.copy {
    background-color: #e7e7e7; /* Grey */
    width: 100%;
    border: none;
    color: black;
    padding: 15px 200px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 15px;
}

.next {
    background-color: #4CAF50; /* Green */
    border: none;
    color: white;
    padding: 10px 30px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 15px;
}

.back {
    background-color: #008CBA; /* Blue */
    border: none;
    color: white;
    padding: 10px 30px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 15px;
}

.return {
    background-color: #F44336; /* Red */
    border: none;
    color: white;
    padding: 10px 30px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 15px;
}