:root {
  --bg: #0b1021;
  --panel: rgba(17, 24, 44, 0.88);
  --panel-soft: #1a2447;
  --text: #ecf1ff;
  --muted: #aab7e6;
  --accent: #7aa2ff;
  --accent-strong: #8dffd4;
  --danger: #ff879c;
  --ring: rgba(122, 162, 255, 0.5);
  --radius: 20px;
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 1rem;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top, #202f61 0%, #0b1021 55%, #060914 100%);
}

.metronome {
  width: min(100%, 480px);
  padding: clamp(1rem, 2vw, 1.5rem);
  border-radius: var(--radius);
  background: var(--panel);
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: var(--shadow);
  backdrop-filter: blur(8px);
}

.metronome__header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  margin-bottom: 1rem;
}

.metronome__header h1 {
  margin: 0;
  font-size: clamp(1.35rem, 2vw, 1.7rem);
}

.metronome__header p {
  margin: 0.25rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.shortcut-hint {
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-bottom-width: 3px;
  border-radius: 0.55rem;
  padding: 0.4rem 0.5rem;
  color: var(--muted);
  user-select: none;
}

.display {
  border-radius: 16px;
  border: 1px solid rgba(255, 255, 255, 0.07);
  background: linear-gradient(180deg, #1d2952 0%, #121a37 100%);
  padding: 1rem;
  transition: box-shadow 180ms ease, border-color 180ms ease;
}

.display.running {
  border-color: rgba(141, 255, 212, 0.4);
  box-shadow: inset 0 0 18px rgba(122, 162, 255, 0.18);
}

.tempo-readout {
  text-align: center;
}

.tempo-readout span {
  font-weight: 800;
  font-size: clamp(2.8rem, 7vw, 3.8rem);
  line-height: 1;
  letter-spacing: 0.04em;
  display: inline-block;
}

.tempo-readout span.pulse {
  animation: bpmPulse 200ms ease-out;
}

.pendulum-wrap {
  height: 88px;
  display: grid;
  place-items: center;
  margin-top: 0.6rem;
  overflow: hidden;
}

.pendulum {
  position: relative;
  width: 10px;
  height: 70px;
  border-radius: 999px;
  background: linear-gradient(180deg, #a8ffd4 0%, #7aa2ff 100%);
  box-shadow: 0 0 16px rgba(122, 162, 255, 0.45);
  transform-origin: 50% calc(100% - 4px);
  transform: rotate(var(--pendulum-angle, 0deg));
  transition: transform var(--swing-duration, 180ms) cubic-bezier(0.2, 0.72, 0.2, 1);
}

.pendulum::before {
  content: "";
  position: absolute;
  top: -13px;
  left: 50%;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  transform: translateX(-50%);
  background: radial-gradient(circle at 35% 30%, #e7fff2 0%, #8dffd4 45%, #5b7dff 100%);
  box-shadow: 0 4px 12px rgba(7, 12, 28, 0.45);
}

.pendulum::after {
  content: "";
  position: absolute;
  bottom: -7px;
  left: 50%;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  transform: translateX(-50%);
  background: #d6e6ff;
  box-shadow: 0 0 0 2px rgba(122, 162, 255, 0.35);
}

.tempo-readout small {
  display: block;
  color: var(--muted);
  margin-top: 0.25rem;
}

.beat-indicators {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0.6rem;
  margin-top: 1rem;
}

.beat-dot {
  aspect-ratio: 1;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.15);
  transform: scale(1);
  transition: transform 120ms ease, background-color 120ms ease, box-shadow 120ms ease;
}

.beat-dot.active {
  background: var(--accent);
  box-shadow: 0 0 14px rgba(122, 162, 255, 0.75);
  transform: scale(1.15);
  animation: beatPop 180ms ease-out;
}

.beat-dot.accent.active {
  background: var(--accent-strong);
  box-shadow: 0 0 16px rgba(141, 255, 212, 0.85);
}

.control-grid,
.row-controls,
.button-grid {
  margin-top: 1rem;
}

.control-label,
.stacked-field span {
  display: block;
  margin-bottom: 0.45rem;
  color: var(--muted);
  font-size: 0.95rem;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
  min-height: 2.6rem;
}

.tempo-buttons,
.button-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.65rem;
  margin-top: 0.65rem;
}

.button-grid.single-row {
  grid-template-columns: 1fr;
}

.row-controls {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  align-items: end;
  gap: 0.8rem;
}

select,
button {
  border: none;
  border-radius: 12px;
  min-height: 3rem;
  padding: 0.65rem 0.8rem;
  font-size: 1rem;
  font-weight: 700;
}

select,
button:not(.primary) {
  background: var(--panel-soft);
  color: var(--text);
}

button {
  cursor: pointer;
  transition: transform 120ms ease, filter 120ms ease;
}

button:hover {
  filter: brightness(1.06);
}

button:active {
  transform: translateY(1px);
}

button.primary {
  background: linear-gradient(135deg, var(--accent), #9a88ff);
  color: #0a1020;
}

button.primary.running {
  background: linear-gradient(135deg, var(--danger), #ffb36b);
}

button.off {
  background: linear-gradient(135deg, #3e4d78, #2e3859);
  color: var(--muted);
}

.toggle-sound {
  display: inline-flex;
  gap: 0.5rem;
  align-items: center;
  color: var(--muted);
  font-weight: 600;
}

.toggle-sound input {
  width: 1.15rem;
  height: 1.15rem;
  accent-color: var(--accent);
}

.help-text {
  margin-top: 1rem;
  color: var(--muted);
  text-align: center;
  font-size: 0.88rem;
}

@keyframes beatPop {
  0% {
    transform: scale(0.92);
  }
  55% {
    transform: scale(1.22);
  }
  100% {
    transform: scale(1.15);
  }
}

@keyframes bpmPulse {
  0% {
    transform: scale(1);
    text-shadow: 0 0 0 rgba(141, 255, 212, 0);
  }
  50% {
    transform: scale(1.06);
    text-shadow: 0 0 14px rgba(141, 255, 212, 0.5);
  }
  100% {
    transform: scale(1);
    text-shadow: 0 0 0 rgba(141, 255, 212, 0);
  }
}

:focus-visible {
  outline: 2px solid var(--ring);
  outline-offset: 2px;
}

@media (max-width: 520px) {
  .row-controls,
  .tempo-buttons,
  .button-grid {
    grid-template-columns: 1fr;
  }

  .beat-indicators {
    gap: 0.45rem;
  }

  .help-text {
    font-size: 0.82rem;
  }
}