Inline plaintext document previews for complete styling

src-ui/src/theme.scss

@@ -246,10 +246,6 @@ $form-check-radio-checked-bg-image-dark: url("data:image/svg+xml,<svg xmlns='htt
       background-color: rgb(var(--bs-dark-rgb)) !important;
     }
   }
-
-  .preview-sticky.bg-white {
-    background-color: var(--pngx-bg-darker) !important;
-  }
 }
 
 body.color-scheme-dark {