Write any CSS you want in the contenteditable -pre- and some JavaScript will tell the browser to start a view transition (take a before screenshot), apply the written styles to the page, then take an after screenshot and transition between the two states (whatever they are!).
Codepen demo → https://goo.gle/3Ps3hZx
View Transitions guide → https://goo.gle/3CqDHMB
GUI Snippets → https://goo.gle/GUIsnippets
GUI Challenges → https://goo.gle/GUIchallenges
Subscribe to Google Chrome Developers → https://goo.gle/ChromeDevs
#GUIsnippets