/* ============================================
   替你说官网 — 设计系统 v5（视觉统一）
   ============================================ */

/* --- CSS Variables --- */
:root {
  --color-primary: #1FCD6C;
  --color-primary-hover: #3DD881;
  --color-primary-active: #17A554;
  --color-bg: #F2F3F4;
  --color-surface: #FFFFFF;
  --color-text: #1A1C1E;
  --color-text-secondary: #6E747C;
  --color-text-weak: #8E9591;
  --color-border: #EBEBEB;
  --color-danger: #FF4D4F;
  --color-icon-bg: rgba(31, 205, 108, 0.08);
  --font-cn: -apple-system, "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --font-en: Inter, -apple-system, system-ui, sans-serif;
  --max-width: 1080px;
  --header-height: 64px;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  font-family: var(--font-cn);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover { color: var(--color-primary-hover); }

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

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
}

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

.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.site-logo:hover { color: var(--color-text); }

.site-logo svg {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.site-nav a {
  font-size: 14px;
  color: var(--color-text-secondary);
  font-weight: 500;
  transition: color 0.2s;
}
.site-nav a:hover { color: var(--color-text); }
.site-nav a.active { color: var(--color-primary); }

/* Nav CTA Button */
.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  background: var(--color-primary);
  color: #fff !important;
  font-size: 13px;
  font-weight: 600;
  border-radius: 50px;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}
.nav-cta:hover {
  background: var(--color-primary-hover);
  color: #fff !important;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(31, 205, 108, 0.3);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  margin: 5px 0;
  transition: 0.3s;
}

/* --- Hero Section --- */
.hero {
  background: var(--color-surface);
  padding: 80px 24px 64px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 900px;
  background: radial-gradient(circle, rgba(31, 205, 108, 0.12) 0%, rgba(31, 205, 108, 0.04) 40%, transparent 70%);
  pointer-events: none;
}

.hero-logo {
  width: 80px;
  height: 80px;
  margin: 0 auto 28px;
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.hero h1 {
  font-size: 48px;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 14px;
  color: var(--color-text);
}

.hero .tagline {
  font-size: 18px;
  color: var(--color-text-secondary);
  font-weight: 400;
  margin-bottom: 36px;
  line-height: 1.7;
}

.hero .cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 36px;
  background: var(--color-primary);
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  border-radius: 50px;
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 4px 16px rgba(31, 205, 108, 0.3);
}
.hero .cta-btn:hover {
  background: var(--color-primary-hover);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(31, 205, 108, 0.35);
}
.hero .cta-btn:active {
  background: var(--color-primary-active);
  transform: translateY(0);
}
.hero .cta-btn svg {
  width: 16px;
  height: 16px;
  transition: transform 0.2s;
}
.hero .cta-btn:hover svg {
  transform: translateX(3px);
}

/* --- Unified Card System --- */
.unified-card {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 28px 24px;
  border: 1px solid var(--color-border);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.unified-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-primary);
  opacity: 0;
  transition: opacity 0.3s;
}

.unified-card:hover {
  border-color: transparent;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.06);
  transform: translateY(-4px);
}

.unified-card:hover::before {
  opacity: 1;
}

/* --- Unified Icon Block --- */
.icon-block {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--color-icon-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  flex-shrink: 0;
}

.icon-block svg {
  width: 24px;
  height: 24px;
}

/* --- Features Section --- */
.features {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 64px 24px;
}

.features-title {
  text-align: center;
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 10px;
  letter-spacing: -0.02em;
}

.features-subtitle {
  text-align: center;
  font-size: 16px;
  color: var(--color-text-secondary);
  margin-bottom: 40px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.feature-card {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 28px 24px;
  border: 1px solid var(--color-border);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-primary);
  opacity: 0;
  transition: opacity 0.3s;
}

.feature-card:hover {
  border-color: transparent;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.06);
  transform: translateY(-4px);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  background: var(--color-icon-bg);
}

.feature-icon svg {
  width: 24px;
  height: 24px;
}

.feature-card h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-text);
}

.feature-card p {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* --- Product Page Sections --- */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 64px 24px;
}

.section-white {
  background: var(--color-surface);
}

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

.section h2 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 10px;
  letter-spacing: -0.02em;
}

.section .section-desc {
  font-size: 16px;
  color: var(--color-text-secondary);
  max-width: 640px;
  margin: 0 auto 40px;
  line-height: 1.8;
}

/* Scenario cards — unified with feature cards */
.scenario-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  max-width: 720px;
  margin: 0 auto;
  text-align: left;
}

.scenario-item {
  padding: 28px 24px;
  background: var(--color-surface);
  border-radius: 12px;
  border: 1px solid var(--color-border);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.scenario-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-primary);
  opacity: 0;
  transition: opacity 0.3s;
}

.scenario-item:hover {
  border-color: transparent;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.06);
  transform: translateY(-4px);
}

.scenario-item:hover::before {
  opacity: 1;
}

.scenario-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--color-icon-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.scenario-icon svg {
  width: 24px;
  height: 24px;
}

.scenario-content h3 {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-text);
}

.scenario-content p {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* --- Footer --- */
.site-footer {
  background: #1A1C1E;
  color: rgba(255, 255, 255, 0.6);
  padding: 40px 24px 28px;
  margin-top: auto;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 40px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.footer-brand svg {
  width: 28px;
  height: 28px;
}

