* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f5f7fb;
  color: #1f2937;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card {
  width: 100%;
  max-width: 700px;
  background: #ffffff;
  padding: 40px;
  border-radius: 18px;
  box-shadow: 0 12px 35px rgba(0, 0, 0, 0.08);
  text-align: center;
  margin: 20px;
}

h1 {
  margin: 0 0 12px;
  font-size: 32px;
  line-height: 1.2;
}

p {
  margin: 0 0 24px;
  font-size: 16px;
  color: #6b7280;
}

.demo-box {
  margin-top: 20px;
  padding: 30px;
  border: 2px dashed #d1d5db;
  border-radius: 14px;
  background: #f9fafb;
}