Looks like Firefox 117+ is working again in Win7 https://github.com/vxiiduu/VxKex
CSS Calendar - Firefox 133 Win7+11 (December 2024)
💾FF119 Win11 https://github.com/hornster02/Firefox-Three-Rows-Simple-Compact-Clean-CSS/raw/main/Firefox%20119.rar
💾FF109 Win7 https://github.com/hornster02/Firefox-Three-Rows-Simple-Compact-Clean-CSS/raw/main/Firefox%20109.rar
Firefox installers can be extracted by WinRar/7-Zip and then used without installation. Profiles can be manually created and run via
firefox.exe -p
or automatically created (if it doesn't already exist) and run via (example)
firefox.exe -profile "a:\000"
Most of the colors I've changed are pink (FF00A3 and E20074) and orange (FB7914) - they can be easily found/replaced. CSS files can be edited and tested even by your pet = data loaded from it are only temporary in RAM memory and after deleting the files there is no trace of them in the profile or Firefox itself
🚫disabling notifications and downloading updates - create "updates" file in "C:\ProgramData\Mozilla" (or "C:\ProgramData\MozillaXXX"). Or deny access (NTFS Permissions Tools). However, these methods may cause a bug in Thunderbird (inability to open settings and browse emails)
🚫disabling compatibility check of the profile - delete "compatibility.ini" file and create "compatibility.ini" folder. The profile may or may not be damaged, but its use will no longer be decided by someone else
Firefox 119 (2023) - 3-LINE - 1080p 
Firefox 119 (2023) - DEFAULT - 
Firefox 119 (2023) - DEFAULT - 
Firefox 119 (2023) - 3-LINE - 
/* IMPORTANT - find ".findbar-find-previous" (userChrome.css) and change "padding-left" number - example
.findbar-find-previous {padding-left: 213px!important;}
Works in FF 109/119 */
.browserContainer > findbar {-moz-box-ordinal-group: 0!important;order: -1 !important;}
.browserContainer > findbar {max-width: 700px!important;margin-top: -25px!important;} /* if the web content jumps when pressing CTRL+F, the number needs to be adjusted */
.findbar-highlight, .findbar-case-sensitive, .findbar-match-diacritics, .findbar-entire-word {max-width: 10%!important;font-size: 10px !important;margin: 0px!important;margin-top: -2px!important;}
.findbar-find-status {max-width: 2000px!important;}
.findbar-label.findbar-find-status {margin-left: -100px!important;max-width: 20%!important;font-size: 10px !important;}
.findbar-find-status[status="notfound"] {margin-left: 0px!important;font-size: 13px !important;}
.findbar-container {scrollbar-width: none!important;}
.findbar-textbox {position: fixed!important;margin-top: -4px!important;} /* position of the textbox */
Firefox 119 (2023) - Pink - opened tabs, orange - bookmarks, without color - history. "width" (userChrome.css *06) and "browser.urlbar.maxRichResults" (about:config or user.js) - 150% DPI
/* IMPORTANT - delete "address bar - bookmarks icon position+size / remove url separator" and "address bar - "switch to tab" color" (userChrome.css). Works in FF 109/119 */
/*.urlbarView-row:first-of-type {display: none !important;}*/
.urlbarView-type-icon {display: none !important;}
.urlbarView-action {display: none !important;}
span.urlbarView-title-separator {display: none !important;}
#urlbar .search-panel-one-offs-header-label {display: none !important;}
/* FF119 */
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner > .urlbarView-no-wrap > span.urlbarView-title.urlbarView-overflowable {background-color: #FB7914 !important;color: black !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px !important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner > .urlbarView-no-wrap > span.urlbarView-title.urlbarView-overflowable {background-color: #FF00A3 !important;color: black !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px !important;}
/* FF109 */
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner > .urlbarView-no-wrap > span.urlbarView-title {background-color: #FB7914 !important;color: black !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px !important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner > .urlbarView-no-wrap > span.urlbarView-title {background-color: #FF00A3 !important;color: black !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px !important;}
/* velikost url textu */
