widthtransition: width 1.5s linear

Invoice 1042USD 1,280
Invoice 1043USD 1,280
Invoice 1044USD 1,280
Invoice 1045USD 1,280
Invoice 1046USD 1,280
Style→Layout→Paint→Composite

Every frame relays out and repaints the page on the main thread, the same thread JavaScript runs on.

transformtransition: transform 1.5s linear

Invoice 1042USD 1,280
Invoice 1043USD 1,280
Invoice 1044USD 1,280
Invoice 1045USD 1,280
Invoice 1046USD 1,280
Style→Layout→Paint→Composite

The sidebar is its own layer. Every frame only moves that layer, on the compositor thread, without waiting for JavaScript.

main-thread frames during the slide–
01.5s