body {
    width: 100%;
    height: 100%;
    border-radius: 0;
    flex-direction: row;
}

header,
footer {
    border-radius: 0;
}

header {
    height: 100%;
    width: 0;
    justify-content: start;
    align-items: start;
    flex-direction: column;
    transition-duration: 0.7s;
}

.logo {
    margin-top: 10px;
    z-index: 999;
}

nav {
    flex-direction: column;
}

header:hover {
    width: 100px;
}

main {
    height: calc(100vh - 40px);
}

footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
}