/* ═══════════════════════════════════════════════════════════
   Fountrace 官网 — common.css
   设计令牌（与 pricing/style.css 同源）+ 公共导航/按钮/页脚
   设计方向：Refined Tech Premium（精致科技风）
   特色：深色优先 + 几何网格背景 + 光晕装饰 + 玻璃态卡片
   ═══════════════════════════════════════════════════════════ */

/* ── 设计令牌 (Design Tokens) ── */
:root {
  /* 色彩 */
  --color-primary: #2563EB;
  --color-primary-light: #3B82F6;
  --color-primary-dark: #1D4ED8;
  --color-primary-glow: rgba(37, 99, 235, 0.15);
  --color-success: #10B981;
  --color-success-glow: rgba(16, 185, 129, 0.12);
  --color-warning: #F59E0B;
  --color-error: #EF4444;

  /* 表面 */
  --bg-base: #0B0F1A;
  --bg-surface: rgba(15, 23, 42, 0.75);
  --bg-card: rgba(20, 30, 55, 0.6);
  --bg-card-hover: rgba(25, 38, 68, 0.7);
  --bg-input: rgba(15, 23, 42, 0.8);
  --border-subtle: rgba(148, 163, 184, 0.1);
  --border-card: rgba(148, 163, 184, 0.12);
  --border-featured: rgba(37, 99, 235, 0.5);

  /* 文字 */
  --text-primary: #F1F5F9;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;
  --text-on-primary: #FFFFFF;

  /* 字体 */
  --font-display: 'Outfit', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: -apple-system, 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', monospace;

  /* 间距 */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2.5rem;
  --space-2xl: 4rem;

  /* 圆角 */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  /* 阴影 */
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-card-hover: 0 8px 40px rgba(0, 0, 0, 0.4), 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-featured: 0 4px 32px rgba(37, 99, 235, 0.2), 0 8px 48px rgba(0, 0, 0, 0.3);
  --shadow-btn: 0 2px 12px rgba(37, 99, 235, 0.3);

  /* 动画 */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 150ms var(--ease-out-expo);
  --transition-normal: 300ms var(--ease-out-expo);
}

/* ── 浅色主题（与桌面应用 LIGHT 同源：暖纸底色护眼 + 冷调蓝色强调互补）── */
[data-theme="light"] {
  /* 强调色：与深色主题同品牌蓝（暖底上 AA 达标） */
  --color-primary: #2563EB;
  --color-primary-light: #3B82F6;
  --color-primary-dark: #1D4ED8;
  --color-primary-glow: rgba(37, 99, 235, 0.15);
  --color-success: #10B981;
  --color-success-glow: rgba(16, 185, 129, 0.12);
  --color-warning: #B57614;
  --color-error: #C0392B;

  /* 表面：暖白纸感（降蓝光/眩光） */
  --bg-base: #FBF7F0;
  --bg-surface: rgba(245, 239, 230, 0.85);
  --bg-card: rgba(255, 251, 244, 0.9);
  --bg-card-hover: #FFFFFF;
  --bg-input: rgba(239, 231, 218, 0.9);
  --border-subtle: rgba(120, 100, 70, 0.12);
  --border-card: rgba(120, 100, 70, 0.18);
  --border-featured: rgba(37, 99, 235, 0.45);

  /* 文字：暖炭非冷黑 */
  --text-primary: #2B2620;
  --text-secondary: #574F45;
  --text-muted: #857C70;

  /* 阴影：暖棕调 */
  --shadow-card: 0 4px 24px rgba(90, 70, 40, 0.08), 0 1px 2px rgba(90, 70, 40, 0.05);
  --shadow-card-hover: 0 8px 40px rgba(90, 70, 40, 0.12), 0 2px 4px rgba(90, 70, 40, 0.07);
  --shadow-featured: 0 4px 32px rgba(37, 99, 235, 0.14), 0 8px 48px rgba(90, 70, 40, 0.1);
  --shadow-btn: 0 2px 12px rgba(37, 99, 235, 0.3);
}

/* ── 基础重置 ── */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-base);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* 内容不足一屏时把页脚压到视口底部（sticky footer） */
main {
  flex: 1 0 auto;
}

a { color: inherit; }

/* ── 背景装饰 ── */
.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--border-subtle) 1px, transparent 1px),
    linear-gradient(90deg, var(--border-subtle) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: 0.4;
  pointer-events: none;
  z-index: 0;
}

.bg-glow {
  position: fixed;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
  z-index: 0;
}

.bg-glow--top {
  top: -200px;
  right: -100px;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.12), transparent 70%);
}

.bg-glow--bottom {
  bottom: -200px;
  left: -100px;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.08), transparent 70%);
}

