html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
  }

  main {
      width: 100%;
      margin: 0;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
  }

  h1 {
      font-size: 3rem;
  }

  #info {
      width: 55%;
      padding: 0;
      margin: 0;
      margin-top: 4vmin;
  }

  #date {
      color: #777777;
      font-size: 1.3em;
  }

  h2 {
      width: 55%;
      padding: 0;
      margin: 0;
      padding-left: 20px;
      padding-bottom: 10px;
      font-size: 2.2em;
      border-bottom: rgb(66, 66, 66) solid 1px;
  }

  #contents {
      width: 55%;
      padding: 0;
      margin: 0;
      margin-top: 4vmin;
      margin-bottom: 15vmin;
  }

  #back {
      margin: 0;
      padding: 0;
      margin-bottom: 15vmin;
      width: 15%;
      display: flex;
      align-items: center;
      justify-content: center;
      background-color: rgb(121, 121, 121);
      border-radius: 100rem;
      -webkit-border-radius: 100rem;
      -moz-border-radius: 100rem;
      -ms-border-radius: 100rem;
      -o-border-radius: 100rem;
      text-decoration: none;
      transition: 0.5s;
      -webkit-transition: 0.5s;
      -moz-transition: 0.5s;
      -ms-transition: 0.5s;
      -o-transition: 0.5s;
  }

  #back:hover {
      opacity: 0.7;
  }

  #contents img {
      width: 100%;
  }

  #back p {
      color: rgb(255, 255, 255);
      font-size: 1.2em;
  }

  @media screen and (max-width:1000px) {
      main {
          padding-top: 60px;
      }
      h1 {
          font-size: 2rem;
      }
      #info {
          width: 90%;
          margin-top: 0vmin;
      }
      #date {
          font-size: 4.3vmin;
      }
      h2 {
          width: 90%;
          padding-left: 10px;
          font-size: 6vmin;
      }
      #contents {
          width: 90%;
          margin-top: 4vmin;
          margin-bottom: 15vmin;
      }
      #back {
          margin-bottom: 20vmin;
          width: 50%;
      }
      #back p {
          font-size: 3.8vmin;
      }
  }