CSS Two Tone Button

HTML

<a href="www.google.com"><span>Button</span></a>

CSS

body {
     margin: 10px;   
}
a {
    border: 1px solid #2b88d9;
    border-radius: 3px;
    display: inline-block;
    padding-right: 10px;
    padding-top: 1px;
    color: white;
    text-decoration: none;
    font-family: sans-serif;
    
    background: #87e0fd; /* Old browsers */
    background: -moz-linear-gradient(top,  #87e0fd 2%, #53cbf1 2%, #05abe0 100%); /* FF3.6+ */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(2%,#87e0fd), color-stop(2%,#53cbf1), color-stop(100%,#05abe0)); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  #87e0fd 2%,#53cbf1 2%,#05abe0 100%); /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  #87e0fd 2%,#53cbf1 2%,#05abe0 100%); /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  #87e0fd 2%,#53cbf1 2%,#05abe0 100%); /* IE10+ */
    background: linear-gradient(top,  #87e0fd 2%,#53cbf1 2%,#05abe0 100%); /* W3C */
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#87e0fd', endColorstr='#05abe0',GradientType=0 ); /* IE6-9 */

}
a:after {
    content: '▼';
    color: white;
}
a:hover span {
    border-right-color: #05abe0;
    background: #87e0fd; /* Old browsers */
    background: -moz-linear-gradient(top,  #87e0fd 0%, #53cbf1 40%, #05abe0 100%); /* FF3.6+ */
    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#87e0fd), color-stop(40%,#53cbf1), color-stop(100%,#05abe0)); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(top,  #87e0fd 0%,#53cbf1 40%,#05abe0 100%); /* Chrome10+,Safari5.1+ */
    background: -o-linear-gradient(top,  #87e0fd 0%,#53cbf1 40%,#05abe0 100%); /* Opera 11.10+ */
    background: -ms-linear-gradient(top,  #87e0fd 0%,#53cbf1 40%,#05abe0 100%); /* IE10+ */
    background: linear-gradient(top,  #87e0fd 0%,#53cbf1 40%,#05abe0 100%); /* W3C */
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#87e0fd', endColorstr='#05abe0',GradientType=0 ); /* IE6-9 */

}
span {
   ...