The Opera browser allows you to completely control the way that the pages you display from the Internet are formatted on your computer. You can't control what the web site you are visiting says (and there is no reason why you would want to) but you can control the way that web pages appear on your browser. This gives you the ability to make all of the web pages on the internet that you visit appear similar to one another with respect to the fonts used, text sizes, link appearance etc.
You do this by defining your own style sheet that the browser will use instead of any style sheet or font definitions that the site author may have defined for use with their pages.
There are three things that you need to do to achieve this.
Step one is to define your style sheet. You do this exactly the same way as you would define an external style sheet that would be uploaded for use by your own web site. Instead of uploading the style sheet to the web, you instead save it to your own hard disk.
Step two is to select the File menu on your Opera browser and go into Preferences. Go to the Documents preference page and enter the location of the style sheet file that you created into the CSS File field under the User CSS heading.
If you don't know how to define an external style sheet then instead of carrying out the above steps then you can instead update the individual definitions under the User Fonts and Colors heading on the Documents preference page to define the way that you want each individual tags formatting to be defined.
The final step is to click the third button on the Browser Progress bar to "Toggle between Document Mode and User Mode".
This article written by Stephen Chapman, Felgall Pty Ltd.