word-wrap: break-word doesn't work in a grid.
For tables there is table-layout: fixed, what is the equivalent for grids?
<div style="background: #e3e3e3; width: 75%;">
 <div style="word-wrap: break-word;">
   normaldivnormaldivnormaldivnormaldivnormaldivnormaldivnormaldivnormaldivnormaldivnormaldivnormaldiv
 </div>
 
 <table>
   <tr><td style="word-wrap: break-word;">
     badtablebadtablebadtablebadtablebadtablebadtablebadtablebadtablebadtablebadtablebadtablebadtablebadtable
   </td></tr>
 </table>
 
 <table style="table-layout: fixed; width: 100%;">
   <tr><td style="word-wrap: break-word;">
     fixedtablefixedtablefixedtablefixedtablefixedtablefixedtablefixedtablefixedtablefixedtablefixedtablefixedtable
   </td></tr>
 </table>
 
 <div style="display: grid;">
   <div style="word-wrap: break-word;">
     griddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddivgriddiv
   </div>
 </div>
</div> 
    