:root {
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --accent-color: #3498db;
    --sidebar-width: 250px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f8f9fa;
}

.wrapper {
    display: flex;
    width: 100%;
    align-items: stretch;
}

#sidebar {
    min-width: var(--sidebar-width);
    max-width: var(--sidebar-width);
    background: var(--primary-color);
    color: #fff;
    transition: all 0.3s;
    min-height: 100vh;
}

#sidebar .sidebar-header {
    padding: 20px;
    background: #1a252f;
}

#sidebar ul.components {
    padding: 20px 0;
}

#sidebar ul li a {
    padding: 12px 20px;
    font-size: 1.05em;
    display: block;
    color: #ecf0f1;
    text-decoration: none;
}

#sidebar ul li a:hover, #sidebar ul li.active > a {
    color: #fff;
    background: var(--accent-color);
}

#content {
    width: 100%;
    padding: 20px;
    min-height: 100vh;
    transition: all 0.3s;
}

@media (max-width: 768px) {
    #sidebar {
        margin-left: -250px;
    }
    #sidebar.active {
        margin-left: 0;
    }
}

.card-box {
    border-radius: 10px;
    border: none;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}