* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}


header {
    background-color: #333;
    color: white;
    padding: 15px;
}


.horizontal ul {
    display: flex;
    list-style: none;
    justify-content: center;
}

.horizontal li {
    margin: 0 10px;
}

.horizontal a {
    color: white;
    text-decoration: none;
}


.container {
    display: flex;
    flex: 1;
}


.vertical {
    width: 220px;
    background: #f4f4f4;
    padding: 15px;
}

.vertical ul {
    list-style: none;
}

.vertical li {
    margin-bottom: 10px;
}


main {
    flex: 1;
    padding: 20px;
}


footer {
    background: #333;
    color: white;
    text-align: center;
    padding: 10px;
}


@media (max-width: 768px) {

    .container {
        flex-direction: column;
    }

    .vertical {
        width: 100%;
    }

    .horizontal ul {
        flex-direction: column;
        align-items: center;
    }

    .horizontal li {
        margin: 5px 0;
    }
}