:root {
  --bg: #f5f6fa;
  --card-bg: #ffffff;
  --text: #1f2430;
  --muted: #6b7280;
  --accent: #3b6ef5;
  --accent-text: #ffffff;
  --border: #e2e5ee;
}

body.dark {
  --bg: #14161d;
  --card-bg: #1e222d;
  --text: #e8eaf1;
  --muted: #9aa1b2;
  --accent: #5b85ff;
  --accent-text: #ffffff;
  --border: #2c3140;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background 0.2s, color 0.2s;
}

.site-header {
  padding: 2rem 1.5rem 1rem;
  text-align: center;
  position: relative;
}

.site-header h1 { margin: 0 0 0.25rem; }

.subtitle { color: var(--muted); margin: 0; }

#theme-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 1rem 1.5rem 3rem;
  display: grid;
  gap: 1.25rem;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
}

.card h2 { margin-top: 0; }

.row { display: flex; gap: 0.5rem; flex-wrap: wrap; }

button {
  background: var(--accent);
  color: var(--accent-text);
  border: none;
  border-radius: 8px;
  padding: 0.5rem 1rem;
  font-size: 1rem;
  cursor: pointer;
}

button:hover { filter: brightness(1.1); }

form { display: grid; gap: 0.75rem; }

label { display: grid; gap: 0.25rem; font-size: 0.9rem; }

.checkbox-label { display: flex; align-items: center; gap: 0.5rem; }

input[type="text"], input[type="email"], select {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 1rem;
}

pre {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  overflow-x: auto;
  font-size: 0.85rem;
}

.site-footer {
  text-align: center;
  padding: 1rem;
  color: var(--muted);
}