Inline style should be moved into scss files.

It will also help #757

Once this is done, the CSP policy could probably be updated to remove unsafe-inline for style-src.

⚠️ For svg, CSP and Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1262842 : https://pokeinthe.io/2016/04/09/black-icons-with-svg-and-csp/