@media screen and (max-width: 670px) {
  header {
    flex-direction: column;
    margin: 20px 0;
  }

  header ul {
    margin-right: 0;
  }

  .top {
    height: 400px;
  }

  .product div {
    flex-direction: column;
    margin: 0 auto;
    margin-bottom: 100px;
  }

  .product div img {
    width: 100%;
    margin-bottom: 20px;
    padding: 0;
  }

  .contents {
    width: 90%;
  }

  .contents_item {
    flex-direction: column;
  }

  .contents_item div {
    margin-bottom: 20px;
  }

  .contents_item img {
    width: 100%;
  }

  .contactForm input[type=email] {
    margin-top: 20px;
    width: 90%;
  }

  .contactForm input[type=submit]{
    width: 90%;
  }

  footer {
    text-align: center;
  }
  footer p {
    font-size: 10px;
  }
}