Ok, now I understand. You want something like a "flex-box" but working in epub 2 and with css2. For that, you can use a "table" with only one cell or <p> or <div> tags but with the property "display: inline-block". I attach an epub with examples about how to do that and below you can see a screenshot of ADE:
Of course, you can play with "widths", "margins" and "paddings".
Regards
Rubén
EDIT: Althought in the epub I think the thing is clear, if you are going to use a table, then the table musn't have any width, so it will resize with the text. On the other hand, with <p> or <div> tags you can use the property "width" since the key here is to use the property "display: inline-block;".