* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
}

.container {
    width: 80%;
    margin: 0 auto;
    max-width: 1200px;
}

header {
    background: #4CAF50;
    color: #fff;
    padding: 20px 0;
}

header h1 {
    text-align: center;
    margin-bottom: 10px;
}

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

nav ul li {
    margin: 0 15px;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
}

.section {
    padding: 40px 0;
}

h2 {
    text-align: center;
    margin-bottom: 20px;
}

p {
    text-align: center;
    margin-bottom: 20px;
}

.material-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
}

.material-item {
    background: #f4f4f4;
    padding: 20px;
    margin: 10px;
    width: 30%;
    text-align: center;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.material-item h3 {
    margin-bottom: 10px;
}

.material-item a {
    color: #4CAF50;
    text-decoration: none;
    font-weight: bold;
}

.material-item a:hover {
    text-decoration: underline;
}

footer {
    background: #333;
    color: #fff;
    padding: 10px 0;
    text-align: center;
    margin-top: 40px;
}

@media (max-width: 768px) {
    .material-item {
        width: 45%;
    }
}

@media (max-width: 500px) {
    .material-item {
        width: 100%;
    }

    nav ul {
        flex-direction: column;
    }

    nav ul li {
        margin-bottom: 10px;
    }
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

table th, table td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}

table th {
    background-color: #4CAF50;
    color: white;
}

table tr:nth-child(even) {
    background-color: #f2f2f2;
}

table tr:hover {
    background-color: #ddd;
}