body{ font-family: Sans-serif, Arial; font-size: 16px; background-color: #383535;}

 .contenedor {
   width: 500px;
   height: 350px;
   background:#34EFB8;
   border: #B126D4 4px dashed;
   margin-left: auto;
   margin-right: auto;
   margin-top: 10%;
   max-width: 20em;
   padding-bottom: 10px;
   padding-top: 10px;
   text-align: center;
   }

#boton{
   margin-top: 40px;
   margin-left: 50px;
    background-color: #E91226;
   border: none;
   border-radius: 6px;
   display: block;
   font-size: 1em;
    height: 50px;
   text-align: center;
   width: 150px;
   }