:root {
    --bg: #0f1115; --fg: #e6e8ec; --muted: #9aa0a6; --border: #262a33;
    --accent: #4f8cff; --accent-fg: #fff; --danger: #ff5c5c; --success: #34d399;
    --card-bg: #171a21; --input-bg: #10131a;
  }
  @media (prefers-color-scheme: light) {
    :root {
      --bg: #f5f6f8; --fg: #1a1d23; --muted: #5a626e; --border: #d5d8de;
      --accent: #2563eb; --accent-fg: #fff; --danger: #dc2626; --success: #16a34a;
      --card-bg: #fff; --input-bg: #fff;
    }
  }
  * { box-sizing: border-box; }
  html, body { margin: 0; padding: 0; }
  body {
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    background: var(--bg); color: var(--fg); line-height: 1.5;
    min-height: 100vh; display: flex; flex-direction: column;
  }
  .container { width: 100%; max-width: 480px; margin: 0 auto; padding: 32px 20px; flex: 1; }
  .container.wide { max-width: 720px; }
  header.site-header {
    padding: 16px 20px; border-bottom: 1px solid var(--border);
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
  }
  header.site-header a { color: var(--fg); text-decoration: none; font-weight: 600; }
  header.site-header a.muted { color: var(--muted); font-weight: 400; font-size: .9rem; }
  h1 { font-size: 1.5rem; margin: 0 0 8px; }
  p { margin: 0 0 12px; color: var(--muted); }
  .card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 10px; padding: 20px; }
  .card + .card { margin-top: 16px; }
  label { display: block; font-size: .9rem; margin-bottom: 6px; }
  input[type="text"], input[type="password"] {
    width: 100%; padding: 10px 12px; border-radius: 8px;
    border: 1px solid var(--border); background: var(--input-bg);
    color: var(--fg); font-size: 1rem; font-family: inherit;
  }
  input:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
  input:disabled { opacity: .6; }
  button, .button {
    padding: 10px 16px; border-radius: 8px; border: 1px solid transparent;
    background: var(--accent); color: var(--accent-fg);
    font-size: 1rem; font-weight: 600; cursor: pointer; font-family: inherit;
    text-align: center; text-decoration: none; display: inline-block;
  }
  button:hover:not(:disabled), .button:hover { filter: brightness(1.1); }
  button:disabled { opacity: .5; cursor: not-allowed; }
  button.secondary, .button.secondary {
    background: transparent; color: var(--fg); border-color: var(--border);
  }
  button.ghost { background: transparent; color: var(--muted); border-color: transparent; font-weight: 400; }
  button.full, .button.full { width: 100%; }
  .field + .field { margin-top: 14px; }
  .field { display: block; }
  .message { padding: 10px 12px; border-radius: 8px; font-size: .9rem; margin: 12px 0; border: 1px solid; }
  .message.error { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 40%, transparent); background: color-mix(in srgb, var(--danger) 10%, transparent); }
  .message.success { color: var(--success); border-color: color-mix(in srgb, var(--success) 40%, transparent); background: color-mix(in srgb, var(--success) 10%, transparent); }
  .message[hidden] { display: none; }
  .secret-box {
    background: var(--input-bg); border: 1px dashed var(--border);
    border-radius: 8px; padding: 14px;
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 1.1rem; letter-spacing: .08em; word-break: break-all;
    text-align: center; cursor: pointer; margin: 12px 0; user-select: all;
  }
  .uri-box {
    background: var(--input-bg); border: 1px solid var(--border); border-radius: 8px;
    padding: 10px; font-family: ui-monospace, monospace; font-size: .75rem;
    word-break: break-all; color: var(--muted); user-select: all; margin: 0 0 12px;
  }
  .codes-list {
    list-style: none; padding: 0; margin: 12px 0;
    display: grid; grid-template-columns: 1fr 1fr; gap: 8px;
  }
  .codes-list li {
    padding: 8px 10px; background: var(--input-bg); border: 1px solid var(--border);
    border-radius: 6px; font-family: ui-monospace, monospace; font-size: .95rem;
    text-align: center; user-select: all;
  }
  .muted { color: var(--muted); font-size: .9rem; }
  .spacer { height: 12px; }
  .flex { display: flex; gap: 10px; align-items: center; }
  a { color: var(--accent); }
  .kv { display: grid; grid-template-columns: 140px 1fr; gap: 8px 12px; }
  .kv dt { color: var(--muted); }
  .kv dd { margin: 0; word-break: break-all; }
  .checkbox-row { display: flex; gap: 8px; align-items: flex-start; margin: 12px 0; font-size: .9rem; }
  .checkbox-row input { margin-top: 3px; }
  .steps { display: flex; gap: 12px; margin-bottom: 20px; font-size: .85rem; color: var(--muted); }
  .steps .step.active { color: var(--accent); font-weight: 600; }
  .steps .step.done { color: var(--success); }