style.css

.audio {
    height: 80px;
}
#submit-btn {
    color: #fff;
    background: #409eff;
    border-color: #409eff;
}
#submit-btn:hover{
    background: #66b1ff;
    border-color: #66b1ff;
    color: #fff;
}
#clear-btn {
    color: #fff;
    background: #e6a23c;
    border-color: #e6a23c;
}