621;
+  --bg-panel: #152131;
+  --bg-panel-elevated: #1c2b3e;
+  --bg-panel-hover: #24364c;
+  --bg-input: #101a26;
+  --bg-overlay: rgba(5, 10, 16, 0.72);
+  --bg-code: #0b121b;
+  --bg-editor: #121d2a;
+  --bg-sidebar: #0e1621;
+
+  /* --- 3. TEXT & KONTRASTE (Mondlicht) --- */
+  --text-main: #e6eef8;
+  --text-muted: #9fb1c6;
+  --text-faint: #6b7d93;
+
+  /* --- 4. RAHMEN, LINIEN & SCHATTEN --- */
+  --border-color: rgba(180, 205, 235, 0.12);
+  --border-subtle: rgba(180, 205, 235, 0.06);
+  --border-strong: rgba(180, 205, 235, 0.24);
+  --shadow-panel: 0 12px 32px rgba(2, 6, 12, 0.55);
+  --scrollbar-thumb: rgba(91, 155, 223, 0.22);
+  --scrollbar-thumb-hover: rgba(91, 155, 223, 0.38);
+
+  /* --- 5. STATUS- & SIGNALFARBEN --- */
+  --color-success: #6fcf97;
+  --bg-success: rgba(111, 207, 151, 0.14);
+  --border-success: rgba(111, 207, 151, 0.36);
+
+  --color-danger: #f28b82;
+  --bg-danger: rgba(242, 139, 130, 0.14);
+  --border-danger: rgba(242, 139, 130, 0.36);
+
+  --color-warning: #f6c177;
+  --bg-warning: rgba(246, 193, 119, 0.14);
+  --border-warning: rgba(246, 193, 119, 0.36);
+
+  /* --- 6. RUNDUNGEN (Weich) --- */
+  --radius-card: 12px;
+  --radius-btn: 8px;
+  --radius-input: 8px;
+  --radius-checkbox: 4px;
+  --radius-pill: 9999px;
+
+  /* --- 7. CODE-SYNTAX-HIGHLIGHTING --- */
+  --code-keyword: #7db2ea;
+  --code-string: #9fd4a3;
+  --code-number: #f6c177;
+  --code-comment: #6b7d93;
+  --code-property: #c3d8f0;
+  --code-function: #c4a7f5;
+  --code-type: #6fd3c8;
+  --code-punctuation: #9fb1c6;
+  --code-variable: #c3d8f0;
+}

frontend/src/themes/theme-fjord.css

@@ -0,0 +1,69 @@
+/* ==========================================================================
+   MINDSIFT THEME: FJORD (Kühles Papier & Gletscherblau)
+   Bläulich-weißes Papier, nebelgraue Seitenleiste, tintenblaue Schrift,
+   klares Fjordblau als Akzent und weiche Ecken.
+   ========================================================================== */
+
+:root[data-theme="fjord"] {
+  /* --- 1. AKZENTFARBE (Fjordblau) --- */
+  --accent-primary: #2b6cb0;
+  --accent-hover: #1f5590;
+  --accent-dim: rgba(43, 108, 176, 0.10);
+  --accent-border: rgba(43, 108, 176, 0.34);
+  --text-on-accent: #ffffff;
+
+  /* --- 2. OBERFLÄCHEN & HINTERGRÜNDE (Papier, Nebel, Eis) --- */
+  --bg-app: #e9eef5;
+  --bg-panel: #f7f9fc;
+  --bg-panel-elevated: #dde5ef;
+  --bg-panel-hover: #cfd9e6;
+  --bg-input: #fbfcfe;
+  --bg-overlay: rgba(14, 24, 38, 0.45);
+  --bg-code: #eef2f8;
+  --bg-editor: #fafcff;
+  --bg-sidebar: #edf2f8;
+
+  /* --- 3. TEXT & KONTRASTE (Tintenblau) --- */
+  --text-main: #14202e;
+  --text-muted: #45556a;
+  --text-faint: #7a8798;
+
+  /* --- 4. RAHMEN, LINIEN & SCHATTEN --- */
+  --border-color: rgba(30, 55, 90, 0.16);
+  --border-subtle: rgba(30, 55, 90, 0.08);
+  --border-strong: rgba(30, 55, 90, 0.30);
+  --shadow-panel: 0 10px 28px rgba(20, 40, 70, 0.10);
+  --scrollbar-thumb: rgba(30, 55, 90, 0.22);
+  --scrollbar-thumb-hover: rgba(30, 55, 90, 0.38);
+
+  /* --- 5. STATUS- & SIGNALFARBEN --- */
+  --color-success: #2f855a;
+  --bg-success: rgba(47, 133, 90, 0.11);
+  --border-success: rgba(47, 133, 90, 0.34);
+
+  --color-danger: #c53030;
+  --bg-danger: rgba(197, 48, 48, 0.09);
+  --border-danger: rgba(197, 48, 48, 0.34);
+
+  --color-warning: #b7791f;
+  --bg-warning: rgba(183, 121, 31, 0.11);
+  --border-warning: rgba(183, 121, 31, 0.34);
+
+  /* --- 6. RUNDUNGEN (Weich) --- */
+  --radius-card: 12px;
+  --radius-btn: 8px;
+  --radius-input: 8px;
+  --radius-checkbox: 4px;
+  --radius-pill: 9999px;
+
+  /* --- 7. CODE-SYNTAX-HIGHLIGHTING (kühle Töne auf Papier) --- */
+  --code-keyword: #2b6cb0;
+  --code-string: #2f855a;
+  --code-number: #b7791f;
+  --code-comment: #7a8798;
+  --code-property: #1a4e7a;
+  --code-function: #6b46c1;
+  --code-type: #0e7490;
+  --code-punctuation: #45556a;
+  --code-variable: #1a4e7a;
+}

