:root {
  --bg: #0f172a;
  --panel: #111827;
  --text: #e5e7eb;
  --sub: #9ca3af;
  --accent: #22c55e;
  --danger: #ef4444;
}

* {
  box-sizing: border-box;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, sans-serif;
  margin: 0;
  padding: 20px;
  min-height: 100vh;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  background: var(--panel);
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

header {
  text-align: center;
  margin-bottom: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header h1 {
  margin: 0;
  font-size: 24px;
}

#totalTime {
  font-size: 14px;
  color: var(--sub);
}

/* Tabs */
.tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  border-bottom: 2px solid #263146;
  flex-wrap: wrap;
}

.tab {
  padding: 10px 15px;
  background: transparent;
  border: none;
  color: var(--sub);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all 0.2s;
}

.tab:hover {
  color: var(--text);
}

.tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* Controls */
.controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 15px;
  margin-bottom: 20px;
}

.control {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.control label {
  font-size: 12px;
  color: var(--sub);
  font-weight: 500;
  text-transform: uppercase;
}

.input-group {
  display: flex;
  gap: 8px;
  align-items: center;
}

input[type="number"],
input[type="range"],
select,
.btn {
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid #263146;
  background: #0b1220;
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.2s;
}

input[type="number"]:focus,
input[type="range"]:focus,
select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(34, 197, 94, 0.1);
}

input[type="range"] {
  flex: 1;
  min-width: 80px;
}

select {
  min-width: 60px;
}

.control.bpm .input-group {
  flex-direction: column;
}

.control.bpm input[type="number"] {
  width: 100%;
}

.control.time-sig .input-group {
  align-items: center;
  gap: 4px;
}

.control.time-sig select {
  flex: 1;
  max-width: 80px;
}

.control.time-sig span {
  color: var(--sub);
  font-weight: bold;
}

/* Buttons */
.btn {
  padding: 10px 16px;
  font-weight: 500;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  min-width: 100px;
  text-align: center;
}

.btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.btn:active:not(:disabled) {
  transform: translateY(0);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn.primary {
  background: var(--accent);
  color: #052e16;
}

.btn.primary:hover:not(:disabled) {
  background: #22b94a;
}

.btn.secondary {
  background: #4b5563;
  color: var(--text);
}

.btn.secondary:hover:not(:disabled) {
  background: #5a6472;
}

.btn.danger {
  background: var(--danger);
  color: #fff;
}

.btn.danger:hover:not(:disabled) {
  background: #dc2626;
}

.btn.small {
  min-width: auto;
  padding: 6px 12px;
  font-size: 12px;
}

/* Visualizer */
.visualizer {
  display: flex;
  gap: 16px;
  align-items: center;
  margin: 20px 0;
  padding: 15px;
  background: #0b1220;
  border-radius: 10px;
  border: 1px solid #263146;
}

.progress {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.track {
  position: relative;
  height: 44px;
  background: #111827;
  border: 1px solid #263146;
  border-radius: 8px;
  overflow: hidden;
}

#progressFill {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 0%;
  background: linear-gradient(90deg, rgba(34, 197, 94, 0.35), rgba(34, 197, 94, 0.6));
  transition: width 0s linear;
}

.segments {
  position: absolute;
  inset: 0;
  display: grid;
  grid-auto-flow: column;
}

.segments > div {
  border-right: 1px solid #1f2937;
}

.segments > div:last-child {
  border-right: none;
}

.timer {
  min-width: 90px;
  text-align: right;
  color: var(--sub);
  font-variant-numeric: tabular-nums;
  font-size: 16px;
  font-weight: 500;
  font-family: 'Courier New', monospace;
}

/* Options */
.options {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 20px;
  padding: 12px;
  background: #0b1220;
  border-radius: 10px;
  border: 1px solid #263146;
}

.option {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
}

.option input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--accent);
}

.option span {
  font-size: 14px;
}

.option.volume {
  margin-left: auto;
  gap: 12px;
}

.option.volume label {
  margin: 0;
}

.option.volume input[type="range"] {
  width: 120px;
}

/* Auto-BPM */
.auto-bpm {
  border: 1px solid #263146;
  border-radius: 10px;
  background: #0b1220;
  padding: 15px;
  margin-bottom: 20px;
}

