html {
            scroll-behavior: smooth;
        }
        body {
            background-color: #0f172a;
            color: #e2e8f0;
            font-family: 'Inter', sans-serif;
        }
        .section-header {
            border-left: 4px solid;
            padding-left: 1rem;
        }
        .blue-section { border-color: #3b82f6; }
        .orange-section { border-color: #f97316; }
        .purple-section { border-color: #a855f7; }
        .green-section { border-color: #22c55e; }
        .white-section { border-color: #f8fafc; }
        .pink-section { border-color: #ec4899; }
        
        .card {
            background: rgba(30, 41, 59, 0.7);
            border-radius: 0.75rem;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255, 255, 255, 0.1);
            transition: all 0.3s ease;
        }
        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
        }
        .section-divider {
            height: 4px;
            background: linear-gradient(90deg, rgba(30, 41, 59, 0), rgba(255, 255, 255, 0.2), rgba(30, 41, 59, 0));
        }
        .progress-bar {
            position: fixed;
            top: 0;
            left: 0;
            height: 4px;
            background: linear-gradient(90deg, #3b82f6, #a855f7, #ec4899);
            z-index: 1000;
            transition: width 0.2s ease;
        }
        .btn {
            transition: all 0.3s ease;
        }
        .btn:hover {
            transform: translateY(-2px);
        }
        #sketch-container {
            width: 100%;
            height: 400px;
            position: relative;
            overflow: hidden;
        }
        .chart-container {
            position: relative;
            margin: auto;
            height: 300px;
            width: 100%;
        }
        .glossary-term {
            text-decoration: underline dotted;
            cursor: help;
        }
        .tooltip {
            position: relative;
            display: inline-block;
        }
        .tooltip .tooltiptext {
            visibility: hidden;
            width: 200px;
            background-color: #1e293b;
            color: #fff;
            text-align: center;
            border-radius: 6px;
            padding: 5px;
            position: absolute;
            z-index: 1;
            bottom: 125%;
            left: 50%;
            margin-left: -100px;
            opacity: 0;
            transition: opacity 0.3s;
            border: 1px solid rgba(255, 255, 255, 0.1);
            font-size: 0.8rem;
        }
        .tooltip:hover .tooltiptext {
            visibility: visible;
            opacity: 1;
        }
        @media (max-width: 768px) {
            .tooltip .tooltiptext {
                width: 150px;
                margin-left: -75px;
            }
        }
        
        /* Navigation styles - Updated for fixed position */
        .fixed-nav {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            background-color: rgba(15, 23, 42, 0.9);
            z-index: 100;
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
            backdrop-filter: blur(10px);
        }

        .nav-menu {
            position: relative;
        }
        
        .nav-menu-item {
            position: relative;
        }
        
        .nav-submenu {
            position: absolute;
            top: 100%;
            left: 0;
            background-color: rgba(30, 41, 59, 0.95);
            border-radius: 0.5rem;
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
            width: 200px;
            opacity: 0;
            visibility: hidden;
            transition: all 0.3s ease;
            z-index: 101;
        }
        
        .nav-menu-item:hover .nav-submenu {
            opacity: 1;
            visibility: visible;
        }
        
        
        /* Animation keyframes */
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .animate-fade-in {
            animation: fadeIn 0.8s ease forwards;
            opacity: 0;
        }
        
        /* Mobile Navigation Styles */
        .mobile-menu-toggle {
            display: flex;
            flex-direction: column;
            justify-content: center;
            width: 30px;
            height: 30px;
            background: none;
            border: none;
            cursor: pointer;
            padding: 0;
            z-index: 1001;
        }

        /* Hide hamburger menu on desktop screens */
        @media (min-width: 768px) {
            .mobile-menu-toggle {
                display: none !important;
            }
        }

        .hamburger-line {
            width: 25px;
            height: 3px;
            background-color: #e2e8f0;
            margin: 3px 0;
            transition: 0.3s;
            border-radius: 2px;
        }

        .mobile-menu-toggle.active .hamburger-line:nth-child(1) {
            transform: rotate(-45deg) translate(-6px, 6px);
        }

        .mobile-menu-toggle.active .hamburger-line:nth-child(2) {
            opacity: 0;
        }

        .mobile-menu-toggle.active .hamburger-line:nth-child(3) {
            transform: rotate(45deg) translate(-6px, -6px);
        }

        /* Mobile Navigation Overlay */
        .mobile-nav-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100vh;
            background: rgba(15, 23, 42, 0.98);
            backdrop-filter: blur(20px);
            z-index: 999;
            transform: translateX(-100%);
            transition: transform 0.3s ease-in-out;
            overflow-y: auto;
        }

        .mobile-nav-overlay.active {
            transform: translateX(0);
        }

        .mobile-nav-container {
            padding: 80px 20px 20px;
            max-width: 100%;
        }

