html, body {
    width: 100%;
    height: 100%;
    box-sizing: border-box;
}

message-panel {
    position: absolute;
    width: 65%;
    top: 0.2em;
    left:0;
    right:0;
    margin-left:auto;
    margin-right:auto;
    z-index: 50;
    box-shadow: 0 1em 2em rgb(200,200,200);
}

html > body > main > header {
    position: absolute;
    left: 1rem;
    top: 1rem;
}

html > body > main {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 1rem;
}

html > body > main > nav {
    width: 100%;
    margin-top: 1rem;
}

html > body > main > section {
    flex: 1;
    overflow: auto;
    padding: 0 1em;
    box-sizing: border-box;
}

html > body > main > footer {
    text-align: right;
}