[Turtle91]

It stands for "Cascading Style Sheet". It has the file extension of ".css". It can be found in the "Styles" folder in Sigil's Book Browser on the left side of the screen. It is a list of definitions on how the book looks, not how it reads.

Some simple definitions are:

p {
     margin:0;
     indent:1.2em;
     text-align:left
   }

h1 {
     margin: 2em 0 2em;
     indent:0;
     font-weight:bold;
     font-size:1.2em;
     text-align:center
     }

That simply says that all paragraphs have zero margin, they are indented 1.2 character heights (so the indent changes with font size), and it is aligned to the left, and all header level 1 tags are bold, are 1.2 times the height of a normal character, are aligned to the center of the display with no indent, and have a margin, or space, of 2 character heights above and below the header.


You can easily edit the way the entire book looks just by updating a few lines in the css file.

You can also effect how a device displays an item...sometimes - but that is a longer story... for example, there must be some definition in your css telling any reading device/app to display tables a certain way. Unfortunately, depending on how good the device/app is, it can ignore some or all of the styling intended by the book creator. That's why it is important to see the css...it'll help determine if it is a css problem or an adilko problem.

Some people who make books don't understand how these definitions work...they typically just use an automated process like smashwords, or some authoring program that says "save as epub" and think they are done. It would make a much better book if they would take a few minutes to learn the basics. There is a pretty good tutorial here on MR...and a good reference on W3Schools