:root {
  color-scheme: light dark;
  --bg: #fff;
  --text: #0b0b0c;
  --muted: #6b6f76;
  --line: #d9dbdf;
  --accent: #00a35a;
  --bad: #c62828;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0b0c;
    --text: #f4f4f5;
    --muted: #9a9ea6;
    --line: #2c2e33;
    --accent: #00c26a;
    --bad: #ff6b6b;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: 16px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.4 system-ui, -apple-system, 'Segoe UI', sans-serif;
}
.card { width: 100%; max-width: 340px; }
h1 {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 28px;
  font-size: 26px;
  font-weight: 800;
  letter-spacing: -0.02em;
}
h1 svg { width: 30px; height: 30px; color: var(--accent); }
label { display: block; margin: 16px 0 6px; font-size: 14px; color: var(--muted); }
input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: transparent;
  color: inherit;
  font: inherit;
}
input:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
#code { letter-spacing: 0.3em; font-variant-numeric: tabular-nums; }
button {
  width: 100%;
  margin-top: 24px;
  padding: 13px;
  border: 0;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
button:disabled { opacity: 0.6; cursor: default; }
#error { margin: 16px 0 0; color: var(--bad); font-size: 14px; }