body { font-family: Arial, sans-serif; background: #f4f4f4; margin: 0; padding: 20px; }
.container { max-width: 400px; margin: 0 auto; background: white; padding: 20px; border-radius: 10px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); text-align: center; }
h1 { color: #333; }
select, input, button { width: 100%; padding: 10px; margin: 10px 0; border: 1px solid #ddd; border-radius: 5px; box-sizing: border-box; }
button { background: #007bff; color: white; cursor: pointer; }
button:hover { background: #0056b3; }
#resultado { margin-top: 20px; font-size: 1.2em; color: #28a745; }