.bt {
    --bt-bg: #f5f0ff;
    --bt-primary: #7000ff;
    --bt-secondary: #0ad;
    --bt-accent: #c0c;
    --bt-text: #1a003d;
    --bt-glass: rgba(112, 0, 255, 0.04);
    --bt-glass-border: rgba(112, 0, 255, 0.18);
    --bt-muted: rgba(26, 0, 61, 0.5);
    --bt-range-track: rgba(112, 0, 255, 0.08);
    --bt-range-track-border: rgba(112, 0, 255, 0.18);
    --bt-preset-color: rgba(26, 0, 61, 0.7);
    --bt-warning-bg: rgba(220, 38, 38, 0.05);
    --bt-warning-border: rgba(220, 38, 38, 0.18);
    --bt-warning-text: rgba(26, 0, 61, 0.6);
    --bt-warning-strong: #dc2626;
    --bt-strobe-border: rgba(112, 0, 255, 0.2);
    --bt-strobe-color: #1a003d;
    --bt-visualizer-bg: rgba(3, 4, 22, 0.88);
    --bt-shadow: 0 8px 32px rgba(112, 0, 255, 0.15);

    max-width: 56rem;
    margin: 0 auto;
    padding: 0 1rem;
  }

  
  .theme-dark .bt {
    --bt-bg: #030416;
    --bt-secondary: #00f2ff;
    --bt-accent: #f0f;
    --bt-text: #fff;
    --bt-glass: rgba(255, 255, 255, 0.03);
    --bt-glass-border: rgba(255, 255, 255, 0.1);
    --bt-muted: rgba(255, 255, 255, 0.5);
    --bt-range-track: rgba(255, 255, 255, 0.05);
    --bt-range-track-border: rgba(255, 255, 255, 0.1);
    --bt-preset-color: rgba(255, 255, 255, 0.7);
    --bt-warning-bg: rgba(255, 0, 0, 0.05);
    --bt-warning-border: rgba(255, 0, 0, 0.1);
    --bt-warning-text: rgba(255, 255, 255, 0.5);
    --bt-warning-strong: rgba(255, 100, 100, 1);
    --bt-strobe-border: rgba(255, 255, 255, 0.1);
    --bt-strobe-color: #fff;
    --bt-visualizer-bg: rgba(0, 0, 0, 0.3);
    --bt-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  }

  
  .bt__card {
    background: var(--bt-bg);
    border: 1px solid var(--bt-glass-border);
    border-radius: 2rem;
    padding: 2rem 1.5rem;
    box-shadow: var(--bt-shadow);
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(20px);
  }

  @media (min-width: 768px) {
    .bt__card {
      padding: 3rem;
      border-radius: 2.5rem;
      gap: 3rem;
    }
  }

  .bt__card::before {
    content: '';
    position: absolute;
    top: -10%;
    right: -10%;
    width: 40%;
    height: 40%;
    background: radial-gradient(circle, rgba(112, 0, 255, 0.12) 0%, transparent 70%);
    pointer-events: none;
  }

  .theme-dark .bt__card::before {
    background: radial-gradient(circle, rgba(112, 0, 255, 0.15) 0%, transparent 70%);
  }

  .bt__card::after {
    content: '';
    position: absolute;
    bottom: -10%;
    left: -10%;
    width: 40%;
    height: 40%;
    background: radial-gradient(circle, rgba(0, 170, 221, 0.1) 0%, transparent 70%);
  }

  .theme-dark .bt__card::after {
    background: radial-gradient(circle, rgba(0, 242, 255, 0.1) 0%, transparent 70%);
    pointer-events: none;
  }

  
  .bt__controls-grid {
    display: grid;
    gap: 2rem;
    position: relative;
    z-index: 1;
  }

  @media (min-width: 640px) {
    .bt__controls-grid {
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
    }
  }

  .bt__control-group {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
  }

  .bt__control-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
  }

  .bt__control-label {
    font-weight: 700;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--bt-muted);
  }

  .bt__value-display {
    font-size: 2.25rem;
    font-weight: 900;
    color: var(--bt-text);
    line-height: 1;
    text-shadow: 0 0 15px rgba(255, 255, 255, 0.2);
  }

  @media (min-width: 768px) {
    .bt__value-display {
      font-size: 2.5rem;
    }
  }

  .bt__value-unit {
    font-size: 1rem;
    font-weight: 400;
    margin-left: 0.25rem;
    opacity: 0.6;
  }

  
  .bt__range {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    background: transparent;
    cursor: pointer;
  }

  .bt__range::-webkit-slider-runnable-track {
    height: 8px;
    background: var(--bt-range-track);
    border-radius: 4px;
    border: 1px solid var(--bt-range-track-border);
  }

