* {
  font-size: 18px;
  font-family: "MS Serif";
  margin: 0;
  padding: 0;
  list-style: none;
  text-decoration: none;
}

#container{
  width: 100% ;
  margin: 0 auto;
}

header {
   position:relative;
   height: 6.5rem;
   background: #003366;
   box-shadow: 0 4px 0.3125rem rgba(0,0,0,.3);
 }

  header h1{
    letter-spacing: 5px;  /*  文字の間 */
    position: absolute;
    top: 2rem;
    left: 3rem;
    font-size: 2rem;
    color: white;
 }

nav {
  letter-spacing: 2px;
  padding: 0.5rem 1rem ;
  float : right;

  margin: 1rem;
  position: relative;
  top: 22%;


}
  nav ul{
    display: flex;
    flex-direction: row;
  }
  nav ul li{
    margin-right: 2rem;
  }
  nav ul li a {
    color: white;
  }

main{
  width: 84%;
  margin: 0 auto;
  display: flex;
  flex-wrap：wrap;
  justify-content:space-between;
}

  section{
    flex: 5;
    padding: 1rem;
    background: #d9e3ee;
  }

    article{
      min-height: 8rem;
      padding: 1rem;
      margin-bottom: 1rem;
      background: #FFF;
    }

  aside{
    flex: 1;
    padding: 1rem;
    background: white;
  }


  #ImgSet {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  width: 100%;
  max-width: 1280px;
  margin: auto;
  }

  #ImgSet li {
  list-style: none;
  }

  #ImgSet img {
  display: block;
  width: 90%;
  margin: auto;
  }

footer {
  padding: 1rem 3rem;
  text-align: center;
  background: #003366;
  color: white;
  font-size: 75%;
}

/*   margin　境界線の外側の余白
     border　境界線
     padding　境界線の内側の余白
     width, height　幅と高さ    */