Reverting to global colours after altering text...

I have picked and applied colours for a global theme.

In entering text in the boxes I overrode the global colours and selected others.

I now want to revert to the global scheme BUT:

1. There is no button in the colour picker to allow you to revert to the global colour scheme. (ie once you select another colour - even to just "try" it - you CANNOT reverse it. (The back button ONLY works if you have JUST done it - not if you have made other changes since.)

2, There appears to be NO WAY to RESET THE WHOLE WEBSITE's colours back to the global settings once you have overridden them on specific pages. (You cannot use the reset defaults as I am advised that resets everything else in addition to the colours.)

3. It appears if you create a new page, the global colours apply - BUT I do NOT want to have to recreate every single page on my website.

There must be a more efficient way to do this???

Any suggestions on how to do it. Thank you.