body {
  font-family: "Avenir Next";
  margin: 0;
  padding: 0;
}
html, body {
  height:100%;
}


a{
  text-decoration: none;
}
li {
  list-style: none;
}
@media screen and (min-width:768px){ /*PC*/
  .first{
    padding-top: 50px;
    text-align: center;
    padding-bottom: 30px;
  }
  img{
    width: 20%;
  }
  .btn-1_1{
    margin: 0 auto;
  }
  .btn-1_1 a{
    display: block;
    width: 8em;
    text-align: center;
    font-size: 1rem;
  }
  .btn-1 {
    margin: 30px auto;
    display: inline-block;
    padding: 1em 2em;
    text-decoration: none;
    background: #26A6A6;/*ボタン色*/
    color: white;
    border-radius: 3px;
  }
}

@media screen and (max-width:767px){ /*iPhone*/
  h1{
    font-size: 1.3rem;
  }
  .first{
    padding: 30px 15px;
    text-align: center;
  }
  img{
    width: 50%;
  }
  .btn-1_1{
    margin: 0 auto;
  }
  .btn-1_1 a{
    display: block;
    width: 4em;
    text-align: center;
    font-size: 1rem;
  }
  .btn-1 {
    margin: 10px auto;
    display: inline-block;
    padding: 0.7em 2em;
    text-decoration: none;
    background: #26A6A6;/*ボタン色*/
    color: white;
    border-radius: 3px;
  }
  }