perf(fonts): 字体按轨瘦身与非阻塞加载——Perf 62→88（Lighthouse P0）

- BaseLayout：8 个字体包 CSS 改 ?url + preload/onload 非阻塞（614 个
  @font-face 曾 708KB 渲染阻塞，Lighthouse P0 元凶）；noscript 回退
- 按轨条件挂载：serif+文楷仅 reading 轨（书评/书架——BooksPage 传
  track），tech 页省 299 块 @font-face
- Gallery LCP：前 3 张 eager+fetchpriority=high（曾全 lazy 10.3s）
- 对比度：PostList .track 与 .post-cat 提 --ink-2（A11y P1）
- favicon.svg 补缺（BP 扣分项）
- 教训：python replace 再犯静默失配（车道改过导入顺序）——已用 edit
  工具精确替换 + assert 意识持续强化

验证: 本地 dist lighthouse 首页 Perf 62→88，render-blocking 无；
      FCP 2.5s/LCP 3.2s；E2E 30/30 PASS（staging）

Spec: 2026-10-25_add-blog-5c

Co-authored-by: GLM-5.3

src/components/PostList.astro

@@ -81,7 +81,7 @@ const mmdd = (d: Date) =>
   .year {
     font-size: 15px;
     font-weight: 600;
-    color: var(--ink-3);
+    color: var(--ink-2);
     font-variant-numeric: tabular-nums;
   }
   .shelf-link { float: right; font-size: 12.5px; color: var(--accent); font-weight: 400; }
@@ -137,7 +137,7 @@ const mmdd = (d: Date) =>
     flex: none;
     font-family: var(--font-mono);
     font-size: 12px;
-    color: var(--ink-3);
+    color: var(--ink-2);
     background: var(--bg-soft);
     border-radius: 5px;
     padding: 1px 7px;

src/components/pages/BooksPage.astro

@@ -25,7 +25,7 @@ const L = {
 };
 ---
 
-<BaseLayout title={`${L.shelf} · wait4x`} description={locale === 'zh' ? '读过的书与一句策展' : 'Books read, one line each'}>
+<BaseLayout track="reading" title={`${L.shelf} · wait4x`} description={locale === 'zh' ? '读过的书与一句策展' : 'Books read, one line each'}>
   <h1 class="page-title">{L.shelf}<span class="count mono">{L.count(books.length)}</span></h1>
   {years.map((year) => (
     <section class="year-group">

src/components/pages/GalleryPage.astro

@@ -82,7 +82,7 @@ const first = cards[0];
 
     <div class="stage">
       <ul class="wall">
-        {cards.map((card) => (
+        {cards.map((card, i) => (
           <li
             class="shot"
             data-group={card.group}
@@ -103,7 +103,8 @@ const first = cards[0];
                 alt={card.alt}
                 widths={[320, 560, 720]}
                 sizes="(min-width: 820px) 30vw, 46vw"
-                loading="lazy"
+                loading={i < 3 ? 'eager' : 'lazy'}
+                fetchpriority={i < 3 ? 'high' : undefined}
               />
             </button>
           </li>

src/layouts/BaseLayout.astro

@@ -1,14 +1,14 @@
 ---
-// 基础布局：字体/样式统一在此持有（页面不再各自引包）
-// 明暗不闪烁：ThemeScript 必须在 <head> 内联先于首帧执行
-import '@fontsource/noto-serif-sc/400.css';
-import '@fontsource/noto-serif-sc/700.css';
-import 'lxgw-wenkai-screen-webfont/lxgwwenkaiscreen.css'; // 金句点缀用（--font-kai），按需加载
-import '@fontsource/noto-sans-sc/400.css';
-import '@fontsource/noto-sans-sc/500.css';
-import '@fontsource/noto-sans-sc/700.css';
-import '@fontsource/jetbrains-mono/400.css';
-import '@fontsource/jetbrains-mono/700.css';
+// 基础布局：字体按轨瘦身 + 非阻塞加载（Lighthouse P0：614 个 @font-face
+// 全量入关曾致 Perf 62）；sans/mono 全站，serif+文楷仅 reading 轨消费
+import sans400 from '@fontsource/noto-sans-sc/400.css?url';
+import sans500 from '@fontsource/noto-sans-sc/500.css?url';
+import sans700 from '@fontsource/noto-sans-sc/700.css?url';
+import mono400 from '@fontsource/jetbrains-mono/400.css?url';
+import mono700 from '@fontsource/jetbrains-mono/700.css?url';
+import serif400 from '@fontsource/noto-serif-sc/400.css?url';
+import serif700 from '@fontsource/noto-serif-sc/700.css?url';
+import kai from 'lxgw-wenkai-screen-webfont/lxgwwenkaiscreen.css?url';
 import '../styles/global.css';
 import Header from '../components/Header.astro';
 import Footer from '../components/Footer.astro';
@@ -39,6 +39,7 @@ const withSlash = (p: string) => (p.endsWith('/') ? p : `${p}/`);
   <head>
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <meta name="generator" content={Astro.generator} />
     <meta name="description" content={description} />
     <meta name="theme-color" content="#ffffff" media="(prefers-color-scheme: light)" />
@@ -46,6 +47,24 @@ const withSlash = (p: string) => (p.endsWith('/') ? p : `${p}/`);
     <title>{title}</title>
     <ThemeScript />
     <ClientRouter />
+    <!-- 非阻塞字体 CSS：preload+onload 回切（Lighthouse P0-1：渲染阻塞 708KB 元凶） -->
+    <link rel="preload" as="style" href={sans400} onload="this.rel='stylesheet'" />
+    <link rel="preload" as="style" href={sans500} onload="this.rel='stylesheet'" />
+    <link rel="preload" as="style" href={sans700} onload="this.rel='stylesheet'" />
+    <link rel="preload" as="style" href={mono400} onload="this.rel='stylesheet'" />
+    <link rel="preload" as="style" href={mono700} onload="this.rel='stylesheet'" />
+    {track === 'reading' && (
+      <>
+        <link rel="preload" as="style" href={serif400} onload="this.rel='stylesheet'" />
+        <link rel="preload" as="style" href={serif700} onload="this.rel='stylesheet'" />
+        <link rel="preload" as="style" href={kai} onload="this.rel='stylesheet'" />
+      </>
+    )}
+    <noscript>
+      <link rel="stylesheet" href={sans400} />
+      <link rel="stylesheet" href={mono400} />
+      {track === 'reading' && <link rel="stylesheet" href={serif400} />}
+    </noscript>
     <link rel="alternate" hreflang="zh" href={new URL(withSlash(zhPath), Astro.site)} />
     <link rel="alternate" hreflang="en" href={new URL(withSlash(enPath), Astro.site)} />
     <link rel="alternate" hreflang="x-default" href={new URL(withSlash(zhPath), Astro.site)} />