流体交互层：按压反馈 + 真半透明材质 + 主题交叉过渡 + 弹层材质化

按 apple-design（Designing Fluid Interfaces）审查落地：
- 全站补 :active 按压缩放反馈（按钮/tab/链接/命令面板/前后栏导航），交互元素加 touch-action
- TopBar、首页标题栏、浮动主题钮改 color-mix 半透明 + blur 真材质，配 reduced-transparency 回退
- 主题切换 250ms 交叉过渡（theme-anim 瞬时类），消除亮度突变
- CommandPalette/ShortcutsPanel 过 <Transition name="pop">：scrim 淡入 + 面板自顶部锚点 scale 进入，退出原路返回
- 首页标题栏收缩由二值跳变改为滚动进度 --sq 连续插值（16–56px）
- reduced-motion 例外：弹层保留短交叉淡入，禁位移与主题过渡
- 触控目标增大（主题钮 40/44px、tab、后台导航项），文章大标题负字距 + 收紧行高

frontend/src/admin/AdminLayout.vue

@@ -156,8 +156,12 @@ watch(() => route.path, () => loadCounts())
       </main>
     </div>
 
-    <CommandPalette v-if="paletteOpen" @close="paletteOpen = false" />
-    <ShortcutsPanel v-if="shortcutsOpen" @close="shortcutsOpen = false" />
+    <Transition name="pop">
+      <CommandPalette v-if="paletteOpen" @close="paletteOpen = false" />
+    </Transition>
+    <Transition name="pop">
+      <ShortcutsPanel v-if="shortcutsOpen" @close="shortcutsOpen = false" />
+    </Transition>
   </div>
   <div v-else class="checking">检查登录状态…</div>
 </template>

frontend/src/components/ThemeSwitcher.vue

@@ -58,7 +58,12 @@ const classes = computed(() => ['theme-switcher', `theme-switcher--${props.varia
   font-family: inherit;
   line-height: 1;
   padding: 0;
-  transition: color 0.15s ease, background-color 0.15s ease, border-color 0.15s ease;
+  touch-action: manipulation;
+  transition:
+    color 0.15s ease,
+    background-color 0.15s ease,
+    border-color 0.15s ease,
+    transform 100ms ease-out;
 }
 
 .theme-switcher:hover {
@@ -67,6 +72,11 @@ const classes = computed(() => ['theme-switcher', `theme-switcher--${props.varia
   border-color: var(--admin-accent-line);
 }
 
+/* 按下瞬间就有反馈 */
+.theme-switcher:active {
+  transform: scale(0.92);
+}
+
 .theme-switcher .ic {
   font-size: 19px;
   line-height: 1;
@@ -75,8 +85,8 @@ const classes = computed(() => ['theme-switcher', `theme-switcher--${props.varia
 /* ---------- inline 形态：嵌入左栏底部 ---------- */
 
 .theme-switcher--inline {
-  width: 36px;
-  height: 36px;
+  width: 40px;
+  height: 40px;
 }
 
 /* ---------- floating 形态：右下角浮动 ---------- */
@@ -86,18 +96,24 @@ const classes = computed(() => ['theme-switcher', `theme-switcher--${props.varia
   right: 18px;
   bottom: 18px;
   z-index: 100;
-  width: 42px;
-  height: 42px;
-  backdrop-filter: blur(6px);
+  width: 44px;
+  height: 44px;
+  background: color-mix(in srgb, var(--admin-card) 78%, transparent);
+  backdrop-filter: blur(16px) saturate(180%);
   box-shadow: var(--admin-shadow);
 }
 
+@media (prefers-reduced-transparency: reduce) {
+  .theme-switcher--floating {
+    background: var(--admin-card);
+    backdrop-filter: none;
+  }
+}
+
 @media (max-width: 480px) {
   .theme-switcher--floating {
     right: 12px;
     bottom: 12px;
-    width: 38px;
-    height: 38px;
   }
 }
 </style>

frontend/src/components/TopBar.vue

@@ -29,11 +29,18 @@ import { site } from '../site'
     top: 0;
     z-index: 20;
     padding: 10px 18px;
-    background-color: var(--paper);
-    backdrop-filter: blur(6px);
+    background: color-mix(in srgb, var(--paper) 80%, transparent);
+    backdrop-filter: blur(10px) saturate(160%);
     border-bottom: 1px solid var(--line);
   }
 
