.product {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  padding: 100rem 0;
}
.product-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  -webkit-column-gap: 25rem;
     -moz-column-gap: 25rem;
          column-gap: 25rem;
  row-gap: 40rem;
}
.product-item {
  border: 1rem solid #f3f3f3;
}
.product-image {
  width: 100%;
}
.product-title {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  border-top: 1rem solid #f3f3f3;
  height: 40rem;
  font-size: 18rem;
}

@media screen and (max-width: 1200px) {
  .product {
    display: block;
    padding: 30rem 0;
  }
  .product-list {
    grid-template-columns: repeat(2, 1fr);
    gap: 10rem;
    margin-top: 20rem;
  }
}
.category {
  width: 340rem;
  margin-right: 40rem;
  -ms-flex-negative: 0;
      flex-shrink: 0;
}
.category-title {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  height: 100rem;
  width: 100%;
  background-color: #138db1;
  color: white;
  font-size: 42rem;
  font-weight: bold;
}
.category-item {
  font-size: 20rem;
}
.category-item-title {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  height: 65rem;
  padding: 0 30rem;
  border-bottom: 1rem solid #ccc;
  cursor: pointer;
}
.category-item-title::after {
  content: ">";
  margin-left: auto;
  -webkit-transition: -webkit-transform 0.3s ease-out;
  transition: -webkit-transform 0.3s ease-out;
  transition: transform 0.3s ease-out;
  transition: transform 0.3s ease-out, -webkit-transform 0.3s ease-out;
}
.category-item.expand .category-item-title {
  color: #138db1;
}
.category-item.expand .category-item-title::after {
  -webkit-transform: rotate(90deg);
          transform: rotate(90deg);
}
.category-item.active .category-sub {
  display: block;
}
.category-sub {
  display: none;
}
.category-sub-item {
  display: block;
  padding: 25rem 30rem;
  cursor: pointer;
}
.category-sub-item:hover {
  background-color: #f3f3f3;
}

@media screen and (max-width: 1200px) {
  .category {
    width: 100%;
    margin-right: 0;
  }
  .category-title {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
        -ms-flex-align: center;
            align-items: center;
    -webkit-box-pack: center;
        -ms-flex-pack: center;
            justify-content: center;
    height: 60rem;
    font-size: 28rem;
  }
  .category-item {
    font-size: 16rem;
  }
  .category-item-title {
    height: 50rem;
  }
  .category-sub-item {
    padding: 10rem 30rem;
  }
}