.example1 input:required {
    border-left: 4px solid #e74c3c;
    background-color: #fdf2f2;
}

.example1 input:optional {
    border-left: 4px solid #27ae60;
    background-color: #f2fdf2;
}

.example1 label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

.example1 input {
    width: 100%;
    padding: 10px;
    margin-bottom: 15px;
    border: 1px solid #ddd;
    border-radius: 4px;
    transition: all 0.3s ease;
}