Fix YouTube background color (#38)

Author: Ari-43

styles/youtube/rose-pine.user.less

@@ -117,6 +117,7 @@
       --yt-frosted-glass-desktop: transparent;
 
       --yt-spec-base-background: @surface !important;
+      --yt-sys-color-baseline--base-background: @surface !important;
       --yt-spec-raised-background: @surface !important;
       --yt-spec-menu-background: @surface !important;
       --yt-spec-inverted-background: @text !important;
@@ -1291,6 +1292,7 @@
 
       --ytcp-general-background-a: @surface !important;
       --yt-spec-base-background: @surface !important;
+      --yt-sys-color-baseline--base-background: @surface !important;
       --yt-spec-black-3: @surface !important;
 
       --yt-spec-brand-background-solid: @surface !important;