body {
  background-image: url("fondo blanco.jpg");
  background-repeat: no-repeat;
  background-position: center center;
  background-attachment: fixed;
  background-size: cover;
  color: black;
  font-family: Arial;
  margin-right: 110px;
  margin-left: 40px;
}







p { 
 margin-right: 110px;
  margin-left: 40px;
}

h1 {
  color: black;
  text-align: center;
  border-style: solid;
  border-radius: 5px;
  margin-top: 20px;
  margin-right: 150px;
  margin-left: 80px;
}

h2 {
  margin-top: 20px;
  margin-right: 150px;
  margin-left: 40px;
}

h3 {
  margin-top: 20px;
  margin-right: 150px;
  margin-left: 40px;
}


img src {
display:block;
margin:auto;
margin-right: 110px;
margin-left: 40px;
}

table, th, td {
  border: 5px solid black;
}


pre {
  margin-top: 20px;
  margin-right: 150px;
  margin-left: 40px;
}
  
code {
  margin-top: 20px;
  margin-right: 150px;
  margin-left: 40px;
}

form {
 margin-right: 110px;
  margin-left: 40px;  
  
}