rm selector hiding anchor links on some devices

fix: #189

partial revert of f5c5546

Author: adityatelange

assets/css/post-single.css

@@ -64,7 +64,7 @@
     font-size: 12px
 }
 
-.post-content a:not(.gist a),
+.post-content a,
 .toc a:hover {
     box-shadow: 0 1px 0
 }