  .bt__range::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    height: 24px;
    width: 24px;
    background: var(--bt-text);
    border-radius: 50%;
    margin-top: -9px;
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.4);
    transition: transform 0.2s, box-shadow 0.2s;
  }

  .bt__range::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: 0 0 20px var(--bt-secondary);
  }

  .bt__range::-moz-range-track {
    height: 8px;
    background: var(--bt-range-track);
    border-radius: 4px;
    border: 1px solid var(--bt-range-track-border);
  }

  .bt__range::-moz-range-thumb {
    height: 24px;
    width: 24px;
    background: var(--bt-text);
    border-radius: 50%;
    border: none;
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.4);
  }

  
  .bt__presets-wrap {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: center;
    position: relative;
    z-index: 1;
  }

  .bt__beat-desc {
    background: linear-gradient(90deg, var(--bt-primary), var(--bt-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 600;
    font-size: 1rem;
    text-align: center;
  }

  .bt__presets {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
  }

  .bt__preset-btn {
    background: var(--bt-glass);
    border: 1px solid var(--bt-glass-border);
    color: var(--bt-preset-color);
    padding: 0.625rem 1.25rem;
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.23, 1, 0.32, 1);
  }

  @media (max-width: 640px) {
    .bt__preset-btn {
      padding: 0.5rem 0.75rem;
      font-size: 0.75rem;
      flex: 1 1 auto;
      text-align: center;
    }
  }

  .bt__preset-btn:hover {
    border-color: var(--bt-secondary);
    color: var(--bt-secondary);
    background: rgba(0, 242, 255, 0.05);
  }

  .bt__preset-btn--active {
    background: var(--bt-text);
    color: var(--bt-bg);
    border-color: var(--bt-text);
    transform: scale(1.05);
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
  }

  
  .bt__actions {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 2.5rem;
    margin: 0.5rem 0;
    position: relative;
    z-index: 1;
  }

  @media (max-width: 640px) {
    .bt__actions {
      flex-direction: column;
      gap: 1rem;
    }
  }

  .bt__play-btn {
    width: 6rem;
    height: 6rem;
    border-radius: 50%;
    background: var(--bt-text);
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    flex-shrink: 0;
  }

  @media (max-width: 640px) {
    .bt__play-btn {
      width: 5rem;
      height: 5rem;
    }
  }

  .bt__play-btn:hover {
    transform: scale(1.1);
    box-shadow: 0 0 40px rgba(255, 255, 255, 0.4);
  }

  .bt__play-btn--playing {
    background: var(--bt-accent);
  }

  .bt__play-svg {
    width: 2.5rem;
    height: 2.5rem;
    fill: var(--bt-bg);
  }

  .bt__play-btn--playing .bt__play-svg {
    fill: white;
  }

  .bt__play-svg--hidden {
    display: none;
  }

  .bt__strobe-btn {
    background: transparent;
    border: 2px solid var(--bt-strobe-border);
    color: var(--bt-strobe-color);
    padding: 1rem 2rem;
    border-radius: 100px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    cursor: pointer;
    transition: all 0.3s ease;
  }

  @media (max-width: 640px) {
    .bt__strobe-btn {
      padding: 0.75rem 1rem;
      font-size: 0.85rem;
      width: 100%;
      box-sizing: border-box;
      text-align: center;
    }
  }

  .bt__strobe-btn:hover {
    border-color: var(--bt-secondary);
    background: rgba(0, 242, 255, 0.05);
  }

  .bt__strobe-btn--active {
    background: var(--bt-secondary);
    border-color: var(--bt-secondary);
    color: var(--bt-bg);
    box-shadow: 0 0 25px rgba(0, 242, 255, 0.4);
  }

  
  .bt__visualizer {
    width: 100%;
    height: 12rem;
    background: var(--bt-visualizer-bg);
    border-radius: 1.5rem;
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.05);
  }

  @media (max-width: 640px) {
    .bt__visualizer {
      height: 7.5rem;
      border-radius: 1rem;
    }
  }

  .bt__strobe {
    position: absolute;
    inset: 0;
    background: white;
    opacity: 0;
    pointer-events: none;
    z-index: 2;
  }

  .bt__strobe--active {
    animation: bt-strobe var(--bt-strobe-duration, 0.25s) infinite;
  }

  @keyframes bt-strobe {
    0% { opacity: 0.9; }
    2% { opacity: 0; }
    100% { opacity: 0; }
  }

  .bt__canvas {
    width: 100%;
    height: 100%;
    filter: blur(2px);
  }

  
  .bt__warning {
    background: var(--bt-warning-bg);
    border: 1px solid var(--bt-warning-border);
    padding: 1.25rem;
    border-radius: 1rem;
    font-size: 0.8rem;
    color: var(--bt-warning-text);
    line-height: 1.6;
    position: relative;
    z-index: 1;
  }

  .bt__warning-title {
    color: var(--bt-warning-strong);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.75rem;
  }