frontend/src/themes/theme-polarized-light.css

@@ -0,0 +1,69 @@
+/* ==========================================================================
+   MINDSIFT THEME: POLARIZED HELL (Lagune & Kreide)
+   Das helle Gegenstück zu Polarized: kreidiges Mintweiß, tiefes Petrol als
+   Akzent, dunkle Schiefer-Schrift, klar und eckig wie das Original.
+   ========================================================================== */
+
+:root[data-theme="polarized-light"] {
+  /* --- 1. AKZENTFARBE (Tiefes Petrol) --- */
+  --accent-primary: #0f766e;
+  --accent-hover: #115e59;
+  --accent-dim: rgba(15, 118, 110, 0.10);
+  --accent-border: rgba(15, 118, 110, 0.34);
+  --text-on-accent: #ffffff;
+
+  /* --- 2. OBERFLÄCHEN & HINTERGRÜNDE (Kreide, Lagune) --- */
+  --bg-app: #e6f0ef;
+  --bg-panel: #f6fbfa;
+  --bg-panel-elevated: #d8e8e6;
+  --bg-panel-hover: #c7dcd9;
+  --bg-input: #fbfefd;
+  --bg-overlay: rgba(8, 30, 28, 0.45);
+  --bg-code: #eaf3f2;
+  --bg-editor: #f9fdfc;
+  --bg-sidebar: #ebf4f3;
+
+  /* --- 3. TEXT & KONTRASTE --- */
+  --text-main: #0f2422;
+  --text-muted: #3f5c59;
+  --text-faint: #728a87;
+
+  /* --- 4. RAHMEN, LINIEN & SCHATTEN --- */
+  --border-color: rgba(15, 80, 75, 0.17);
+  --border-subtle: rgba(15, 80, 75, 0.08);
+  --border-strong: rgba(15, 80, 75, 0.32);
+  --shadow-panel: 0 8px 24px rgba(10, 45, 42, 0.09);
+  --scrollbar-thumb: rgba(15, 80, 75, 0.22);
+  --scrollbar-thumb-hover: rgba(15, 80, 75, 0.38);
+
+  /* --- 5. STATUS- & SIGNALFARBEN --- */
+  --color-success: #15803d;
+  --bg-success: rgba(21, 128, 61, 0.10);
+  --border-success: rgba(21, 128, 61, 0.34);
+
+  --color-danger: #be123c;
+  --bg-danger: rgba(190, 18, 60, 0.09);
+  --border-danger: rgba(190, 18, 60, 0.34);
+
+  --color-warning: #b45309;
+  --bg-warning: rgba(180, 83, 9, 0.10);
+  --border-warning: rgba(180, 83, 9, 0.34);
+
+  /* --- 6. RUNDUNGEN (Klar & eckig wie Polarized) --- */
+  --radius-card: 0px;
+  --radius-btn: 2px;
+  --radius-input: 2px;
+  --radius-checkbox: 0px;
+  --radius-pill: 9999px;
+
+  /* --- 7. CODE-SYNTAX-HIGHLIGHTING --- */
+  --code-keyword: #0f766e;
+  --code-string: #9a3412;
+  --code-number: #b45309;
+  --code-comment: #728a87;
+  --code-property: #155e75;
+  --code-function: #7e22ce;
+  --code-type: #0e7490;
+  --code-punctuation: #3f5c59;
+  --code-variable: #155e75;
+}

