wp visual editor double lines

Hello,

I am using wp visual editor. The visual editor spacing is double lines instead of single. After spending hours debugging the problem. I found the issue is in the
wp-content.css file where line-height: 1.5; in the body area.

I am sure manually changing the value from 1.5 to 0 for example will fix the double line but it’s not a good way. I have created a custom editor-style.css but the values in the custom css did not overwrite the wp-content.css.

Any suggestions? Thanks.