:root {
  color-scheme: light dark;
  --bg: #fafafa;
  --text: #262626;
  --text-secondary: #5a5a5a;
  --card-bg: #ffffff;
  --border: #e2e2e2;
  --accent: #007acc;
  --accent-dark: #005a99;
  --code-bg: #f0f0f0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16181c;
    --text: #e8e8e8;
    --text-secondary: #a8a8a8;
    --card-bg: #1f2227;
    --border: #30343a;
    --accent: #4db8ff;
    --accent-dark: #2a8fd6;
    --code-bg: #262a30;
  }
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  margin: 0;
  padding: 0;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

a {
  color: var(--accent);
}

.topnav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding: 10px 20px;
  font-size: 0.85rem;
}

.nav-links,
.lang-switch {
  display: flex;
  gap: 4px;
}

.topnav a {
  text-decoration: none;
  color: var(--text-secondary);
  padding: 4px 8px;
  border-radius: 4px;
}

.topnav a.active,
.topnav a:hover {
  color: var(--text);
  background: var(--code-bg);
}

.hero {
  text-align: center;
  padding: 64px 20px;
  background: linear-gradient(135deg, var(--accent-dark), var(--accent));
  color: white;
}

.hero h1 {
  font-size: 2.75rem;
  margin: 0 0 10px;
  letter-spacing: -0.02em;
}

.subtitle {
  font-size: 1.15rem;
  margin: 0 auto 30px;
  max-width: 640px;
  opacity: 0.95;
}

.download-buttons {
  margin-top: 20px;
}

.button {
  display: inline-block;
  padding: 12px 24px;
  margin: 5px;
  border-radius: 6px;
  text-decoration: none;
  font-weight: 600;
}

.button.primary {
  background: white;
  color: var(--accent-dark);
}

.button.secondary {
  background: rgba(255, 255, 255, 0.15);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.button.primary:hover {
  background: #eef6fc;
}

.button.secondary:hover {
  background: rgba(255, 255, 255, 0.25);
}

main {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  margin: 48px auto;
}

section:first-of-type {
  margin-top: 40px;
}

h2 {
  font-size: 1.5rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}

main ol {
  padding-left: 1.4em;
}

main ol li {
  margin-bottom: 12px;
  padding-left: 6px;
}

.features {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 12px;
}

.features li {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
}

.features li strong {
  color: var(--accent);
}

code {
  background: var(--code-bg);
  border-radius: 4px;
  padding: 1px 5px;
  font-size: 0.92em;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 12px;
}

th, td {
  text-align: left;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}

th {
  color: var(--text-secondary);
  font-weight: 600;
}

/* Architecture diagram */
.arch-diagram {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin: 24px 0;
}

.arch-box {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  min-width: 150px;
  text-align: center;
  font-size: 0.9rem;
}

.arch-box .label {
  display: block;
  font-weight: 600;
  margin-bottom: 4px;
}

.arch-box .sub {
  display: block;
  color: var(--text-secondary);
  font-size: 0.8rem;
}

.arch-arrow {
  font-size: 1.4rem;
  color: var(--text-secondary);
}

.arch-side {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px dashed var(--border);
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-align: center;
}

footer {
  text-align: center;
  margin: 40px 0 60px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

footer a {
  color: var(--text-secondary);
  margin: 0 6px;
}

@media (max-width: 600px) {
  .hero h1 {
    font-size: 2.1rem;
  }
  .arch-arrow {
    transform: rotate(90deg);
  }
}