h1 {
    color: blue;
}

[data-loader] {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
    height: .2em;
    padding: 0;
    margin: 0;
    background-color: blue;
    transition: all 500ms;
}

body {
    display: grid;
    grid-template-columns: 15em 1fr;
    grid-template-rows: 3em 1fr 3em;

    grid-template-areas:
        "nav header"
        "nav main"
        "nav footer";

    margin: 0;
    height: 100vh;
}

@media (max-width: 1080px) {
    body {
        grid-template-columns: 1fr;
        grid-template-rows: 3em 1fr 3em;

        grid-template-areas:
            "header"
            "main"
            "footer";
    }

    nav {
        position: fixed;
        left: 0;
        top: 0;
        bottom: 0;
        width: 15em;
    }
}

body > * {
    padding: 1em;
}

hgroup * {
    margin: 0;
}

nav {
    grid-area: nav;

    background-color: lightgray;
}

header {
    grid-area: header;

    background-color: orange;

    display: flex;
    justify-content: space-evenly;
    align-items: center;
}

main {
    grid-area: main;

    background-color: darkgray;
}

footer {
    grid-area: footer;

    background-color: grey;

    display: flex;
    justify-content: flex-start;
    align-items: center;
}