/* ===========================
   AI Act 合规指南 - 主布局
   =========================== */

/* Google Fonts — CJK + Display + Body + Mono */
@import url('https://fonts.googleapis.com/css2?family=DM+Serif+Display:ital@0;1&family=DM+Sans:wght@300;400;500;600;700&family=IBM+Plex+Mono:wght@400;500&family=Noto+Serif+SC:wght@400;600;700&family=Noto+Sans+SC:wght@300;400;500;600;700&family=Playfair+Display:wght@400;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ===========================
   整体布局：左侧固定导航 + 右侧内容
   =========================== */

.site-layout {
  display: flex;
  min-height: 100vh;
}

/* ===========================
   左侧导航
   =========================== */

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
}

.nav-logo {
  padding: var(--space-xl) var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.nav-logo-text {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: 0.18em;
  line-height: 1.3;
}

.nav-logo-sub {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--color-muted);
  margin-top: 3px;
  letter-spacing: 0.04em;
}

.nav-footer-email {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--color-teal);
  text-decoration: none;
  margin-bottom: 4px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.nav-footer-email:hover { color: var(--color-teal-hover); }

.nav-links {
  flex: 1;
  padding: var(--space-md) 0;
}

.nav-links a {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  color: var(--color-muted);
  font-size: 0.9rem;
  transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast);
  border-left: 3px solid transparent;
}

.nav-links a:hover {
  color: var(--color-text);
  background: rgba(59, 130, 246, 0.05);
}

.nav-links a.active {
  color: var(--color-primary);
  background: rgba(59, 130, 246, 0.08);
  border-left-color: var(--color-primary);
  font-weight: 500;
}

.nav-links a .nav-icon {
  width: 20px;
  text-align: center;
  flex-shrink: 0;
}

.nav-section-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  padding: var(--space-md) var(--space-lg) 2px;
}

.nav-divider {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-sm) var(--space-lg);
}

.nav-links a.nav-cta {
  color: var(--color-teal);
  font-weight: 600;
}

.nav-links a.nav-cta:hover,
.nav-links a.nav-cta.active {
  color: var(--color-teal);
  background: var(--color-teal-dim);
  border-left-color: var(--color-teal);
}

.nav-footer {
  padding: var(--space-md) var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.nav-footer-tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-muted);
}

/* ===========================
   右侧内容区
   =========================== */

.site-content {
  flex: 1;
  margin-left: var(--nav-width);
  min-height: 100vh;
}

.page-container {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--space-3xl) var(--space-xl);
}

/* ===========================
   面包屑
   =========================== */

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-bottom: var(--space-2xl);
}

.breadcrumb a {
  color: var(--color-muted);
}

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

.breadcrumb .separator {
  color: var(--color-border);
}

.breadcrumb .current {
  color: var(--color-text);
}

/* ===========================
   页面内锚点导航（TOC）
   =========================== */

.page-toc {
  position: fixed;
  right: var(--space-xl);
  top: var(--space-3xl);
  width: 180px;
  font-size: 0.8rem;
}

.page-toc-title {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-sm);
}

.page-toc a {
  display: block;
  padding: var(--space-xs) 0;
  color: var(--color-muted);
  border-left: 2px solid var(--color-border);
  padding-left: var(--space-md);
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.page-toc a:hover,
.page-toc a.active {
  color: var(--color-text);
  border-left-color: var(--color-primary);
}

/* ===========================
   页面头部
   =========================== */

.page-header {
  margin-bottom: var(--space-3xl);
  padding-bottom: var(--space-2xl);
  border-bottom: 1px solid var(--color-border);
}

.page-header .section-label {
  margin-bottom: var(--space-sm);
}

.page-header h1 {
  margin-bottom: var(--space-md);
}

.page-header .lead {
  font-size: 1.1rem;
  color: var(--color-muted);
  max-width: 650px;
  line-height: 1.8;
}

/* ===========================
   内容章节
   =========================== */

.content-section {
  margin-bottom: var(--space-3xl);
}

.content-section h2 {
  padding-top: var(--space-xl);
}

/* ===========================
   移动端汉堡按钮
   =========================== */

.nav-toggle {
  display: none;
  position: fixed;
  top: var(--space-md);
  left: var(--space-md);
  z-index: 200;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-sm);
  cursor: pointer;
  color: var(--color-text);
  font-size: 1.25rem;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
}

.nav-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  z-index: 90;
}

.nav-overlay.visible {
  display: block;
}

/* ===========================
   响应式：移动端
   =========================== */

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    transform: translateX(-100%);
    transition: transform var(--transition-base);
  }

  .site-nav.open {
    transform: translateX(0);
  }

  .site-content {
    margin-left: 0;
  }

  .page-container {
    padding: var(--space-xl) var(--space-md);
    padding-top: calc(var(--space-xl) + 56px);
  }

  .page-toc {
    display: none;
  }
}

/* 隐藏TOC当内容区不够宽 */
@media (max-width: 1200px) {
  .page-toc {
    display: none;
  }
}

/* ===========================
   打印样式
   =========================== */

@media print {
  .site-nav,
  .nav-toggle,
  .page-toc,
  .cta-section {
    display: none;
  }

  .site-content {
    margin-left: 0;
  }

  body {
    background: #fff;
    color: #000;
  }
}

/* =============================================
   TOP NAV — Marketing pages (index, pricing)
   ============================================= */

#topNav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-top-h, 64px);
  z-index: 500;
  transition:
    background 0.4s ease,
    border-color 0.4s ease,
    box-shadow 0.4s ease,
    transform 0.3s ease;
  border-bottom: 1px solid transparent;
}

