:root {
    --bg-dark: #111;
    --text-dark: #eee;
    --accent-yellow: #ffd700;
    --accent-blue: #00bfff;
  
    --bg-light: #fafafa;
    --text-light: #111;
  }
  
  html[data-theme="dark"] {
    background-color: var(--bg-dark);
    color: var(--text-dark);
  }
  
  html[data-theme="light"] {
    background-color: var(--bg-light);
    color: var(--text-light);
  }
  
  body {
    margin: 0;
    font-family: sans-serif;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
  }
  
  header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    font-size: 1.5rem;
    font-weight: bold;
  }
  
  #theme-toggle {
    background: none;
    border: 1px solid #fff;
    border-radius: 1.5rem;
    padding: 0.3rem 0.8rem;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s;
  }
  
  main {
    flex-grow: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
  }
  
  canvas {
    width: 100%;
    height: 100%;
    display: block;
  }