.urlbarView-tags, .urlbarView-url, .urlbarView-title:not(:empty) ~ .urlbarView-action {font-size: 1.0em!important;}
/* posunutí url od názvu */
.urlbarView-url {margin-left: 20px !important;}
/* levá mezera pri otevrení adresního rádku */
#urlbar-results {margin-left: 1px!important;}
/* prípadné zvetšení (na výšku) vybraných rádku pomocí myši/klávesnice - zpusobuje neprijemné poskakování textu v prípade nedostatecných mezer mezi rádky */
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner:hover {margin-left: 0px !important;padding-bottom: 0px !important;padding-top: 0px !important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner > .urlbarView-no-wrap:hover {margin-left: 0px !important;padding-bottom: 0px !important;padding-top: 0px !important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner:hover {margin-left: 0px !important;padding-bottom: 0px !important;padding-top: 0px !important;}
.urlbarView-row[type="switchtab"][selected] .urlbarView-row-inner {margin-left: 0px !important;padding-bottom: 0px !important;padding-top: 0px !important;}
.urlbarView-row[type="bookmark"][selected] .urlbarView-row-inner {margin-left: 0px !important;padding-bottom: 0px !important;padding-top: 0px !important;}
/* ikony+text - nevybraný */
.urlbarView-favicon {position: fixed!important;margin-left: 2px !important;}
.urlbarView-title {margin-left: 25px!important;}
/* ikony - vybrané myší */
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner:hover > .urlbarView-no-wrap > .urlbarView-favicon {position: fixed!important;background-color: #FB7914 !important;padding-left: 5px !important;padding-right: 5px !important;margin-left: -3px !important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner:hover > .urlbarView-no-wrap > .urlbarView-favicon {position: fixed!important;background-color: #FF00A3 !important;padding-left: 5px !important;padding-right: 5px !important;margin-left: -3px !important;}
/* text - vybraný myší - FF109 */
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner:hover > .urlbarView-no-wrap > .urlbarView-title {background-color: var(--hover-bg-row) !important;color: var(--hover-text-row) !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px!important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner:hover > .urlbarView-no-wrap > .urlbarView-title {background-color: var(--hover-bg-row) !important;color: var(--hover-text-row) !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px!important;}
/* text - vybraný myší - FF119 */
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner:hover > .urlbarView-no-wrap > span.urlbarView-title.urlbarView-overflowable {background-color: var(--hover-bg-row) !important;color: var(--hover-text-row) !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px!important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner:hover > .urlbarView-no-wrap > span.urlbarView-title.urlbarView-overflowable {background-color: var(--hover-bg-row) !important;color: var(--hover-text-row) !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px!important;}
/* text - vybraný klávesnicí */
.urlbarView-row[type="bookmark"][selected] > .urlbarView-row-inner > .urlbarView-no-wrap > span.urlbarView-title {background-color: var(--hover-bg-row) !important;color: var(--hover-text-row) !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px!important;}
.urlbarView-row[type="switchtab"][selected] > .urlbarView-row-inner > .urlbarView-no-wrap > span.urlbarView-title {background-color: var(--hover-bg-row) !important;color: var(--hover-text-row) !important;padding-left: 2px !important;padding-right: 2px !important;margin-left: 23px!important;}
/* ikony - vybrané klávesnicí */
.urlbarView-row[type="bookmark"][selected] > .urlbarView-row-inner > .urlbarView-no-wrap > .urlbarView-favicon {position: fixed!important;background-color: #FB7914 !important;padding-left: 5px !important;padding-right: 5px !important;margin-left: -3px !important;}
.urlbarView-row[type="switchtab"][selected] > .urlbarView-row-inner > .urlbarView-no-wrap > .urlbarView-favicon {position: fixed!important;background-color: #FF00A3 !important;padding-left: 5px !important;padding-right: 5px !important;margin-left: -3px !important;}
Firefox 119 (2023) - Pink - opened tabs, green - bookmarks, without color - history - 150% DPI
