:root {
    --bg: #f2f2f7; --card: #ffffff; --text: #0d0d14;
    --muted: #737380; --brand: #595ced; --border: #d9d9e0;
  }
  @media (prefers-color-scheme: dark) {
    :root {
      --bg: #121217; --card: #212129; --text: #f2f2f7;
      --muted: #9999a6; --brand: #787aff; --border: #3a3a45;
    }
  }
  * { box-sizing: border-box; }
  body {
    margin: 0; background: var(--bg); color: var(--text);
    font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
          "Helvetica Neue", Arial, sans-serif;
    padding: 24px 16px;
  }
  main {
    max-width: 720px; margin: 0 auto; background: var(--card);
    border: 1px solid var(--border); border-radius: 16px; padding: 32px;
  }
  h1 { font-size: 24px; margin: 0 0 4px; }
  h2 { font-size: 18px; margin: 24px 0 8px; }
  .muted { color: var(--muted); font-size: 14px; }
  .lang { float: right; }
  .lang button {
    background: none; border: 1px solid var(--border); border-radius: 8px;
    color: var(--brand); padding: 4px 10px; cursor: pointer; font-size: 14px;
  }
  .lang button.on { background: var(--brand); color: #fff; border-color: var(--brand); }
  a { color: var(--brand); }