.category-material-container .category-materials {
    font-size: 0;
    display: flex;
    flex-wrap: wrap;
}

.category-material-container .category-materials .category-materials-item:not(:empty) {
    font-size: initial;
}

.category-material-container .category-materials-item-image {
    background-size: cover;
    width: 100%;
    height: 200px;
    background-repeat: no-repeat;
    background-position: center;
}

      .category-material-container {
        position: relative;
      }

      #loader {
        display: none;
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(255, 255, 255, 0.7);
        z-index: 9999;
      }

      /* Loader animation */
      @keyframes loader-spin {
        0% {
          transform: rotate(0deg);
        }

        100% {
          transform: rotate(360deg);
        }
      }

      #loader::after {
        content: '';
        position: absolute;
        display: block;
        width: 50px;
        height: 50px;
        margin: auto;
        border-radius: 50%;
        border: 5px solid #f3f3f3;
        border-top: 5px solid #3498db;
        animation: loader-spin 1s linear infinite;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
      }