Colour in about:config changes when searching - v135.0

At some point recently, the background colour of about:config started changing to white when my search reaches the third letter. Below is the code in userContent.css. What do I need to add?

@-moz-document url-prefix("about:"), url-prefix("chrome://"), url-prefix("resource://"){ :root { --in-content-page-color: #000080 !important; --in-content-text-color: #000080 !important; --in-content-page-background: #dbc3a3 !important; --in-content-box-background: #e2cfb6 !important; --in-content-deemphasized-text: var(--in-content-text-color) !important; scrollbar-color: #6495ed #d9d9d9 !important; --background-color-box: var(--in-content-page-background) !important; --text-color: var(--in-content-text-color) !important; color:var(--in-content-text-color) !important; }