Move popup styling to the active color scheme

Closes #498

Author: Ihor Oleksandrov

popup.html

@@ -1,32 +1,11 @@
 <style>
-html {
-    background-color: #232628;
-    color: #CCCCCC;
-}
 body {
     font-size: ${fontSize}px;
-    color: #cccc99;
 }
 div {
     margin: 5px;
     word-wrap:break-word;
 }
-a {
-    color: #6699cc;
-}
-.type {
-    color: #60C3E0;
-    font-style: italic;
-}
-.name {
-    color: #60D04E;
-}
-.param {
-    color: #F0AB40;
-}
-.current {
-    text-decoration: underline;
-}
 </style>
 <div><b>${signature}</b></div>
 <div style="margin-left: 15px">${description}</div>