.footer-brand span {
  font-size: 16px;
  font-weight: 600;
  color: #fff;
}

.footer-desc {
  font-size: 13px;
  line-height: 1.6;
  max-width: 320px;
}

.footer-links-group {
  display: flex;
  gap: 48px;
}

.footer-col h4 {
  color: rgba(255, 255, 255, 0.9);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 14px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-col a {
  display: block;
  color: rgba(255, 255, 255, 0.5);
  font-size: 13px;
  margin-bottom: 10px;
  transition: color 0.2s;
}
.footer-col a:hover { color: var(--color-primary); }

.footer-bottom {
  max-width: var(--max-width);
  margin: 24px auto 0;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.4);
}
.footer-bottom a:hover { color: var(--color-primary); }

.footer-icp {
  text-align: center;
  font-size: 12px;
  color: rgba(255, 255, 255, 0.3);
  margin-top: 16px;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
}

.footer-icp a {
  color: rgba(255, 255, 255, 0.3);
}
.footer-icp a:hover { color: rgba(255, 255, 255, 0.5); }

/* --- Legal Document --- */
.legal-doc {
  max-width: 800px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}

.legal-doc-header {
  text-align: center;
  margin-bottom: 48px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--color-border);
}

.legal-doc-header h1 {
  font-size: 32px;
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.doc-meta {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.doc-meta-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--color-text-secondary);
  background: var(--color-bg);
  padding: 6px 14px;
  border-radius: 20px;
}

.doc-meta-item strong {
  color: var(--color-text);
  font-weight: 600;
}

/* Legal TOC */
.legal-toc {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 24px 28px;
  margin-bottom: 48px;
}

.legal-toc h3 {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.legal-toc ol {
  list-style: none;
  counter-reset: toc;
  padding: 0;
}

.legal-toc li {
  counter-increment: toc;
  margin-bottom: 6px;
}

.legal-toc li a {
  font-size: 14px;
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 0;
  transition: all 0.2s;
}

.legal-toc li a::before {
  content: counter(toc, cjk-ideographic) '、';
  color: var(--color-text-weak);
  font-size: 13px;
  min-width: 28px;
}

.legal-toc li a:hover {
  color: var(--color-primary);
}

/* Legal body */
.legal-body {
  background: var(--color-surface);
  border-radius: 16px;
  padding: 40px 36px;
  border: 1px solid var(--color-border);
}

.legal-body .doc-intro {
  font-size: 15px;
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: 36px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--color-border);
}

.legal-body h2 {
  font-size: 20px;
  font-weight: 700;
  margin: 40px 0 16px;
  padding-top: 20px;
  color: var(--color-text);
  scroll-margin-top: calc(var(--header-height) + 20px);
}

.legal-body h2:first-of-type {
  margin-top: 0;
  padding-top: 0;
}

.legal-body h3 {
  font-size: 16px;
  font-weight: 600;
  margin: 24px 0 10px;
  color: var(--color-text);
}

.legal-body p {
  font-size: 15px;
  color: var(--color-text-secondary);
  margin-bottom: 12px;
  line-height: 1.8;
}

.legal-body ul, .legal-body ol {
  padding-left: 20px;
  margin-bottom: 16px;
}

.legal-body li {
  font-size: 15px;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
  line-height: 1.7;
}

.legal-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0 24px;
  font-size: 14px;
}

.legal-body table th,
.legal-body table td {
  text-align: left;
  padding: 12px 14px;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

.legal-body table th {
  background: var(--color-bg);
  color: var(--color-text);
  font-weight: 600;
  font-size: 13px;
}

.legal-body table tr:last-child td {
  border-bottom: none;
}

.legal-body strong {
  color: var(--color-text);
  font-weight: 600;
}

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

/* --- Utility --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .hero {
    padding: 56px 20px 48px;
  }
  .hero-logo {
    width: 64px;
    height: 64px;
    margin-bottom: 20px;
  }
  .hero h1 {
    font-size: 32px;
  }
  .hero .tagline {
    font-size: 16px;
    margin-bottom: 28px;
  }
  .hero .cta-btn {
    padding: 12px 28px;
    font-size: 15px;
  }

  .features {
    padding: 48px 20px;
  }
  .features-title {
    font-size: 24px;
  }
  .features-subtitle {
    margin-bottom: 28px;
  }
  .features-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .feature-card {
    padding: 24px 20px;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-surface);
    flex-direction: column;
    padding: 16px 24px;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 8px 24px rgba(0,0,0,0.06);
  }
  .site-nav.open { display: flex; }
  .site-nav a {
    padding: 12px 0;
    border-bottom: 1px solid var(--color-border);
    font-size: 15px;
  }
  .site-nav a:last-child { border-bottom: none; }
  .site-nav .nav-cta {
    margin-top: 8px;
    text-align: center;
    justify-content: center;
    padding: 10px 20px;
    border-bottom: none;
  }
  .nav-toggle { display: block; }

  .section {
    padding: 48px 20px;
  }
  .section h2 {
    font-size: 24px;
  }
  .section .section-desc {
    margin-bottom: 28px;
  }
  .scenario-list {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .scenario-item {
    padding: 24px 20px;
  }

  .footer-inner {
    flex-direction: column;
    gap: 28px;
  }
  .footer-links-group {
    gap: 32px;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }

  .legal-doc {
    padding: 32px 16px 64px;
  }
  .legal-body {
    padding: 28px 20px;
  }
  .legal-doc-header h1 {
    font-size: 24px;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 28px;
  }
  .doc-meta {
    flex-direction: column;
    gap: 8px;
    align-items: center;
  }
  .legal-toc {
    padding: 20px;
  }
}