body { font-family: Arial; background: #f5f5f5; margin: 0; padding: 20px; }
header { background: white; padding: 20px; margin-bottom: 20px; border-radius: 5px; }
main { background: white; padding: 30px; border-radius: 5px; max-width: 600px; margin: 0 auto; }
label { display: block; margin: 15px 0; }
input { width: 100%; padding: 10px; border: 1px solid #ddd; border-radius: 4px; }
.btn { padding: 10px 20px; background: #4CAF50; color: white; border: none; border-radius: 4px; cursor: pointer; margin: 20px 0; }
#result { background: #e8f5e9; padding: 15px; border-radius: 4px; margin-top: 20px; }