.btn-cart-small{
  min-height:40px;

  padding:6px 14px;

  border:3px solid var(--noir);
  background:var(--blanc);
  color:var(--noir);

  font-family:var(--font-main);
  font-size:20px;
  line-height:1;

  text-decoration:none;
  cursor:pointer;

  display:inline-flex;
  align-items:center;
  justify-content:center;

  box-shadow:6px 6px 0 var(--noir);

  transition:transform 0.2s ease,
              box-shadow 0.2s ease,
              background 0.2s ease,
              color 0.2s ease;
}

/* hover identique à ton style global */
.btn-cart-small:hover{
  background:var(--noir);
  color:var(--blanc);
  box-shadow:9px 9px 0 var(--gris);
  transform:translate(-3px,-3px);
}

.btn-cart-small{
  margin-left:auto;
}