[RbnJrg]

Try the following:

  <div class="center block">

      <p class="hindent">This is a stanza</p>

      <p class="hindent">This is a stanza of beautiful poetry and a very quite long one</p>

      <p class="hindent">This is a stanza of beautiful poetry and the most long stanza in this poetry</p>

      <p class="hindent1">This is a stanza of beautiful poetry</p>

      <p class="hindent">This is a stanza of beautiful poetry</p>

      <p class="hindent">This is a stanza of beautiful poetry</p>

      <p class="hindent1">This is a stanza of beautiful poetry</p>

      <p class="hindent">This is a stanza of beautiful poetry</p>

      <p class="hindent">This is a stanza of beautiful poetry</p>

      <p class="hindent1">This is a stanza of beautiful poetry</p>

      <p class="hindent">This is a stanza of beautiful poetry</p>

      <p class="hindent">This is a stanza of beautiful poetry</p>

  </div>

and

.block {
    margin: 1em 0;
    display: block;
    width: fit-content; 
    max-width: 85%;
    margin-left: auto;
    margin-right: auto;
    text-align: left;
}

Of course, this "solution" is not working on ADE 2.x.