body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    margin: 0;
    background-color: #f4f7f9;
    color: #333;
    line-height: 1.6;
}

header {
    background-color: #5cb85c; /* A friendly green */
    color: white;
    padding: 15px 20px;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    display: flex;
    align-items: center;
    justify-content: center;
}

#site-logo {
    height: 40px;
    width: 40px;
    margin-right: 15px;
}

header h1 {
    margin: 0;
    font-size: 1.8em;
}

.container {
    display: flex;
    max-width: 1200px;
    min-height: calc(100vh - 150px); /* Adjust based on header/footer height */
    margin: 20px auto;
    background-color: white;
    box-shadow: 0 0 15px rgba(0,0,0,0.05);
    border-radius: 8px;
    overflow: hidden;
}

nav {
    flex: 0 0 220px; /* Fixed width for navigation */
    background-color: #ffffff;
    padding: 20px;
    border-right: 1px solid #e0e0e0;
}

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

nav li {
    padding: 12px 15px;
    margin-bottom: 10px;
    cursor: pointer;
    border-radius: 6px;
    transition: background-color 0.2s ease-in-out, color 0.2s ease-in-out;
    color: #333;
    font-weight: 500;
}

nav li:hover {
    background-color: #e9ecef;
}

nav li.active {
    background-color: #5cb85c;
    color: white;
    font-weight: bold;
}

main#guide-content {
    flex-grow: 1;
    padding: 25px 30px;
}

.guide-section {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

.guide-section.active-guide {
    display: block;
}

.guide-section h2 {
    color: #3d8b3d; /* Darker green for headings */
    border-bottom: 2px solid #e0e0e0;
    padding-bottom: 10px;
    margin-top: 0;
    margin-bottom: 20px;
    font-size: 1.6em;
}

.guide-section p, .guide-section ul {
    margin-bottom: 15px;
}

.guide-section ul {
    padding-left: 20px;
}

.guide-section ul li {
    margin-bottom: 8px;
}

.guide-section strong {
    color: #5cb85c;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

footer {
    text-align: center;
    padding: 20px;
    background-color: #333;
    color: #aaa;
    font-size: 0.9em;
}