.btn{
    display: inline-block;
    padding: 10px 20px;
    margin: 10px;
    text-decoration: none;
    border: 2px solid #000;
    color: #fff;
    border-radius: 5px;
    font-family: Arial, sans-serif;
    font-size: 16px;
}
.btn:nth-child(1) {
    background-color: #007bff;
}
.btn:nth-child(2) {
    background-color: #28a745;
}
.btn:nth-child(3) {
    background-color: #dc3545;
}
.btn:nth-child(4) {
    background-color: #ffc107;
}
.btn:nth-child(5) {
    background-color: #6610f2;
}
.btn:hover {
    opacity: 0.8;
}