:root {
  --bg: #0f1115;
  --panel: #171a21;
  --fg: #f2f4f8;
  --muted: #8b93a7;
  --accent: #4ade80;
  --accent-dark: #22c55e;
  --danger: #f87171;
  --border: #262b36;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f6f8;
    --panel: #ffffff;
    --fg: #14171f;
    --muted: #6b7280;
    --accent: #16a34a;
    --accent-dark: #15803d;
    --danger: #dc2626;
    --border: #e3e6eb;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 24px;
  background: var(--bg);
  color: var(--fg);
  font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", "Noto Sans JP", system-ui, sans-serif;
}

.app {
  width: 100%;
  max-width: 420px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px 24px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, .18);
}

.title {
  margin: 0 0 20px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .12em;
  text-align: center;
  color: var(--muted);
}

.display {
  text-align: center;
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: clamp(44px, 14vw, 64px);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: 24px;
}

.display .ms {
  font-size: .5em;
  color: var(--muted);
}

.controls {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 10px;
}

.btn {
  padding: 13px 8px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: transparent;
  color: var(--fg);
  font-size: 15px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background .15s, opacity .15s, transform .05s;
}

.btn:hover:not(:disabled) { background: rgba(127, 127, 127, .12); }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:disabled { opacity: .38; cursor: default; }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #06210f;
}
.btn-primary:hover:not(:disabled) { background: var(--accent-dark); border-color: var(--accent-dark); }

.btn-primary.running {
  background: var(--danger);
  border-color: var(--danger);
  color: #2a0707;
}
.btn-primary.running:hover:not(:disabled) { filter: brightness(.92); background: var(--danger); }

.laps {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  max-height: 220px;
  overflow-y: auto;
  font-variant-numeric: tabular-nums;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 14px;
}

.laps:empty { margin: 0; }

.laps li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 9px 4px;
  border-top: 1px solid var(--border);
}

.laps li .no { color: var(--muted); font-weight: 600; }
.laps li .split { color: var(--muted); }

.hint {
  margin: 0;
  font-size: 12px;
  color: var(--muted);
  text-align: center;
}