frontend/src/themes/theme-suri-light.css

@@ -0,0 +1,69 @@
+/* ==========================================================================
+   MINDSIFT THEME: SURI HELL (Lavendel & Pflaume)
+   Das helle Gegenstück zu Suri: lavendelhelles Papier, pflaumendunkle
+   Schrift, samtiger Orchideen-Akzent und weich gerundete Ecken.
+   ========================================================================== */
+
+:root[data-theme="suri-light"] {
+  /* --- 1. AKZENTFARBE (Orchidee) --- */
+  --accent-primary: #8e44c9;
+  --accent-hover: #7431a8;
+  --accent-dim: rgba(142, 68, 201, 0.10);
+  --accent-border: rgba(142, 68, 201, 0.34);
+  --text-on-accent: #ffffff;
+
+  /* --- 2. OBERFLÄCHEN & HINTERGRÜNDE (Lavendel) --- */
+  --bg-app: #efe9f4;
+  --bg-panel: #fbf8fd;
+  --bg-panel-elevated: #e6dcef;
+  --bg-panel-hover: #d9cce6;
+  --bg-input: #fdfbfe;
+  --bg-overlay: rgba(30, 18, 40, 0.45);
+  --bg-code: #f2ecf7;
+  --bg-editor: #fdfaff;
+  --bg-sidebar: #f2ecf7;
+
+  /* --- 3. TEXT & KONTRASTE (Pflaume) --- */
+  --text-main: #23182e;
+  --text-muted: #574a68;
+  --text-faint: #8a7c9c;
+
+  /* --- 4. RAHMEN, LINIEN & SCHATTEN --- */
+  --border-color: rgba(70, 40, 100, 0.16);
+  --border-subtle: rgba(70, 40, 100, 0.08);
+  --border-strong: rgba(70, 40, 100, 0.30);
+  --shadow-panel: 0 10px 28px rgba(50, 25, 75, 0.10);
+  --scrollbar-thumb: rgba(70, 40, 100, 0.22);
+  --scrollbar-thumb-hover: rgba(70, 40, 100, 0.38);
+
+  /* --- 5. STATUS- & SIGNALFARBEN --- */
+  --color-success: #2f855a;
+  --bg-success: rgba(47, 133, 90, 0.11);
+  --border-success: rgba(47, 133, 90, 0.34);
+
+  --color-danger: #c2185b;
+  --bg-danger: rgba(194, 24, 91, 0.09);
+  --border-danger: rgba(194, 24, 91, 0.34);
+
+  --color-warning: #b7791f;
+  --bg-warning: rgba(183, 121, 31, 0.11);
+  --border-warning: rgba(183, 121, 31, 0.34);
+
+  /* --- 6. RUNDUNGEN (Weich wie Suri) --- */
+  --radius-card: 10px;
+  --radius-btn: 6px;
+  --radius-input: 6px;
+  --radius-checkbox: 4px;
+  --radius-pill: 9999px;
+
+  /* --- 7. CODE-SYNTAX-HIGHLIGHTING --- */
+  --code-keyword: #7431a8;
+  --code-string: #2f855a;
+  --code-number: #b7791f;
+  --code-comment: #8a7c9c;
+  --code-property: #5b2a86;
+  --code-function: #b4235f;
+  --code-type: #0e7490;
+  --code-punctuation: #574a68;
+  --code-variable: #5b2a86;
+}