LT-281: Replacing variables for theme calls

Packages/viewerbase/client/components/studyBrowser/imageThumbnail/imageThumbnail.styl

@@ -1,15 +1,15 @@
 @import "{design}/app"
 
 .thumbnailEntry.active .imageThumbnail
-  border-color: $activeColor
+  theme('border-color', '$activeColor')
   box-shadow: none
   transition($sidebarTransition)
 
 .imageThumbnail
-  background-color: $primaryBackgroundColor
+  theme('box-shadow', 'inset 0 0 0 1px $uiBorderColorDark')
+  theme('background-color', '$primaryBackgroundColor')
   border: 5px solid transparent
   border-radius: 12px
-  box-shadow: inset 0 0 0 1px $uiBorderColorDark
   height: 135px
   margin: 0 auto
   padding 1px 7px
@@ -18,7 +18,7 @@
   width: 217px
 
   &:hover
-    border-color: $hoverColor
+    theme('border-color', '$hoverColor')
     box-shadow: none
 
 .imageThumbnailCanvas
@@ -28,7 +28,7 @@
 .thumbnailLoadingIndicator
   display: none
   pointer-events: none
-  color: $textSecondaryColor
+  theme('color', '$textSecondaryColor')
   height: 20px
   width: 100%
   top: 0