Refactor gene widget.

Author: Isaac1m

rnacentral/portal/static/css/gene.css

@@ -115,8 +115,6 @@
     border-radius: 12px;
     padding: 1.5rem;
     margin-bottom: 1.5rem;
-    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
-    border-left: 4px solid #3498db;
 }
 
 .gene__widget-header {