body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f4f7f6;
    margin: 0;
    padding: 20px;
    color: #333;
}
.container {
    max-width: 600px;
    background: white;
    margin: 30px auto;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}
h1 {
    margin-top: 0;
    color: #2c3e50;
    font-size: 22px;
    border-bottom: 2px solid #ecf0f1;
    padding-bottom: 10px;
}
.form-group {
    margin-bottom: 15px;
}
label {
    font-weight: bold;
    display: block;
    margin-bottom: 5px;
    color: #34495e;
    font-size: 14px;
}
input[type="text"], input[type="number"] {
    width: 100%;
    padding: 10px;
    border: 1px solid #bdc3c7;
    border-radius: 4px;
    box-sizing: border-box;
    font-size: 14px;
}
.btn-invia {
    background: #3498db;
    color: white;
    border: none;
    padding: 14px 20px;
    font-size: 16px;
    font-weight: bold;
    border-radius: 4px;
    cursor: pointer;
    width: 100%;
    margin-top: 15px;
    transition: background 0.2s;
}
.btn-invia:hover {
    background: #2980b9;
}
#notifica {
    padding: 15px;
    border-radius: 4px;
    margin-bottom: 20px;
    font-weight: bold;
    display: none;
}
.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}