        /* Mobile Progress Container */
        .mobile-progress-container {
            background: rgba(30, 41, 59, 0.8);
            border-radius: 12px;
            padding: 16px;
            margin-bottom: 24px;
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .mobile-progress-bar {
            height: 6px;
            background: linear-gradient(90deg, #3b82f6, #a855f7, #ec4899);
            border-radius: 3px;
            transition: width 0.3s ease;
            margin-bottom: 8px;
        }

        .mobile-progress-text {
            color: #e2e8f0;
            font-size: 14px;
            font-weight: 500;
        }

        /* Mobile Navigation Content */
        .mobile-nav-content {
            display: flex;
            flex-direction: column;
            gap: 8px;
        }

        .mobile-nav-section {
            border-radius: 12px;
            overflow: hidden;
            background: rgba(30, 41, 59, 0.6);
            border: 1px solid rgba(255, 255, 255, 0.1);
        }

        .mobile-nav-item {
            width: 100%;
            padding: 16px 20px;
            background: none;
            border: none;
            text-align: left;
            cursor: pointer;
            transition: all 0.3s ease;
            color: #e2e8f0;
            display: flex;
            align-items: center;
            gap: 12px;
            font-size: 16px;
            font-weight: 500;
            min-height: 60px;
        }

        .mobile-nav-item:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        .mobile-nav-icon {
            font-size: 20px;
            width: 24px;
            text-align: center;
        }

        .mobile-nav-title {
            flex: 1;
        }

        .mobile-nav-arrow {
            font-size: 14px;
            transition: transform 0.3s ease;
            color: #94a3b8;
        }

        .mobile-nav-section.active .mobile-nav-arrow {
            transform: rotate(90deg);
        }

        /* Mobile Submenu */
        .mobile-nav-submenu {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease;
            background: rgba(15, 23, 42, 0.8);
        }

        .mobile-nav-section.active .mobile-nav-submenu {
            max-height: 200px;
        }

        .mobile-nav-subitem {
            display: block;
            padding: 12px 20px 12px 56px;
            color: #94a3b8;
            text-decoration: none;
            transition: all 0.3s ease;
            font-size: 14px;
            border-left: 3px solid transparent;
        }

        .mobile-nav-subitem:hover {
            background: rgba(255, 255, 255, 0.1);
            color: #e2e8f0;
        }

        /* Color-coded navigation items */
        .mobile-nav-main[data-color="teal"] {
            border-left: 4px solid #2dd4bf;
        }
        .mobile-nav-main[data-color="blue"] {
            border-left: 4px solid #3b82f6;
        }
        .mobile-nav-main[data-color="orange"] {
            border-left: 4px solid #fb923c;
        }
        .mobile-nav-main[data-color="purple"] {
            border-left: 4px solid #a855f7;
        }
        .mobile-nav-main[data-color="green"] {
            border-left: 4px solid #22c55e;
        }
        .mobile-nav-main[data-color="white"] {
            border-left: 4px solid #f8fafc;
        }
        .mobile-nav-main[data-color="pink"] {
            border-left: 4px solid #ec4899;
        }
        .mobile-nav-main[data-color="yellow"] {
            border-left: 4px solid #facc15;
        }

        /* Responsive adjustments */
        @media (max-width: 640px) {
            .mobile-nav-container {
                padding: 70px 16px 16px;
            }

            .mobile-nav-item {
                padding: 14px 16px;
                font-size: 15px;
                min-height: 54px;
            }

            .mobile-nav-subitem {
                padding: 10px 16px 10px 48px;
                font-size: 13px;
            }

            .mobile-progress-container {
                padding: 12px;
                margin-bottom: 20px;
            }
        }

        /* Prevent body scroll when mobile menu is open */
        body.mobile-nav-open {
            overflow: hidden;
        }

        /* Enhanced touch targets for mobile */
        @media (max-width: 768px) {
            .mobile-nav-item,
            .mobile-nav-subitem {
                min-height: 44px; /* iOS recommended minimum touch target */
            }
        }

        /* Floating Action Button */
        .fab-nav {
            position: fixed;
            bottom: 20px;
            right: 20px;
            width: 56px;
            height: 56px;
            border-radius: 50%;
            background: linear-gradient(135deg, #3b82f6, #a855f7);
            border: none;
            color: white;
            font-size: 20px;
            cursor: pointer;
            box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
            z-index: 998;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .fab-nav:hover {
            transform: scale(1.1);
            box-shadow: 0 12px 24px rgba(0, 0, 0, 0.4);
        }

        .fab-nav:active {
            transform: scale(0.95);
        }

        .fab-nav.hidden {
            transform: scale(0);
            opacity: 0;
        }

        /* Ensure FAB is hidden on desktop screens */
        @media (min-width: 768px) {
            .fab-nav {
                display: none !important;
            }
        }

        /* Custom scrollbar */
        ::-webkit-scrollbar {
            width: 8px;
            height: 8px;
        }
        ::-webkit-scrollbar-track {
            background: #1e293b;
        }
        ::-webkit-scrollbar-thumb {
            background: #475569;
            border-radius: 4px;
        }
        ::-webkit-scrollbar-thumb:hover {
            background: #64748b;
        }