<meta name="viewport" content='width=device-width, initial-scale=1'>


* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Oxygen', sans-serif;
    min-height: 100vh;

    display: flex;

    flex-direction: column;
    
    justify-content: space-between;
}

img {
    /* para que nunca sea mayor que la caja que las contiene */
    max-width: 100%;
    height: auto;
}

header,
footer {
    background-color: steelblue;
    padding: .25em;
    height: 10em;
}

header {
    height: 7em;
    
    display: flex;
    
    justify-content: space-between;
    
    align-items: center;
}

#logo {
    display: block;
    width: 17em;
    margin-left: 0.5em;
}

header {
    
    display: flex;
    
    justify-content: space-between;

    align-items: center;
    
}
header a {
    color: aliceblue;
    font-size: 2em;
    text-decoration: none;
    font-weight: bold;
    margin-right: 1em;
}

main {
    display: flex;
    flex-direction: column;
    justify-content: center;
    background-color: gainsboro;
    height: 80vh;
   
}

.materias nav {
    
}

.materias nav ul {
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    height: 50vh;
    
}

main ul li {

    background-color: coral;
    font-size: 4em;
    margin: 1em;
    align-content: center;
    
}

.materias nav ul li a {
    text-align: left;
}


nav ul {
    list-style: none;
    
    display: flex;
    
    justify-content: space-between;
    
}

main ul li {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
}

main nav ul li {
    display: flex;
    flex-grow: 1;
    justify-content: center;
}

footer nav ul li {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 40vw;
}

footer nav ul li a {
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: rgba(0,0,0,.25);
    border: 10px solid rgba(0,0,0,.35);
    color: white;
    text-decoration: none;
    height: 8em;
    width: 20vw;
    font-size-adjust: auto;

    
}

footer nav ul {
    display: flex;
    justify-content: space-between;
    align-content: center;
    
    
}