diff --git a/frontend/src/assets/themes/paper-moments.theme b/frontend/src/assets/themes/paper-moments.theme
index 36869b0..289afc7 100644
--- a/frontend/src/assets/themes/paper-moments.theme
+++ b/frontend/src/assets/themes/paper-moments.theme
@@ -1,6 +1,6 @@
 theme_id: paper-moments
 name: 纸间时光 · Paper Moments
-version: 1.8.1
+version: 1.9.0
 author: NotesAgent
 description: 奶油纸张、手帐虚线与粉蓝胶带，把每天的灵感好好收藏。
 min_app_version: 0.2.0
@@ -9,6 +9,9 @@ css_entry: theme.css
 license: MIT
 ---
 [data-theme="paper-moments"] {
+  --color-markdown-selection: #ecd3c7;
+  --color-editor-scroll-background: #fff9e9;
+  --color-editor-scroll-text: #875343;
   --color-callout-info: #406b7b;
   --color-callout-success: #536f43;
   --color-callout-warning: #875f25;
diff --git a/frontend/src/components/common/MarkdownContent.vue b/frontend/src/components/common/MarkdownContent.vue
index 0fdf620..9072245 100644
--- a/frontend/src/components/common/MarkdownContent.vue
+++ b/frontend/src/components/common/MarkdownContent.vue
@@ -24,7 +24,7 @@ watch([() => props.source, diagramTheme, () => themeStore.currentThemeId, () =>
 </script>
 
 <template>
-  <DiagramInteractions :data-heading-style="headingAppearance.preferences.custom ? 'custom' : undefined" :style="headingAppearance.cssVariables"><div class="markdown-content" v-html="html" /></DiagramInteractions>
+  <DiagramInteractions :data-heading-style="headingAppearance.preferences.custom ? 'custom' : undefined" :style="headingAppearance.cssVariables"><div class="markdown-content" :data-code-wrap="markdownPreferences.normalized.wrapCode" :data-line-numbers="markdownPreferences.normalized.lineNumbers" :style="{ '--markdown-code-indent': markdownPreferences.normalized.indent }" v-html="html" /></DiagramInteractions>
 </template>
 
 <style>
@@ -36,12 +36,10 @@ watch([() => props.source, diagramTheme, () => themeStore.currentThemeId, () =>
 .markdown-content li::marker { color: var(--color-markdown-marker); font-weight: 700; }
 .markdown-content .shiki { overflow: auto; margin: .85em 0; padding: 16px; border: 1px solid var(--color-code-border); border-radius: 6px; background: var(--color-code-background) !important; color: var(--color-code-text); font-family: var(--font-ui-mono); font-size: .875em; line-height: 1.45; tab-size: 4; }
 .markdown-content code { padding: .1em .3em; border-radius: var(--radius-sm); background: var(--color-background-tertiary); font-family: var(--font-ui-mono); }
-.markdown-content .shiki code { display: block; min-width: max-content; padding: 0; background: transparent; font: inherit; }
 .markdown-content :not(pre) > code { background: var(--color-code-background); color: var(--color-code-text); border: 1px solid var(--color-code-border); }
 .markdown-content div.markdown-math { overflow-x: auto; padding-block: .5em; }
 .markdown-content h4, .markdown-content h5, .markdown-content h6 { margin: 1em 0 .5em; font-weight: 600; }
 .markdown-content input[type="checkbox"] { margin-right: .45em; accent-color: var(--color-accent-primary); }
-.markdown-content .shiki .line { display: block; min-height: 1.45em; }
 .markdown-content blockquote { padding-left: 1em; border-left: 3px solid var(--color-accent-primary); color: var(--color-text-secondary); }
 .markdown-content table { width: 100%; margin: .65em 0; border-collapse: collapse; }
 .markdown-content th, .markdown-content td { padding: .45em .65em; border: 1px solid var(--color-markdown-grid); text-align: left; }
diff --git a/frontend/src/features/editor/EditorPane.vue b/frontend/src/features/editor/EditorPane.vue
