:root {
  color-scheme: light dark;
  --bg: #f5f7f4;
  --surface: #ffffff;
  --text: #1b1f1c;
  --muted: #5b655e;
  --line: #d4dbd5;
  --accent: #2e7d32;
  --on-accent: #ffffff;
  --error: #b3261e;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111412;
    --surface: #1c211d;
    --text: #e4e9e4;
    --muted: #a3ada5;
    --line: #38403a;
    --accent: #81c784;
    --on-accent: #0c2410;
    --error: #f2b8b5;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: 24px 16px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

main {
  width: 100%;
  max-width: 400px;
  padding: 28px 24px;
  border-radius: 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  text-align: center;
}

main img { border-radius: 18px; }
h1 { margin: 12px 0 4px; font-size: 1.5rem; }
main > p { margin: 0 0 20px; color: var(--muted); }
form { display: grid; gap: 6px; text-align: left; }
label { margin-top: 8px; font-size: .875rem; font-weight: 600; }

input {
  width: 100%;
  min-height: 48px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: transparent;
  color: inherit;
  font-size: 1rem;
}

#code { font-size: 1.25rem; letter-spacing: .12em; text-transform: uppercase; }

button {
  min-height: 48px;
  margin-top: 16px;
  border: 0;
  border-radius: 24px;
  background: var(--accent);
  color: var(--on-accent);
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

button:disabled { opacity: .6; }
input:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
#error { margin: 8px 0 0; color: var(--error); }