/* ── 语言切换（zh / EN） ── */
.lang-toggle {
  height: 40px;
  padding: 0 0.9rem;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-card);
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.lang-toggle:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ── 主题切换按钮 ── */
.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-card);
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  color: var(--text-secondary);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.theme-toggle:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: scale(1.05);
}

.icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

/* ── 公共导航 ── */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--space-md) var(--space-lg);
}

.site-nav__inner {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(16px);
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  font-family: var(--font-display);
}

/* 应用图标（与桌面端同源） */
.brand__icon {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  display: block;
  flex-shrink: 0;
}

.brand__zh,
.brand__en {
  align-self: baseline;
}

.brand__zh {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text-primary);
}

.brand__en {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary-light);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

.nav-links a:hover { color: var(--text-primary); }

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-card);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  place-items: center;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

/* ── 容器 ── */
.container {
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

.container--narrow {
  max-width: 820px;
}

/* ── 按钮 ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--text-on-primary);
  box-shadow: var(--shadow-btn);
}

.btn--primary:hover {
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.4);
  transform: translateY(-1px);
}

.btn--primary:active { transform: translateY(0); }

.btn--outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-card);
}

.btn--outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-glow);
}

.btn--lg {
  padding: 0.9rem 2rem;
  font-size: 1rem;
}

.btn--full { width: 100%; }

/* ── 通用区块标题 ── */
.section {
  padding: var(--space-2xl) 0;
}

.section__eyebrow {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary-light);
  margin-bottom: var(--space-md);
}

.section__title {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3.5vw, 2.3rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin-bottom: var(--space-sm);
}

.section__subtitle {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 620px;
}

.section__head--center {
  text-align: center;
}

.section__head--center .section__subtitle {
  margin-left: auto;
  margin-right: auto;
}

/* ── 玻璃卡片基元 ── */
.glass-card {
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-card);
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow-card);
}

/* ── 页脚 ── */
.footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--border-subtle);
  margin-top: var(--space-2xl);
}

.footer__inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 34px var(--space-lg) 26px;
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  justify-content: space-between;
  align-items: flex-start;
}

.footer__brand {
  max-width: 300px;
}

.footer__brand .fbrand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
}

.footer__brand .fbrand__icon {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  object-fit: cover;
  display: block;
  flex-shrink: 0;
}

.footer__brand .fbrand__name {
  font-family: "Songti SC", "STSong", "SimSun", "Noto Serif SC", serif;
  font-size: 20px;
  font-weight: 400;
  letter-spacing: 2px;
  color: var(--text-primary);
}

.footer__tagline {
  margin-top: 12px;
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer__cols {
  display: flex;
  flex-wrap: wrap;
  gap: 48px;
}

.footer__col h4 {
  font-family: var(--font-display);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  margin-bottom: 14px;
}

.footer__col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.footer__col a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color var(--transition-fast);
}

.footer__col a:hover { color: var(--color-primary); }

.footer__bottom {
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--space-md) var(--space-lg) var(--space-xl);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm) var(--space-lg);
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.footer__bottom a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer__bottom a:hover { color: var(--color-primary); }

.footer__icp { letter-spacing: 0.02em; }

/* ── 关键帧 ── */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.8); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.85); }
}

/* ── 响应式：导航折叠 ── */
@media (max-width: 820px) {
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg-surface);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-card);
    padding: var(--space-sm) var(--space-lg);
    display: none;
  }

  .nav-links.is-open { display: flex; }

  .nav-links a {
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-subtle);
  }

  .nav-links li:last-child a { border-bottom: none; }

  .nav-toggle { display: grid; }
}

@media (max-width: 600px) {
  .container { padding: var(--space-lg) var(--space-md); }
  .footer__inner { flex-direction: column; }
}

/* ── 无障碍：减动效 ── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto;
  }
}

/* ── 错误页（404 / 5xx） ── */
.err {
  min-height: 62vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  text-align: center;
}

.err__code {
  font-family: var(--font-display);
  font-size: clamp(4.5rem, 12vw, 7.5rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1;
  color: var(--text-primary);
}

.err__code b { color: var(--color-primary); }

.err__title {
  margin: 1.4rem 0 0.6rem;
  font-size: clamp(1.3rem, 3vw, 1.7rem);
  font-weight: 600;
  color: var(--text-primary);
}

.err__lead {
  max-width: 34em;
  margin: 0 auto;
  color: var(--text-secondary);
  font-size: 1rem;
}

.err__note {
  max-width: 38em;
  margin: 1.1rem auto 0;
  padding: 0.9rem 1.2rem;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.err__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  justify-content: center;
  margin-top: 2rem;
}

.err__links .btn { white-space: nowrap; }

.err__hint {
  margin-top: 1.6rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.err__hint a { color: var(--color-primary); }