index da67c2f..2f34070 100644
--- a/frontend/src/features/editor/EditorPane.vue
+++ b/frontend/src/features/editor/EditorPane.vue
@@ -3,12 +3,14 @@ import { defineAsyncComponent, ref, watch } from 'vue'
 import { useEditorStore } from '@/stores/editor'
 import { useSettingsStore } from '@/stores/settings'
 import { useThemeStore } from '@/stores/theme'
+import EditorScrollButtons from './EditorScrollButtons.vue'
 const VisualMarkdownEditor = defineAsyncComponent(() => import('./VisualMarkdownEditor.vue'))
 
 const editorStore = useEditorStore()
 const settingsStore = useSettingsStore()
 const themeStore = useThemeStore()
 const sourceEditor = ref<HTMLTextAreaElement | null>(null)
+const container = ref<HTMLElement | null>(null)
 watch(() => editorStore.headingRequest, request => {
   const input = sourceEditor.value
   if (!request || !input || request.path !== editorStore.currentFilePath) return
@@ -24,13 +26,17 @@ function updateContent(event: Event) {
 </script>
 
 <template>
+  <div ref="container" class="editor-scroll-pane">
   <VisualMarkdownEditor v-if="editorStore.mode === 'wysiwyg'" :key="`${editorStore.currentFilePath ?? 'empty'}:${editorStore.contentRevision}:${themeStore.resolvedCodeBlockTheme}:${settingsStore.language}`"
     :initial-content="editorStore.content" />
   <textarea v-else ref="sourceEditor" class="editor-pane source" :value="editorStore.content" :spellcheck="settingsStore.spellCheck"
     :lang="settingsStore.language" :aria-label="settingsStore.language === 'en' ? 'Markdown source editor' : 'Markdown 源码编辑器'" @input="updateContent" />
+  <EditorScrollButtons :container="container" :content="editorStore.content" />
+  </div>
 </template>
 
 <style scoped>
+.editor-scroll-pane { position: relative; display: flex; flex-direction: column; flex: 1; min-height: 0; min-width: 0; overflow: hidden; }
 .editor-pane {
   box-sizing: border-box;
   flex: 1;
diff --git a/frontend/src/features/editor/EditorScrollButtons.spec.ts b/frontend/src/features/editor/EditorScrollButtons.spec.ts
new file mode 100644
index 0000000..c6f26aa
--- /dev/null
+++ b/frontend/src/features/editor/EditorScrollButtons.spec.ts
@@ -0,0 +1,47 @@
+// @vitest-environment happy-dom
+import { afterEach, expect, it, vi } from 'vitest'
+import { mount } from '@vue/test-utils'
+import EditorScrollButtons from './EditorScrollButtons.vue'
+
+afterEach(() => { vi.useRealTimers(); vi.unstubAllGlobals(); document.body.innerHTML = '' })
+
+it('shows only useful directions, scrolls the editor, and hides empty or short documents', async () => {
+  vi.useFakeTimers()
+  vi.stubGlobal('matchMedia', () => ({ matches: false }))
+  const container = document.createElement('div')
+  const viewport = document.createElement('textarea')
+  viewport.className = 'source'
+  container.append(viewport)
+  document.body.append(container)
+  Object.defineProperty(viewport, 'scrollHeight', { configurable: true, value: 1000 })
+  Object.defineProperty(viewport, 'clientHeight', { configurable: true, value: 200 })
+  const scroll = vi.fn()
+  viewport.scrollTo = scroll
+  const wrapper = mount(EditorScrollButtons, { props: { container, content: 'A long note' } })
+  const update = async (top: number) => {
+    viewport.scrollTop = top
+    viewport.dispatchEvent(new Event('scroll'))
+    await vi.advanceTimersByTimeAsync(40)
+  }
+  try {
+    await update(0)
+    expect(wrapper.findAll('button')).toHaveLength(1)
+    expect(wrapper.find('button').attributes('aria-label')).toBe('滑动到底部')
+    await wrapper.find('button').trigger('click')
