* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
            background: #F9FAFB;
            color: #111827;
            line-height: 1.5;
            -webkit-font-smoothing: antialiased;
        }

        :root {
            --primary: #0A66C2;
            --primary-dark: #004182;
            --primary-light: #378FE9;
            --secondary: #7C3AED;
            --success: #059669;
            --warning: #F59E0B;
            --error: #DC2626;
            --gray-50: #F9FAFB;
            --gray-100: #F3F4F6;
            --gray-200: #E5E7EB;
            --gray-300: #D1D5DB;
            --gray-400: #9CA3AF;
            --gray-500: #6B7280;
            --gray-600: #4B5563;
            --gray-700: #374151;
            --gray-800: #1F2937;
            --gray-900: #111827;
            --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
            --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
            --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
            --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
        }

        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 32px;
        }

        @media (max-width: 768px) {
            .container {
                padding: 0 20px;
            }
        }

        /* Navigation */
        .navbar {
            position: sticky;
            top: 0;
            background: rgba(255, 255, 255, 0.98);
            backdrop-filter: blur(8px);
            border-bottom: 1px solid var(--gray-200);
            z-index: 1000;
            padding: 0;
        }

        .navbar .container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 72px;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 8px;
            text-decoration: none;
        }

        .logo-icon {
            width: 32px;
            height: 32px;
            background: linear-gradient(135deg, var(--primary), var(--secondary));
            border-radius: 8px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .logo-icon i {
            color: white;
            font-size: 18px;
        }

        .logo-text {
            font-size: 22px;
            font-weight: 800;
            color: var(--gray-900);
        }

        .nav-links {
            display: flex;
            gap: 32px;
            align-items: center;
        }

        .nav-links a {
            text-decoration: none;
            color: var(--gray-600);
            font-weight: 500;
            font-size: 15px;
            transition: color 0.2s;
        }

        .nav-links a:hover,
        .nav-links a.active {
            color: var(--primary);
        }

        .nav-buttons {
            display: flex;
            gap: 12px;
            align-items: center;
        }

        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            padding: 10px 20px;
            border-radius: 8px;
            font-weight: 600;
            font-size: 14px;
            transition: all 0.2s;
            cursor: pointer;
            border: none;
            font-family: inherit;
        }

        .btn-primary {
            background: var(--primary);
            color: white;
        }

        .btn-primary:hover {
            background: var(--primary-dark);
            transform: translateY(-1px);
        }

        .btn-secondary {
            background: white;
            color: var(--gray-700);
            border: 1px solid var(--gray-300);
        }

        .btn-secondary:hover {
            background: var(--gray-50);
            border-color: var(--gray-400);
        }

        .btn-outline {
            background: transparent;
            border: 1px solid var(--gray-300);
            color: var(--gray-600);
        }

        .btn-outline:hover {
            border-color: var(--primary);
            color: var(--primary);
        }

        /* Page Header */
        .page-header {
            background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
            color: white;
            padding: 48px 0;
        }

        .page-header h1 {
            font-size: 36px;
            font-weight: 800;
            margin-bottom: 16px;
        }

        .page-header p {
            font-size: 18px;
            opacity: 0.9;
            max-width: 600px;
        }

        /* Main Layout */
        .courses-layout {
            display: grid;
            grid-template-columns: 300px 1fr;
            gap: 32px;
            padding: 40px 0;
        }

        @media (max-width: 1024px) {
            .courses-layout {
                grid-template-columns: 1fr;
            }
        }

        /* Filters Sidebar */
        .filters-sidebar {
            background: white;
            border-radius: 20px;
            border: 1px solid var(--gray-200);
            padding: 24px;
            position: sticky;
            top: 100px;
            height: fit-content;
        }

        @media (max-width: 1024px) {
            .filters-sidebar {
                display: none;
            }
            .filters-sidebar.mobile-open {
                display: block;
                margin-bottom: 24px;
            }
        }

        .filter-section {
            margin-bottom: 28px;
            padding-bottom: 28px;
            border-bottom: 1px solid var(--gray-200);
        }

        .filter-section:last-child {
            border-bottom: none;
            margin-bottom: 0;
            padding-bottom: 0;
        }

        .filter-title {
            font-weight: 600;
            font-size: 14px;
            color: var(--gray-900);
            margin-bottom: 16px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .filter-options {
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

