:root {
  --bg: #f4f6f8;
  --card: #ffffff;
  --text: #1c2733;
  --muted: #5b6b7b;
  --accent: #1a7f4e;
  --accent-dark: #14663e;
  --border: #d6dee6;
  --notice-bg: #fff6e0;
  --notice-border: #e6c96a;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141a21;
    --card: #1e262f;
    --text: #e8edf2;
    --muted: #9aa8b6;
    --accent: #2fa76c;
    --accent-dark: #278f5c;
    --border: #35404c;
    --notice-bg: #3a3421;
    --notice-border: #8a7a3a;
  }
}

* { box-sizing: border-box; }
*
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  padding: 2rem 1rem;
}

main { width: 100%; max-width: 30rem; }

h1 { font-size: 1.5rem; margin: 0 0 0.25rem; }

.sub { color: var(--muted); margin: 0 0 1.5rem; font-size: 0.95rem; }

form, #result {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
}

fieldset { border: 0; margin: 0 0 1rem; padding: 0; }

label { display: block; font-weight: 600; margin-bottom: 0.3rem; font-size: 0.95rem; }

.hint { font-weight: 400; color: var(--muted); font-size: 0.85rem; }

input[type="number"], input[type="time"], select {
  width: 100%;
  padding: 0.55rem 0.7rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
}

.row { display: flex; gap: 1rem; }

.row > div { flex: 1; }

.radio-group { display: flex; gap: 1.25rem; margin-top: 0.4rem; }

.radio-group label { font-weight: 400; display: flex; align-items: center; gap: 0.35rem; margin: 0; }

.radio-group[hidden] { display: none; }

button {
  width: 100%;
  padding: 0.7rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: 0;
  border-radius: 8px;
  cursor: pointer;
}

button:hover { background: var(--accent-dark); }

button:disabled { opacity: 0.6; cursor: wait; }

#result { margin-top: 1rem; display: none; }

#result.visible { display: block; }

.notice {
  background: var(--notice-bg);
  border: 1px solid var(--notice-border);
  border-radius: 8px;
  padding: 0.6rem 0.8rem;
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.error { color: #c0392b; font-weight: 600; }

.big { font-size: 1.6rem; font-weight: 700; color: var(--accent); }

.accent { color: var(--accent); font-weight: 700; }

dl { margin: 0; }

dt { font-size: 0.85rem; color: var(--muted); margin-top: 0.75rem; }

dd { margin: 0.1rem 0 0; font-size: 1.1rem; font-weight: 600; }