<center>Test.</center>

<div style="background:tomato;color:#fff;font-size:21px;font-weight:700;padding:10px 0;text-align:center">Can you really do styled text inside posts?</div>

Not, we can't :(

"</span><span style="background:khaki;">another try...</span><span>"

<?php echo' "</span><div style='background:tomato;color:#fff;font-size:21px;font-weight:700;padding:10px 0;text-align:center'>Ok last try...</div><span>" '; ?>