#body {
    background-color: #151515;
}
#contenedor {
    background-color: #fff;
    margin-top: 10px;
    border-radius: 20px;
    padding: 10px 0;
}
div.codigo {
    font-size: 1.5vw
}
div.codigo code {
    display: none;
    white-space: pre;
}
header {
    text-align: center;
}
header h1 {
    font-size: 10vw;
}

header h3 {
    font-size: 5vw;
}
article {
    text-align: justify;
    padding: 30px 5vw;
}
article h1, article h3 {
    text-align: center;
}
article h3 {
    color: #566573;
}
article img {
    max-width: 90%;
    margin: 5px auto;
    display: block;
}
.contenedor-video { 
    position: relative; 
    padding-bottom: 56.25%; 
    padding-top: 30px; 
    height: 0;  
    overflow: hidden; 
}

.contenedor-video iframe, .contenedor-video object, .contenedor-video embed { 
    position: absolute; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%; 
}
.del {text-decoration: line-through;}
@media (min-width: 500px) and (max-width: 800px) {
    header h1{
        font-size: 2rem;
    }
    header h3 {
        font-size: 1.5rem;
    }
}
@media (min-width: 800px) and (max-width: 1199px) {
    header h1{
        font-size: 2.3rem;
    }
    header h3 {
        font-size: 1.5rem;
    }
}

@media (min-width: 1200px) {
    header h1{
        font-size: 2.5rem;
    }
    header h3 {
        font-size: 1.75rem;
    }
}