Module:Chem2/sandbox/styles.css

 .template-chem2-su{
 display:inline-block;
 font-size:80%;
 line-height:1;
 vertical-align:-0.35em;
 }

 .template-chem2-su>span{
 display:block;
 text-align:left;
 }

 /* Ignore the linter error about this selector being "overqualified"; this is the
  correct selector to override the default stylesheet. */
 sub.template-chem2-sub{
 font-size:80%;
 vertical-align:-0.35em;
 }

 sup.template-chem2-sup{
 font-size:80%;
 vertical-align:0.65em;
 }