How does the effect on the date headers work for this site?

http://www.crystal-clouds.net/awards/

she made a div for her site called header and in her CSS specified the following:

.header {font-family: Arial; width:100%;text-align:center;padding:0px;color: #FFFFFF;letter-spacing:2px;font-size:11px;font-weight:normal;line-height:13px;FILTER: Shadow(Color=#3886AE, Direction=90);}

the part that creates the effect is in bold.