header{     
    border: 5px solid black;
    height: 15%;           
    font-weight: bold;
    font-size: large;
    display: flex;    
    position: absolute;
    top: 2%;
    left: 1%;
    right: 1%;
    overflow: hidden; 
}

div.header{
    margin: auto;
    text-align: center;
}

h1, h2{
    color: gray; 
    margin : 5px;
}

article{    
    border: 5px solid black;
    width: 70.3%;
    height: 59%;
    position: absolute;
    top: calc(2% + 15% + 10px + 2%);
    left: 1%;
    overflow: auto; 
}

section{
    height: 90%;
    position: absolute;
    top: 0%;
    left: 0%;
    right: 0%;    
}

div.theme{
    border: 1px solid gray;
    height: 20%;
    position: absolute;
    top: 2%;
    left: 1%;
    right: 1%; 
    display: flex;
    align-items: center;
}

span{
    font-weight: bold;
}

div.content{
    border: 1px solid gray;
    height: 70%;
    position: absolute;
    top: calc( 20% + 2px + 4%);
    left: 1%;
    right: 1%; 
    text-align: justify;
    font-family: Arial, Helvetica, sans-serif;
    font-size: large;
    overflow: auto;
}

div.button{
    height: 10%;
    position: absolute;
    bottom: 0%;
    left: 0%;
    right: 0%;
}

#back{
    width: 10%;
    height: 100%;
    position: absolute;
    left: 1%;
    background-color: orange;
    font-weight: bolder;
    font-size: large;
    border: 2px inset orange;
    cursor: pointer;
}

#next{
    width: 10%;
    height: 100%;
    position: absolute;
    right: 1%;
    background-color: orange;
    font-weight: bolder;
    font-size: large;
    border: 2px inset orange;
    cursor: pointer;
}

aside{   
    border: 5px solid black;
    width: 25.3%;
    height: 59%;  
    position: absolute;
    top: calc(2% + 15% + 10px + 2%);
    right: 1%;
    overflow: hidden; 
}

footer{
    border: 5px solid black; 
    height: 15%;
    font-weight: bold;
    font-size: large;
    background-color: blue;
    color: white;
    position: absolute;    
    top: calc(2% + 15% + 10px + 2% + 59% + 10px + 2%);  
    left: 1%;
    right: 1%; 
    overflow: hidden;     
}

div.author{
    width: 50%;
    height: 100%;    
    position: absolute;
    overflow: auto;
}

div.logo{
    width: 110px;
    border: 1px solid white;
    position: absolute;
    right: 0%;
    top: 0%;
    bottom: 0%;
    overflow: hidden;
}

p{
    margin: 3px;
}

a{
    color: white;
}

#section2, #section3, #section4, #section5{
    display: none;
}

img.mexico{
    width: 100%;
    height: 100%;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-top: -55%;
    margin-left: -50%;    
}

img.unadm{
    width: 100%;
    height: 100%;
}