/**
 * Container for the interesting part of a highlight reftest, to be
 * used on both the test page and any reference pages.
 */
.highlight_reftest {
    /*
        https://drafts.csswg.org/css-pseudo-4/#highlight-bounds
        For text, the corresponding overlay must cover at least
        the entire em box and may extend further above/below the
        em box to the line box edges.
    */
    line-height: 1;
}