That's strange.
Zen Cart automatically calculates how wide each of those category listings should be; in your case, since there are only two to display, it gives each 50%.
Margins or padding will add to that, and can make the correct number not fit, and browser rounding errors can make the total come to infinitesimally more than 100% which will bump the last one in line down, but I tested your site and neither of those is the problem.
Your stylesheet has
#logo, .centerBoxContents, .specialsListBoxContents, .categoryListBoxContents, .centerBoxContentsAlsoPurch, .attribImg {
float: center;
}
which is a problem. There is no such thing as "float: center;", and the original float: left; is what makes them line up in rows.
If you want other elements in that list to be centered, separate the selectors and restyle like this```
.categoryListBoxContents {
float: left;
}
#logo, .centerBoxContents, .specialsListBoxContents, .centerBoxContentsAlsoPurch, .attribImg {
text-align: center;
}
Nevermind, Kobra answered while I was looking at your site...