Greetings! I would like to firstly ask if you've changed any preferences recently. These include: dark/light mode, colourways and/or customised Firefox using Firefox Colour.

You can select a theme that has dark text on the tabs (toolbars) if you currently use a theme with light text to prevent Firefox from using a dark background for webpages.

You can change this pref on the about:config page from 3 to 2 to revert to the Firefox 94 behavior regarding to prefer dark or light background for webpages. You can use 0 (dark) or 1 (light) to set a specific state.

• about:config => layout.css.prefers-color-scheme.content-override [dark:0, light:1, system:2, browser:3]

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

There may also be a button on the Google page (possibly labelled Settings) which enables you to change to a light theme.