:root {
  color-scheme: light dark;
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #16192b;
  --muted: #6b7180;
  --line: #e7e9f2;
  --brand: #4f46e5;
  --shadow: 0 10px 40px rgba(30, 34, 70, 0.12);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0e16;
    --card: #161927;
    --ink: #eef0f6;
    --muted: #9aa0b4;
    --line: #272b3d;
    --brand: #9d97ff;
    --shadow: 0 14px 50px rgba(0, 0, 0, 0.5);
  }
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  padding: 24px;
  display: grid;
  place-items: center;
  color: var(--ink);
  background: var(--bg);
  font-family:
    -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

.card {
  width: min(100%, 560px);
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--card);
  box-shadow: var(--shadow);
}

h1 {
  margin: 0 0 18px;
  font-size: 24px;
}

p {
  line-height: 1.55;
}

.muted {
  color: var(--muted);
}

.btn {
  display: block;
  width: 100%;
  margin-top: 20px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: var(--brand);
  font-weight: 700;
  text-align: center;
  text-decoration: none;
}