body, html {
    margin: 0;
    padding: 0;
    height: 100%;
}

.sidebar {
    width: 250px;
    float: left; /* oder position: fixed/absolute */
}

.main-wrapper {
    margin-left: 250px;
    width: auto; /* oder 100%, wichtig: KEIN fixed width! */
}

.layout-content {
    margin-left: 250px;
}

#footer {
    width: 100%;
    margin: 0;
    background-color: lightgrey;
    padding: 20px;
    text-align: center;
    box-sizing: border-box;
    border-top-left-radius: 10px;
    border-top-right-radius: 10px;
}

.footer-content {
    margin: 0;
    padding: 0;
}


footer a {
    color: #dc3545;
    text-decoration: none;
    margin-right: 10px;
}

footer a:hover {
    text-decoration: underline;
}

spacer {
    display: block;
    height: 250px;
}

/* Responsive */
@media (max-width: 768px) {
    footer {
        padding: 15px;
    }
}

@media (max-width: 480px) {
    footer {
        padding: 10px;
        font-size: 14px;
    }
}