/* IMPORTANT - delete "address bar - bookmarks icon position+size / remove url separator" and "address bar - "switch to tab" color" (userChrome.css). Works in FF 109/119 */
/*.urlbarView-row:first-of-type {display: none !important;}*/
.urlbarView-type-icon {display: none !important;}
.urlbarView-action {display: none !important;}
span.urlbarView-title-separator {display: none !important;}
#urlbar .search-panel-one-offs-header-label {display: none !important;}
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner > .urlbarView-no-wrap > .urlbarView-favicon {position: fixed!important;background-color: #40E0D0 !important;padding-left: 5px !important;padding-right: 5px !important;margin-left: -2px !important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner > .urlbarView-no-wrap > .urlbarView-favicon {position: fixed!important;background-color: #FF00A3 !important;padding-left: 5px !important;padding-right: 5px !important;margin-left: -2px !important;}
.urlbarView-row[type="bookmark"] > .urlbarView-row-inner > .urlbarView-no-wrap > .urlbarView-title {margin-left: 27px!important;}
.urlbarView-row[type="switchtab"] > .urlbarView-row-inner > .urlbarView-no-wrap > .urlbarView-title {margin-left: 27px!important;}
/* velikost url textu */
.urlbarView-tags, .urlbarView-url, .urlbarView-title:not(:empty) ~ .urlbarView-action {font-size: 1.0em!important;}
/* posunutí url od názvu */
.urlbarView-url {margin-left: 30px !important;}
/* levá mezera pri otevrení adresního rádku */
#urlbar-results {margin-left: 1px!important;}
/* ikony+text - nevybraný */
.urlbarView-favicon {position: fixed!important;margin-left: 3px !important;}
.urlbarView-title {margin-left: 27px!important;}
Firefox 119 (2023) - DEFAULT - opened tabs+bookmarks+history - 150% DPI
Firefox 119 (2023) - DEFAULT - 
Firefox 109 (2023) - 1-LINE - 
Firefox 109 (2023) - 3-LINE - 150% system DPI
Firefox 109 (2023) - 2-LINE - folder+context menu - 150% DPI
Firefox 109 (2023) - 2-LINE - places.xhtml. Dark space - The best dynamic theme - 150% DPI
Firefox 119 (2023) - 2-LINE - 
Firefox 119 (2023) - DEFAULT - 
Firefox 109 (2023) - 2-LINE - 
Firefox 109 (2023) - DEFAULT - 
Firefox 99 (2022) - 2-LINE 
Firefox 99 (2022) - DEFAULT 
Firefox 89 (2021) - 2-LINE 
Firefox 89 (2021) - DEFAULT 
Firefox 79 (2020) - 2-LINE 
Firefox 79 (2020) - DEFAULT 
Firefox 69 (2019) - 2-LINE 
Firefox 69 (2019) - DEFAULT 
Firefox 59 (2018) - 2-LINE 
Firefox 59 (2018) - DEFAULT 
Firefox 49 (2016) - 2-LINE 
Firefox 49 (2016) - DEFAULT 
Firefox 39 (2015) - 2-LINE 
Firefox 39 (2015) - DEFAULT 
Firefox 29 (2014) - 2-LINE 
Firefox 29 (2014) - DEFAULT 
Firefox 19 (2013) - 2-LINE 
Firefox 19 (2013) - DEFAULT 
Firefox 9 (2011) - 2-LINE 
Firefox 9 (2011) - DEFAULT 
Firefox 3.5 (2009-2011) - 2-LINE 
Firefox 3.5 (2009-2011) - DEFAULT 
Firefox 2 (2006-2008) - 2-LINE 
Firefox 2 (2006-2008) - DEFAULT 
Customization (userChrome.css)
custom keyboard shortcuts.ahk (Autohotkey v1.1)
F1 - Library window (History) CTRL+SHIFT+H
F2 - Find Previous (searchbar)
F3 - Find Next (searchbar) - works without script
Home - New Tab
END - Close Tab
PgUp - Go one Tab to the Right
PgDn - Go one Tab to the Left
INS - Focus Address bar
Del (hold 0.5 second) - Copy URL (Activate Bottom "Notepad++", KeyWait CTRL+V and Activate Bottom "Firefox" is disabled)
suggestions for improvements
-remove the titles/checkboxes in the "find in page" bar and replace them with buttons/icons
-show all downloads in the pop-up window (with scrollbar) and get rid of the "show all downloads" window
-renaming bookmarks directly (long/short right mouse click)
-tabs with play/pause button and hotkey (remove useless volume button)
-combine "Edit Folder/Bookmark" in the context menu into a single entry at one specific position (properties in FF79-)
-popup status bar around mouse cursor
-remove 3 dots in bookmarks names (if are too long)
-add-ons in the "Customize Toolbar" menu
-decrease mouse vert sensitivity when the cursor approaches the left/right sides of bookmarks (folders)
-separate audio/video cache from normal cache. What's the point of the current setup where important cache data is overwritten by useless video that also reduces SSD lifetime? Constantly modifying NTFS permissions for cache folder is not very comfortable...