        .filter-option {
            display: flex;
            align-items: center;
            gap: 12px;
            cursor: pointer;
            font-size: 14px;
            color: var(--gray-600);
        }

        .filter-option input {
            width: 16px;
            height: 16px;
            cursor: pointer;
            accent-color: var(--primary);
        }

        .filter-count {
            margin-left: auto;
            font-size: 12px;
            color: var(--gray-400);
        }

        .filter-actions {
            display: flex;
            gap: 12px;
            margin-top: 20px;
            padding-top: 20px;
            border-top: 1px solid var(--gray-200);
        }

        .filter-actions button {
            flex: 1;
            padding: 10px;
            font-size: 13px;
        }

        /* Mobile Filter Bar */
        .mobile-filter-bar {
            display: none;
            background: white;
            border: 1px solid var(--gray-200);
            border-radius: 12px;
            padding: 12px 16px;
            margin-bottom: 20px;
            justify-content: space-between;
            align-items: center;
        }

        @media (max-width: 1024px) {
            .mobile-filter-bar {
                display: flex;
            }
        }

        .filter-trigger {
            display: flex;
            align-items: center;
            gap: 8px;
            background: none;
            border: none;
            font-size: 14px;
            font-weight: 500;
            color: var(--gray-700);
            cursor: pointer;
        }

        .active-filters-count {
            background: var(--primary);
            color: white;
            font-size: 12px;
            padding: 2px 8px;
            border-radius: 20px;
        }

        /* Search Bar */
        .search-bar {
            margin-bottom: 24px;
        }

        .search-box {
            display: flex;
            align-items: center;
            gap: 12px;
            background: white;
            border: 1px solid var(--gray-200);
            border-radius: 12px;
            padding: 12px 16px;
            transition: all 0.2s;
        }

        .search-box:focus-within {
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(10, 102, 194, 0.1);
        }

        .search-box i {
            color: var(--gray-400);
        }

        .search-box input {
            border: none;
            outline: none;
            flex: 1;
            font-size: 14px;
            background: transparent;
            font-family: inherit;
        }

        /* Course Cards */
        .courses-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
            gap: 24px;
        }

        @media (max-width: 768px) {
            .courses-grid {
                grid-template-columns: 1fr;
            }
        }

        .course-card {
            background: white;
            border-radius: 20px;
            border: 1px solid var(--gray-200);
            overflow: hidden;
            transition: all 0.3s ease;
            cursor: pointer;
        }

        .course-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-xl);
            border-color: transparent;
        }

        .course-banner {
            height: 160px;
            background-size: cover;
            background-position: center;
            position: relative;
        }

        .course-badge {
            position: absolute;
            top: 16px;
            right: 16px;
            padding: 6px 12px;
            border-radius: 20px;
            font-size: 12px;
            font-weight: 600;
        }

        .badge-placement {
            background: var(--success);
            color: white;
        }

        .badge-certification {
            background: var(--warning);
            color: white;
        }

        .badge-bestseller {
            background: var(--error);
            color: white;
        }

        .course-content {
            padding: 20px;
        }

        .course-category {
            font-size: 12px;
            font-weight: 600;
            color: var(--primary);
            text-transform: uppercase;
            margin-bottom: 8px;
        }

        .course-title {
            font-size: 18px;
            font-weight: 700;
            margin-bottom: 8px;
            line-height: 1.4;
        }

        .course-instructor {
            font-size: 13px;
            color: var(--gray-500);
            margin-bottom: 12px;
        }

        .course-stats {
            display: flex;
            gap: 16px;
            margin-bottom: 16px;
            font-size: 13px;
            color: var(--gray-600);
        }

        .course-stats span {
            display: flex;
            align-items: center;
            gap: 4px;
        }

        .course-stats i {
            color: var(--warning);
        }

        .course-skills {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
            margin-bottom: 16px;
        }

        .skill-tag {
            background: var(--gray-100);
            padding: 4px 10px;
            border-radius: 6px;
            font-size: 11px;
            color: var(--gray-600);
        }

        .course-footer {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding-top: 16px;
            border-top: 1px solid var(--gray-200);
        }

        .course-price {
            font-size: 20px;
            font-weight: 800;
            color: var(--gray-900);
        }

