Here are some things you can do right now:
In Opera GX you can goto the URL opera://settings/web_modding and add CSS for a domain to change any font stuff that CSS allows you to change. In regular Opera, you can use a User CSS extension or ever write your own extension.
Example:
Create a folder on your desktop and put these 2 files in it:
manifest.json:
{
"manifest_version": 3,
"name": "Red Font for Example.com",
"version": "0.1",
"description": "Changes all font color to red on example.com.",
"content_scripts": [
{
"matches": [
"*://example.com/*"
],
"css": [
"content.css"
],
"run_at": "document_start"
}
],
"permissions": []
}
content.css:
* {
color: red !important;
font-size: 24px !important;
font-family: Consolas !important;
}
Then, in Opera, goto the URL opera://extensions, turn on developer mode, click "Load unpacked" and point it to the folder where manifest.json is at. Then, enable "Allow access to search page results" and "Allow in incognito". Then, goto https://example.com/.
You can see https://www.w3schools.com/cssref/pr_font_font.php for more info on font-related CSS properties etc.
