diff --git a/src/assets/fonts/Inter-var.woff2 b/src/assets/fonts/Inter-var.woff2
new file mode 100644
index 0000000..5a8d3e7
Binary files /dev/null and b/src/assets/fonts/Inter-var.woff2 differ
diff --git a/src/features/snippets/SnippetCard.tsx b/src/features/snippets/SnippetCard.tsx
index 17ea97c..8534f5d 100644
--- a/src/features/snippets/SnippetCard.tsx
+++ b/src/features/snippets/SnippetCard.tsx
@@ -1,5 +1,6 @@
 import { Pencil, Trash2 } from "lucide-react";
-import { useEffect, useMemo, useState } from "react";
+import { useCallback, useEffect, useMemo, useState } from "react";
+import type { MouseEvent } from "react";
 import type { Snippet } from "@/types/snippet";
 import { deadlineToDateInput } from "@/lib/snippetDeadline";
 import { Button } from "@/components/ui/button";
@@ -9,6 +10,7 @@ import { SnippetEditDialog } from "@/features/snippets/components/SnippetEditDia
 import { TagPill } from "@/features/snippets/components/TagPill";
 import { colorForTagName, tagsFromString } from "@/features/snippets/lib/tagFieldUtils";
 import { formatWhen } from "@/features/snippets/lib/formatWhen";
+import { toggleMarkdownTaskAt } from "@/features/snippets/lib/markdownTasks";
 import { parseSnippetMarkdown } from "@/features/snippets/lib/parseSnippetMarkdown";
 
 type Props = {
@@ -92,6 +94,41 @@ export function SnippetCard({ snippet, treeColorByName, treeDisplayByName, onRep
     }
   };
 
+  const handleMarkdownMouseDown = useCallback(
+    (e: MouseEvent<HTMLDivElement>) => {
+      const t = e.target;
+      if (!(t instanceof HTMLInputElement)) return;
+      if (!t.classList.contains("snippet-task-cb") || t.type !== "checkbox") return;
+      e.preventDefault();
+      e.stopPropagation();
+      const idx = Number(t.getAttribute("data-snippet-task-idx"));
+      if (!Number.isFinite(idx) || busy) return;
+      const newBody = toggleMarkdownTaskAt(snippet.body, idx);
+      if (newBody === null) return;
+      void (async () => {
+        setBusy(true);
+        setError(null);
+        try {
+          const res = await fetch(`/api/snippets/${snippet.id}`, {
+            method: "PATCH",
+            headers: { "Content-Type": "application/json" },
+            body: JSON.stringify({ title: null, body: newBody }),
+          });
+          if (!res.ok) {
+            const err = (await res.json().catch(() => null)) as { error?: string } | null;
+            throw new Error(err?.error ?? res.statusText);
+          }
+          onReplace((await res.json()) as Snippet);
+        } catch (err) {
+          setError(err instanceof Error ? err.message : "Aufgabe konnte nicht gespeichert werden");
+        } finally {
+          setBusy(false);
+        }
+      })();
+    },
+    [snippet.body, snippet.id, busy, onReplace],
+  );
+
   async function clearDeadlineRemote() {
     setBusy(true);
     setError(null);
@@ -151,8 +188,12 @@ export function SnippetCard({ snippet, treeColorByName, treeDisplayByName, onRep
               }
             }}
           >
-            <div className="snippet-md-card-wrap">
-              <div className="snippet-md overflow-auto" dangerouslySetInnerHTML={{ __html: viewHtml }} />
+            <div className="snippet-md-card-wrap snippet-md-viewport overflow-hidden rounded-sm">
+              <div
+                className="snippet-md max-h-full overflow-x-auto overflow-y-auto pr-0.5"
+                dangerouslySetInnerHTML={{ __html: viewHtml }}
+                onMouseDown={handleMarkdownMouseDown}
+              />
             </div>
           </div>
         </CardContent>
diff --git a/src/features/snippets/components/SnippetEditDialog.tsx b/src/features/snippets/components/SnippetEditDialog.tsx
index 56dde68..7b0c17e 100644
--- a/src/features/snippets/components/SnippetEditDialog.tsx
+++ b/src/features/snippets/components/SnippetEditDialog.tsx
@@ -1,4 +1,5 @@
-import { useEffect, useMemo, useRef, useState } from "react";
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
+import type { MouseEvent } from "react";
 import type { Snippet } from "@/types/snippet";
 import { Button } from "@/components/ui/button";
 import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from "@/components/ui/dialog";
@@ -10,6 +11,7 @@ import { useTagSuggestions } from "@/features/snippets/hooks/useTagSuggestions";
 import { TagPill } from "@/features/snippets/components/TagPill";
 import { TagSuggestDropdown } from "@/features/snippets/components/TagSuggestDropdown";
 import { colorForTagName, splitTagsField, tagsFromString } from "@/features/snippets/lib/tagFieldUtils";
+import { toggleMarkdownTaskAt } from "@/features/snippets/lib/markdownTasks";
 import { parseSnippetMarkdown } from "@/features/snippets/lib/parseSnippetMarkdown";
 
 type Props = {
@@ -55,6 +57,21 @@ export function SnippetEditDialog({
 
   const previewHtml = useMemo(() => parseSnippetMarkdown(body), [body]);
 
