/* =========================================================================
   Vibe Coding 小程序全书 — Neutral 极简设计系统（参考 awesome-open-assets 视觉语言）
   纯白底 · neutral-200 细边框 · rounded-2xl · 轻阴影 · 零渐变零光效
   顶栏：白底 90% + 轻 backdrop-blur + 1px 底边
   ========================================================================= */

/* ---------- 设计 Token ---------- */
:root {
  --font: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  /* 中性色板（浅色） */
  --bg: #ffffff;
  --card: #ffffff;
  --border: #e5e5e5;
  --border-strong: #d4d4d4;
  --hover: #f5f5f5;
  --text: #0a0a0a;
  --text-soft: #525252;
  --text-faint: #737373;
  --text-ghost: #a3a3a3;

  /* 语义色 */
  --accent: #0a0a0a;
  --accent-contrast: #ffffff;
  --mark: #fef08a;

  --shadow: 0 1px 0 rgba(15, 23, 42, .04);
  --shadow-hover: 0 18px 45px rgba(15, 23, 42, .10);

  --r-lg: 22px;
  --r-md: 16px;
  --r-sm: 10px;
  --maxw: 1240px;
  --nav-h: 56px;
  color-scheme: light;
}

[data-theme="dark"] {
  --bg: #0a0a0a;
  --card: #171717;
  --border: #262626;
  --border-strong: #404040;
  --hover: #262626;
  --text: #fafafa;
  --text-soft: #a3a3a3;
  --text-faint: #737373;
  --text-ghost: #525252;

  --accent: #fafafa;
  --accent-contrast: #0a0a0a;
  --mark: #854d0e;

  --shadow: 0 1px 0 rgba(0, 0, 0, .3);
  --shadow-hover: 0 18px 45px rgba(0, 0, 0, .5);
  color-scheme: dark;
}

/* ---------- 基础 ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  background: var(--bg);
  overflow-x: hidden;
  transition: background .3s ease, color .3s ease;
}

a { color: inherit; text-decoration: none; }
::selection { background: var(--mark); }

::-webkit-scrollbar { width: 10px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 99px;
  border: 2px solid transparent;
  background-clip: content-box;
}
::-webkit-scrollbar-thumb:hover { background: var(--text-ghost); background-clip: content-box; }

.ic { width: 18px; height: 18px; flex: 0 0 auto; display: inline-block; vertical-align: -3px; }
.ic-sm { width: 14px; height: 14px; }

/* ---------- 顶部导航 ---------- */
.nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg) 90%, transparent);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--maxw);
  height: var(--nav-h);
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; min-width: 0; }
.brand-logo { display: block; width: 28px; height: 28px; flex: 0 0 auto; }
.brand-name { font-size: 15px; letter-spacing: -.02em; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.brand-accent { color: var(--text-faint); font-weight: 600; }
.nav-actions { display: flex; align-items: center; gap: 8px; }

/* 搜索框 */
.search-wrap { position: relative; flex: 1; max-width: 380px; }
.search-box {
  display: flex; align-items: center; gap: 8px;
  height: 36px; padding: 0 14px;
  border: 1px solid var(--border); border-radius: 99px;
  background: var(--card); color: var(--text-faint);
  transition: border-color .15s ease;
}
.search-box:focus-within { border-color: var(--border-strong); color: var(--text-soft); }
.search-box input {
  border: 0; outline: 0; background: transparent; color: var(--text);
  font: 14px var(--font); width: 100%;
}
.search-box input::placeholder { color: var(--text-ghost); }
.search-box kbd {
  font: 11px var(--mono); color: var(--text-ghost);
  border: 1px solid var(--border); border-radius: 6px; padding: 1px 5px;
}

/* 搜索结果下拉 */
.search-results {
  position: absolute; top: calc(100% + 8px); left: 0; right: 0;
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--r-md); box-shadow: var(--shadow-hover);
  max-height: 60vh; overflow-y: auto; display: none;
}
.search-results.open { display: block; }
.search-results .sr-item {
  display: block; padding: 10px 14px; border-bottom: 1px solid var(--border);
}
.search-results .sr-item:last-child { border-bottom: 0; }
.search-results .sr-item:hover { background: var(--hover); }
.search-results .sr-chapter { font-size: 12px; color: var(--text-faint); }
.search-results .sr-snippet { font-size: 13.5px; color: var(--text); margin-top: 2px; }
.search-results .sr-snippet mark { background: var(--mark); color: inherit; border-radius: 3px; }
.search-results .sr-empty { padding: 16px; text-align: center; color: var(--text-faint); font-size: 13.5px; }

