<div class="storeItem">
   
  <div class="buttonList">
    <button>An item</button>
    <button>Star</button>
    <button>Another one</button>
    <button>btn</button>
  </div>  
</div>

.storeItem {
  background: white;
  border: 1px solid #EDEDED;
  box-shadow: 0 12px 24px 0 rgba(0, 0, 0, 0.09);
  position: relative;
  display: flex;
  flex-direction: column;
  max-width: 400px;
}



.buttonList{
  width: 100%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
  grid-gap: 1px;
  background: #E1E1E1;
  border-top: 1px solid #E1E1E1;
}

button {
  background: white;
  border: 0;
  font-size: 1rem;
  padding: 1rem;
}