Useful addons
Avast Online Security https://addons.mozilla.org/en-US/firefox/addon/avast-online-security/
Enhancer for YouTube https://addons.mozilla.org/en-US/firefox/addon/enhancer-for-youtube/
YouTube Ad Auto-skipper https://addons.mozilla.org/en-US/firefox/addon/youtube-ad-auto-skipper/
Hide YouTube Fullscreen Controls https://addons.mozilla.org/en-US/firefox/addon/hide-youtube-controls/
SaveFrom.net helper https://addons.mozilla.org/en-US/firefox/addon/savefromnet-helper/
I don't care about cookies https://addons.mozilla.org/en-US/firefox/addon/i-dont-care-about-cookies/
Disable HTML5 Autoplay https://addons.mozilla.org/en-US/firefox/addon/disable-autoplay/
Image Video Block https://addons.mozilla.org/en-US/firefox/addon/image-video-block/
Large Image Blocker https://addons.mozilla.org/en-US/firefox/addon/large-image-blocker/
Load Background Tabs Lazily https://addons.mozilla.org/en-US/firefox/addon/load-background-tabs-lazily/
Print Edit WE https://addons.mozilla.org/en-US/firefox/addon/print-edit-we/
Save Page WE https://addons.mozilla.org/en-US/firefox/addon/save-page-we/
Firefox Color https://addons.mozilla.org/en-US/firefox/addon/firefox-color/
THEME https://addons.mozilla.org/en-US/firefox/addon/41444-21/
THEME https://addons.mozilla.org/en-US/firefox/addon/41444-22/
https://www.reddit.com/r/FirefoxCSS/
https://firefoxcss-store.github.io/
https://www.userchrome.org/
about:about
about:downloads
chrome://browser/content/places/places.xhtml
https://firefox-source-docs.mozilla.org/devtools-user/browser_toolbox/index.html
https://support.mozilla.org/en-US/kb/keyboard-shortcuts-perform-firefox-tasks-quickly
https://www.mozilla.org/en-US/firefox/releases/
https://whattrainisitnow.com/calendar/
https://ftp.mozilla.org/pub/firefox/releases/
https://ftp.mozilla.org/pub/devedition/releases/
https://caniuse.com/
https://www.deviceinfo.me/
about:config
dpi
layout.css.devPixelsPerPx
turning off the full screen warning
full-screen-api.warning.timeout;0
default zooming of PDF files
pdfjs.defaultZoomValue;page-width
find in page - colors
ui.textSelectBackgroundAttention
ui.textHighlightBackground
ui.textHighlightForeground
new tab - color
browser.display.background_color;#eeeeee
scrollbars
widget.non-native-theme.scrollbar.size
widget.non-native-theme.win.scrollbar.use-system-size
widget.non-native-theme.scrollbar.size.override
widget.disable-dark-scrollbar
widget.non-native-theme.win11.scrollbar.force-overlay-style
widget.windows.overlay-scrollbars.enabled
disabling tooltips when hovering over bookmarks
browser.chrome.toolbar_tips
disable animations (interface of the program and the website itself) - probably no need to be afraid of blindly toggling the "animat" and "transition" preferences
browser.fullscreen.animate;false
browser.tabs.animate;false
image.animation_mode;none
ui.prefersReducedMotion;1
svg.disabled;true
full-screen-api.transition-duration.leave
full-screen-api.transition-duration.enter
a compact density option will be added to the "customize toolbar" menu
browser.compactmode.show
set compact density immediately by number 1
browser.uidensity
disable the graphical user interface "Proton"
browser.proton.enabled
address bar - number of items
browser.urlbar.maxRichResults
address bar - disable autoFill
browser.urlbar.autoFill;false
address bar - disable search engine
keyword.enabled;false
address bar - disable "Firefox suggest"
browser.urlbar.groupLabels.enabled;false
address bar - disable faded font
browser.urlbar.formatting.enabled;false
address bar - hide reader icon
reader.parse-on-load.enabled;false
tabs - disable previews when dragging
nglayout.enable_drag_images;false
tabs - minimum width
browser.tabs.tabMinWidth
tabs pinned - disable autoreload
browser.sessionstore.restore_pinned_tabs_on_demand
disable the request to delete settings when the browser is not started for a long time
browser.disableResetPrompt;true
disable query to enable DRM
browser.eme.ui.enabled;false
slow Firefox startup - turn off notifications
browser.slowStartup.notificationDisabled
do not turn off firefox when closing the last tab
browser.tabs.closeWindowWithLastTab;false
open in tabs only
browser.link.open_newwindow.restriction;0
location query
geo.enabled
disable "insecure login" warning
security.insecure_field_warning.contextual.enabled;false
ctrl+shift+j
devtools.chrome.enabled;true
disable autoplay
media.autoplay.enabled;false
media.autoplay.allow-muted;false
enable support for WEBM playback
media.mediasource.webm.enabled
disable enforcement of signing add-ons
xpinstall.signatures.required;false
disable blacklisting of add-ons
extensions.blocklist.enabled;false
not to allow arbitrary banning of add-ons
extensions.legacy.enabled;true
do not save the list of currently opened tabs to disk = reduce writing to SSD
browser.sessionstore.resume_from_crash;false
do not create bookmarks backups
browser.bookmarks.max_backups;0
disabling automatic page refresh
accessibility.blockautorefresh;true
maximum cache size on SSD
browser.cache.disk.capacity
maximum size of the cached file on the SSD
browser.cache.disk.max_entry_size
cache isolation
browser.cache.cache_isolation;true
connection timeout
network.http.connection-timeout
firefox.exe - priority "normal"
dom.ipc.processPriorityManager.enabled;false
limiting the number of firefox.exe processes (the advantage is less CPU+RAM requirements and the disadvantage is worse security)
fission.autostart;false