/* 图标按钮 */
.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--card); color: var(--text-soft);
  cursor: pointer; transition: border-color .15s ease, color .15s ease;
}
.icon-btn:hover { border-color: var(--border-strong); color: var(--text); }
.nav-hamburger { display: none; }

/* ---------- 布局 ---------- */
.layout {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: calc(var(--nav-h) + 24px) 20px 0;
  display: grid;
  grid-template-columns: 232px minmax(0, 1fr);
  gap: 40px;
  align-items: start;
}

/* ---------- 侧边栏目录 ---------- */
.toc {
  position: sticky; top: calc(var(--nav-h) + 24px);
  max-height: calc(100vh - var(--nav-h) - 48px);
  overflow-y: auto;
  padding: 8px 0;
}
.toc-title {
  font-size: 12px; font-weight: 600; color: var(--text-faint);
  text-transform: uppercase; letter-spacing: .08em;
  padding: 0 12px 8px;
}
.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-list a {
  display: block; padding: 7px 12px; margin: 1px 0;
  border-radius: var(--r-sm); font-size: 14px; color: var(--text-soft);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  transition: background .15s ease, color .15s ease;
}
.toc-list a:hover { background: var(--hover); color: var(--text); }
.toc-list a.active { background: var(--accent); color: var(--accent-contrast); font-weight: 600; }

/* ---------- 英雄区（仅首页） ---------- */
.hero { padding: 40px 0 8px; }
.hero h1 {
  font-size: clamp(28px, 4.5vw, 44px);
  line-height: 1.2; letter-spacing: -.03em;
  margin: 0 0 12px;
}
.hero .hero-sub { font-size: 17px; color: var(--text-soft); margin: 0 0 20px; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 24px; }
.hero-meta span {
  font-size: 12.5px; color: var(--text-soft);
  border: 1px solid var(--border); border-radius: 99px; padding: 3px 12px;
}
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  height: 42px; padding: 0 20px; border-radius: 99px;
  font-size: 14.5px; font-weight: 600; cursor: pointer;
  border: 1px solid var(--border); background: var(--card); color: var(--text);
  transition: border-color .15s ease, box-shadow .15s ease;
}
.btn:hover { border-color: var(--border-strong); box-shadow: var(--shadow); }
.btn-primary { background: var(--accent); color: var(--accent-contrast); border-color: var(--accent); }
.btn-primary:hover { opacity: .92; }

/* ---------- 正文排版 ---------- */
.article { min-width: 0; padding-bottom: 64px; }
.chapter-head { margin-bottom: 24px; }
.chapter-kicker { font-size: 12.5px; color: var(--text-faint); letter-spacing: .06em; }
.chapter-head h1 { font-size: clamp(24px, 3.4vw, 34px); line-height: 1.3; letter-spacing: -.02em; margin: 4px 0 0; }

.prose { font-size: 16px; }
.prose h2 {
  font-size: 22px; letter-spacing: -.01em;
  margin: 48px 0 16px; padding-top: 8px;
  border-top: 1px solid var(--border);
}
.prose h3 { font-size: 17.5px; margin: 32px 0 12px; }
.prose h4 { font-size: 15.5px; margin: 24px 0 8px; }
.prose p { margin: 14px 0; }
.prose ul, .prose ol { margin: 12px 0; padding-left: 24px; }
.prose li { margin: 6px 0; }
.prose li > ul, .prose li > ol { margin: 4px 0; }
.prose a { color: var(--text); text-decoration: underline; text-decoration-color: var(--border-strong); text-underline-offset: 3px; }
.prose a:hover { text-decoration-color: var(--text); }
.prose strong { font-weight: 650; }
.prose hr { border: 0; border-top: 1px solid var(--border); margin: 36px 0; }

/* 代码 */
.prose code {
  font: .875em var(--mono);
  background: var(--hover); border: 1px solid var(--border);
  border-radius: 6px; padding: .12em .38em;
  word-break: break-all;
}
.prose pre {
  background: var(--hover); border: 1px solid var(--border);
  border-radius: var(--r-md); padding: 16px 18px;
  overflow-x: auto; margin: 18px 0;
}
.prose pre code { background: none; border: 0; padding: 0; font-size: 13px; line-height: 1.7; word-break: normal; }