#topNav.scrolled {
  background: rgba(5, 10, 18, 0.82);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom-color: rgba(255,255,255,0.06);
  box-shadow: 0 4px 32px rgba(0,0,0,0.4);
}

#topNav.nav-hidden {
  transform: translateY(-100%);
}

#topNav.menu-open {
  background: rgba(5, 10, 18, 0.96);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.nav-top-inner {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 32px;
}

/* Logo */
.nav-top-logo {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  flex-shrink: 0;
  line-height: 1;
}
.logo-mark {
  font-family: var(--font-mono-new, 'IBM Plex Mono', monospace);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: #f0f6ff;
  transition: color 0.2s;
}
.nav-top-logo:hover .logo-mark { color: #06b6d4; }
.logo-sub {
  font-family: var(--font-mono-new, 'IBM Plex Mono', monospace);
  font-size: 0.58rem;
  color: #6b8aad;
  letter-spacing: 0.04em;
  margin-top: 2px;
}

/* Links */
.nav-top-links {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-left: auto;
}
.nav-top-link {
  font-family: var(--font-body, 'DM Sans', sans-serif);
  font-size: 0.88rem;
  font-weight: 400;
  color: #6b8aad;
  text-decoration: none;
  padding: 6px 14px;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
}
.nav-top-link:hover,
.nav-top-link.active {
  color: #f0f6ff;
  background: rgba(255,255,255,0.05);
}
.nav-top-cta {
  font-family: var(--font-body, 'DM Sans', sans-serif);
  font-size: 0.88rem;
  font-weight: 600;
  color: #0a1220;
  background: #06b6d4;
  text-decoration: none;
  padding: 7px 18px;
  border-radius: 7px;
  margin-left: 8px;
  transition: background 0.2s, transform 0.2s;
}
.nav-top-cta:hover {
  background: #0891b2;
  color: #0a1220;
  transform: translateY(-1px);
}
.nav-top-cta.active { background: #0891b2; }

/* Hamburger */
.nav-top-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 6px;
  cursor: pointer;
  padding: 8px;
  margin-left: 8px;
  flex-shrink: 0;
}
.nav-top-hamburger span {
  display: block;
  height: 1.5px;
  background: #a8c0d8;
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

/* ── Marketing page layout ── */
.marketing-page {
  padding-top: var(--nav-top-h, 64px);
}

.sec {
  padding: 100px 0;
}
.sec-sm {
  padding: 60px 0;
}
.sec + .sec {
  border-top: 1px solid rgba(255,255,255,0.06);
}

.wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 28px;
}

/* Section meta label */
.sec-label {
  font-family: var(--font-mono-new, 'IBM Plex Mono', monospace);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: #06b6d4;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.sec-label::before {
  content: '';
  display: block;
  width: 24px;
  height: 1px;
  background: #06b6d4;
  opacity: 0.6;
}

/* Section headings */
.sec-h2 {
  font-family: var(--font-display, 'DM Serif Display', serif);
  font-size: clamp(1.9rem, 3.5vw, 2.7rem);
  font-weight: 400;
  line-height: 1.2;
  color: #f0f6ff;
  margin-bottom: 16px;
}
.sec-lead {
  font-size: 1.05rem;
  color: #6b8aad;
  max-width: 560px;
  line-height: 1.75;
  margin-bottom: 56px;
}

/* ── Cards ── */
.card-dark {
  background: #0d1421;
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 12px;
  padding: 28px;
}
.card-dark-sm {
  background: #0d1421;
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 10px;
  padding: 20px 24px;
}

/* ── Buttons ── */
.btn-hero-primary {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--font-body, 'DM Sans', sans-serif);
  font-size: 1rem; font-weight: 600;
  color: #050a12; background: #06b6d4;
  padding: 14px 28px; border-radius: 10px;
  text-decoration: none; border: none; cursor: pointer;
  transition: background 0.2s, transform 0.2s, box-shadow 0.2s;
}
.btn-hero-primary:hover {
  background: #0891b2; color: #050a12;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(6,182,212,0.25);
}

.btn-hero-ghost {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--font-body, 'DM Sans', sans-serif);
  font-size: 1rem; font-weight: 500;
  color: #a8c0d8; background: transparent;
  padding: 14px 28px; border-radius: 10px;
  text-decoration: none;
  border: 1px solid rgba(255,255,255,0.12);
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.btn-hero-ghost:hover {
  color: #f0f6ff;
  border-color: rgba(255,255,255,0.25);
  background: rgba(255,255,255,0.04);
}

/* ── Responsive: mobile nav ── */
@media (max-width: 768px) {
  .nav-top-hamburger {
    display: flex;
  }

  .nav-top-links {
    display: none;
    position: absolute;
    top: var(--nav-top-h, 64px);
    left: 0; right: 0;
    background: rgba(5, 10, 18, 0.97);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255,255,255,0.08);
    flex-direction: column;
    align-items: stretch;
    padding: 12px 20px 20px;
    gap: 4px;
  }
  .nav-top-links.open { display: flex; }

  .nav-top-link,
  .nav-top-cta {
    font-size: 1rem;
    padding: 12px 16px;
    border-radius: 8px;
    margin-left: 0;
    text-align: center;
  }
  .nav-top-cta {
    margin-top: 8px;
  }

  .sec { padding: 64px 0; }
  .wrap { padding: 0 20px; }
  .sec-h2 { font-size: 1.75rem; }
}