/* 参识AI - Brand Style */
:root {
  --color-primary: #1a56db;
  --color-primary-dark: #1e40af;
  --color-accent: #0ea5e9;
  --color-bg: #ffffff;
  --color-bg-alt: #f8fafc;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --max-width: 1100px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: 0.5px;
}

.site-logo span {
  color: var(--color-accent);
}

.site-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  margin-left: 32px;
  font-size: 0.95rem;
  transition: color 0.2s;
}

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

/* Hero */
.hero {
  padding: 80px 24px 64px;
  text-align: center;
  background: linear-gradient(180deg, #eff6ff 0%, var(--color-bg) 100%);
}

.hero h1 {
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--color-text);
  max-width: 720px;
  margin: 0 auto 20px;
  line-height: 1.3;
}

.hero .highlight {
  color: var(--color-primary);
}

.hero .subtitle {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto 36px;
}

.hero-cta {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 12px 32px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: #fff;
}

/* Sections */
.section {
  padding: 72px 24px;
}

.section-alt {
  background: var(--color-bg-alt);
}

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

.section-title {
  font-size: 1.8rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
}

.section-desc {
  text-align: center;
  color: var(--color-text-muted);
  max-width: 640px;
  margin: 0 auto 48px;
  font-size: 1.05rem;
}

/* Value Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 32px;
  transition: box-shadow 0.2s, transform 0.2s;
}

.card:hover {
  box-shadow: 0 4px 24px rgba(0,0,0,0.06);
  transform: translateY(-2px);
}

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.card-icon.blue { background: #eff6ff; color: var(--color-primary); }
.card-icon.green { background: #f0fdf4; color: #16a34a; }
.card-icon.purple { background: #faf5ff; color: #9333ea; }

.card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.card p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* Features */
.feature-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  margin-bottom: 64px;
}

.feature-row:last-child {
  margin-bottom: 0;
}

.feature-text h3 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.feature-text p {
  color: var(--color-text-muted);
  margin-bottom: 8px;
}

.feature-visual {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 48px;
  text-align: center;
  font-size: 3rem;
}

/* FAQ */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--color-border);
  padding: 24px 0;
}

.faq-item:first-child {
  border-top: 1px solid var(--color-border);
}

.faq-item dt {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-text);
}

.faq-item dd {
  color: var(--color-text-muted);
  margin-left: 0;
}

/* CTA */
.cta-section {
  text-align: center;
  padding: 72px 24px;
  background: linear-gradient(180deg, var(--color-bg) 0%, #eff6ff 100%);
}

.cta-section h2 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.cta-section p {
  color: var(--color-text-muted);
  margin-bottom: 28px;
}

/* Footer */
.site-footer {
  background: var(--color-text);
  color: #cbd5e1;
  padding: 40px 24px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.footer-inner h4 {
  color: #fff;
  font-size: 0.95rem;
  margin-bottom: 12px;
}

.footer-inner p {
  font-size: 0.88rem;
  line-height: 1.8;
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 32px auto 0;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.1);
  text-align: center;
  font-size: 0.82rem;
  color: #94a3b8;
}

/* Breadcrumb */
.breadcrumb {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 24px 0;
  font-size: 0.88rem;
  color: var(--color-text-muted);
}

.breadcrumb a {
  color: var(--color-text-muted);
  text-decoration: none;
}

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

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

/* Page header for inner pages */
.page-header {
  padding: 48px 24px 24px;
  text-align: center;
}

.page-header h1 {
  font-size: 2rem;
  font-weight: 800;
}

.page-header p {
  color: var(--color-text-muted);
  margin-top: 8px;
}

.content-section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 24px 64px;
}

/* Responsive */
@media (max-width: 768px) {
  .site-nav a {
    margin-left: 16px;
    font-size: 0.85rem;
  }
  .hero h1 {
    font-size: 1.8rem;
  }
  .feature-row {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .footer-inner {
    grid-template-columns: 1fr;
  }
  .section {
    padding: 48px 16px;
  }
}