body{
      font-family : serif;
      font-size :20px ;
      background-image: url(教室　夜.jpg);
      background-color:rgba(255,255,255,0.05);
      background-blend-mode:lighten;
      background-size: cover;
      background-attachment: fixed;
      color:white;
      }

h1{
      color:white;
      background-color:    ;
      font-weight:900 ;
      font-size:50px;
   }