Update README.md

Author: not-holar

README.md

@@ -23,13 +23,13 @@ Welcome to the repo for my Firefox theme, a theme that aims to look nice and cle
 ### Optional
 
 The toolbar layout i use:
-![](https://raw.githubusercontent.com/not-holar/my_firefox_theme/master/firefox/toolbar_layout.png)
+![](https://raw.githubusercontent.com/not-holar/my_firefox_theme/main/firefox/toolbar_layout.png)
 
 ## Tree Style Tabs
 
 1. [Download Tree Style Tabs from Mozilla.org](https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/).
-2. Set the main settings (important ones are underlined) like so: [Settings Screenshot](https://raw.githubusercontent.com/not-holar/my_firefox_theme/master/tree_style_tabs/settings.png).
-3. Scroll down and copy-paste everything from [tree_style_tabs/extra_style_rules.css](tree_style_tabs/extra_style_rules.css) to [here](https://raw.githubusercontent.com/not-holar/my_firefox_theme/master/tree_style_tabs/put_css_here.png).
+2. Set the main settings (important ones are underlined) like so: [Settings Screenshot](https://raw.githubusercontent.com/not-holar/my_firefox_theme/main/tree_style_tabs/settings.png).
+3. Scroll down and copy-paste everything from [tree_style_tabs/extra_style_rules.css](tree_style_tabs/extra_style_rules.css) to [here](https://raw.githubusercontent.com/not-holar/my_firefox_theme/main/tree_style_tabs/put_css_here.png).
 4. Allow TST to run in private windows to not lose tabs in incognito.
 
 ## Taskbar Icon