:root {
  --color-primary: #1e40af;
  --color-primary-hover: #1e3a8a;
  --color-accent: #60a5fa;
  --color-text: #1f2937;
  --color-text-soft: #4b5563;
  --color-text-muted: #6b7280;
  --color-bg: #ffffff;
  --color-bg-soft: #f9fafb;
  --color-border: #e5e7eb;
  --max-width: 720px;
  --radius: 12px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

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

.lang-bar {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  padding: 16px 24px;
  font-size: 14px;
  color: var(--color-text-muted);
}

.lang-bar a {
  color: var(--color-text-muted);
}

.lang-bar a.active {
  color: var(--color-primary);
  font-weight: 600;
}

.hero {
  padding: 64px 0 48px;
  text-align: center;
}

.hero img.logo {
  width: 80px;
  height: 80px;
  margin-bottom: 24px;
}

.hero h1 {
  margin: 0 0 12px;
  font-size: 34px;
  letter-spacing: -0.02em;
}

.hero .subtitle {
  margin: 0 0 8px;
  font-size: 18px;
  color: var(--color-text-soft);
}

.hero .tagline {
  margin: 0 0 32px;
  font-size: 15px;
  color: var(--color-text-muted);
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: 16px;
  font-weight: 600;
  background: var(--color-primary);
  color: #fff;
  border: none;
  cursor: pointer;
  transition: background 0.15s;
}

.btn:hover {
  background: var(--color-primary-hover);
  text-decoration: none;
}

.btn[aria-disabled="true"] {
  background: var(--color-text-muted);
  cursor: not-allowed;
}

.features {
  display: grid;
  gap: 24px;
  padding: 32px 0;
  grid-template-columns: 1fr;
}

.feature {
  padding: 20px;
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.feature h3 {
  margin: 0 0 8px;
  font-size: 16px;
}

.feature p {
  margin: 0;
  font-size: 14px;
  color: var(--color-text-soft);
}

.legal {
  padding: 48px 0 24px;
}

.legal h1 {
  margin: 0 0 8px;
  font-size: 28px;
}

.legal .effective {
  margin: 0 0 32px;
  font-size: 14px;
  color: var(--color-text-muted);
}

.legal h2 {
  margin: 32px 0 8px;
  font-size: 18px;
}

.legal h3 {
  margin: 16px 0 8px;
  font-size: 16px;
}

.legal p,
.legal li {
  font-size: 15px;
  color: var(--color-text);
}

.legal ul {
  padding-left: 20px;
}

.legal a {
  word-break: break-all;
}

.footer {
  margin-top: 48px;
  padding: 32px 0;
  border-top: 1px solid var(--color-border);
  font-size: 14px;
  color: var(--color-text-muted);
  text-align: center;
}

.footer .links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 12px;
}

.footer .links a {
  color: var(--color-text-soft);
}

.footer .copyright {
  color: var(--color-text-muted);
}

@media (min-width: 640px) {
  .hero {
    padding: 96px 0 64px;
  }

  .hero h1 {
    font-size: 42px;
  }

  .hero .subtitle {
    font-size: 20px;
  }

  .features {
    grid-template-columns: 1fr 1fr 1fr;
  }
}