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

requirements.dev.txt

@@ -13,13 +13,7 @@ click==8.1.7
 coverage==7.4.1
     # via -r requirements.dev.in
 django==5.0.8
-    # via
-    #   django-appconf
-    #   django-debug-toolbar
-django-appconf==1.0.6
-    # via django-compressor
-django-compressor==4.4
-    # via -r requirements.dev.in
+    # via django-debug-toolbar
 django-debug-toolbar==4.2.0
     # via -r requirements.dev.in
 execnet==2.1.1
@@ -28,8 +22,6 @@ greenlet==3.0.3
     # via playwright
 iniconfig==2.0.0
     # via pytest
-libsass==0.23.0
-    # via -r requirements.dev.in
 mypy-extensions==1.0.0
     # via black
 packaging==23.2
@@ -55,10 +47,6 @@ pytest-django==4.7.0
     # via -r requirements.dev.in
 pytest-xdist==3.6.1
     # via -r requirements.dev.in
-rcssmin==1.1.1
-    # via django-compressor
-rjsmin==1.2.1
-    # via django-compressor
 sqlparse==0.5.0
     # via
     #   django