body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: lightgreen;
    display: flex;
    flex-direction: column;
}

header {
    background-color: #333;
    color: #fff;
    padding: 15px;
    text-align: center;
    width: 100%;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
}

nav {
    background-color: #333;
    color: #fff;
    width: 200px;
    height: 100vh;
    position: fixed;
    top: 100px; /* Adjusted to account for the header height */
    left: 0;
    padding-top: 20px;
    overflow-y: auto;
}

nav a {
    display: block;
    padding: 10px;
    color: #fff;
    text-decoration: none;
}

nav a:hover {
    background-color: #444;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

.main-category {
    color: red;
}

.container {
    margin-left: 200px; /* To account for the sidebar */
    padding: 100px 30px 20px 20px; /* Top padding adjusted to avoid overlap with the header */
    flex: 1;
    overflow-y: auto;
}

.category {
    margin-bottom: 30px;
}

.category h2 {
    background-color: #444;
    color: #fff;
    padding: 10px;
    margin: 0;
}