body { font-family: sans-serif; background: #f7f7f7; padding: 20px; }
.container { 
  max-width: 600px; 
  margin: auto; 
  background: white; 
  padding: 20px; 
  border-radius: 8px; 
  box-shadow: 0 0 10px rgba(0,0,0,0.1); 
  box-sizing: border-box;
}
form label { display: block; margin-top: 10px; }
form input[type="text"],
form input[type="email"],
form input[type="number"] {
  width: calc(100% - 16px); 
  padding: 8px; 
  margin-top: 5px;
  box-sizing: border-box;
}
button { 
  margin-top: 20px; 
  padding: 10px 20px; 
  background: #0077cc; 
  color: white; 
  border: none; 
  border-radius: 4px; 
  cursor: pointer; 
}
#result { margin-top: 20px; }