:root {
  --color-bg: #ffffff;
  --color-text: #1a1a2e;
  --color-text-muted: #5c6370;
  --color-primary: #2d6cdf;
  --color-primary-dark: #1e4fae;
  --color-border: #e5e8ef;
  --color-bg-alt: #f6f8fb;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}

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

.site-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.95rem;
}

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

/* Hero */
.hero {
  padding: 120px 0 100px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.02em;
}

.tagline {
  margin-top: 16px;
  font-size: 1.25rem;
  color: var(--color-text-muted);
}

.btn {
  display: inline-block;
  margin-top: 32px;
  padding: 12px 32px;
  border-radius: 8px;
  font-size: 1rem;
  text-decoration: none;
  transition: background 0.2s ease;
}

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

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

/* Sections */
.section {
  padding: 72px 0;
}

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

.section h2 {
  font-size: 1.75rem;
  margin-bottom: 16px;
}

.section p {
  color: var(--color-text-muted);
  max-width: 640px;
}

/* Grid & Cards */
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 24px;
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 24px;
}

.section-alt .card {
  background: #ffffff;
}

.card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.card p {
  font-size: 0.95rem;
}

/* Hero intro */
.lede {
  margin-top: 20px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
  color: var(--color-text-muted);
  font-size: 1.1rem;
}

/* Contact list */
.contact-list {
  list-style: none;
  max-width: 640px;
  color: var(--color-text-muted);
}

.contact-list li {
  padding: 6px 0;
}

.contact-list a {
  color: var(--color-primary);
  text-decoration: none;
}

.contact-list a:hover {
  text-decoration: underline;
}

/* Policy page */
.policy-meta {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 32px;
}

.section h1 {
  font-size: 2rem;
  margin-bottom: 12px;
}

.section h2 {
  margin-top: 36px;
}

.section ul {
  padding-left: 24px;
  color: var(--color-text-muted);
  max-width: 640px;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 32px 0;
  color: var(--color-text-muted);
  font-size: 0.9rem;
  text-align: center;
}

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

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

.site-footer span[aria-hidden] {
  margin: 0 8px;
}

@media (max-width: 720px) {
  .grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 600px) {
  .site-nav {
    gap: 16px;
  }

  .hero {
    padding: 80px 0 64px;
  }
}