Instead of hiding all markdown clutter and then make exceptions, I tried to specify the elements to be hidden. Here are the codes for hiding Hide Bold, Italic, Strikethrough syntax
/* Hide Bold, Italic, Strikethrough Syntax */
div:not(.CodeMirror-activeline)>.CodeMirror-line span.cm-formatting-strong,
div:not(.CodeMirror-activeline)>.CodeMirror-line span.cm-formatting-em,
div:not(.CodeMirror-activeline)>.CodeMirror-line span.cm-formatting-strikethrough,
{ display: none; }