/* 引用块（提示框） */
.prose blockquote {
  margin: 18px 0; padding: 14px 18px;
  background: var(--hover); border: 1px solid var(--border);
  border-left: 3px solid var(--text-faint);
  border-radius: 0 var(--r-md) var(--r-md) 0;
  color: var(--text-soft);
}
.prose blockquote p { margin: 6px 0; }
.prose blockquote > :first-child { margin-top: 0; }
.prose blockquote > :last-child { margin-bottom: 0; }

/* 表格 */
.prose table {
  width: 100%; border-collapse: collapse; margin: 18px 0;
  font-size: 14px; display: block; overflow-x: auto;
}
.prose th, .prose td {
  border: 1px solid var(--border); padding: 8px 12px;
  text-align: left; vertical-align: top;
}
.prose th { background: var(--hover); font-weight: 650; white-space: nowrap; }
.prose tbody tr:nth-child(even) { background: color-mix(in srgb, var(--hover) 45%, transparent); }

/* 任务清单 */
.prose input[type="checkbox"] { margin-right: 6px; vertical-align: -1px; }

/* 本章目录 */
.chapter-toc {
  border: 1px solid var(--border); border-radius: var(--r-md);
  padding: 14px 18px; margin: 0 0 28px;
  background: var(--card); box-shadow: var(--shadow);
}
.chapter-toc summary {
  cursor: pointer; font-size: 13px; font-weight: 600; color: var(--text-soft);
  list-style: none; user-select: none;
}
.chapter-toc summary::-webkit-details-marker { display: none; }
.chapter-toc summary::before { content: "▸ "; color: var(--text-faint); }
.chapter-toc[open] summary::before { content: "▾ "; }
.chapter-toc ul { margin: 10px 0 0; padding-left: 20px; }
.chapter-toc li { font-size: 13.5px; margin: 4px 0; }
.chapter-toc a { color: var(--text-soft); }
.chapter-toc a:hover { color: var(--text); text-decoration: underline; }

/* 上下章导航 */
.chapter-nav {
  display: grid; grid-template-columns: 1fr 1fr; gap: 12px;
  margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--border);
}
.chapter-nav a {
  border: 1px solid var(--border); border-radius: var(--r-md);
  padding: 12px 16px; transition: border-color .15s ease, box-shadow .15s ease;
}
.chapter-nav a:hover { border-color: var(--border-strong); box-shadow: var(--shadow); }
.chapter-nav .cn-dir { font-size: 12px; color: var(--text-faint); }
.chapter-nav .cn-title { font-size: 14px; font-weight: 600; margin-top: 2px; }
.chapter-nav .cn-next { text-align: right; }

/* ---------- 页脚 ---------- */
.footer {
  border-top: 1px solid var(--border);
  padding: 28px 20px; margin-top: 24px;
}
.footer-inner {
  max-width: var(--maxw); margin: 0 auto;
  display: flex; flex-wrap: wrap; gap: 8px 20px;
  align-items: center; justify-content: space-between;
  font-size: 13px; color: var(--text-faint);
}
.footer a { color: var(--text-soft); }
.footer a:hover { color: var(--text); text-decoration: underline; }

/* 回到顶部 */
.back-top {
  position: fixed; right: 24px; bottom: 24px; z-index: 90;
  width: 40px; height: 40px; border-radius: 50%;
  border: 1px solid var(--border); background: var(--card); color: var(--text-soft);
  display: none; align-items: center; justify-content: center;
  cursor: pointer; box-shadow: var(--shadow);
}
.back-top.show { display: inline-flex; }
.back-top:hover { border-color: var(--border-strong); color: var(--text); }

/* 侧栏遮罩（移动端） */
.toc-mask {
  position: fixed; inset: 0; z-index: 110;
  background: rgba(0, 0, 0, .4); display: none;
}
.toc-mask.open { display: block; }

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .layout { grid-template-columns: 1fr; gap: 0; }
  .toc {
    position: fixed; top: var(--nav-h); left: 0; bottom: 0;
    width: 264px; z-index: 120;
    background: var(--bg); border-right: 1px solid var(--border);
    padding: 16px 12px; max-height: none;
    transform: translateX(-100%); transition: transform .25s ease;
  }
  .toc.open { transform: translateX(0); }
  .nav-hamburger { display: inline-flex; }
  .search-wrap { max-width: none; }
  .search-wrap kbd { display: none; }
}
@media (max-width: 560px) {
  .brand-name { display: none; }
  .chapter-nav { grid-template-columns: 1fr; }
  .hero { padding: 24px 0 4px; }
}