html{
}
body {
  background-color: #F6BF00;
  margin: 0px;
  padding: 0px;
}
.container {
  margin: 1em 1em 1em 4px;
  padding: 0px;
  color: white;
  min-height: 100%;
  font-family: Tahoma, Verdana, Arial, Helvetica, sans-serif;
}

nav {
  float: left;
}

@media(min-width:768px){
  .container {
    min-width: 768px;
  }
  nav { width: 80px; }
  .logo-nav { width: 80px; }
  .main{ margin-left: 84px; }
}
@media(max-width:767px){
  .container {
    min-width: 0px; /* 後で調整 */
  }
  nav { width: 40px; }
  .logo-nav { width: 40px; }
  .main{ margin-left: 44px; }
}

.main {
  background-color: #191817;
  padding: 1em;
  border-radius: 6px;
  box-shadow: 0.3em 0.3em 1em #000000;
}
footer {
  margin-top: 0.4em;
  margin-left: 84px;
  color: #191817;
  font-size: 9px;
}