:root {
      --bg-dark: linear-gradient(135deg, #23232e, #545675);
      --bg-light: linear-gradient(135deg, #9d9db7, #f6f6f9);
      --text-dark: #e4e4e4;
      --text-light: #1a1a1a;
      --accent-dark: #b2b3c7;
      --accent-light: #A898BD;
      --accent: var(--accent-dark);
    }

    body.light {
      --accent: var(--accent-light);
    }

    body {
      margin: 0;
      padding: 0;
      font-family: system-ui, sans-serif;
      background: var(--bg-dark);
      color: var(--text-dark);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      height: 100vh;
      transition: background 0.3s, color 0.3s;
    }

    body.light {
      background: var(--bg-light);
      color: var(--text-light);
    }

    #theme-toggle {
      position: absolute;
      top: 1rem;
      right: 1rem;
      background: none;
      border: none;
      color: inherit;
      font-size: 1.4rem;
      cursor: pointer;
    }

    .container {
      width: 100%;
      max-width: 480px;
      padding: 2rem;
      box-sizing: border-box;
    }

    header {
      text-align: center;
      margin: 4rem 0 2rem;
    }

    h1 {
      margin: 0;
      font-size: 3rem;
    }

    .options {
      text-align: center;
    }

    .settings label,
    .options label {
      display: block;
      margin: 2rem 0;
    }

    .length-control {
      display: flex;
      gap: 0.5rem;
      align-items: center;
      margin-bottom: 1rem;
    }

    input[type="range"] {
      flex: 1;
      accent-color: var(--accent);
    }

    input[type="number"],
    input[type="text"] {
      border-radius: 0.5rem;
      padding: 0.5rem;
      border: none;
      font-size: 1rem;
    }

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

    .output {
      display: flex;
      gap: 0.5rem;
      margin: 2rem 25%;
    }

    #copy-button {
      padding: 0.5rem 1rem;
      font-size: 1rem;
      background: var(--accent);
      border: none;
      border-radius: 0.5rem;
      cursor: pointer;
    }

    .actions {
      text-align: center;
    }

    #generate-button {
      padding: 0.7rem 2rem;
      font-size: 1rem;
      background: var(--accent);
      border: none;
      border-radius: 0.5rem;
      cursor: pointer;
    }