Customize
How to customize?
In setting panel, it`s very easy to customize element`s font, color, background, width to your blog as you want.
Code mode
You can use CSS code to customize your theme in this mode.
What is CSS?
Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics (that is, the look and formatting) of a document written in a markup language. Its most common application is to style web pages written in HTML and XHTML.------Wikipedia
How to use code mode.
You can type CSS code into textbox in code panel, and it will apply it immediately.