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

:root {
  --bg: #0f172a;
  --card: #1e293b;
  --border: #334155;
  --text: #cbd5e1;
  --text-light: #94a3b8;
  --heading: #f1f5f9;
  --accent: #34d399;
  --accent-dark: #059669;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}
.header-inner {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.header-inner img { width: 32px; height: 32px; border-radius: 8px; }
.header-inner a {
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--heading);
  text-decoration: none;
}
.header-inner a:hover { color: var(--accent); }

/* Navigation */
nav { border-bottom: 1px solid var(--border); }
nav ul {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
  list-style: none;
  display: flex;
  gap: 0.25rem;
  overflow-x: auto;
}
nav a {
  display: block;
  padding: 0.75rem 1rem;
  color: var(--text-light);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}
nav a:hover, nav a.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* Language switcher */
.lang-switch {
  max-width: 800px;
  margin: 0 auto;
  padding: 1rem 1.5rem 0;
  text-align: right;
}
.lang-switch a {
  color: var(--text-light);
  text-decoration: none;
  font-size: 0.8125rem;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  transition: color 0.2s, background 0.2s;
}
.lang-switch a:hover, .lang-switch a.active {
  color: var(--accent);
  background: rgba(52, 211, 153, 0.1);
}

/* Main content */
main {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

h1 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--heading);
  margin-bottom: 0.5rem;
}
h2 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--accent);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}
p { margin-bottom: 1rem; }
ul, ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}
li { margin-bottom: 0.5rem; }
strong { color: var(--heading); }

.subtitle {
  color: var(--text-light);
  font-size: 0.875rem;
  margin-bottom: 2rem;
}

/* Guide sections */
.guide-section {
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 0.75rem;
  background: var(--card);
  overflow: hidden;
}
.guide-section summary {
  padding: 1rem 1.25rem;
  font-weight: 600;
  font-size: 1.0625rem;
  color: var(--heading);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: color 0.2s;
}
.guide-section summary::-webkit-details-marker { display: none; }
.guide-section summary::before {
  content: '▶';
  font-size: 0.625rem;
  color: var(--accent);
  transition: transform 0.2s;
  flex-shrink: 0;
}
.guide-section[open] > summary::before {
  transform: rotate(90deg);
}
.guide-section summary:hover { color: var(--accent); }
.guide-section-content {
  padding: 0 1.25rem 1.25rem;
  border-top: 1px solid var(--border);
}
.guide-intro {
  color: var(--text-light);
  font-size: 0.875rem;
  margin-top: 1rem;
  margin-bottom: 0.75rem;
}
.guide-section-content h4 {
  color: #38bdf8;
  font-size: 0.9375rem;
  font-weight: 600;
  margin-top: 1.25rem;
  margin-bottom: 0.5rem;
}
.guide-section-content ol {
  padding-left: 1.5rem;
  margin-bottom: 0;
}
.guide-section-content li {
  font-size: 0.875rem;
  color: var(--text);
  margin-bottom: 0.375rem;
  line-height: 1.6;
}

/* FAQ */
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 0;
}
.faq-item:last-child { border-bottom: none; }
.faq-q {
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 0.5rem;
}
.faq-a { color: var(--text-light); margin: 0; }

/* Hero (landing page) */
.hero {
  text-align: center;
  padding: 3rem 0;
}
.hero img { width: 80px; height: 80px; border-radius: 16px; margin-bottom: 1rem; }
.hero h1 { font-size: 2.25rem; margin-bottom: 0.25rem; }
.hero .slogan { color: var(--accent); font-size: 1rem; margin-bottom: 2rem; }
.hero .desc { max-width: 560px; margin: 0 auto 2rem; color: var(--text-light); }

.feature-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 2rem 0;
}
.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
}
.feature-card h3 {
  color: var(--heading);
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 0.375rem;
}
.feature-card p { color: var(--text-light); font-size: 0.8125rem; margin: 0; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-light);
  font-size: 0.8125rem;
}
.site-footer a { color: var(--accent); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

/* Responsive */
@media (max-width: 640px) {
  .feature-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 1.75rem; }
}