+  @media (prefers-reduced-transparency: reduce) {
+    .topbar {
+      background: var(--paper);
+      backdrop-filter: none;
+    }
+  }
+
   .brand {
     font-family: var(--serif);
     font-size: 17px;

frontend/src/site.js

@@ -64,7 +64,13 @@ export const site = reactive({
 
 // data-theme   → 前台皮肤（paper / sage / rose / ink）
 // data-admin-theme → 后台明暗（light / dark），跟 site.themeMode 同步
-function applyTheme() {
+function applyTheme(animate = false) {
+  // 亮度突变是 Apple 明确点名的反模式：用户主动切换时给一次 250ms 交叉过渡
+  if (animate && typeof document !== 'undefined') {
+    const el = document.documentElement
+    el.classList.add('theme-anim')
+    setTimeout(() => el.classList.remove('theme-anim'), 300)
+  }
   const isDark = site.themeMode === 'dark' || (site.themeMode === 'auto' && systemPrefersDark())
   document.documentElement.setAttribute('data-theme', effectiveTheme(site.themeMode, site.light_skin_id))
   document.documentElement.setAttribute('data-admin-theme', isDark ? 'dark' : 'light')
@@ -95,7 +101,7 @@ export async function loadSite() {
   return site
 }
 
-// 访客切模式 → 落 localStorage + 立刻应用
+// 访客切模式 → 落 localStorage + 立刻应用（带交叉过渡）
 watch(
   () => site.themeMode,
   () => {
@@ -104,7 +110,7 @@ watch(
     } catch (_) {
       /* private mode 等场景静默 */
     }
-    applyTheme()
+    applyTheme(true)
   }
 )
 

frontend/src/styles.css

@@ -620,7 +620,7 @@ h4 {
   display: flex;
   align-items: center;
   gap: 10px;
-  padding: 8px 12px;
+  padding: 10px 12px;
   border-radius: 6px;
   font-size: 14px;
   color: var(--admin-ink-soft);
@@ -1825,3 +1825,78 @@ body:not(.admin-shell-active) :where(a, button, input, select, textarea, [tabind
 .cmd-overlay {
   overscroll-behavior: contain;
 }
+
+/* ============================================================
+   流体交互层（apple-design 审查落地）
+   ============================================================ */
+
+/* 按压反馈：从按下瞬间就有反应，而不是 hover 或松手 */
+button:active:not(:disabled),
+a.btn:active,
+a.pill:active,
+.tab:active,
+.tag-chip:active,
+.rail-left .item:active,
+.admin-side .item:active,
+.cmd-panel .row:active {
+  transform: scale(0.97);
+}
+
+/* 触屏：去掉浏览器对双击缩放的猜测延迟 */
+button,
+a.btn,
+a.pill,
+.tab,
+.tag-chip,
+.rail-left .item,
+.admin-side .item {
+  touch-action: manipulation;
+}
+
+/* 主题切换：亮度突变改为一次性的 250ms 交叉过渡（仅切换瞬间挂载） */
+html.theme-anim,
+html.theme-anim * {
+  transition: background-color 250ms ease, color 250ms ease, border-color 250ms ease !important;
+}
+
+/* 弹层材质化：从触发源方向 scale+fade 进入，退出走同一条路径 */
+.cmd-panel {
+  transform-origin: top center;
+}
+.pop-enter-active {
+  transition: opacity 160ms ease-out;
+}
+.pop-enter-active .cmd-panel {
+  transition: transform 240ms cubic-bezier(0.2, 0.8, 0.25, 1), opacity 160ms ease-out;
+}
+.pop-enter-from {
+  opacity: 0;
+}
+.pop-enter-from .cmd-panel {
+  transform: scale(0.96) translateY(-10px);
+  opacity: 0;
+}
+.pop-leave-active {
+  transition: opacity 130ms ease-in;
+}
+.pop-leave-to {
+  opacity: 0;
+}
+
+/* reduce ≠ 无反馈：保留短交叉淡入，去掉位移/缩放与主题过渡 */
+@media (prefers-reduced-motion: reduce) {
+  .pop-enter-active,
+  .pop-leave-active {
+    transition: opacity 150ms ease !important;
+  }
+  .pop-enter-active .cmd-panel {
+    transition: opacity 150ms ease !important;
+  }
+  .pop-enter-from .cmd-panel {
+    transform: none;
+  }
+  html.theme-anim,
+  html.theme-anim * {
+    transition: none !important;
+  }
+}

