:root {
  color-scheme: light dark;
  --bg: #f8f9fc;
  --bg-elevated: #ffffff;
  --text: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #86868b;
  --border: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.12);
  --accent: #5856d6;
  --accent-2: #af52de;
  --accent-soft: rgba(88, 86, 214, 0.12);
  --accent-glow: rgba(88, 86, 214, 0.25);
  --success: #34c759;
  --success-soft: rgba(52, 199, 89, 0.12);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04), 0 4px 16px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 60px rgba(88, 86, 214, 0.15);
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 999px;
  --header-height: 64px;
  --content-width: 1120px;
  --article-width: 760px;
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, "PingFang SC", sans-serif;
  --transition: 0.2s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0a0c;
    --bg-elevated: #161618;
    --text: #f5f5f7;
    --text-secondary: #a1a1a6;
    --text-tertiary: #6e6e73;
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.14);
    --accent-soft: rgba(120, 118, 255, 0.18);
    --accent-glow: rgba(120, 118, 255, 0.22);
    --success-soft: rgba(48, 209, 88, 0.14);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 16px rgba(0, 0, 0, 0.25);
    --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.45);
  }
}

*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, var(--accent-glow), transparent 70%),
    radial-gradient(ellipse 60% 40% at 100% 0%, rgba(175, 82, 222, 0.12), transparent 60%);
  z-index: -1;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

a:hover { color: var(--accent-2); }

img, svg { display: block; max-width: 100%; }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.88em;
  padding: 0.15em 0.45em;
  border-radius: 6px;
  background: var(--accent-soft);
  color: var(--text);
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(18px) saturate(1.4);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
}

.header-inner {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  font-weight: 600;
  font-family: var(--font-display);
  letter-spacing: -0.02em;
}

.brand:hover { color: var(--text); opacity: 0.85; }

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 9px;
  box-shadow: var(--shadow-sm);
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-name { font-size: 1.05rem; }

.brand-sub {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.nav-link:hover {
  color: var(--text);
  background: var(--accent-soft);
}

.nav-link.is-active {
  color: var(--accent);
  background: var(--accent-soft);
}

/* Layout */

.page {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 24px 80px;
}

.page-article {
  max-width: var(--article-width);
  margin: 0 auto;
  padding: 0 24px 80px;
}

/* Hero (home) */

.hero {
  padding: 72px 0 56px;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  margin-bottom: 24px;
  border-radius: var(--radius-full);
  background: var(--success-soft);
  color: var(--success);
  font-size: 0.85rem;
  font-weight: 600;
  border: 1px solid color-mix(in srgb, var(--success) 25%, transparent);
}

.hero-icon {
  width: 96px;
  height: 96px;
  margin: 0 auto 28px;
  border-radius: 22px;
  box-shadow: var(--shadow-lg);
}

.hero h1 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 6vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.05;
  background: linear-gradient(135deg, var(--text) 0%, var(--accent) 55%, var(--accent-2) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-lead {
  margin: 0 auto;
  max-width: 560px;
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 28px;
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
}

/* Cards */

.section-title {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-bottom: 48px;
}

.card {
  padding: 24px;
  border-radius: var(--radius-md);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}

.card-icon {
  width: 44px;
  height: 44px;
  margin-bottom: 16px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-size: 1.25rem;
  background: linear-gradient(135deg, var(--accent-soft), rgba(175, 82, 222, 0.1));
}

.card h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.card p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

.link-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 14px;
}

.link-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 22px;
  border-radius: var(--radius-md);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.link-card:hover {
  color: var(--text);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: color-mix(in srgb, var(--accent) 30%, var(--border));
}

.link-card-text strong {
  display: block;
  font-size: 1rem;
  margin-bottom: 4px;
}

.link-card-text span {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.link-card-arrow {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 1.1rem;
}

/* Legal pages */

.doc-hero {
  padding: 48px 0 32px;
  text-align: center;
}

.doc-hero h1 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.doc-meta {
  margin: 0;
  font-size: 0.92rem;
  color: var(--text-tertiary);
}

.doc-toolbar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 20px;
}

.doc-toolbar a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
}

.doc-toolbar a:hover {
  color: var(--accent);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
}

.doc-body {
  padding: 8px 28px 36px;
  border-radius: var(--radius-lg);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.doc-body > p:first-child { margin-top: 0; }

.doc-body h2 {
  margin: 2.2rem 0 0.75rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 650;
  letter-spacing: -0.02em;
  padding-top: 0.25rem;
}

.doc-body h2:first-of-type { margin-top: 0.5rem; }

.doc-body h3 {
  margin: 1.5rem 0 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
}

.doc-body p,
.doc-body li {
  color: var(--text-secondary);
}

.doc-body strong { color: var(--text); }

.doc-body ul,
.doc-body ol {
  margin: 0.5rem 0 1rem;
  padding-left: 1.35rem;
}

.doc-body li { margin: 0.4rem 0; }

.callout {
  display: flex;
  gap: 14px;
  padding: 18px 20px;
  margin: 1.25rem 0 1.75rem;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--accent-soft), rgba(175, 82, 222, 0.08));
  border: 1px solid color-mix(in srgb, var(--accent) 22%, var(--border));
}

.callout-icon {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  background: var(--bg-elevated);
  font-size: 0.95rem;
}

.callout p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--text);
  line-height: 1.6;
}

.lang-divider {
  display: flex;
  align-items: center;
  gap: 16px;
  margin: 3rem 0 2rem;
  color: var(--text-tertiary);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.lang-divider::before,
.lang-divider::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border-strong);
}

/* Footer */

.site-footer {
  margin-top: auto;
  padding: 32px 24px;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-inner {
  max-width: var(--content-width);
  margin: 0 auto;
}

.site-footer p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-tertiary);
  line-height: 1.6;
}

.site-footer a {
  color: var(--text-secondary);
  font-weight: 500;
}

.site-footer a:hover { color: var(--accent); }

/* Responsive */

@media (max-width: 640px) {
  .brand-sub { display: none; }
  .doc-body { padding: 8px 18px 28px; }
  .hero { padding-top: 48px; }
  .nav-link { padding: 6px 10px; font-size: 0.82rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .card, .link-card { transition: none; }
}