@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600&display=swap');

:root {
  --bg: #f5f6fa;
  --text: #222;
  --card-bg: #fff;
  --primary: #4f46e5; /* xanh tím hiện đại */
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  padding: 16px;
}

.card {
  background: var(--card-bg);
  padding: 32px;
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
  text-align: center;
  max-width: 400px;
  width: 100%;
}

h1 {
  margin: 0 0 16px;
  font-size: 20px;
  font-weight: 600;
}

p {
  margin: 12px 0;
  font-size: 15px;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.btn {
  display: inline-block;
  margin-top: 8px;
  padding: 10px 18px;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.2s;
}

.btn:hover {
  background: #3730a3; /* tím đậm hơn khi hover */
}