        .course-price small {
            font-size: 12px;
            font-weight: 400;
            color: var(--gray-500);
            text-decoration: line-through;
            margin-left: 8px;
        }

        .enroll-btn {
            background: var(--primary);
            color: white;
            border: none;
            padding: 8px 20px;
            border-radius: 8px;
            font-weight: 600;
            font-size: 14px;
            cursor: pointer;
            transition: all 0.2s;
        }

        .enroll-btn:hover {
            background: var(--primary-dark);
            transform: translateY(-1px);
        }

        /* Results Info */
        .results-info {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 24px;
            font-size: 14px;
            color: var(--gray-500);
        }

        .sort-select {
            display: flex;
            align-items: center;
            gap: 8px;
            background: white;
            border: 1px solid var(--gray-200);
            border-radius: 8px;
            padding: 8px 12px;
            font-size: 13px;
        }

        .sort-select select {
            border: none;
            background: transparent;
            font-size: 13px;
            font-family: inherit;
            cursor: pointer;
            outline: none;
        }

        /* Loading State */
        .loading {
            text-align: center;
            padding: 60px;
            color: var(--gray-400);
        }

        .spinner {
            width: 50px;
            height: 50px;
            border: 4px solid var(--gray-200);
            border-top-color: var(--primary);
            border-radius: 50%;
            animation: spin 0.8s linear infinite;
            margin: 0 auto 16px;
        }

        @keyframes spin {
            to { transform: rotate(360deg); }
        }

        /* Empty State */
        .empty-state {
            text-align: center;
            padding: 60px;
            background: white;
            border-radius: 20px;
            border: 1px solid var(--gray-200);
        }

        .empty-state i {
            font-size: 64px;
            color: var(--gray-300);
            margin-bottom: 16px;
        }

        /* Modal */
        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
            z-index: 2000;
            align-items: center;
            justify-content: center;
        }

        .modal.active {
            display: flex;
        }

        .modal-content {
            background: white;
            border-radius: 24px;
            max-width: 500px;
            width: 90%;
            padding: 32px;
            text-align: center;
        }

        .modal-content i {
            font-size: 48px;
            color: var(--success);
            margin-bottom: 16px;
        }

        .modal-content h3 {
            font-size: 20px;
            margin-bottom: 8px;
        }

        .modal-content p {
            color: var(--gray-500);
            margin-bottom: 24px;
        }

        /* Toast */
        .toast {
            position: fixed;
            bottom: 24px;
            right: 24px;
            background: white;
            padding: 12px 20px;
            border-radius: 12px;
            box-shadow: var(--shadow-lg);
            display: flex;
            align-items: center;
            gap: 12px;
            z-index: 2000;
            transform: translateY(100px);
            opacity: 0;
            transition: all 0.3s ease;
            border: 1px solid var(--gray-200);
        }

        .toast.show {
            transform: translateY(0);
            opacity: 1;
        }

        /* Footer */
        .footer {
            background: var(--gray-900);
            color: white;
            padding: 48px 0 32px;
            margin-top: 60px;
        }

        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1fr;
            gap: 48px;
        }

        @media (max-width: 768px) {
            .footer-grid {
                grid-template-columns: 1fr;
                gap: 32px;
            }
        }

        .footer-logo {
            display: flex;
            align-items: center;
            gap: 8px;
            margin-bottom: 16px;
        }

        .footer-logo .logo-icon {
            background: white;
        }

        .footer-logo .logo-icon i {
            color: var(--primary);
        }

        .footer-logo .logo-text {
            color: white;
        }

        .footer-description {
            color: var(--gray-400);
            font-size: 14px;
            margin-bottom: 24px;
        }

        .footer-links h4 {
            font-size: 14px;
            font-weight: 600;
            margin-bottom: 20px;
        }

        .footer-links ul {
            list-style: none;
        }

        .footer-links li {
            margin-bottom: 12px;
        }

        .footer-links a {
            color: var(--gray-400);
            text-decoration: none;
            font-size: 14px;
        }

        .footer-links a:hover {
            color: white;
        }

        .copyright {
            text-align: center;
            padding-top: 32px;
            border-top: 1px solid var(--gray-800);
            color: var(--gray-500);
            font-size: 13px;
            margin-top: 48px;
        }