Hi wahhadesign,
You may try to disable the advanced CSS editor with CSS lint (detailed CSS quality report). The option is below the CSS editor.

A crash may occur when you insert a large amount of CSS (e.g. 100kb+). The editor also becomes slow on my Core M7 laptop when inserting ~50kb CSS. For this reason, when using many conditional CSS rows, the editor is only loaded when you specifically select a conditional CSS entry to edit and the editor is destroyed when closing the editor.
Critical CSS should be approximately <20kb and the editor will then be fast with most average CPU PC’s.
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