Find the line of code that reads "font-size:" and then a number. Changing the number will increase or decrease the size of the header font, with the higher numbers resulting in larger fonts.

Increasing or decreasing the size of the text in your operating system or Web browser can be tricky, but our easy guide walks you through it.

Fortunately, Tumblr enables you to change the font size for your blog's text by giving you direct access to the raw CSS or Cascading Style Sheet code of your theme.