chore: fix headers (#6293)

Author: AtofStryker

src/css/custom.scss

@@ -122,8 +122,6 @@
   --ifm-heading-font-family: Poppins;
   --ifm-heading-font-weight: var(--ifm-font-weight-bold);
   --ifm-line-height-base: 1.6;
-  --ifm-heading-color: theme(colors.gray.1000);
-  --ifm-code-font-size: 95%;
   --ifm-pre-line-height: 1.5em;
 
   --ifm-code-background-color: #282a36;