:root {
    font-family: system-ui, sans-serif;
    color: #1f2937;
    background: #f8fafc;
  }
  
  * {
    box-sizing: border-box;
  }
  
  body {
    max-width: 900px;
    min-height: 100vh;
    margin: 0 auto;
    padding: 2rem;
  }
  
  button {
    padding: 0.75rem 1rem;
    border: 1px solid currentColor;
    border-radius: 0.5rem;
    font: inherit;
    cursor: pointer;
  }
  
  .site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
  }
  
  .card {
    margin-top: 3rem;
    padding: 2rem;
    border: 1px solid #cbd5e1;
    border-radius: 1rem;
    background: white;
  }
  
  .dark-theme {
    color: #f8fafc;
    background: #0f172a;
  }
  
  .dark-theme .card {
    background: #1e293b;
  }
/* 
  #theme-button {
    font-weight: bold;
    font-size: 2rem;
    border: 5px solid red;
  } */