/* ============================================================
   ANLAN AI · 恒启安澜 — Design Tokens (Single Source of Truth)
   ------------------------------------------------------------
   Stage A 基础设施。所有页面 <link> 这一份。
   合并自：① 首页 index.html 内联 :root  ② 用例库 shell.css :root
   - DARK 为默认值（:root），沿用现有色值，未改动。
   - LIGHT 为 [data-theme="light"] override，只覆盖颜色，结构/字体不变。
   - 默认 dark（现状不变）。Light/Dark 切换由 assets/theme.js + 内联防闪烁脚本驱动。
   ============================================================ */

/* ============================================================
   COLOR + TOKENS — DARK (default)
   现有两套 --color-* 的并集。用例库多出的 amber/green/gold-bg/font-mono 一并纳入。
   值未改动（红线：#D4A574 金 / #000 黑 / #5DDDC8 teal 等不动）。
   ============================================================ */
:root {
  /* Surfaces */
  --color-bg: #000000;
  --color-surface: #0A0A0C;
  --color-surface-elevated: #111114;

  /* Text */
  --color-text: #F0F0F2;
  --color-text-muted: rgba(240, 240, 242, 0.60);
  --color-text-subtle: rgba(240, 240, 242, 0.36);

  /* Borders */
  --color-border: rgba(240, 240, 242, 0.08);
  --color-border-hover: rgba(240, 240, 242, 0.16);

  /* Primary: Warm Gold / Amber */
  --color-gold: #D4A574;
  --color-gold-light: #E8C9A0;
  --color-gold-dark: #B8956A;
  --color-gold-bg: rgba(212, 165, 116, 0.08);

  /* Secondary: Cool Teal */
  --color-teal: #5DDDC8;
  --color-teal-muted: rgba(93, 221, 200, 0.10);

  /* Accent: Indigo for depth */
  --color-indigo: #7B6EF6;
  --color-indigo-muted: rgba(123, 110, 246, 0.10);

  /* Status: Amber (risk) */
  --color-amber: #F59E0B;
  --color-amber-muted: rgba(245, 158, 11, 0.10);

  /* Status: Green (ok) */
  --color-green: #4ade80;
  --color-green-muted: rgba(74, 222, 128, 0.10);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Noto Sans SC', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* Radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  /* Motion */
  --duration-slow: 400ms;
  --duration-normal: 200ms;
  --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================================
   COLOR — LIGHT  米白纸面 + 深字 + 深铜
   只覆盖颜色变量。字体/半径/动效继承 :root。
   起点值取自 design-handoff/.../css/anlan-tokens.css 的 light 调色板，
   并对 muted/subtle 微调以保证正文对比度（WCAG AA on #FBF8F1）。
   ============================================================ */
[data-theme="light"] {
  /* Surfaces */
  --color-bg: #F6F2EA;            /* warm cream paper */
  --color-surface: #FBF8F1;
  --color-surface-elevated: #FFFFFF;

  /* Text — 提高 muted/subtle 不透明度以确保浅底可读 */
  --color-text: #1A1410;
  --color-text-muted: rgba(26, 20, 16, 0.64);
  --color-text-subtle: rgba(26, 20, 16, 0.42);

  /* Borders */
  --color-border: rgba(26, 20, 16, 0.12);
  --color-border-hover: rgba(26, 20, 16, 0.24);

  /* Primary: deeper bronze on light（保证铜色在米白上够深） */
  --color-gold: #8A6A3A;
  --color-gold-light: #B8935A;
  --color-gold-dark: #6E5530;
  --color-gold-bg: rgba(138, 106, 58, 0.08);

  /* Secondary: teal */
  --color-teal: #0F9D8A;
  --color-teal-muted: rgba(15, 157, 138, 0.12);

  /* Accent: indigo */
  --color-indigo: #6D28D9;
  --color-indigo-muted: rgba(109, 40, 217, 0.10);

  /* Status: amber */
  --color-amber: #B45309;
  --color-amber-muted: rgba(180, 83, 9, 0.10);

  /* Status: green */
  --color-green: #3F8F4F;
  --color-green-muted: rgba(63, 143, 79, 0.10);
}

/* ============================================================
   VIEW TRANSITIONS — 跨页面原生淡入淡出（同源导航）
   不引框架。reduced-motion 下关闭动画。
   ============================================================ */
@view-transition {
  navigation: auto;
}