+  const handlePreviewMouseDown = useCallback(
+    (e: MouseEvent<HTMLDivElement>) => {
+      const t = e.target;
+      if (!(t instanceof HTMLInputElement)) return;
+      if (!t.classList.contains("snippet-task-cb") || t.type !== "checkbox") return;
+      e.preventDefault();
+      e.stopPropagation();
+      const idx = Number(t.getAttribute("data-snippet-task-idx"));
+      if (!Number.isFinite(idx) || busy) return;
+      const next = toggleMarkdownTaskAt(body, idx);
+      if (next !== null) onBodyChange(next);
+    },
+    [body, busy, onBodyChange],
+  );
+
   useEffect(() => {
     if (!open) setShowPreview(false);
   }, [open]);
@@ -136,7 +153,11 @@ export function SnippetEditDialog({
               placeholder="Markdown …"
             />
             {showPreview ? (
-              <div className="dialog-snippet-preview snippet-md" dangerouslySetInnerHTML={{ __html: previewHtml }} />
+              <div
+                className="dialog-snippet-preview snippet-md"
+                dangerouslySetInnerHTML={{ __html: previewHtml }}
+                onMouseDown={handlePreviewMouseDown}
+              />
             ) : null}
           </div>
           <div className="flex shrink-0 flex-wrap items-end gap-2">
diff --git a/src/features/snippets/lib/markdownTasks.ts b/src/features/snippets/lib/markdownTasks.ts
new file mode 100644
index 0000000..7067e49
--- /dev/null
+++ b/src/features/snippets/lib/markdownTasks.ts
@@ -0,0 +1,31 @@
+/**
+ * GFM-Tasklisten (`- [ ]` / `- [x]`) in Dokumentreihenfolge erkennen und umschalten.
+ */
+
+/** GFM task lines: `- [ ]`, `* [x]`, `1. [ ]`; optional indent; text after `]` optional. */
+const TASK_LINE =
+  /^(\s*)([-*+]|\d+\.)\s+\[([ xX])\]\s*(.*)$/;
+
+export function listMarkdownTaskLineIndices(body: string): number[] {
+  const lines = body.split(/\r?\n/);
+  const out: number[] = [];
+  for (let i = 0; i < lines.length; i++) {
+    if (TASK_LINE.test(lines[i]!)) out.push(i);
+  }
+  return out;
+}
+
+/** Kippt die n-te Task-Zeile im Dokument (`[ ]` ↔ `[x]`). `null` bei ungültigem Index. */
+export function toggleMarkdownTaskAt(body: string, taskIndex: number): string | null {
+  const lines = body.split(/\r?\n/);
+  const taskLineIndices = listMarkdownTaskLineIndices(body);
+  if (taskIndex < 0 || taskIndex >= taskLineIndices.length) return null;
+  const li = taskLineIndices[taskIndex]!;
+  const line = lines[li]!;
+  const m = line.match(TASK_LINE);
+  if (!m) return null;
+  const checked = m[3] === "x" || m[3] === "X";
+  const next = checked ? " " : "x";
+  lines[li] = line.replace(/\[[ xX]\]/, `[${next}]`);
+  return lines.join("\n");
+}
diff --git a/src/features/snippets/lib/parseSnippetMarkdown.ts b/src/features/snippets/lib/parseSnippetMarkdown.ts
index fcc09fd..f0837d1 100644
--- a/src/features/snippets/lib/parseSnippetMarkdown.ts
+++ b/src/features/snippets/lib/parseSnippetMarkdown.ts
@@ -1,7 +1,10 @@
 import hljs from "highlight.js/lib/common";
 import { marked } from "marked";
 
-marked.setOptions({ gfm: true });
+marked.setOptions({ gfm: true, pedantic: false });
+
+/** Pro `parseSnippetMarkdown`-Aufruf: Checkbox-Indizes von 0 … */
+const taskCheckboxSeq = { n: 0 };
 
 /** Markdown-Sprachkennungen → highlight.js-Name */
 const LANG_ALIASES: Record<string, string> = {
@@ -41,11 +44,11 @@ function escapeHtml(s: string): string {
     .replace(/"/g, "&quot;");
 }
 
-let hljsConfigured = false;
+let markedExtensionsConfigured = false;
 
