P.S. I already use a 1 pixel blur-shadow to bolden all text on Firefox on Linux Mint. If it's possible to use 2 shadows, I could perhaps use a white 5 px blur behind links, with a font-colored 1 px blur on top of that, with the font on top as usual.

Hi Marja, it depends. Some sites are themed based on a signal from the browser about whether you prefer a light or dark theme. This would be one way to decide what text/background colors to apply to links. More info: https://developer.mozilla.org/docs/Web/CSS/@media/prefers-color-scheme

But some sites use a dark or light theme regardless of your browser's expressed preference, so in that case, you would need a script that can detect the appearance of the page in order to choose the best color scheme.

Are you currently using text-shadow? You can layer shadows starting from different positions, but it still has some transparency so this isn't very nice:

text-shadow: #eee -10px -5px 20px, #eee 10px 5px 20px, #eee -10px 5px 20px, #eee 10px -5px 20px;

Although it gives the link a crude appearance, what about a simple background color?

background-color: #ffe !important; border-radius: 4px;

Hopefully that won't be too blinding on dark-themed sites.

There is text-shadow and box shadow that supports multiple colors apart from an outline, so you can possibly use a set for dark and white.

• https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow
• https://developer.mozilla.org/en-US/docs/Web/CSS/box-shadow

I'm not sure what is best in your case, so my try at subreddit FirefoxCSS.

• https://www.reddit.com/r/FirefoxCSS/

Note that websites can use an image as a clickable link (i.e. no text), so be cautious with using !important to override background-color as this can cause images to disappear.

Thanks. I've tried the background color. It's a bit too intense. I think something which halfway lightens the backgrounds might work better.

There's a user script called NoBrighter on greasyfork .org which may suit you. It is very simple to configure.