rt 1: -->
    <div class="container"><div class="alignCenter"><!--center--></div></div>
    <div class="container"><div class="alignStart"><!--start--></div></div>
    <div class="container"><div class="alignEnd"><!--end--></div></div>
    <div class="container"><div class="alignStart"><!--self-start--></div></div>
    <div class="container"><div class="alignEnd"><!--self-end--></div></div>
    <br>
    <!-- <self-position>, part 2: -->
    <div class="container"><div class="alignStart"><!--flex-start--></d