In Antenna House Formatter, you can use CSS classes and pseudo-elements to create change bars and notes. For example, the .changed1 class with a ::before pseudo-element can be used to add a change bar and a note in the margin. The -ah-change-bar-* properties control the appearance and positioning of the change bar, and standard CSS properties are used to style the note content and adjust the layout.

<div class="changed1">
    <!-- ...content... -->
</div>

.changed1 {
}
.changed1::before {
    -ah-change-bar-class: abc;
    -ah-change-bar-style: solid;
    -ah-change-bar-color: black;
    -ah-change-bar-offset: 4em;
    -ah-change-bar-side: left;
    content: "This is a change log.";
    font-size: 0.8em;
    width: 2.5em;
    background-color: lightpink;
    left: -3.5em;
}
.changed1::after {
    content: '';
    -ah-change-bar-class: abc;
}
            

This text has no changes so there is no change bar.

This text has changes so there is a change bar without a note.

In HTML/CSS for Antenna House Formatter, .changed1::before acts as the change bar start (with the note and all -ah-change-bar-* properties), and .changed1::after acts as the change bar end. These pseudo-elements, together with the -ah-change-bar-class, -ah-change-bar-style, -ah-change-bar-color, -ah-change-bar-offset, and related properties, provide the same effect as <fo:change-bar-begin> and <fo:change-bar-end> in XSL-FO.