.fallback-demo {
      margin: 20px 0;
    }
    
    .fallback-demo .box {
      padding: 15px;
      margin: 10px 0;
      border-radius: 6px;
      font-weight: bold;
    }
    
    .fallback-demo .box-1 {
      /* --undefined-color is not defined, so fallback #27ae60 is used */
      background: var(--undefined-color, #27ae60);
      color: white;
    }
    
    .fallback-demo .box-2 {
      --defined-color: #8e44ad;
      /* --defined-color exists, so it's used instead of fallback */
      background: var(--defined-color, #27ae60);
      color: white;
    }
    
    .fallback-demo .box-3 {
      /* Nested fallbacks demonstration */
      background: var(--missing-primary, var(--missing-secondary, #e67e22));
      color: white;
    }
    
    .fallback-toggle {
      background: #007bff;
      color: white;
      border: none;
      padding: 10px 20px;
      border-radius: 4px;
      cursor: pointer;
      margin: 10px 0;
    }