html, body {
  background-color: #fff;
  color: #636b6f;
  font-family: 'Raleway', sans-serif;
  font-weight: 100;
  height: 100vh;
  margin: 0;
}

/* 높이를 화면 전체로 */
.full-height {
  height: 100vh;
}

.flex-center {
  align-items: center;
  display: flex;
  justify-content: center;
}

.flex-column {
  flex-direction: column;
}

.position-ref {
  position: relative;
}

.full-width {
  width: 100vh;
}

.top-right {
  position: absolute;
  right: 10px;
  top: 18px;
}

.links > a {
  color: #636b6f;
  padding: 0 25px;
  font-weight: 600;
  letter-spacing: .1rem;
  text-decoration: none;
  text-transform: uppercase;
}

@media only screen and (max-width : 768px){
  .menu_style {

  }

  .content_style {
    /*display: none;*/
    text-align: center;
  }

  #index-image {
    display: none;
  }

  .links > a {
    text-align: center;
    display: block;
    margin-bottom: 30px;
  }
}
@media only screen and (min-width : 769px) {
  .menu_style {
    margin: auto;
    text-align: center;
    font-size: medium;
    margin-top: 50px;
    margin-bottom: 50px;
  }

  .content_style {
    height: 500px;
    text-align: center;
  }

  #index-image {
    width: 400px;
    height: auto;
    padding-right: 52px;
    padding-top: 5px;
  }

}