body {
   margin:0;
   }
    
     header {
       font-weight: bold;
       text-align: center;
       background-color:#331845;
       color: #fff;
       border-bottom: 3px solid #444;
       padding: 1rem;
     }
   
     h1 {
       color: #708090;
       text-align: center;
     }
     
     h2, h3, h4 {
       color: green;
       text-align: center;
     }
     
     .text-center {
       text-align: center;
     }
     .erler{border-bottom: 2px solid gray;}