::view-transition-old(root),
::view-transition-new(root) {
  animation-duration: 200ms;
  animation-timing-function: var(--ease-smooth, cubic-bezier(0.4, 0, 0.2, 1));
}
/* 温和 crossfade：旧页淡出、新页淡入 */
::view-transition-old(root) {
  animation-name: anlan-vt-fade-out;
}
::view-transition-new(root) {
  animation-name: anlan-vt-fade-in;
}
@keyframes anlan-vt-fade-out {
  to { opacity: 0; }
}
@keyframes anlan-vt-fade-in {
  from { opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  ::view-transition-old(root),
  ::view-transition-new(root) {
    animation: none !important;
  }
}

/* ============================================================
   SHARED CHROME — nav / footer / theme toggle / lang switch / breadcrumb
   从现有 index.html 的 <style> 抠出，全部改走 token 变量。
   默认链接色提到约 85% 白；仅 .nav-link.gold（澜读）用金色。
   ============================================================ */

/* ---- NAV (parent shell, 半透明 + blur，跨页同构以利 view transition) ---- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 48px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--color-bg);            /* 回退色，下面用半透明覆盖 */
  background: color-mix(in srgb, var(--color-bg) 78%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-border);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 14px;
  font-weight: 500;
  font-size: 15px;
  letter-spacing: 0.2em;
  color: var(--color-text);
}
.nav-brand .brand-sep {
  width: 1px;
  height: 22px;
  background: var(--color-border-hover);
  margin: 0 4px;
  align-self: center;
}
.nav-brand svg {
  color: var(--color-text);
}

.nav-links {
  display: flex;
  gap: 36px;
  list-style: none;
  align-items: center;
  margin: 0;
  padding: 0;
}

.nav-link {
  font-size: 14px;
  font-weight: 400;
  /* 默认链接色：~85% 白（dark）/ 等价深字（light），比 muted 更亮一档 */
  color: color-mix(in srgb, var(--color-text) 85%, transparent);
  transition: color var(--duration-normal) var(--ease-smooth);
  position: relative;
  text-decoration: none;
}
.nav-link:hover {
  color: var(--color-text);
}
/* 当前页：白字 + 金色下划线 */
.nav-link.active {
  color: var(--color-text);
  font-weight: 500;
}
.nav-link.active::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -22px;
  height: 2px;
  background: var(--color-gold);
  border-radius: 2px;
}
/* 澜读：金色（唯一彩色导航项） */
.nav-link.gold {
  color: var(--color-gold);
}
.nav-link.gold:hover {
  color: var(--color-gold-light);
}

/* ---- 滚动阅读进度条（细线，贴在 nav 顶端，增强方位感） ---- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0;
  z-index: 101;            /* 略高于 .nav (100)，盖在其上沿 */
  background: linear-gradient(90deg, var(--color-gold-dark), var(--color-gold), var(--color-gold-light));
  box-shadow: 0 0 8px rgba(212, 165, 116, 0.45);
  transform-origin: left center;
  transition: width 80ms linear;
  pointer-events: none;
}
@media (prefers-reduced-motion: reduce) {
  .scroll-progress { transition: none; }
}

/* ---- 用例库 teaser（首页内联入口，替代原 3 卡示例） ---- */
.uc-teaser {
  max-width: 760px;
  margin: 40px auto 0;
}
.uc-teaser-line {
  font-size: clamp(15px, 1.5vw, 17px);
  color: var(--color-text-muted);
  line-height: 1.7;
  margin: 0 auto 28px;
}
.uc-teaser-chips {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 36px;
}
.uc-chip {
  font-size: 13px;
  padding: 7px 16px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border-hover);
  background: var(--color-surface);
  color: color-mix(in srgb, var(--color-text) 80%, transparent);
  white-space: nowrap;
  transition: border-color var(--duration-normal) var(--ease-smooth), color var(--duration-normal) var(--ease-smooth);
}
.uc-chip:hover {
  border-color: var(--color-gold);
  color: var(--color-gold);
}
.uc-teaser .btn {
  font-size: 14px;
}

/* nav 内的图标 / 语言切换 / 主题钮 容器 */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-left: 8px;
}

