:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #121c3a;
  --muted: #5b6478;
  --primary: #2446a8;
  --danger: #d93a3f;
  --line: #e3e7f0;
  --ok: #1e9e4a;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1424;
    --card: #182036;
    --ink: #e8ecf6;
    --muted: #a3acc2;
    --primary: #7d9bf0;
    --danger: #f07b7f;
    --line: #2a3452;
    --ok: #5fd08a;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.65 system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}
main { max-width: 760px; margin: 0 auto; padding: 24px 16px 64px; }
header { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 16px; }
.brand { font-weight: 800; font-size: 22px; color: var(--primary); letter-spacing: -0.5px; }
.lang { display: flex; gap: 4px; }
.lang button {
  border: 1px solid var(--line); background: var(--card); color: var(--ink);
  border-radius: 999px; padding: 4px 12px; cursor: pointer; font: inherit; font-size: 14px;
}
.lang button[aria-pressed='true'] { background: var(--primary); color: #fff; border-color: var(--primary); }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 20px; margin-bottom: 16px; }
h1 { font-size: 26px; line-height: 1.25; margin: 0 0 4px; }
h2 { font-size: 18px; margin: 24px 0 8px; }
.muted { color: var(--muted); font-size: 14px; }
ul { padding-left: 20px; }
li { margin: 4px 0; }
a { color: var(--primary); }
.fill { background: rgba(240, 140, 46, 0.18); border-radius: 4px; padding: 0 4px; }
label { display: block; font-weight: 600; margin: 12px 0 6px; }
input {
  width: 100%; padding: 12px; border-radius: 12px; border: 1px solid var(--line);
  background: var(--bg); color: var(--ink); font: inherit;
}
input.code { letter-spacing: 8px; font-size: 22px; text-align: center; font-weight: 700; }
button.primary, button.danger {
  margin-top: 16px; width: 100%; padding: 14px; border: 0; border-radius: 12px;
  font: inherit; font-weight: 700; color: #fff; cursor: pointer;
}
button.primary { background: var(--primary); }
button.danger { background: var(--danger); }
button:disabled { opacity: 0.6; cursor: default; }
.msg { margin-top: 12px; padding: 12px; border-radius: 12px; display: none; }
.msg.error { display: block; background: rgba(217, 58, 63, 0.12); color: var(--danger); }
.msg.ok { display: block; background: rgba(30, 158, 74, 0.12); color: var(--ok); }
[hidden] { display: none !important; }
footer { margin-top: 24px; text-align: center; }