+    expect(scroll).toHaveBeenLastCalledWith({ top: 1000, behavior: 'smooth' })
+    await update(400)
+    expect(wrapper.findAll('button')).toHaveLength(2)
+    await update(800)
+    expect(wrapper.findAll('button')).toHaveLength(1)
+    expect(wrapper.find('button').attributes('aria-label')).toBe('滑动到顶部')
+    await wrapper.find('button').trigger('click')
+    expect(scroll).toHaveBeenLastCalledWith({ top: 0, behavior: 'smooth' })
+    await wrapper.setProps({ content: '  \n' })
+    await update(400)
+    expect(wrapper.findAll('button')).toHaveLength(0)
+    Object.defineProperty(viewport, 'scrollHeight', { value: 200 })
+    await wrapper.setProps({ content: 'Short note' })
+    await update(0)
+    expect(wrapper.findAll('button')).toHaveLength(0)
+  } finally { wrapper.unmount() }
+})
diff --git a/frontend/src/features/editor/EditorScrollButtons.vue b/frontend/src/features/editor/EditorScrollButtons.vue
new file mode 100644
index 0000000..41b9f5f
--- /dev/null
+++ b/frontend/src/features/editor/EditorScrollButtons.vue
@@ -0,0 +1,62 @@
+<script setup lang="ts">
+import { computed, onBeforeUnmount, ref, watch } from 'vue'
+import { Top, Bottom } from '@element-plus/icons-vue'
+import AppIcon from '@/components/common/AppIcon.vue'
+import { t } from '@/i18n'
+
+const props = defineProps<{ container: HTMLElement | null; content: string }>()
+const hasContent = computed(() => !!props.content.trim())
+const canUp = ref(false), canDown = ref(false)
+let viewport: HTMLElement | null = null
+let frame = 0
+let mutation: MutationObserver | undefined
+let resize: ResizeObserver | undefined
+function update() {
+  frame = 0
+  const next = props.container?.querySelector<HTMLElement>('.milkdown-host, textarea.source') ?? null
+  if (next !== viewport) {
+    viewport?.removeEventListener('scroll', schedule)
+    resize?.disconnect()
+    viewport = next
+    viewport?.addEventListener('scroll', schedule, { passive: true })
+  }
+  if (viewport) {
+    resize?.observe(viewport)
+    for (const child of viewport.children) resize?.observe(child)
+    const document = viewport.querySelector('.ProseMirror')
+    if (document) resize?.observe(document)
+  }
+  const max = viewport ? viewport.scrollHeight - viewport.clientHeight : 0
+  const visible = hasContent.value && max > 2
+  canUp.value = visible && viewport!.scrollTop > 2
+  canDown.value = visible && viewport!.scrollTop < max - 2
+}
+function schedule() { if (!frame) frame = requestAnimationFrame(update) }
+function scroll(to: 'top' | 'bottom') {
+  viewport?.scrollTo({ top: to === 'top' ? 0 : viewport.scrollHeight,
+    behavior: window.matchMedia('(prefers-reduced-motion: reduce)').matches ? 'auto' : 'smooth' })
+}
+watch(() => props.container, container => {
+  mutation?.disconnect()
+  resize?.disconnect()
+  mutation = new MutationObserver(schedule)
+  resize = new ResizeObserver(schedule)
+  if (container) mutation.observe(container, { childList: true, subtree: true, characterData: true, attributes: true })
+  schedule()
+}, { immediate: true, flush: 'post' })
+watch(() => props.content, schedule)
+onBeforeUnmount(() => {
+  cancelAnimationFrame(frame)
+  mutation?.disconnect()
+  resize?.disconnect()
+  viewport?.removeEventListener('scroll', schedule)
+})
+</script>
+
+<template>
+  <div v-if="canUp || canDown" class="editor-scroll-buttons" :aria-label="t('文档滚动', 'Document scrolling')">
+    <button v-if="canUp" type="button" class="button-secondary" :title="t('滑动到顶部', 'Scroll to top')" :aria-label="t('滑动到顶部', 'Scroll to top')" @click="scroll('top')"><AppIcon :icon="Top" :size="20" /></button>
