to remove rule:
stylesheet.deleteRule(index),
(loop to find the right value)
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// https://webplatform.github.io/docs/tutorials/Dynamic_style_-_manipulating_CSS_with_JavaScript/
// https://stackoverflow.com/questions/70251599/how-to-use-cssstylesheet-insertrule-to-change-a-root-property/71875353
to manipulate the “—” rules such as “—marksVariableName, it has to be done in the” selector and use insertRule:”
this should turn the background color from red to whatever value is in the hash.