:root {
  color-scheme: light dark;
  --bg: #f5f6fa;
  --card-bg: #ffffff;
  --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
  --text: #1f2330;
  --muted: #5a6072;
  --cta-bg: #2f6fed;
  --cta-bg-hover: #1f56cf;
  --cta-text: #ffffff;
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161c;
    --card-bg: #1d2030;
    --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
    --text: #e8ebf2;
    --muted: #9aa2b4;
    --cta-bg: #4f8bff;
    --cta-bg-hover: #6ea0ff;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  min-width: 320px;
  max-width: 480px;
  text-align: center;
  box-shadow: var(--card-shadow);
}

.sentence {
  margin: 0 0 1.5rem;
  font-size: 1.05rem;
  color: var(--muted);
  line-height: 1.5;
}

.cta {
  display: inline-block;
  background: var(--cta-bg);
  color: var(--cta-text);
  text-decoration: none;
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  transition: background 120ms ease;
}

.cta:hover,
.cta:focus {
  background: var(--cta-bg-hover);
}

.cta:focus-visible {
  outline: 2px solid var(--cta-bg);
  outline-offset: 2px;
}