.auto-bpm h3 {
  margin: 0 0 12px 0;
  font-size: 16px;
  color: var(--accent);
}

.auto-header {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.auto-header h3 {
  margin: 0;
}

.switch {
  position: relative;
  display: inline-block;
  width: 46px;
  height: 22px;
  cursor: pointer;
}

.switch:hover {
  cursor: pointer;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: inherit;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #1f2937;
  border: 1px solid #263146;
  transition: 0.3s;
  border-radius: 24px;
}

.slider:hover {
  background-color: #253246;
}

.slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 3px;
  bottom: 2px;
  background-color: var(--text);
  transition: 0.3s;
  border-radius: 50%;
}

input:checked + .slider {
  background-color: var(--accent);
  border-color: var(--accent);
}

input:checked + .slider:hover {
  background-color: #22b94a;
}

input:checked + .slider:before {
  transform: translateX(24px);
}

.auto-bpm.disabled {
  opacity: 0.5;
}

.auto-bpm.disabled * {
  cursor: not-allowed;
}

.auto-bpm.disabled .switch,
.auto-bpm.disabled .switch:hover,
.auto-bpm.disabled .switch .slider,
.auto-bpm.disabled .switch .slider:hover {
  cursor: pointer;
}

.auto-controls {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 12px;
  align-items: center;
}

.toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
}

.toggle input[type="checkbox"] {
  accent-color: var(--accent);
  cursor: pointer;
}

.toggle span {
  font-size: 14px;
}

.auto-inputs {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
}

.input-row {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.input-row label {
  font-size: 12px;
  color: var(--sub);
  font-weight: 500;
  text-transform: uppercase;
}

.input-row input,
.input-row select {
  width: 100%;
}

/* Countdown */
#countdown {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 120px;
  color: var(--accent);
  font-weight: bold;
  display: none;
  z-index: 1000;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

#countdown.active {
  display: block;
}

/* Responsive */
@media (max-width: 600px) {
  body {
    padding: 10px;
  }

  .container {
    padding: 12px;
    border-radius: 10px;
  }

  header {
    flex-direction: column;
    gap: 8px;
    align-items: flex-start;
  }

  header h1 {
    display: none;
  }

  #totalTime {
    align-self: flex-end;
  }

  .controls {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }

  .control.bpm .input-group {
    flex-direction: row;
    align-items: center;
  }

  .control.bpm input[type="number"] {
    width: 74px;
    flex: 0 0 auto;
  }

  .control.buttons {
    grid-column: 1 / -1;
  }

  .tabs {
    gap: 6px;
    margin-bottom: 14px;
  }

  .tab {
    flex: 1;
    min-width: 0;
    padding: 12px 8px;
    font-size: 15px;
  }

  .control label,
  .input-row label {
    font-size: 11px;
  }

  .input-group {
    gap: 6px;
  }

  input[type="number"],
  input[type="range"],
  select,
  .btn {
    min-height: 44px;
    font-size: 16px;
  }

  .control.buttons {
    gap: 10px;
  }

  .control.buttons .btn {
    width: 100%;
  }

  .options {
    flex-direction: column;
    align-items: stretch;
  }

  .option.volume {
    margin-left: 0;
    flex-direction: column;
    align-items: stretch;
    width: 100%;
  }

  .auto-inputs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .auto-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
  }

  .auto-controls .toggle {
    flex: 0 0 auto;
    min-height: 44px;
    padding: 0 2px;
  }

  .auto-controls .btn.small {
    margin-left: auto;
    min-height: 40px;
  }

  .input-row input,
  .input-row select {
    width: 100%;
  }

  .visualizer {
    flex-direction: column;
    align-items: stretch;
    justify-content: center;
    gap: 12px;
    padding: 12px;
  }

  .progress {
    width: 100%;
  }

  .track {
    height: 30px;
  }

  .timer {
    width: 100%;
    text-align: center;
  }

  #countdown {
    font-size: 80px;
  }
}