:root {
  --bg: #0f0f0f;
  --card: #1a1a1a;
  --text: #ffffff;
  --text-muted: #9ca3af;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --danger: #ef4444;
  --border: #2a2a2a;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, sans-serif;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.timer-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 1.5rem;
  padding: 3rem 4rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  min-width: 320px;
}

/* ── Display ── */
.display {
  font-family: 'Courier New', Courier, monospace;
  font-size: clamp(4rem, 15vw, 8rem);
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text);
  transition: color 0.3s;
  user-select: none;
}

.display-cs {
  font-size: 0.5em;
  opacity: 0.65;
  vertical-align: baseline;
  letter-spacing: 0;
}

.display.expired {
  color: var(--danger);
  animation: pulse 0.8s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.3; }
}

/* ── Inputs ── */
.inputs {
  display: flex;
  align-items: flex-end;
  gap: 0.5rem;
}

.inputs label {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
}

.inputs label span {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.inputs input[type="number"] {
  width: 5rem;
  padding: 0.5rem 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  color: var(--text);
  font-size: 1.5rem;
  font-family: 'Courier New', Courier, monospace;
  text-align: center;
  outline: none;
  transition: border-color 0.2s;
  -moz-appearance: textfield;
}

.inputs input[type="number"]::-webkit-inner-spin-button,
.inputs input[type="number"]::-webkit-outer-spin-button {
  opacity: 1;
}

.inputs input[type="number"]:focus {
  border-color: var(--accent);
}

.inputs .colon {
  font-size: 2rem;
  font-weight: 700;
  padding-bottom: 0.25rem;
  color: var(--text-muted);
}

/* ── Controls ── */
.controls {
  display: flex;
  gap: 1rem;
}

button {
  padding: 0.6rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}

button:active {
  transform: scale(0.97);
}

#btnStartPause {
  background: var(--accent);
  color: #fff;
}

#btnStartPause:hover {
  background: var(--accent-hover);
}

button.secondary {
  background: var(--border);
  color: var(--text-muted);
}

button.secondary:hover {
  background: #3a3a3a;
  color: var(--text);
}