body {
    margin: 0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #e8e8e8;
    display: flex;
    min-height: 100vh;
}

#sidebar {
    width: 260px;
    background: #2d2d2d;
    color: #fff;
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

#sidebar .logo-area {
    padding: 20px 16px 12px;
    border-bottom: 1px solid #444;
    display: flex;
    align-items: center;
    gap: 10px;
}

#sidebar .logo-area .logo-icon {
    width: 40px;
    height: 40px;
    flex-shrink: 0;
}

#sidebar .logo-area .site-title {
    font-size: 15px;
    font-weight: 700;
    line-height: 1.3;
    color: #fff;
    text-decoration: none;
}

#sidebar .nav-menu {
    padding: 12px 0;
    flex-grow: 1;
}

#sidebar .nav-menu a {
    display: block;
    padding: 10px 20px;
    color: #ccc;
    text-decoration: none;
    font-size: 14px;
    border-left: 3px solid transparent;
    transition: all 0.15s;
}

#sidebar .nav-menu a:hover,
#sidebar .nav-menu a.active {
    background: rgba(255,255,255,0.08);
    color: #fff;
    border-left-color: #4a90d9;
}

#sidebar .footer-links {
    padding: 16px 20px;
    border-top: 1px solid #444;
    font-size: 12px;
}

#sidebar .footer-links a {
    color: #999;
    text-decoration: none;
    display: block;
    margin-bottom: 6px;
}

#sidebar .footer-links a:hover {
    color: #fff;
}

#main {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

#header {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    padding: 30px 40px;
    display: flex;
    align-items: center;
    gap: 20px;
}

#header .header-banner {
    max-width: 100%;
    max-height: 120px;
    border-radius: 6px;
}

#header .header-text h1 {
    margin: 0;
    color: #fff;
    font-size: 28px;
    font-weight: 700;
}

#header .header-text p {
    margin: 4px 0 0;
    color: #aac4e0;
    font-size: 14px;
}

#content {
    padding: 40px;
    background: #fff;
    flex-grow: 1;
    max-width: 900px;
}

#content h1 {
    color: #1a1a2e;
    font-size: 26px;
    margin: 0 0 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #4a90d9;
}

#content h2 {
    color: #2d2d2d;
    font-size: 20px;
    margin: 28px 0 12px;
}

#content h3 {
    color: #333;
    font-size: 16px;
    margin: 20px 0 8px;
}

#content p {
    color: #444;
    line-height: 1.7;
    font-size: 15px;
    margin: 0 0 14px;
}

#content ul, #content ol {
    color: #444;
    line-height: 1.7;
    font-size: 15px;
    margin: 0 0 14px;
    padding-left: 24px;
}

#content li {
    margin-bottom: 6px;
}

#content a {
    color: #4a90d9;
    text-decoration: none;
}

#content a:hover {
    text-decoration: underline;
}

#content img {
    max-width: 100%;
    height: auto;
    margin: 20px 0;
    border-radius: 4px;
}

#content .separator {
    display: block;
    margin: 30px auto;
    max-width: 100%;
}

#content .video-container {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    margin: 20px 0;
    border-radius: 6px;
}

#content .video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#content .box {
    background: #f0f6ff;
    border-left: 4px solid #4a90d9;
    padding: 16px 20px;
    margin: 16px 0;
    border-radius: 0 6px 6px 0;
}

#content .box h3 {
    margin-top: 0;
}

#content .columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin: 16px 0;
}

#content .columns ul {
    margin: 0;
}

#content .book-ref {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid #ddd;
    font-size: 13px;
    color: #888;
}

#content .book-ref h3 {
    font-size: 14px;
    color: #555;
}

#content .book-ref p {
    font-size: 13px;
    color: #888;
    margin: 0 0 4px;
}

#content .book-ref ol {
    font-size: 13px;
    color: #888;
    margin: 4px 0 4px 20px;
}

#content .tag {
    display: inline-block;
    background: #e8f0fe;
    color: #1a73e8;
    font-size: 13px;
    padding: 3px 10px;
    border-radius: 12px;
    margin-right: 6px;
    margin-bottom: 6px;
}

#content .attachment {
    display: inline-block;
    background: #f5f5f5;
    border: 1px solid #ddd;
    padding: 8px 16px;
    border-radius: 4px;
    color: #333;
    text-decoration: none;
    margin: 6px 4px 6px 0;
    font-size: 14px;
}

#content .attachment:hover {
    background: #e8e8e8;
    text-decoration: none;
}

#footer {
    background: #f5f5f5;
    padding: 16px 40px;
    font-size: 12px;
    color: #888;
    border-top: 1px solid #ddd;
    text-align: center;
}

#footer a {
    color: #666;
    text-decoration: none;
}

@media (max-width: 768px) {
    body {
        flex-direction: column;
    }
    #sidebar {
        width: 100%;
        min-height: auto;
    }
    #sidebar .nav-menu a {
        padding: 8px 16px;
    }
    #header {
        padding: 20px;
        flex-direction: column;
        text-align: center;
    }
    #content {
        padding: 20px;
    }
    #content .columns {
        grid-template-columns: 1fr;
    }
}