-function ensureMarkedHighlighter(): void {
-  if (hljsConfigured) return;
-  hljsConfigured = true;
+function ensureMarkedExtensions(): void {
+  if (markedExtensionsConfigured) return;
+  markedExtensionsConfigured = true;
   marked.use({
     renderer: {
       code({ text, lang }) {
@@ -58,12 +61,18 @@ function ensureMarkedHighlighter(): void {
           return `<pre class="snippet-pre"><code class="hljs language-plaintext">${escapeHtml(text)}</code></pre>\n`;
         }
       },
+      checkbox({ checked }) {
+        const idx = taskCheckboxSeq.n++;
+        const chk = checked ? " checked" : "";
+        return `<input type="checkbox" class="snippet-task-cb"${chk} data-snippet-task-idx="${idx}" aria-label="Aufgabe umschalten" /> `;
+      },
     },
   });
 }
 
-ensureMarkedHighlighter();
+ensureMarkedExtensions();
 
 export function parseSnippetMarkdown(md: string): string {
+  taskCheckboxSeq.n = 0;
   return marked.parse(md) as string;
 }
diff --git a/src/index.css b/src/index.css
index 3fd9796..fb83fe0 100644
--- a/src/index.css
+++ b/src/index.css
@@ -12,7 +12,8 @@
 
 @font-face {
   font-family: 'Inter';
-  src: url('./assets/fonts/Inter-Variable.ttf') format('truetype');
+  /* src: url('./assets/fonts/Inter-Variable.ttf') format('truetype'); */
+  src: url('./assets/fonts/Inter-var.woff2') format('woff2');
   font-style: normal;
   font-weight: normal;
   font-display: swap;
@@ -62,7 +63,7 @@ body::before {
 /* Markdown rendering (marked HTML) */
 @layer components {
   .snippet-md {
-    font-size: 0.8rem;
+    font-size: 0.76rem;
     font-family: 'Inter';
   }
 
@@ -92,7 +93,7 @@ body::before {
     border-radius: var(--radius-sm, 0.25rem);
     background-color: var(--muted);
     padding: 0.125rem 0.25rem;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
   }
 
   .snippet-md :where(pre:not(.snippet-pre)) {
@@ -106,7 +107,7 @@ body::before {
   .snippet-md :where(pre:not(.snippet-pre) code) {
     background-color: transparent;
     padding: 0;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
   }
 
   /* Highlight.js Codeblöcke */
@@ -129,7 +130,7 @@ body::before {
     width: max-content;
     min-width: 100%;
     padding: 0;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
     line-height: 1.55;
     tab-size: 2;
     background: transparent !important;
@@ -153,26 +154,27 @@ body::before {
 
   .snippet-md :where(h1) {
     margin-block: 0 0.5rem;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
     font-weight: 600;
   }
 
   .snippet-md :where(h2) {
     margin-block: 0.75rem 0.5rem;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
     font-weight: 600;
   }
 
   .snippet-md :where(h3) {
     margin-block: 0.5rem 0.25rem;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
     font-weight: 600;
   }
 
+  /* Listen: outside + Einzug, damit Verschachtelung sichtbar ist */
   .snippet-md :where(ul, ol) {
     margin-block: 0.5rem;
-    list-style-position: inside;
-    padding-inline-start: 0;
+    list-style-position: outside;
+    padding-inline-start: 1.35rem;
   }
 
   .snippet-md :where(ul) {
@@ -184,14 +186,30 @@ body::before {
   }
 
   .snippet-md :where(li) {
-    margin-block: 0.125rem;
-    padding-inline-start: 0.25rem;
+    margin-block: 0.2rem;
+    padding-inline-start: 0.15rem;
+  }
+
+  .snippet-md :where(li > ul, li > ol) {
+    margin-block: 0.35rem;
+  }
+
+  .snippet-md input.snippet-task-cb {
+    margin-inline-end: 0.35rem;
+    vertical-align: middle;
+    accent-color: var(--primary);
+    cursor: pointer;
+  }
+
+  /* Karteninhalt: begrenzte Höhe, langer Text scrollt */
+  .snippet-md-viewport {
+    max-height: min(52vh, 28rem);
   }
 
   .snippet-md :where(table) {
     width: 100%;
     border-collapse: collapse;
-    font-size: 0.8rem;
+    font-size: 0.76rem;
   }
 
   .snippet-md :where(th, td) {
@@ -212,7 +230,7 @@ body::before {
 
   /* Snippet-Karten: etwas dichter, Fokus auf Fließtext */
   .snippet-md-card-wrap .snippet-md {
-    font-size: 0.8rem;
+    font-size: 0.76rem;
     line-height: 1.55;
   }
 
@@ -266,7 +284,7 @@ body::before {
   }
 
   .dialog-snippet-preview {
-    @apply min-h-0 flex-1 overflow-auto rounded-md border bg-muted/30 p-3 lg:w-1/2;
+    @apply min-h-0 max-h-[min(50vh,26rem)] flex-1 overflow-auto rounded-md border bg-muted/30 p-3 lg:w-1/2;
   }
 
   .dialog-snippet-textarea {