custom css not taking effect anymore

For the last two years or so I had my Hemingway theme customized as follows (using simple custom css). But now, since updating to wp 5.4, none of this is effective anymore. It is still in the customizer and it says “published”, but it simply gets overwritten by something else (I think). The weird thing is that some aspects, I think, are still active (like that the header margin is smaller), but others don’t (e.g. the font in the posts is different).
Also, now some title boxes are added in the post which I want to get rid of, but since custom css isn’t working anymore, I have no idea how to get rid of them. Anyone know why this is suddenly not working anymore, and how to fix it?

.post {margin-top: -25%;}

.post {font-family: “Times New Roman”, Times, serif;}

.header {margin-bottom: -7%;}
.header {margin-top: -7%}

.header {font-size: 65%;}

.blog-menu {margin-left: -7%}
.blog-menu {margin-right: -90%}

/*navigation-inner*/

.post {margin-right: -50%}

The page I need help with: [log in to see the link]