+    <button v-if="canDown" type="button" class="button-secondary" :title="t('滑动到底部', 'Scroll to bottom')" :aria-label="t('滑动到底部', 'Scroll to bottom')" @click="scroll('bottom')"><AppIcon :icon="Bottom" :size="20" /></button>
+  </div>
+</template>
+
diff --git a/frontend/src/features/themes/CommunityThemePreview.spec.ts b/frontend/src/features/themes/CommunityThemePreview.spec.ts
index dbb74ff..91aef5e 100644
--- a/frontend/src/features/themes/CommunityThemePreview.spec.ts
+++ b/frontend/src/features/themes/CommunityThemePreview.spec.ts
@@ -6,6 +6,7 @@ vi.mock('@/styles/features.css?raw', async () => ({ default: (await import('node
 vi.mock('@/styles/tokens.css?raw', async () => ({ default: (await import('node:fs')).readFileSync(process.cwd() + '/src/styles/tokens.css', 'utf8') }))
 vi.mock('@/styles/callouts.css?raw', async () => ({ default: (await import('node:fs')).readFileSync(process.cwd() + '/src/styles/callouts.css', 'utf8') }))
 import CommunityThemePreview from './CommunityThemePreview.vue'
+vi.mock('@/styles/markdown-behavior.css?raw', async () => ({ default: (await import('node:fs')).readFileSync(process.cwd() + '/src/styles/markdown-behavior.css', 'utf8') }))
 import { mockCommunityThemes } from '@/services/themePackageService'
 const themes = [...['light','dark','sepia'].map(theme_id => ({theme_id,name:theme_id,builtin:true})), ...mockCommunityThemes.map(t => ({...t,builtin:false}))]
 it.each(themes)('previews shared component states safely for $theme_id', theme => {
@@ -16,6 +17,9 @@ it.each(themes)('previews shared component states safely for $theme_id', theme =
     const doc = new DOMParser().parseFromString(iframe.attributes('srcdoc')!, 'text/html')
     expect(doc.documentElement.dataset.theme).toBe(theme.theme_id)
     expect(doc.querySelector('script')).toBeNull()
+    for (const selector of ['.editor-scroll-buttons button', '.markdown-content h6', '.task-list-item input:checked', '.markdown-content[data-code-wrap="true"][data-line-numbers="true"] .line', '.heading-fold-toggle']) expect(doc.querySelector(selector), selector).not.toBeNull()
+    expect(doc.querySelector('style')!.textContent).toContain('.editor-scroll-buttons button:focus-visible')
+    expect(doc.querySelector('style')!.textContent).toContain(".markdown-content[data-code-wrap='true'] .shiki code")
     expect(doc.querySelectorAll('.specimen-callouts > aside.markdown-callout')).toHaveLength(14)
     expect(doc.querySelector('.specimen-callouts > details[open]')).not.toBeNull()
     expect(doc.querySelector('.specimen-callouts > details:not([open])')).not.toBeNull()
@@ -25,6 +29,12 @@ it.each(themes)('previews shared component states safely for $theme_id', theme =
     expect(doc.querySelector('style')!.textContent).toContain('.button-primary:hover')
     expect(doc.querySelector('style')!.textContent).not.toContain('color:white')
     const rules = Array.from(doc.styleSheets[0]!.cssRules) as CSSStyleRule[]
+    // The sandbox cannot inherit MarkdownContent's component stylesheet.
+    const codeRule = rules.find(rule => rule.selectorText === '.markdown-content .shiki code')!
+    const lineRule = rules.find(rule => rule.selectorText === '.markdown-content .shiki .line')!
+    expect(codeRule.style.getPropertyValue('display')).toBe('block')
+    expect(lineRule.style.getPropertyValue('display')).toBe('block')
+    expect(lineRule.style.getPropertyValue('min-height')).toBe('1.45em')
     const rootRule = rules.filter(rule => rule.selectorText === 'html').pop()!
     const bodyRule = rules.filter(rule => rule.selectorText === 'body').pop()!
