.single-product p, 
.single-product table, 
.single-products span{
    font-size: 20px;
}

.single-product p {
    line-height: 1.6em;
}

input#quantity_6659be65a3d26 {
    z-index: 10;
    background-color: red;
    width: 100px!important; 
    height: 30px!important;
}

[type="hidden"] + span, 
[type="hidden"] + span + span{
    display: none!important;
}