body {
    padding-top: 60px; 
}

header {
    position: fixed; /*← fixedで固定 */
    width: 100%; 
    height: 60px; 
    background: #CCC; 
    padding: 20px 60px; 
    box-sizing: border-box;
    top: 0; 
    left: 0; 
    display: flex; 
    align-items: center; 
  
   /* ロゴとメニューを横並びにする */
    display: flex; 
    justify-content:space-between;
}

header .nav .menu {
    display: flex; 
}

header .nav .menu li {
    list-style: none; 
    margin-left: 40px;
}

header .nav .menu li a{
   color: #000000;
   font-weight:bold;
   text-decoration: none;
}

header .nav .menu li a:hover{
    color: #0000FF;
}

main {
    text-align:center;
}

main img {
  width: 56.25%;
  object-fit: contain;
}

h2 {
   color: #B78D4A;
   text-decoration: none;
   padding-top: 100px;
}

details {
  border: 1px solid #aaaaaa;
  border-radius: 4px;
  margin: 60px 0 0;
  padding: 0.5em 0.5em 0;
}

summary {
  color: #B78D4A;
  text-decoration: none;
  font-weight: bold;
  font-size: 20;
  margin: -0.5em -0.5em 0;
  padding: 0.5em;
}

footer {
    background-color: #4169E1;
    padding:1em;
    margin-top:100px;
}

footer p {
    font-size: .8em;
    color: #ffffff;
    max-width: 800px;
    padding: 0;
    text-align:center;
    margin:0 auto;
    font-weight:bold;
}