If you opened MakerWorld and found something was different but couldn’t tell what, it probably was the new dark mode! In an update that arrived on January 1st, 2025, MakerWorld released a new dark mode that will follow your system preference by default.
However, if you don’t like it, you can always go to your preferences (https://makerworld.com/en/my/settings/preferences) and select the theme you prefer.