/* ---- 语言切换 (中/EN 占位) ---- */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
}
.lang-switch a,
.lang-switch span {
  color: var(--color-text-muted);
  transition: color var(--duration-normal) var(--ease-smooth);
  text-decoration: none;
}
.lang-switch a:hover {
  color: var(--color-text);
}
.lang-switch .active {
  color: var(--color-text);
  font-weight: 500;
}
.lang-switch .sep {
  opacity: 0.4;
}

/* ---- Light/Dark 切换钮 ---- */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 32px;
  padding: 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: color var(--duration-normal) var(--ease-smooth),
              border-color var(--duration-normal) var(--ease-smooth);
  font-family: var(--font-mono);
}
.theme-toggle:hover {
  color: var(--color-text);
  border-color: var(--color-border-hover);
}
.theme-toggle svg {
  width: 14px;
  height: 14px;
  display: block;
}

/* ---- GitHub 星标徽章 pill (GitHub mark + ★ + 实时 star 数) ---- */
.gh-stars {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 12px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--duration-normal) var(--ease-smooth),
              border-color var(--duration-normal) var(--ease-smooth),
              background var(--duration-normal) var(--ease-smooth);
}
.gh-stars:hover {
  color: var(--color-text);
  border-color: var(--color-border-hover);
}
.gh-stars .gh-stars-mark { display: block; flex-shrink: 0; }
.gh-stars .gh-stars-icon { display: block; flex-shrink: 0; color: var(--color-gold); }
.gh-stars .gh-stars-num {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  line-height: 1;
  color: var(--color-text);
}

/* ---- MOBILE NAV ---- */
.nav-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}
.nav-menu-btn span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: var(--color-text-muted);
  transition: all 0.3s ease;
}

.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 99;
  background: color-mix(in srgb, var(--color-bg) 95%, transparent);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 32px;
}
.mobile-nav.open {
  display: flex;
}
.mobile-nav a {
  font-size: 18px;
  color: var(--color-text-muted);
  letter-spacing: 0.1em;
  transition: color 0.2s;
  text-decoration: none;
}
.mobile-nav a:hover {
  color: var(--color-text);
}
.mobile-nav a.gold {
  color: var(--color-gold);
}
.mobile-nav-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: none;
  border: none;
  color: var(--color-text-muted);
  font-size: 28px;
  cursor: pointer;
  padding: 8px;
  line-height: 1;
}

/* ---- BREADCRUMB (子页面上下文) ---- */
.breadcrumb {
  position: relative;
  z-index: 5;
  padding: 88px 48px 0;
  max-width: 1280px;
  margin: 0 auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--color-text-subtle);
  text-transform: uppercase;
}
.breadcrumb a {
  color: var(--color-text-muted);
  transition: color var(--duration-normal);
  text-decoration: none;
}
.breadcrumb a:hover {
  color: var(--color-gold);
}
.breadcrumb .sep {
  color: var(--color-text-subtle);
  margin: 0 10px;
  opacity: 0.4;
}
.breadcrumb .here {
  color: var(--color-gold);
}

/* ---- FOOTER (parent shell) ---- */
.footer {
  padding: 64px 48px 48px;
  border-top: 1px solid var(--color-border);
  max-width: 1280px;
  margin: 80px auto 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 24px;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}
.footer-brand svg {
  width: 32px;
  height: 32px;
  color: var(--color-text);
}
.footer-brand span {
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.18em;
}
.footer-links {
  display: flex;
  gap: 24px;
  align-items: center;
}
.footer-links a {
  font-size: 13px;
  color: var(--color-text-muted);
  transition: color var(--duration-normal);
  text-decoration: none;
}
.footer-links a:hover {
  color: var(--color-text);
}
.footer-copy {
  font-size: 13px;
  color: var(--color-text-subtle);
}

/* ---- RESPONSIVE (chrome only) ---- */
@media (max-width: 768px) {
  .nav {
    padding: 16px 20px;
  }
  .nav-links {
    display: none;
  }
  .nav-menu-btn {
    display: flex;
  }
  .breadcrumb {
    padding: 80px 20px 0;
  }
  .footer {
    flex-direction: column;
    gap: 20px;
    text-align: center;
    padding: 40px 20px;
  }
  .footer-links {
    flex-wrap: wrap;
    justify-content: center;
  }
}

@media (min-width: 769px) {
  .nav-menu-btn {
    display: none;
  }
  .mobile-nav {
    display: none !important;
  }
}