:root {
  --bg: #fff;
  --fg: #000;
  --muted: #6b6b6b;
  --field: #f2f2f2;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #000; --fg: #fff; --muted: #9a9a9a; --field: #1a1a1a; }
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px 16px;
  background: var(--bg);
  color: var(--fg);
  font: 17px/1.5 -apple-system, BlinkMacSystemFont, "SF Pro Text", system-ui, sans-serif;
}
main { max-width: 440px; text-align: center; }
img { display: block; margin: 0 auto; }
h1 { font-size: 32px; letter-spacing: -0.02em; margin: 16px 0 8px; }
p { margin: 0 0 20px; }
.hint { color: var(--muted); font-size: 14px; margin-top: 16px; }
.button {
  display: inline-block;
  padding: 12px 24px;
  border-radius: 999px;
  background: var(--fg);
  color: var(--bg);
  font-weight: 600;
  text-decoration: none;
}
.key {
  padding: 14px 12px;
  border-radius: 12px;
  background: var(--field);
  font: 600 clamp(15px, 4.4vw, 20px)/1.2 ui-monospace, "SF Mono", monospace;
  letter-spacing: 0.04em;
  user-select: all;
}
a { color: inherit; }
form { display: grid; gap: 12px; }
input {
  width: 100%;
  padding: 13px 16px;
  border: 0;
  border-radius: 12px;
  background: var(--field);
  color: var(--fg);
  font: inherit;
}
button.button { border: 0; font: inherit; font-weight: 600; cursor: pointer; }
button.button:disabled { opacity: 0.5; cursor: default; }
.steps { margin: 0 0 20px; padding-left: 1.3em; text-align: left; }
.steps li { margin-bottom: 12px; padding-left: 4px; }
.requires { padding: 12px 14px; border-radius: 12px; background: var(--field); font-size: 15px; }