     // The embedded document must override the app-shell overflow lock.
diff --git a/frontend/src/features/themes/CommunityThemePreview.vue b/frontend/src/features/themes/CommunityThemePreview.vue
index cab8cfe..d328cf2 100644
--- a/frontend/src/features/themes/CommunityThemePreview.vue
+++ b/frontend/src/features/themes/CommunityThemePreview.vue
@@ -6,6 +6,7 @@ import { getCommunityThemePreviewCss, mockCommunityThemes } from '@/services/the
 import tokensCss from '@/styles/tokens.css?raw'
 import featuresCss from '@/styles/features.css?raw'
 import headingsCss from '@/styles/headings.css?raw'
+import markdownBehaviorCss from '@/styles/markdown-behavior.css?raw'
 import calloutsCss from '@/styles/callouts.css?raw'
 import { calloutTypes } from '@/utils/callouts'
 import specimenHtml from './themeSpecimen.html?raw'
@@ -25,6 +26,7 @@ const previewDocument = computed(() => {
   const style = doc.createElement('style')
   style.textContent = `${tokensCss}\n${featuresCss}\n${calloutsCss}\n${headingsCss}\n${props.css ?? getCommunityThemePreviewCss(props.themeId)}\nhtml { height:100% !important; overflow-y:auto !important; overflow-x:hidden !important; overscroll-behavior:contain; } body { height:auto !important; min-height:100%; overflow:visible !important; margin:0; padding:24px; background:var(--color-background-primary); color:var(--color-text-primary); font:16px/1.6 system-ui; } article { min-width:0; } .theme-specimen { display:grid; gap:16px; margin-top:20px; } .surface-nested { padding:12px; border:1px solid var(--color-border-default); border-radius:var(--radius-md); } .specimen-markdown { overflow:auto; } .specimen-markdown code { background:var(--color-code-background, var(--color-background-secondary)); color:var(--color-code-text, var(--color-text-primary)); padding:3px 6px; border-radius:4px; } .specimen-markdown pre { padding:12px; background:var(--color-background-secondary); } .specimen-markdown blockquote { border-left:3px solid var(--color-accent-primary); padding-left:12px; } .specimen-markdown table { width:100%; border-collapse:collapse; } .specimen-markdown td,.specimen-markdown th { padding:8px; border:1px solid var(--color-border-default); } .specimen-markdown th { background:var(--color-markdown-table-header); } .specimen-chart > div { display:flex; align-items:flex-end; gap:12px; height:100px; border-bottom:1px solid var(--color-border-default); } .specimen-chart span { width:36px; } .specimen-long { overflow-wrap:anywhere; } @media(max-width:480px) { body { padding:12px; } .form-grid { grid-template-columns:minmax(0,1fr); } }`
 
+  style.textContent += `\n${markdownBehaviorCss}\n.specimen-scroll { position:relative; min-height:110px; }`
   doc.head.append(style)
   const article = doc.createElement('article')
   article.className = 'panel'
diff --git a/frontend/src/features/themes/ThemesView.spec.ts b/frontend/src/features/themes/ThemesView.spec.ts
index 162e86e..59f4fed 100644
--- a/frontend/src/features/themes/ThemesView.spec.ts
+++ b/frontend/src/features/themes/ThemesView.spec.ts
@@ -105,6 +105,6 @@ it('offers and applies the paper theme update without discarding the active them
   const card = wrapper.findAll('article.theme-card').find(item => item.text().includes('Paper Moments'))!
