.rn-grid{
 display:grid;
 grid-template-columns:repeat(3,1fr);  /* 3 colunas idênticas */
 gap:var(--rn-gap);
 align-items:stretch;                   /* cards com mesma altura */
}
.rn-card{
 display:flex;
 flex-direction:column;
 background:#fff;
 border:1px solid #e7ebf2;
 border-radius:var(--rn-radius);
 overflow:hidden;
}
.rn-card__body{padding:20px;flex:1;}
@media(max-width:900px){ .rn-grid{grid-template-columns:1fr 1fr;} }
@media(max-width:600px){ .rn-grid{grid-template-columns:1fr;} }