MobileRead Forums - Sigil 0.6.0 & CSS problem?

I just installed Sigil 0.6.0 and tried to use a custom CSS to create a epub book, to my surprise the CSS files seems has no effect on the doc. This is what I did:
1) moused over Style, then clicked Add Blank Stylesheet, then added the following code

Code:

/* Style Sheet for ePub Books */

/* Set margins at 2% (This gives a white border around the book) */



body {margin-left:2%;

    margin-right:2%;

    margin-top:2%;

    margin-bottom:2%;}



/* Text indent will make a paragraph indent, like putting a tab at the beginning of each new paragraph

The margin settings get rid of the white space between paragraphs, again so it looks more like a book

The text-align line justifies the margins. If you don't want them justified, change it to left, or remove

 that line. You don't have to specify a font, but you can */



p {text-indent: .3em;

    margin-left:0;

    margin-right:0;

    margin-top:0;

    margin-bottom:0;

    text-align: left;

    font-family:"Arial";}



/* Here we make our headings centered

We've also made the headings the same font as the body text */



h1 { text-align: center;

    font-family:"Arial";

        font-size: 1.3em;}

h2 { text-align: center;

    font-family:"Arial";

        font-size: 1.2em;}

h3 { text-align: center;

    font-family:"Arial";

        font-size: 1.1em;}

2) entered text in Book View
3) added

Code:

<link rel="stylesheet" type="text/css" href="../Style/Style0001.css" />

to the <head> section as seen here (the file name is Style0001.css under Styles folder):

Code:

<?xml version="1.0" encoding="utf-8" standalone="no"?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"

  "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">



<html xmlns="http://www.w3.org/1999/xhtml">

<head>

  <title></title>

  <link href="../Style/Style0001.css" rel="stylesheet" type="text/css" />

</head>

What am I missing? My <h1> does not change, and when I went to Preview View, the h1 showed 2em instead of 1.3em defined in my CSS.