   await card.findAll('button').find(button => button.text() === '更新')!.trigger('click')
   await flushPromises()
-  expect(store.allThemes.find(theme => theme.theme_id === 'paper-moments')?.version).toBe('1.8.1')
+  expect(store.allThemes.find(theme => theme.theme_id === 'paper-moments')?.version).toBe('1.9.0')
   expect(document.getElementById('theme-style-paper-moments')!.textContent).toContain('.surface-nested')
 })
diff --git a/frontend/src/features/themes/themeSpecimen.html b/frontend/src/features/themes/themeSpecimen.html
index a5f2805..1062c8d 100644
--- a/frontend/src/features/themes/themeSpecimen.html
+++ b/frontend/src/features/themes/themeSpecimen.html
@@ -20,3 +20,20 @@ console.log(note);</code></pre><table><thead><tr><th>名称</th><th>状态</th><
 
 <section class="surface-nested markdown-preferences"><h2>Markdown 语法预设</h2><label>标题样式 <select class="select"><option>ATX (#)</option><option>Setext</option></select></label><label><input type="checkbox" checked> 警告框与提示框</label><button class="button-secondary">保存为预设</button></section>
 <section class="milkdown"><div class="ProseMirror"><h2><button class="heading-fold-toggle" aria-expanded="true" aria-label="折叠示例标题"></button>悬停查看折叠箭头</h2><p>折叠按钮跟随主题，键盘聚焦时也可见。</p></div></section>
+<section class="markdown-content specimen-markdown">
+  <h2>Markdown 行为与状态</h2>
+  <h4>四级标题</h4><h5>五级标题</h5><h6>六级标题</h6>
+  <p><a href="#markdown-preview-target">链接：检查悬停与键盘焦点</a>，<code>行内代码</code>与<strong>强调</strong>、<em>斜体</em>、<del>删除线</del>。选中这段文字检查主题选区颜色。</p>
+  <ul><li>无序列表<ul><li>嵌套列表</li></ul></li></ul><ol><li>有序列表</li><li>第二项</li></ol>
+  <ul><li class="task-list-item"><input type="checkbox" disabled> 未完成任务</li><li class="task-list-item"><input type="checkbox" checked disabled> 已完成任务</li></ul>
+  <blockquote><p>普通引用</p><blockquote>嵌套引用</blockquote></blockquote><hr>
+  <details class="markdown-callout" data-callout="tip"><summary class="callout-title">点击展开提示</summary><div class="callout-body"><p>提示内的 <code>代码</code> 与列表也继承主题。</p></div></details>
+  <p id="markdown-preview-target">ATX 和 Setext 解析后使用相同标题样式；关闭扩展语法时保留源码展示。</p>
+  <pre><code>&gt; [!NOTE]
+关闭警告框扩展时显示原始内容
+```mermaid
+graph LR; A--&gt;B
+```</code></pre>
+</section>
+<section class="surface-nested specimen-scroll"><p>工作区滚动按钮：悬停、按下或 Tab 聚焦检查配色。</p><div class="editor-scroll-buttons"><button class="button-secondary" aria-label="滑动到顶部" title="滑动到顶部">↑</button><button class="button-secondary" aria-label="滑动到底部" title="滑动到底部">↓</button></div></section>
+<section class="markdown-content specimen-markdown" data-code-wrap="true" data-line-numbers="true"><h3>代码换行与行号</h3><pre class="shiki"><code><span class="line">const description = "这是一段用于检查代码自动换行、行号与主题配色的较长说明，较窄视口下也应该保留可读内容。";</span><span class="line">console.log(description);</span></code></pre></section>
diff --git a/frontend/src/main.ts b/frontend/src/main.ts
index f67f339..a8fb329 100644
--- a/frontend/src/main.ts
+++ b/frontend/src/main.ts
@@ -4,6 +4,7 @@ import App from './App.vue'
 import router from './router'
 import './styles/tokens.css'
 import './styles/features.css'
+import './styles/markdown-behavior.css'
 import { useThemeStore } from './stores/theme'
 import { useSettingsStore } from './stores/settings'
 import { watch } from 'vue'
diff --git a/frontend/src/services/themePackageService.ts b/frontend/src/services/themePackageService.ts
index faf6424..3f2a031 100644
--- a/frontend/src/services/themePackageService.ts
+++ b/frontend/src/services/themePackageService.ts
@@ -361,7 +361,7 @@ export const mockCommunityThemes: ThemeManifest[] = [
   {
     theme_id: 'ocean-blue',
     name: 'Ocean Blue',
-    version: '1.5.0',
