Apply transparent gradient overlay and hex color for bg
<p>I am working on a project. In which I need some gradient Button. but i want to use a class for the gradient overlay and new one for hex color bg. My problem is there is no hex bg.<br>
i just want to be able to change hex color anytime by changing class by js. I don't want !important on hex value.<br><br>
Thanks for the help in advance!</p>

<p><div class="snippet" data-lang="js" data-hide="false">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>body {
    font-family: arial;
    color: #FFF;
    font-size: 20px;
}
.c {
    background-color: #9C27B0;
}
.GB {
    border-radius: 6px;
    padding-left: 30px;
    padding-right: 30px;
    padding-top: 20px;
    padding-bottom: 20px;
    font-size: 26px;
    color: #fff;
    display: inline-block;
    text-decoration: none;
background: -moz-linear-gradient(90deg, rgba(0,0,0,0) 38%, rgba(0,0,0,0.29) 89%, rgba(0,0,0,0.34) 99%, rgba(0,0,0,0.35) 100%);
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%, rgba(0,0,0,0.35)), color-stop(1%, rgba(0,0,0,0.34)), color-stop(11%, rgba(0,0,0,0.29)), color-stop(62%, rgba(0,0,0,0)));
    background: -webkit-linear-gradient(90deg, rgba(0,0,0,0) 38%, rgba(0,0,0,0.29) 89%, rgba(0,0,0,0.34) 99%, rgba(0,0,0,0.35) 100%);
    background: -o-linear-gradient(90deg, rgba(0,0,0,0) 38%, rgba(0,0,0,0.29) 89%, rgba(0,0,0,0.34) 99%, rgba(0,0,0,0.35) 100%);
    background: -ms-linear-gradient(90deg, rgba(0,0,0,0) 38%, rgba(0,0,0,0.29) 89%, rgba(0,0,0,0.34) 99%, rgba(0,0,0,0.35) 100%);
    background: linear-gradient(0deg, rgba(0,0,0,0) 38%, rgba(0,0,0,0.29) 89%, rgba(0,0,0,0.34) 99%, rgba(0,0,0,0.35) 100%);
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#000000', endColorstr='#000000',GradientType=0 );
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    -o-user-select: none;
    user-select: none;
    cursor: pointer;
}
.GB:active {
    position: relative;
    border-bottom: 0px solid rgba(0,0,0,0.21);
    margin-top: 0px;
    color: #FFF;
    background: -moz-linear-gradient(90deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.32) 1%, rgba(0,0,0,0.27) 11%, rgba(0,0,0,0) 62%);
    background: -webkit-gradient(linear, left top, left bottom, color-stop(38%, rgba(0,0,0,0)), color-stop(89%, rgba(0,0,0,0.27)), color-stop(99%, rgba(0,0,0,0.32)), color-stop(100%, rgba(0,0,0,0.35)));
    background: -webkit-linear-gradient(90deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.32) 1%, rgba(0,0,0,0.27) 11%, rgba(0,0,0,0) 62%);
    background: -o-linear-gradient(90deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.32) 1%, rgba(0,0,0,0.27) 11%, rgba(0,0,0,0) 62%);
    background: -ms-linear-gradient(90deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.32) 1%, rgba(0,0,0,0.27) 11%, rgba(0,0,0,0) 62%);
    background: linear-gradient(0deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.32) 1%, rgba(0,0,0,0.27) 11%, rgba(0,0,0,0) 62%);
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#000000', endColorstr='#000000',GradientType=0 );
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;a class="GB c"&gt;Button&lt;/a&gt;</code></pre>
</div>
</div>
</p>

<p>color.<br></p>