macOS Safari Web Inspector Font Size

macOS-Safari-Web-Inspector-Font-Size.css

/*

1. Reboot & hold Cmd+R
2. Open Terminal Utility
3. Type "csrutil disable", reboot
4. Add lines to end of file: /System/Library/PrivateFrameworks/WebInspectorUI.framework/Versions/Current/Resources/Main.css
4.1 For Safari 14+: /Library/Apple/System/Library/StagedFrameworks/Safari/WebInspectorUI.framework/Versions/A/Resources/Main.css
5. Enable csrutil at reboot - "csrutil enable"

*/

.cm-s-default,.syntax-highlighted,.spreadsheet-css-declaration,.spreadsheet-style-declaration-editor{font-size:12px}
.tree-outline.dom li, .spreadsheet-style-declaration-editor{line-height:18px!important}

/*

UPD. For macOS Catalina:
sudo mount -uw /
sudo chmod -R 775 /System/Library/PrivateFrameworks/WebInspectorUI.framework/Versions/Current/Resources/Main.css
// For Safari 14+: sudo chmod -R 775 /Library/Apple/System/Library/StagedFrameworks/Safari/WebInspectorUI.framework/Versions/A/Resources/Main.css

UPD 2. Editing with Sublime Text example (as root):
sudo ln -s "/Applications/Sublime Text.app/Contents/MacOS/Sublime Text" /usr/bin/st
sudo st /System/Library/PrivateFrameworks/WebInspectorUI.framework/Versions/Current/Resources/Main.css
// For Safari 14+: sudo st /Library/Apple/System/Library/StagedFrameworks/Safari/WebInspectorUI.framework/Versions/A/Resources/Main.css

*/