:root {
  --bg: #f7f7f7;
  --panel: #ffffff;
  --border: #ddd;
  --text: #222;
  --muted: #666;
  --accent: #2e6df5;
  --hover-bg: #f0f4ff;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #181a1f;
    --panel: #23262d;
    --border: #3a3d44;
    --text: #e6e6e6;
    --muted: #999;
    --accent: #6da0ff;
    --hover-bg: #2a2f3a;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

header {
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 1.5rem;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  max-width: 1100px;
  margin: 0 auto;
  flex-wrap: wrap;
}

header h1 {
  margin: 0;
  font-size: 1.5rem;
  letter-spacing: 0.02em;
}

header p {
  margin: 0.25rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.lang-switch {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.lang-switch button {
  padding: 0.4rem 0.75rem;
  border: 0;
  border-radius: 0;
  background: var(--panel);
  color: var(--muted);
  font-size: 0.85rem;
  font: inherit;
  cursor: pointer;
}

.lang-switch button.active {
  background: var(--accent);
  color: #fff;
}

.lang-switch button:not(.active):hover {
  background: var(--bg);
  color: var(--text);
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  transition: border-color 0.15s ease, transform 0.15s ease;
  display: flex;
  flex-direction: column;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.card-link {
  display: block;
  padding: 1.25rem 1.25rem 0.75rem;
  text-decoration: none;
  color: inherit;
  flex: 1;
}

.card-link:hover {
  background: var(--hover-bg);
}

.card-icon {
  color: var(--accent);
  margin-bottom: 0.5rem;
  line-height: 0;
}

.card h2 {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
}

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.card-meta {
  padding: 0.5rem 1.25rem 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
}

.card-meta a {
  color: var(--muted);
  text-decoration: none;
}

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

.about {
  margin-top: 2.5rem;
  padding: 1.25rem 1.5rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.about h2 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
}

.about p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.about code {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.05rem 0.3rem;
  font-size: 0.85em;
}

footer {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--muted);
  font-size: 0.85rem;
}

footer a {
  color: var(--muted);
}