Just so to make things easier for a lot of developers trying to get code blocks working on tumblr:
public string Celebration()
{
return "yey, simple code blocks on tumblr!";
}
Number 1: Append this to your CSS:
pre {
padding: 15px;
background: #333;
color: #fff;
border: 1px solid #222;
}
Number 2: I recommend using Markdown as your tumblr editor.
Number 3: With Markdown as your editor, just place 4 spaces before the text you wish to turn into a code block.
By doing so, you get these styled code-blocks I currently use in my blog. Cheers!
Edit: This technique might not work anymore. Here is a more updated version for enabling codeblocks in tumblr.