* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: system-ui, -apple-system, sans-serif;
  background: #f4f6fb;
  color: #222;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background: linear-gradient(135deg, #4f46e5, #06b6d4);
  color: #fff;
  text-align: center;
  padding: 3rem 1rem;
}

main {
  flex: 1;
  max-width: 800px;
  width: 100%;
  margin: 2rem auto;
  padding: 0 1rem;
  display: grid;
  gap: 1.5rem;
}

.card {
  background: #fff;
  padding: 1.5rem;
  border-radius: 12px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.06);
}

.card h2 { margin-bottom: 0.5rem; color: #4f46e5; }

button {
  margin-top: 1rem;
  padding: 0.6rem 1.2rem;
  border: none;
  border-radius: 8px;
  background: #4f46e5;
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
}

button:hover { background: #4338ca; }

code { background: #eef; padding: 0.1rem 0.3rem; border-radius: 4px; }

footer { text-align: center; padding: 1rem; color: #666; }