+    version: '1.6.0',
     author: 'community',
     description: '宁静的海洋蓝色主题，适合长时间阅读',
     min_app_version: '0.2.0',
@@ -373,7 +373,7 @@ export const mockCommunityThemes: ThemeManifest[] = [
   {
     theme_id: 'midnight-purple',
     name: 'Midnight Purple',
-    version: '2.3.0',
+    version: '2.4.0',
     author: 'night-owl',
     description: '深紫色暗夜主题，适合编码',
     min_app_version: '0.2.0',
@@ -464,6 +464,9 @@ export function getCommunityThemePreviewCss(themeId: string): string {
   return buildCommunityThemeCss(themeId, t.is_dark) + `
 [data-theme="${themeId}"] {
   color-scheme: ${t.is_dark ? 'dark' : 'light'};
+  --color-markdown-selection: ${t.is_dark ? '#443252' : '#d4eaf5'};
+  --color-editor-scroll-background: var(--color-surface-elevated);
+  --color-editor-scroll-text: var(--color-accent-primary);
   --color-callout-info: ${t.is_dark ? '#9dbbff' : '#126589'};
   --color-callout-success: ${t.is_dark ? '#a7d58c' : '#267049'};
   --color-callout-warning: ${t.is_dark ? '#efc886' : '#885c13'};
diff --git a/frontend/src/stores/theme.ts b/frontend/src/stores/theme.ts
index f49bc3c..9fb1756 100644
--- a/frontend/src/stores/theme.ts
+++ b/frontend/src/stores/theme.ts
@@ -6,9 +6,9 @@ import * as themePkg from '@/services/themePackageService'
 import { t } from '@/i18n'
 
 const builtinThemes = (): ThemeConfig[] => [
-  { theme_id: 'light', name: t('浅色', 'Light'), version: '1.3.0', description: t('默认浅色主题', 'Default light theme'), is_dark: false, builtin: true, code_theme: 'github-light' },
-  { theme_id: 'dark', name: t('深色', 'Dark'), version: '1.3.0', description: t('默认深色主题', 'Default dark theme'), is_dark: true, builtin: true, code_theme: 'github-dark' },
-  { theme_id: 'sepia', name: t('护眼', 'Sepia'), version: '1.3.0', description: t('护眼暖色调', 'Warm, low-glare theme'), is_dark: false, builtin: true, code_theme: 'github-light' },
+  { theme_id: 'light', name: t('浅色', 'Light'), version: '1.4.0', description: t('默认浅色主题', 'Default light theme'), is_dark: false, builtin: true, code_theme: 'github-light' },
+  { theme_id: 'dark', name: t('深色', 'Dark'), version: '1.4.0', description: t('默认深色主题', 'Default dark theme'), is_dark: true, builtin: true, code_theme: 'github-dark' },
+  { theme_id: 'sepia', name: t('护眼', 'Sepia'), version: '1.4.0', description: t('护眼暖色调', 'Warm, low-glare theme'), is_dark: false, builtin: true, code_theme: 'github-light' },
 ]
 
 export type CodeBlockThemePreference = 'auto' | 'github-light' | 'github-dark'
diff --git a/frontend/src/styles/markdown-behavior.css b/frontend/src/styles/markdown-behavior.css
new file mode 100644
index 0000000..93c4454
--- /dev/null
+++ b/frontend/src/styles/markdown-behavior.css
@@ -0,0 +1,34 @@
+/* Shared interaction layer: colors follow the active theme; syntax preferences
+   continue to be handled by the parser/editor rather than CSS-generated content. */
+:is(.markdown-content, .milkdown .ProseMirror) a:not(.callout-title) {
+  color: var(--color-text-link); text-decoration: underline; text-underline-offset: .18em;
+  text-decoration-color: color-mix(in srgb, currentColor 45%, transparent);
+}
+:is(.markdown-content, .milkdown .ProseMirror) a:hover { text-decoration-color: currentColor; }
+:is(.markdown-content, .milkdown .ProseMirror) a:focus-visible { outline: 2px solid var(--color-border-focus); outline-offset: 3px; border-radius: var(--radius-sm); }
+:is(.markdown-content, .milkdown .ProseMirror) input[type='checkbox'] { accent-color: var(--color-accent-primary); }
+:is(.markdown-content, .milkdown .ProseMirror) input[type='checkbox']:disabled { opacity: 1; }
+.markdown-content .task-list-item { list-style: none; }
