Revert "Chage primary color to better match SWH theme"

This reverts commit ae901af0.

Two people within the team reported it's hard to read for them with the new theme (color-blindness).

This addresses this immediate issue; and we search for an accessible way to have the SWH(-ish?) palette on the docs later.

docs/_static/custom.css

-html[data-theme="light"] {
-  --pst-color-primary: #e20026;
-  --pst-color-secondary: #52566D;
-}
-
-html[data-theme="dark"] {
-  --pst-color-primary: #e20026;
-  --pst-color-secondary: #dbdbdb;
-  --pst-color-secondary-text: #141325;
-}
-
-
 table.swh-logos-table td,
 table.swh-logos-table th {
   text-align: center;