Sunday, 29. November 2009, 15:27:26
CSS, *.css, User Style Sheets, View
...
If web page looks different from normal then you might have enabled User Mode or style sheet. To bring back normal look disable all except Author Mode in .

Normal look (Author mode)

Accessibility layout

Block structure

Outline

Table of contents
Look with various styles
Sunday, 6. September 2009, 15:43:10
User CSS, Subscriptions, User Style Sheets, News
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Latest news page used to show your blog posts and photos in green color and others in blue color but this was removed in carambola release. 
You can bring back colors by using user style sheet.
Add the following code to user CSS file and reload news page to apply style sheet.
/* Subscriptions (Latest news) */
.newscontainer h2 { background:#2b7fb6; color:#fff; }
.newsowner h2 { background:#82a70b; }

News page before

News page after
Sunday, 23. August 2009, 08:55:44
IRC, CSS, *.css, im.css
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Opera automatically highlights text when other people say your IRC username, to tell you to pay attention. But if you are away for a while you have to scroll up and check. You can use CSS to summarise how many times people have said your name so that you can quickly see if you missed something.
The following will display a counter at the top right corner of the chat window showing how many times people have said your username.
- Copy C:\Program Files\Opera\styles\im.css in Windows or /usr/share/opera/styles/im.css in Linux to profile\styles directory. This is to avoid overwriting during update and to make backup easy.
- Add the following CSS code to the bottom of copied file and save.
.highlight {
counter-increment: personals;
}
.highlight:after {
position: fixed;
top: 0px; right: 0px;
content: "Your name has been mentioned "counter(personals)" times";
border: 1px dotted #552;
padding: 1px;
background-color: #ffffe1;
width: 25em;
}
- Specify path to IM Style File and save.
- Restart Opera.

Opera IRC
[Using CSS to disable features of Opera IRC chat]
Wednesday, 1. July 2009, 15:26:01
CSS, User Style Sheets, Friend Request, Hide
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A user style sheet is a text file with CSS declarations. It allows you to have control over the look and feel of website. It can be used to hide annoying things like ads, change fonts and colors, etc.
!important declaration should be added to a rule to take precedence over author style sheet.
User style sheets can be applied to all sites (restart required to apply style sheet) or per-site basis (reload required to apply style sheet).
Example 1: Hide friend request link in My Opera

My Opera friend request link in top bar
- Create a text file with the following and save preferably inside profile\styles directory with CSS file extension.
/* Friend request */
#friendrequest { display: none !important; }

CSS to hide friend request link and share this button
- Add path to CSS file in site preferences.

Path to CSS file in site preferences
- Reload page to apply style sheet.

My Opera friend request link hidden by CSS
Example 2: Hide sponsored links in Google

Useless Google sponsored links
Google sponsored links can't be blocked by content blocker but it can hidden by following CSS code.
/* Top sponsored links */
#tads { display: none !important; }
/* Side sponsored links */
#mbEnd { display: none !important; }