:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f5f7f8;
  color: #172126;
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100svh; display: grid; place-items: center; }
main { width: min(100% - 40px, 420px); text-align: center; padding: 48px 0; }
.mark { width: 64px; height: 64px; margin: 0 auto 24px; display: grid; place-items: center; background: #13765d; color: white; border-radius: 8px; font-size: 17px; font-weight: 750; }
h1 { margin: 0 0 24px; font-size: 30px; line-height: 1.2; letter-spacing: 0; }
.state { margin: 0; font-size: 20px; font-weight: 650; }
.remaining { min-height: 24px; margin: 8px 0 32px; color: #526067; font-variant-numeric: tabular-nums; }
button { width: 100%; height: 52px; border: 0; border-radius: 8px; background: #13765d; color: white; font: inherit; font-size: 17px; font-weight: 700; cursor: pointer; }
button:disabled { cursor: default; opacity: .5; }
button:focus-visible { outline: 3px solid #172126; outline-offset: 3px; }
.error { min-height: 24px; margin: 18px 0 0; color: #a22929; font-size: 14px; }
@media (prefers-color-scheme: dark) {
  :root { color-scheme: dark; background: #111719; color: #eef3f4; }
  .remaining { color: #aab6ba; }
  button:focus-visible { outline-color: #eef3f4; }
}