Theme improvements (#822)

* start converting

* small fixes

* reorganize theme files

* cleanup search bar

* increase spacing

* small tweaks

* fix select styles in Chrome

* cleanup menus

* improve button icons

* restore badges

* remove unused classes

* restore some overrides

* restore bookmark form

* add summary outline

* avoid layout shifts

* restore bookmark details

* increase border radius for modals

* improve details modal

* restore reader mode

* restore settings

* cleanup variables

* start with dark theme

* more dark theme...

* more light theme...

* more dark theme...

* add postcss build

* remove sass processor

* update docker build

* fix alt color

* remove endless symbol

* fix tests

* update assets

* remove sass files

* fix docker build

* cleanup spacing

* improve theme

* update test scripts

* update CI workflow

* fix test

package.json

@@ -4,7 +4,10 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "build": "rollup -c",
+    "build": "npm run build-js && npm run build-theme-light && npm run build-theme-dark",
+    "build-js": "rollup -c",
+    "build-theme-light": "postcss -o bookmarks/static/theme-light.css bookmarks/styles/theme-light.css",
+    "build-theme-dark": "postcss -o bookmarks/static/theme-dark.css bookmarks/styles/theme-dark.css",
     "dev": "rollup -c -w"
   },
   "repository": {
@@ -22,6 +25,11 @@
     "@rollup/plugin-node-resolve": "^15.2.3",
     "@rollup/plugin-terser": "^0.4.4",
     "@rollup/wasm-node": "^4.13.0",
+    "cssnano": "^7.0.6",
+    "postcss": "^8.4.45",
+    "postcss-cli": "^11.0.0",
+    "postcss-import": "^16.1.0",
+    "postcss-nesting": "^13.0.0",
     "rollup-plugin-svelte": "^7.2.0",
     "spectre.css": "^0.5.8",
     "svelte": "^4.0.0"