As a workaround for anyone using Firefox, the "Dark Background and Light Text" worked better for me.
https://addons.mozilla.org/en-US/firefox/addon/dark-background-light-text/
Despite the extension's name, it lets you choose any color for the background and text on its general preferences.
This extension also has the "Recommended" badge, which upon hover states: "Firefox only recommends add-ons that meet our standards for security and performance."
After install, head to its general preferences, set the "Default method of changing page colors" preference to "disabled". Otherwise, it will trigger dark mode on every site, which for enjoyers of light themes is not the desired outcome.
Then, in Laracasts, or any dark theme-only site, choose the "Invert" option from the extension's menu. It will remember those settings.
If you don't like the inverted colors, the extension's general preferences lets you choose any colors for the background and text colors. After choosing your preferred ones, then choose one of the "Simple CSS" or the "Stylesheet processor" option from the extension's menu on the site you want to use light colors.