body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.6;
    background-color: #f4f4f4;
}


header {
    position: sticky;
    top: 0;
    background-color: #333;
    color: white;
    text-align: center;
    padding: .01rem;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

header h1 {
    margin: 0;
}

footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 0.5rem;
    position: fixed;
    bottom: 0;
    width: 100%;
    left: 0;
    z-index: 100;
}

footer p {
    margin: 0;
}

footer a {
    color: #2980b9;
    text-decoration: none;
    font-weight: bold;
    padding-left: 10px;
}

footer a:hover {
    color: #1abc9c;
}

.main-nav {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
}

.main-nav ul {
    list-style-type: none;
    padding: 0;
    text-align: center;
    margin: 5px 0;
    display: flex;
}

.main-nav ul li {
    margin: 0 15px;
}

.main-nav ul li a {
    color: white;
    text-decoration: none;
    font-size: 18px;
    padding: 8px 16px;
    border-radius: 4px;
}

.main-nav ul li a:hover {
    background-color: #ddd;
    color: #000;
}


.section-nav {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
}

.section-nav ul {
    list-style-type: none;
    padding: 0;
    margin: 10px 0;
    display: flex; 
}

.section-nav ul li {
    margin-right: 15px;
}

.section-nav ul li:last-child {
    margin-right: 0;
}

.section-nav ul li a {
    color: #2980b9;
    text-decoration: none;
    font-size: 16px;
    padding: 6px 12px;
    display: inline-block;
}

.section-nav ul li a:hover {
    background-color: #ecf0f1;
    color: #1abc9c;
    border-radius: 4px;
}

main {
    padding: 20px;
    background-color: white;
    margin: 20px auto;
    border-radius: 8px;
    max-width: 1400px;
}


mark {
    background-color: #333;
    color: #fff;
}


table {
    width: 80%;
    border-collapse: collapse;
    margin: 20px auto;
}

table, th, td {
    border: 2px solid #ddd;
}

th, td {
    padding: 12px;
    text-align: left;
    font-size: 16px;
}

th {
    background-color: #2c3e50;
    color: white;
    font-weight: bold;
    text-transform: uppercase;
    letter-spacing: 1px;
}

td {
    background-color: #ecf0f1;
    color: #333;
    border-bottom: 1px solid #ddd;
}

tr:nth-child(even) td {
    background-color: #f9f9f9;
}

tr:first-child td {
    border-top: 2px solid #ddd;
}


h2 {
    color: #333;
    margin-top: 20px;
}
h3 {
    color: #333;
    text-align: center;
}


.image-box {
    display: flex;
    justify-content: center;
    margin: 20px 0;
    width: 400px;
    max-width: 300px;
    height: 300px;
    overflow: hidden;
    border-radius: 8px;
}

.image-box img {
    width: 100%;
    height: auto;
    object-fit: cover;
}


.float-left {
    float: left;
    margin: 0 20px 20px 0;
}

.float-right {
    float: right;
    margin: 0 0 20px 20px;
}


.clearfix::after {
    content: "";
    clear: both;
    display: table;
}


article {
    margin-bottom: 30px;
    padding: 20px;
    background-color: #f9f9f9;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}


@media (max-width: 768px) {
    .main-nav ul li, .section-nav ul li {
        display: block;
        margin-bottom: 10px;
    }

    main {
        margin: 10px;
    }

    .image-box {
        width: 100%;
        margin: 20px auto;
    }

    table {
        width: 90%;
    }

    .float-left, .float-right {
        float: none;
        margin: 20px auto;
    }
}