How to configure and use custom CSS stylesheets in Vivaldi?

One of the unique features of the Vivaldi browser is the ability to fully customize the interface and web pages using custom CSS stylesheets. This feature is aimed at advanced users, developers, and designers who want to change the appearance of both the browser itself and websites according to their individual preferences. To get started with custom CSS, you need to enable the user interface debugging mode in the settings.

First, prepare the files with your CSS code in any text editor. Then go to the main browser settings, find the Appearance section, and look for the Custom CSS Modifications block. Specify the path to the folder where your styles are stored so that the browser can load them every time it starts. Using these files, you can change the colors of interface elements, hide unnecessary panels, reduce margins, or completely redesign the visual presentation of Vivaldi's controls.

In addition to changing the browser interface itself, Vivaldi allows you to apply custom styles to specific websites via the script and style injection feature. This is useful if you want to enable a dark theme on a site that does not support it, or change the font size for better readability. Create a rule in the page content settings by specifying the site address and the corresponding CSS code, and the browser will automatically apply these styles every time the page loads.