This CL maps the colors being used in
the web app to variables to make it easier to
change color palette without having to track color
changes across files.

Bug: v8:10673

Change-Id: Icf1c53396b8a831367c4ed420931e6233d780a07
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2298005
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68864}