<div id="mceu_53-body">
  <div id="mceu_46" class="mce-widget mce-btn mce-active" tabindex="-1" aria-pressed="true" role="button" aria-label="Minature image">
    Minature
  </div>
  <div id="mceu_47" class="mce-widget mce-btn" tabindex="-1" aria-pressed="false" role="button" aria-label="Align left">
    Align left
  </div>
  <div id="mceu_48" class="mce-widget mce-btn" tabindex="-1" aria-pressed="false" role="button" aria-label="Align right">
    Align right
  </div>
</div>

/*
Forum question answer only:
https://www.sitepoint.com/community/t/conditionals-in-less/369281

I want to add a condition in Less which can set display: none; for aria-label="Align left" and aria-label="Align right" when aria-pressed="true" for aria-label="Minature image".

*/

[aria-pressed="true"][aria-label="Minature image"] ~ [aria-label="Align left"],
[aria-pressed="true"][aria-label="Minature image"]
  ~ [aria-label="Align right"] {
  display: none;
}