.mainPage {
    width: 96vw;
    margin: 0vh 1vw;
}

.sidebar {
    position: sticky;
    width: 5vw;
    margin: 24px 10px;
    top: 24px;
    min-width: 80px;
} 

.content {
    display:flex;
}

a:visited {
    color:blue;
}

.notExist {
    color: red;
}

.notExist:visited {
    color: darkred;
}