*{margin:0 auto;
}
html{
  text-align:center;
  background: rgb(58,180,111);
background: linear-gradient(90deg, rgba(58,180,111,0.9915677584134616) 0%, 
rgba(29,253,238,1) 50%, 
rgba(0,0,0,1) 100%);}
  
#contenedor{
  
  text-align:center;
  width:80%;
  height:800px;
  background: rgb(2,211,213);
background: linear-gradient(180deg, 
rgba(2,211,213,1) 15%, 
rgba(255,255,255,1) 60%);
  
}

p{ width:95%; }

 ul {
   display:flex;
   list-style:none;
   background:#10c2e6;
 }
   ul li{
   }
   
     ul li a{ 
       display:block; 
       width:160px; 
       height:30px; 
       padding: 5px;
       // border: 1px solid #bd0e22; 
       //background:#1f9438; 
       text-decoration:none; 
       background: #10c2e6;
       color:#fff; 
       font-family:Courier New; 
       font-size:1.1em; 
       font-weight:bold; 
       text-transform:uppercase; 
       letter-spacing:2px; 
       }
       ul li a:hover{ 
       background:rgb(2,211,213);
background: linear-gradient(180deg, 
rgba(2,211,213,1) 15%, 
rgba(255,255,255,1) 60%);
       }
       
       
       .marco { 
          width:20%;
          border:2px solid #ddd;
          border