html {
    padding: 0;
    margin: 0;
    height: 100%;
    font-family: sans-serif;
    --link: #3498db;
    --link-hover: #2980b9;
}

a {
    text-decoration: none;
    color: var(--link);
}

a:hover, a:active {
    text-decoration: underline;
    color: var(--link-hover);
}

body {
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100%;
}

header {
    padding: 1em;
    color: #fff;
    background-color: #3F4454;
    display: flex;
    align-items: center;
    position: sticky;
    top: 0;
    flex: 0 0 auto;
    --link: #fff;
    --link-hover: #fff;
}

header h1 {
    order: 2;
    margin-left: 1em;
}

header img {
    order: 1;
    max-width: 64px;
    max-height: 64px;
}

main {
    flex: 1 1 auto;
}

article {
    margin: 3em auto;
    padding: 0 1em;
    width: 40em;
    max-width: calc(100% - 2em);
}

article p {
    line-height: 1.35;
}

article div.notice {
    color: #fff;
    background-color: #d35400;
    padding: 0.7em;
    border-radius: 0.5em;
}

footer {
    flex: 0 0 auto;
    padding: 1em;
    background-color: #7f8c8d;
    color: #ddd;
    --link: #ddd;
    --link-hover: #fff;
}

footer p {
    text-align: center;
}