I just tested this and it does look like the page I generated in sculptor also has that lag. The reason for this is the way the style sheet is imported. It is using the @import url call to import the style sheet. If you use the link method to include the style sheets that are needed, the css will load right away. For example, this is how Sculptor generates it:
<style type="text/css" media="all">
<!--
@import url("CSSSculptor/1ColumnFixedCentered_CaboSunset_css/screen.css");
-->
</style>
You can add this into the body tag for it to load instantly:
<link rel="stylesheet" type="text/css" href="CSSSculptor/1ColumnFixedCentered_CaboSunset_css/screen.css" />