#####Problem
The layout and component spacing of the different views and elements of the Mismatch Finder app were defined using `$dimension-layout` and `$dimension-spacing` WiKit tokens, which consume values in `rem` and `em` units respectively.
We need to replace these legacy styles, but the new Wikimedia design system (Codex) doesn't include equivalent tokens that consumeuse the same units of measurement, which we prefer to use due to consistent scaling/accessibility and predictability reasons. Instead, it provides only spacing tokens in `px`.
#####Solution
In order to unblock the migration project, we'll need to create a set of reusable spacing variables to replace existing WiKit `$dimension-layout` and `$dimension-spacing` tokens.
The layout spacing of Mismatch Finder (in all the main page, header and footer) should not change as a consequence of this replacement (see T350189) and reuse them to replace WiKit tokens in the Mismatch finder.
#####Considerations
These custom variables will also be needed when we migrate Query Builder and Special:NewLexeme.The layout spacing of Mismatch Finder (in all the main page, It would be worth considering if they can be made reusableheader and footer) should not change as a consequence of this replacement.
#####Acceptance criteria
[] WiKit layout and spacing tokens used to style the Mismatch Finder app are replaced by our new reusable custom variables (T350189)
[] Current layout and spacing values remain unaltered after the replacement