.subir {
    float:right;
    position: fixed;
    bottom: 25px;
    right: 10px;
    width: 50px;
    height: 60px;
    font-size: 13pt;
    background-color: rgba(255,255,255,0.8);
    box-shadow: -1px -1px 4px rgba(0,0,0,0.2);
    color: #6d6e71;
    text-decoration: none;
    text-align: center;
    background-color:rgba(255,255,0,0.2); /*yellow*/
}

.subir a:hover, .subir a:focus {
    background-color:rgba(255,255,0,0.7); /*yellow*/
    color: #f1f1f1;
   text-decoration: none;
}


/*
.btn {
    display: inline-block;
    padding: 0px;
    margin-bottom: 0;
    font-size: 14px;
    font-weight: 400;
    line-height: 1.42857143;
    text-align: center;
    white-space: nowrap;
    vertical-align: middle;
    -ms-touch-action: manipulation;
    touch-action: manipulation;
    cursor: pointer;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    background-image: none;
    border: 1px solid transparent;
    border-radius: 4px;
}
*/