:root {
  color-scheme: dark;
  --bg: #0f1115;
  --card: rgba(24, 27, 35, 0.9);
  --card-border: rgba(255, 255, 255, 0.08);
  --text: #f5f7fb;
  --muted: #9ca7b8;
  --accent: #ff6b6b;
  --accent-soft: rgba(255, 107, 107, 0.14);
  --button: #1f2430;
  --button-border: rgba(255, 255, 255, 0.08);
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.38);
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top, rgba(255, 107, 107, 0.18), transparent 30%),
    linear-gradient(180deg, #161922, var(--bg));
}
.app-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 20px;
}
.timer-card {
  width: min(100%, 460px);
  padding: 28px;
  border-radius: 28px;
  background: var(--card);
  border: 1px solid var(--card-border);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}
.header { text-align: center; }
.eyebrow {
  margin: 0 0 10px;
  color: var(--accent);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: 12px;
  font-weight: 700;
}
h1 {
  margin: 0;
  font-size: clamp(28px, 6vw, 38px);
}
.subtitle {
  margin: 10px 0 0;
  color: var(--muted);
  line-height: 1.6;
}
.modes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 24px;
}
.mode-btn,
.primary-btn,
.secondary-btn {
  border: 0;
  border-radius: 999px;
  padding: 12px 16px;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
.mode-btn {
  color: var(--text);
  background: var(--button);
  border: 1px solid var(--button-border);
}
.mode-btn.active {
  background: var(--accent-soft);
  color: #fff;
  border-color: rgba(255, 107, 107, 0.4);
}
.dial-wrap {
  position: relative;
  width: min(100%, 320px);
  margin: 26px auto 0;
}
.dial {
  width: 100%;
  display: block;
  transform: rotate(-90deg);
}
.dial-track,
.dial-progress {
  fill: none;
  stroke-width: 14;
}
.dial-track { stroke: rgba(255,255,255,0.08); }
.dial-progress {
  stroke: var(--accent);
  stroke-linecap: round;
  transition: stroke-dashoffset 0.4s ease;
}
.dial-content {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  text-align: center;
}
.dial-label {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 14px;
}
.time-display {
  margin: 0;
  font-size: clamp(52px, 14vw, 72px);
  font-weight: 800;
  letter-spacing: -0.04em;
}
.session-hint {
  margin: 10px 0 0;
  color: var(--muted);
}
.controls {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 24px;
}
.primary-btn {
  background: var(--accent);
  color: #0f1115;
}
.secondary-btn {
  background: var(--button);
  color: var(--text);
  border: 1px solid var(--button-border);
}
.quick-settings {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 22px;
}
.quick-settings label,
.checkbox-row {
  color: var(--muted);
  font-size: 14px;
}
.quick-settings label {
  display: grid;
  gap: 8px;
}
.quick-settings input[type="number"] {
  width: 100%;
  border-radius: 14px;
  border: 1px solid var(--button-border);
  background: #12161f;
  color: var(--text);
  padding: 12px;
  font: inherit;
}
.footer {
  margin-top: 22px;
  display: grid;
  gap: 14px;
}
.checkbox-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.tip {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}
@media (max-width: 560px) {
  .timer-card { padding: 20px; border-radius: 22px; }
  .modes,
  .quick-settings,
  .controls { grid-template-columns: 1fr; }
}