[html] text-align:center won't work with form <label> tag (?)

This is because label is an inline element, and is therefore only as big as the text it contains.

The possible is to display your label as a block element like this:

#formItem label {
    display: block;
    text-align: center;
    line-height: 150%;
    font-size: .85em;
}

However, if you want to use the label on the same line with other elements, you either need to set display: inline-block; and give it an explicit width (which doesn't work on most browsers), or you need to wrap it inside a div and do the alignment in the div.