+:is(.markdown-content, .milkdown .ProseMirror) blockquote:not(.markdown-callout) { border-inline-start: 3px solid var(--color-markdown-marker); color: var(--color-text-secondary); }
+:is(.markdown-content, .milkdown .ProseMirror) hr { border: 0; border-top: 1px solid var(--color-markdown-grid); }
+:is(.markdown-content, .milkdown .ProseMirror) :is(h1,h2,h3,h4,h5,h6) { scroll-margin-top: 16px; }
+:is(.markdown-content, .milkdown .ProseMirror) :is(p,li,h1,h2,h3,h4,h5,h6,code)::selection,
+.editor-pane.source::selection { background: var(--color-markdown-selection); color: var(--color-text-primary); }
+.milkdown .ProseMirror .selectedCell::after { background: color-mix(in srgb, var(--color-accent-primary) 18%, transparent); pointer-events: none; }
+.milkdown .ProseMirror .heading-fold-toggle[aria-expanded='false'] { color: var(--color-accent-primary); background: var(--color-accent-soft); }
+.markdown-callout[data-collapsed='true'] { border-style: dashed; border-inline-start-style: solid; }
+.markdown-content details.markdown-callout:not([open]) { border-style: dashed; border-inline-start-style: solid; }
+.editor-pane.source { caret-color: var(--color-accent-primary); }
+.markdown-content .shiki code { display: block; min-width: max-content; padding: 0; background: transparent; font: inherit; }
+.markdown-content .shiki .line { display: block; min-height: 1.45em; }
+.markdown-content[data-code-wrap] .shiki { tab-size: var(--markdown-code-indent, 4); }
+.markdown-content[data-code-wrap='true'] .shiki code { min-width: 0; white-space: pre-wrap; overflow-wrap: anywhere; }
+.markdown-content[data-line-numbers='true'] .shiki code { counter-reset: code-line; }
+.markdown-content[data-line-numbers='true'] .shiki .line { position: relative; padding-inline-start: 3.5em; }
+.markdown-content[data-line-numbers='true'] .shiki .line::before { counter-increment: code-line; content: counter(code-line); position: absolute; inset-inline-start: 0; width: 2.5em; text-align: end; color: var(--color-code-muted); user-select: none; }
+:is(.milkdown-host, .editor-pane.source) { scrollbar-color: var(--color-border-default) var(--color-background-primary); }
+.editor-scroll-buttons { position: absolute; right: 24px; bottom: 24px; z-index: 10; display: flex; flex-direction: column; gap: 8px; }
+.editor-scroll-buttons button { display: inline-flex; align-items: center; justify-content: center; width: 38px; height: 38px; min-height: 38px; padding: 0; border-radius: var(--radius-md); background: var(--color-editor-scroll-background); color: var(--color-editor-scroll-text); border: 1px solid var(--color-border-default); box-shadow: var(--shadow-sm); }
+.editor-scroll-buttons button:hover { background: var(--color-background-hover); border-color: var(--color-accent-primary); }
+.editor-scroll-buttons button:active { background: var(--color-accent-soft); }
+.editor-scroll-buttons button:focus-visible { outline: 2px solid var(--color-border-focus); outline-offset: 2px; }
diff --git a/frontend/src/styles/tokens.css b/frontend/src/styles/tokens.css
index 47b4648..5dee836 100644
--- a/frontend/src/styles/tokens.css
+++ b/frontend/src/styles/tokens.css
@@ -1,4 +1,7 @@
 :root {
+  --color-markdown-selection: color-mix(in srgb, var(--color-accent-primary) 24%, var(--color-background-primary));
+  --color-editor-scroll-background: var(--color-surface-elevated);
+  --color-editor-scroll-text: var(--color-accent-primary);
   /* Callout heading colors also serve as borders; keep text readable on tint. */
   --color-callout-info: var(--color-info);
   --color-callout-success: var(--color-success);