Enlarge .collapser width/click-area

Make it a bit easier to target with the mouse.

Author: stanio

src/viewer.css

@@ -29,7 +29,8 @@ body {
 
 .collapser {
   position: absolute;
-  left: -1.5ch;
+  left: -2.2ch;
+  padding: 0 .6ch;
   cursor: pointer;
   transform: rotate(90deg);
   transition: transform .2s;