:root {
  --blue: #4a7fc1;
  --coral: #e87272;
  --bg: #f8f9fa;
  --card: #ffffff;
  --text: #1a1a2e;
  --muted: #6c757d;
  --border: #e9ecef;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Hiragino Sans', 'Yu Gothic UI',
    'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 15px;
}

/* Header */
.site-header {
  background: linear-gradient(135deg, var(--blue) 0%, #3a6aa8 100%);
  color: white;
  padding: 40px 20px 32px;
  text-align: center;
}

.site-header img {
  width: 88px;
  height: 88px;
  border-radius: 20px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
  margin-bottom: 16px;
}

.site-header h1 {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.01em;
  margin-bottom: 4px;
}

.site-header .subtitle {
  font-size: 13px;
  opacity: 0.82;
}

/* Nav */
nav {
  background: white;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: center;
  gap: 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 14px 24px;
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

nav a:hover,
nav a.active {
  color: var(--blue);
  border-bottom-color: var(--blue);
}

/* Main */
main {
  max-width: 760px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

/* Page title */
.page-title {
  margin-bottom: 28px;
}

.page-title h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}

.page-title .updated {
  font-size: 12px;
  color: var(--muted);
}

/* Lang toggle */
.lang-toggle {
  display: flex;
  gap: 8px;
  margin-bottom: 28px;
}

.lang-btn {
  padding: 6px 16px;
  border-radius: 20px;
  border: 1.5px solid var(--border);
  background: white;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  color: var(--muted);
  transition: all 0.15s;
}

.lang-btn.active {
  background: var(--blue);
  border-color: var(--blue);
  color: white;
}

/* Content sections */
.lang-content {
  display: none;
}

.lang-content.active {
  display: block;
}

/* Section */
.section {
  background: var(--card);
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 16px;
  border: 1px solid var(--border);
}

.section h3 {
  font-size: 15px;
  font-weight: 700;
  color: var(--blue);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.section h3::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 16px;
  background: var(--coral);
  border-radius: 2px;
  flex-shrink: 0;
}

.section p {
  color: var(--text);
  margin-bottom: 10px;
}

.section p:last-child {
  margin-bottom: 0;
}

.section ul,
.section ol {
  padding-left: 20px;
  color: var(--text);
}

.section li {
  margin-bottom: 6px;
}

/* Table */
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin-top: 8px;
}

th {
  background: var(--bg);
  padding: 10px 12px;
  text-align: left;
  font-weight: 600;
  font-size: 12px;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
}

td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

tr:last-child td {
  border-bottom: none;
}

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

td a:hover {
  text-decoration: underline;
}

/* Footer */
footer {
  text-align: center;
  padding: 32px 20px;
  font-size: 12px;
  color: var(--muted);
  border-top: 1px solid var(--border);
}

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

footer a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 480px) {
  .site-header {
    padding: 28px 16px 24px;
  }

  .site-header img {
    width: 72px;
    height: 72px;
  }

  nav a {
    padding: 12px 16px;
    font-size: 12px;
  }

  .section {
    padding: 18px 16px;
  }
}