Thanks for reporting this. For now, you can add this CSS to your theme’s stylesheet, or to the plugin’s stylesheet at wp-content/plugins/genesis-simple-share/lib/css/share.css
:
.share-tall .twitter .box.no-count:before {
border: 1px solid #09b0ed;
border-top-left-radius: 3px;
border-top-right-radius: 3px;
box-sizing: border-box;
content: '\f202';
color: #09b0ed;
cursor: pointer;
display: block;
line-height: 1;
height: 55px;
font-family: 'Genericons';
font-size: 20px;
padding-top: 17px;
position: relative;
text-align: center;
-webkit-font-smoothing: antialiased;
-webkit-transition: all 0.3s ease-in-out;
-moz-transition: all 0.3s ease-in-out;
-ms-transition: all 0.3s ease-in-out;
-o-transition: all 0.3s ease-in-out;
transition: all 0.3s ease-in-out;
}
.share-tall .twitter:hover .box.no-count:before {
background: #09b0ed;
color: #fff;
}