* {
    margin: 0em;
    padding: 0em;
    border: 0em;
    box-sizing: border-box;
    background-color: #75aef0;
}

header {
    display: flex;
    background-color: #4d90de;  
    justify-content: space-between;

}

header img {
    display: flex;
    background-color: #4d90de;
}

header nav {
    display: flex;
    background-color: #4d90de;
}

header nav ul {
    display: flex;
    background-color: #4d90de;
}

header nav ul li a {
    display: flex;
    background-color: #1179f2;
}
    
main {
    display: flex;
    
}

section {
    display: flex;
    flex-direction: column;
    text-align: center;
}

aside.stibel {
    margin: 2em;
    text-align: justify;
    
}

aside.stibel a{
    display: inline;
}

footer {
    display: flex;
    flex-direction: column;
    text-align: center;
    
}

.boton {
    display: flex;
    list-style: none;
    background-color: #4d90de;
    justify-content: center;

}
.barra {
    background-color: #4d90de;
}
@media screen and (min-width: 30em)