Per-site fonts and spacing by Дмитрий

Customize the base text style separately for a website: size, font, spacing and colors. Open the popup, choose Enable on this site, then edit the fields you need. A site is unchanged until enabled; opening the popup alone applies nothing.

SETTINGS PER WEBSITE
• Base text-size slider: 80–200%.
• Letter spacing and line height.
• Text color and base background color.
• An installed font name, or serif, sans-serif, monospace.
Empty fields do not override that property. Edits apply immediately and persist across reloads. Pages on the same hostname share settings; subdomains are separate. Reset removes the current hostname's setting without affecting other sites.

NOT A FONT CATALOGUE
The add-on does not download or load fonts. Enter an installed typeface name or use a generic family. Font availability is determined by the browser; websites can still load their own web fonts. There is no file upload or Google Fonts catalogue.

IMPORTANT: BASE STYLE, NOT A COMPLETE SITE THEME
The CSS targets body. Individual elements can retain their own sizes, fonts, spacing and backgrounds. MDN and Wikipedia, for example, retain some site-defined line heights and backgrounds. This is not a full light/dark theme. Custom colors may reduce contrast with site elements; use Reset if the result is unsuitable.

The size percentage is relative to the base CSS size, not page zoom or a multiplier for each original element. Preservation of every layout and compatibility with every site are not guaranteed. Embedded frames, Shadow DOM and internal browser pages are outside its scope. Android is untested.

VERIFICATION AND PRIVACY
Desktop Firefox checks cover W3C, MDN and Wikipedia: actual text styles, persistence after reload, reset and independence between sites. Refresh existing pages after installation.

Only enabled hostnames and their settings are stored locally. No analytics, account sync, remote code or extension-owned network requests. Page text, forms, passwords and cookies are not collected. HTTP/HTTPS website access is required to apply styles. Interface in English and Russian.