:root {
  --bg: #ffffff;
  --text: #1a1a2e;
  --text-secondary: #555;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --border: #e5e7eb;
  --card-bg: #f9fafb;
  --code-bg: #f3f4f6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --accent: #60a5fa;
    --accent-hover: #93bbfc;
    --border: #334155;
    --card-bg: #1e293b;
    --code-bg: #1e293b;
  }
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Noto Sans JP", sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 780px;
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
}

header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

header .meta {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

h2 {
  font-size: 1.35rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--border);
}

h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-top: 1.75rem;
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1rem;
}

ul,
ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.35rem;
}

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

a:hover {
  text-decoration: underline;
  color: var(--accent-hover);
}

.format-links {
  display: flex;
  gap: 1rem;
  margin-top: 0.5rem;
  font-size: 0.85rem;
}

.format-links a {
  padding: 0.25rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  transition: background 0.15s;
}

.format-links a:hover {
  background: var(--card-bg);
  text-decoration: none;
}

footer {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-align: center;
}

/* Index page styles */
.doc-list {
  list-style: none;
  padding: 0;
}

.doc-list li {
  margin-bottom: 1.5rem;
  padding: 1.25rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card-bg);
}

.doc-list li h3 {
  margin-top: 0;
  margin-bottom: 0.4rem;
}

.doc-list li p {
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}