frontend/src/views/HomeView.vue

@@ -20,10 +20,13 @@ const tag = computed(() => route.query.tag || '')
 const page = computed(() => Number(route.query.page || 1))
 const size = computed(() => site.posts_per_page || 10)
 
-// 滚动时收缩顶部标题栏：隐藏大标题，只留 tabs 贴顶
-const scrolled = ref(false)
+// 滚动收缩标题栏：16–56px 区间内连续插值 --sq（0→1），
+// 反馈跟随滚动本身，而不是在阈值处二值跳变
+const headEl = ref(null)
 function onScroll() {
-  scrolled.value = window.scrollY > 24
+  if (!headEl.value) return
+  const p = Math.min(1, Math.max(0, (window.scrollY - 16) / 40))
+  headEl.value.style.setProperty('--sq', p.toFixed(3))
 }
 onMounted(() => {
   onScroll()
@@ -88,7 +91,7 @@ applyDocTitle('')
       <LeftNav />
 
       <main class="main">
-        <header class="sticky-head" :class="{ 'is-compact': scrolled }">
+        <header ref="headEl" class="sticky-head">
           <h1 class="page-title">{{ heading }}</h1>
           <nav class="tabs">
             <button
@@ -149,14 +152,22 @@ applyDocTitle('')
 }
 
 .sticky-head {
+  --sq: 0;
   position: sticky;
   top: 0;
   z-index: 10;
-  background-color: var(--paper);
-  backdrop-filter: blur(6px);
+  background: color-mix(in srgb, var(--paper) 82%, transparent);
+  backdrop-filter: blur(8px) saturate(160%);
   border-bottom: 1px solid var(--line);
   padding: 8px 16px 0;
-  transition: padding 0.2s ease;
+}
+
+/* 系统要求减少半透明时回退为实心材质 */
+@media (prefers-reduced-transparency: reduce) {
+  .sticky-head {
+    background: var(--paper);
+    backdrop-filter: none;
+  }
 }
 
 .page-title {
@@ -164,40 +175,25 @@ applyDocTitle('')
   font-size: 17px;
   font-weight: 600;
   overflow: hidden;
-  max-height: 26px;
-  opacity: 1;
-  transition:
-    max-height 0.2s ease,
-    opacity 0.2s ease;
+  max-height: calc(26px * (1 - var(--sq)));
+  opacity: calc(1 - var(--sq));
 }
 
 .tabs {
   display: flex;
   gap: 2px;
-  margin-top: 4px;
-  transition: margin-top 0.2s ease;
-}
-
-/* 滚动后：收起大标题，只留 tabs 紧贴顶部 */
-.sticky-head.is-compact {
-  padding-top: 6px;
-}
-.sticky-head.is-compact .page-title {
-  max-height: 0;
-  opacity: 0;
-}
-.sticky-head.is-compact .tabs {
-  margin-top: 0;
+  margin-top: calc(4px * (1 - var(--sq)));
 }
 
 .tab {
   position: relative;
-  padding: 5px 12px 7px;
+  padding: 8px 12px 9px;
   background: none;
   border: 0;
   cursor: pointer;
   font-size: 13.5px;
   color: var(--muted);
+  transition: transform 100ms ease-out;
 }
 
 .tab:hover {

frontend/src/views/PostView.vue

@@ -147,7 +147,9 @@ const initial = computed(() => (site.author_name || 'O').trim().slice(0, 1).toUp
 .title {
   margin: 20px 0 0;
   font-size: 32px;
-  line-height: 1.35;
+  line-height: 1.2;
+  /* 大号衬线标题需要负字距，越紧越像"排"出来的而不是"摆"出来的 */
+  letter-spacing: -0.015em;
 }
 
 .lede {