/* Extra small devices (phones, 600px and down) */
@media only screen and (min-width: 600px) {
  .main-container {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 95%;
    flex-direction: column;
  }

  .item {
    width: 100%;
    height: 50px;
  }

  .yellow {
    background-color: yellow;
  }

  .blue {
    background-color: blue;
  }

  .red {
    background-color: red;
  }

  .green {
    background-color: green;
  }

  .pink {
    background-color: pink;
  }

  .purple {
    background-color: purple;
  }

  .backgroundimage {
    background-image: url(img/image1.jpg);
  }

  .backgroundimage:hover {
    background-image: url(img/image1_hover.jpg);
  }

  .bigdiv {
    position: relative;
  }

  .frontphoto {
    display: block;
    z-index: 10;
    position: absolute;
    top: 0;
    left: 0;
  }

  .frontphoto:hover {
    display: none;
  }

  .backphoto {
    display: block;
    z-index: 9;
    position: absolute;
    top: 0;
    left: 0;
  }
}

/* Small devices (portrait tablets and large phones, 600px and up) */
@media only screen and (min-width: 600px) {}

/* Medium devices (landscape tablets, 768px and up) */
@media only screen and (min-width: 768px) {
  .main-container {
    flex-direction: row;
  }

  .item {
    height: 100px;
  }
}

/* Large devices (laptops/desktops, 992px and up) */
@media only screen and (min-width: 992px) {}

/* Extra large devices (large laptops and desktops, 1200px and up) */
@media only screen and (min-width: 1200px) {}