body {
      margin: 0;
      font-family: system-ui, sans-serif;
      background-color: #000;
      color: #fff;
      transition: background-color 0.8s ease, color 0.8s ease;
      overflow-x: hidden;
    }

    body.light-on {
      background-color: #fff;
      color: #000;
    }

    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    .bulb-container {
      cursor: pointer;
      display: flex;
      flex-direction: column;
      align-items: center;
      transform-origin: top center;
      animation: swing 3.5s ease-in-out infinite;
    }

    @keyframes swing {
      0% { transform: rotate(0deg); }
      25% { transform: rotate(3deg); }
      50% { transform: rotate(0deg); }
      75% { transform: rotate(-3deg); }
      100% { transform: rotate(0deg); }
    }

    .string {
      width: 2px;
      height: 100px;
      background-color: #aaa;
    }

    .socket {
      width: 36px;
      height: 30px;
      background: linear-gradient(#666, #444);
      border-radius: 6px;
      margin-bottom: 4px;
    }

    .bulb {
      width: 90px;
      height: 120px;
      background: radial-gradient(circle at 30% 30%, #ffffff, #e5e5e5);
      border-radius: 50% 50% 45% 45%;
      position: relative;
      box-shadow: 0 0 0 rgba(255,255,255,0);
      transition: box-shadow 0.6s ease, background 0.6s ease;
    }

    body.light-on .bulb {
      background: radial-gradient(circle at 30% 30%, #fff, #fde047);
      box-shadow: 0 0 90px 35px rgba(253, 224, 71, 0.9);
    }

    .bulb::before {
      content: "";
      position: absolute;
      top: 30px;
      left: 50%;
      transform: translateX(-50%);
      width: 32px;
      height: 22px;
      border: 2px solid rgba(0,0,0,0.15);
      border-top: none;
      border-radius: 0 0 16px 16px;
    }

    .filament {
      position: absolute;
      top: 45px;
      left: 50%;
      transform: translateX(-50%);
      width: 30px;
      height: 14px;
      border: 2px solid #bbb;
      border-top: none;
      border-radius: 0 0 20px 20px;
      opacity: 0.3;
      transition: opacity 0.4s ease, box-shadow 0.4s ease;
    }

    body.light-on .filament {
      opacity: 1;
      border-color: #f59e0b;
      box-shadow: 0 0 12px rgba(245, 158, 11, 0.9);
    }

    .content {
      opacity: 0;
      pointer-events: none;
      transition: opacity 1s ease;
      position: absolute;
      inset: 0;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      padding: 2rem;
    }

    body.light-on .content {
      opacity: 1;
      pointer-events: auto;
    }

    .content-inner {
      max-width: 800px;
    }

    .content-inner h1 {
      font-size: clamp(2.5rem, 5vw, 3.5rem);
      margin-bottom: 1rem;
    }

    .content-inner p {
      font-size: 1.2rem;
      line-height: 1.6;
      margin-bottom: 2rem;
    }

    .cta-buttons a {
      display: inline-block;
      margin: 0 0.5rem;
      padding: 0.8rem 1.6rem;
      border-radius: 999px;
      font-weight: 600;
      text-decoration: none;
      border: 2px solid #000;
      color: #000;
      transition: all 0.2s ease;
    }

    .cta-buttons a.primary {
      background: #000;
      color: #fff;
    }

    .cta-buttons a.pop {
      background: orange;
      color: blue;
    }

    .cta-buttons a:hover {
      transform: translateY(-2px);
    }

    .hint {
      position: absolute;
      bottom: 2rem;
      font-size: 0.9rem;
      color: #aaa;
      opacity: 0.8;
    }

    body.light-on .hint {
      display: none;
    }

    h3 {
      color: blue;
    }