.resource-item {
    width: 100%;
    padding-bottom: 10px;
    border-bottom: 1px solid #333;
}

#data-table,
.filtering {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
        flex-wrap: wrap;
}

.filtering {
    -webkit-box-pack: justify;
        -ms-flex-pack: justify;
            justify-content: space-between;
    margin-bottom: 30px;
}
.filter-select {
    border: 1px solid #333;
    border-radius: 6px;
    height: 35px;
    padding: 0 15px;
    background: #fff;
}
.quicksearch {
    border: 1px solid #333;
    border-radius: 6px;
    height: 45px;
    padding: 0 15px;
  text-align: center;
}

.resource-item {
    width: calc(33.33% - 20px);
    margin: 10px;
    -webkit-box-sizing: border-box;
            box-sizing: border-box;
    -webkit-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
}

.resource-item img {
    margin: 5px 0;
}

.resource-item:after {
    content: "";
    display: table;
    clear: both;
}

@media (max-width: 780px) {
    .resource-item {
      width: calc(49.99% - 20px);
    }
    .filtering .filters{
      width: 100%;
      text-align: center;
    }
    .filtering .quicksearch{
      margin: 20px auto;
    }
}
@media (max-width: 580px) {
    .filters label {
      width: 100%;
      display: block;
    }
    .resource-item {
      width: 100%;
    }
}


.hidden-by-default {
  display: none !important;
  opacity: 0.5;
}

.resource-item {
  display: block;
}

<style>
  .hidden-by-default {
    display: none;
  }
</style>