body {
    margin: 0;
    overflow: hidden;
    background: radial-gradient(ellipse at 60% 40%, #1a223f 0%, #090a16 100%);
    color: #f3f6ff;
    font-family: 'Segoe UI', 'Roboto', Arial, sans-serif;
    transition: background 0.5s cubic-bezier(.4,0,.2,1), color 0.3s;
  }
  
  canvas {
    display: block;
    margin: 0 auto;
    box-shadow: 0 0 120px 20px #ffe06655, 0 0 0 0 #0000;
    border-radius: 18px;
    background: transparent !important;
    transition: box-shadow 0.7s;
  }
  
  #ui-panel {
    position: absolute;
    top: 1.5em;
    left: 1.5em;
    background: rgba(27, 30, 50, 0.62);
    box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.22);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-radius: 18px;
    padding: 2em 1.5em 1.5em 1.5em;
    min-width: 250px;
    z-index: 10;
    border: 1.5px solid rgba(255,255,255,0.13);
    transition: background 0.4s, box-shadow 0.4s;
  }
  
  #ui-panel h2 {
    font-size: 1.15em;
    letter-spacing: 0.03em;
    margin: 0 0 1em 0;
    font-weight: 700;
    color: #ffe066;
    text-shadow: 0 2px 10px #222a;
  }
  
  #planet-controls {
    display: flex;
    flex-direction: column;
    gap: 1em;
  }
  
  .planet-control {
    display: flex;
    align-items: center;
    gap: 0.7em;
    font-size: 1em;
    padding: 0.3em 0.2em;
    border-radius: 10px;
    transition: background 0.2s;
  }
  
  .planet-control:hover {
    background: rgba(255, 255, 255, 0.07);
  }
  
  .planet-control label {
    width: 75px;
    font-weight: 500;
    color: #ffe066;
    letter-spacing: 0.02em;
  }
  
  input[type="range"] {
    width: 110px;
    background: linear-gradient(90deg, #ffe066 0%, #00c3ff 100%);
    height: 4px;
    border-radius: 2px;
    outline: none;
    transition: accent-color 0.3s;
    box-shadow: 0 1px 6px #0002;
  }
  
  input[type="range"]:hover {
    accent-color: #00c3ff;
  }
  
  #pause-btn, #resume-btn, #toggle-theme {
    margin-top: 1em;
    margin-right: 0.6em;
    padding: 0.4em 1.1em;
    border: none;
    border-radius: 8px;
    background: linear-gradient(90deg, #ffe066 0%, #00c3ff 100%);
    color: #232323;
    font-weight: 600;
    font-size: 1em;
    letter-spacing: 0.02em;
    box-shadow: 0 2px 12px #0003;
    cursor: pointer;
    transition: background 0.3s, color 0.3s, opacity 0.2s;
  }
  
  #pause-btn[disabled], #resume-btn[disabled] {
    opacity: 0.5;
    cursor: not-allowed;
  }
  
  #toggle-theme {
    background: linear-gradient(90deg, #232323 0%, #ffe066 100%);
    color: #ffe066;
    margin-right: 0;
  }
  
  #tooltip {
    position: absolute;
    background: linear-gradient(90deg, #ffe066cc 0%, #2a5bdecc 100%);
    color: #1a223f;
    padding: 0.5em 1em;
    border-radius: 8px;
    pointer-events: none;
    font-size: 1.05em;
    font-weight: 500;
    z-index: 20;
    box-shadow: 0 2px 12px #0007;
    border: none;
    text-shadow: 0 2px 8px #ffe06655;
    filter: drop-shadow(0 2px 10px #ffe06666);
    transition: background 0.2s, color 0.2s;
  }
  
  body.light {
    background: linear-gradient(135deg, #f6f6fa 0%, #e3e4e8 100%);
    color: #232323;
    transition: background 0.5s, color 0.3s;
  }
  body.light #ui-panel {
    background: rgba(255,255,255,0.83);
    color: #232323;
    box-shadow: 0 8px 32px 0 rgba(60, 60, 120, 0.12);
    border: 1px solid #ffe06633;
  }
  body.light #ui-panel h2,
  body.light .planet-control label {
    color: #232323;
    text-shadow: none;
  }
  body.light #tooltip {
    background: linear-gradient(90deg, #ffe066cc 0%, #00c3ffcc 100%);
    color: #232323;
    border: none;
  }
  body.light #pause-btn, 
  body.light #resume-btn, 
  body.light #toggle-theme {
    background: linear-gradient(90deg, #00c3ff 0%, #ffe066 100%);
    color: #232323;
  }
  body.light input[type="range"] {
    accent-color: #00c3ff;
    background: linear-gradient(90deg, #00c3ff 0%, #ffe066 100%);
  }
  
  @media (max-width: 700px) {
    #ui-panel {
      left: 50%;
      top: 1em;
      transform: translateX(-50%);
      min-width: 0;
      width: 95vw;
      padding: 1.2em 0.7em 1em 0.7em;
      font-size: 0.97em;
    }
    .planet-control label {
      width: 60px;
    }
  }
  
  @media (max-width: 480px) {
    #ui-panel {
      padding: 0.7em 0.3em 0.7em 0.3em;
      font-size: 0.93em;
    }
    .planet-control label {
      width: 48px;
      font-size: 0.95em;
    }
  }