*{
 box-sizing:border-box
}
body{
  magrin: 0;
  background-color:#ffffff;
}
img{width:100%;height:100%}

#header-box{
  display:flex;
  justify-content:space-between;
  align-items:center;
  margin:20px;
  height: 100%
}


#main-box{
  display:flex;
  flex-direction:column-reverse;
  justify-content:center;
  height: 100%;
}

#main-text{
margin:20px
}


#footer-box{
  display:flex;
  justify-content:space-between;
  align-items:center;
  margin:20px;
  height: 100%
}

.frame{
padding:10px;
border:solid 1px
}

@media screen and (min-width:768px)
{
 #main-box{
  flex-direction:row;
 }
 #section-box{
  flex-direction:row;
 }
}