:root {
  --bg: #feffff;
  --text: #15141a;
  --muted: #5b5b66;
  --border: #d9d9de;
  --accent: #0a66c2;
  --accent-contrast: #ffffff;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1a202c;
    --text: #f0f0f4;
    --muted: #b7c3d5;
    --border: #3d4d67;
    --accent: #3f9cff;
    --accent-contrast: #0b1220;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  display: grid;
  grid-template-rows: auto 1fr auto;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

header {
  padding: 22px 24px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 16px;
  font-weight: 600;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-contrast);
  font-weight: 800;
}

main {
  display: grid;
  align-content: center;
  justify-items: center;
  text-align: center;
  gap: 22px;
  padding: 24px;
}

h1 {
  margin: 0;
  max-width: 16ch;
  font-size: clamp(34px, 7vw, 60px);
  line-height: 1.08;
  letter-spacing: -0.02em;
}

main > p {
  margin: 0;
  max-width: 46ch;
  font-size: 18px;
  color: var(--muted);
}

.button {
  margin-top: 6px;
  padding: 13px 26px;
  border-radius: 9px;
  background: var(--accent);
  color: var(--accent-contrast);
  font-weight: 650;
  font-size: 16px;
  text-decoration: none;
}
.button:hover { filter: brightness(1.06); }
.button:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }

.note {
  font-size: 13px;
  max-width: 40ch;
}

footer {
  padding: 20px 24px;
  text-align: center;
  font-size: 12px;
  color: var(--muted);
}

@media (prefers-reduced-motion: no-preference) {
  .button { transition: filter 0.15s; }
}