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

            :root {
                --primary: #2c7be5;
                --primary-dark: #1a68d1;
                --secondary: #6e84a3;
                --success: #00d97e;
                --warning: #f6c343;
                --danger: #e63757;
                --light: #f9fbfd;
                --dark: #12263f;
                --gray-100: #f9fbfd;
                --gray-200: #edf2f9;
                --gray-300: #d8e2ef;
                --gray-400: #b6c1d2;
                --gray-500: #9da9bb;
                --gray-600: #748194;
                --gray-700: #5e6e82;
                --gray-800: #4d5969;
                --gray-900: #344050;
                --border-radius: 0.5rem;
                --shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
                --shadow-lg: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
                --surface: white;
                --background: #f8f9fa;
                --border: #dee2e6;
            }

            body {
                font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
                line-height: 1.6;
                color: var(--gray-800);
                background-color: var(--gray-100);
                margin: 0;
                padding: 0;
            }

            .container {
                max-width: 1200px;
                margin: 0 auto;
                padding: 0 1rem;
            }

            header {
                background: linear-gradient(135deg, var(--primary), var(--primary-dark));
                color: white;
                padding: 1.5rem 0;
                box-shadow: var(--shadow);
            }

            header .container {
                display: flex;
                justify-content: space-between;
                align-items: center;
            }

            header h1 {
                margin: 0;
                font-size: 1.75rem;
                font-weight: 600;
            }

            .user-nav {
                display: flex;
                gap: 1rem;
                align-items: center;
            }

            .user-nav a {
                color: white;
                text-decoration: none;
                padding: 0.5rem 1rem;
                border-radius: var(--border-radius);
                transition: background-color 0.2s;
            }

            .user-nav a:hover {
                background-color: rgba(255, 255, 255, 0.1);
            }

            .btn {
                display: inline-block;
                font-weight: 500;
                text-align: center;
                white-space: nowrap;
                vertical-align: middle;
                user-select: none;
                border: 1px solid transparent;
                padding: 0.5rem 1rem;
                font-size: 0.875rem;
                line-height: 1.5;
                border-radius: var(--border-radius);
                transition: all 0.15s ease-in-out;
                cursor: pointer;
                text-decoration: none;
            }

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

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

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

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

            main {
                padding: 2rem 0;
            }

            .hero {
                background: white;
                border-radius: var(--border-radius);
                padding: 2rem;
                margin-bottom: 2rem;
                box-shadow: var(--shadow);
                text-align: center;
            }

            .hero h2 {
                margin-top: 0;
                color: var(--dark);
                font-size: 1.75rem;
            }

            .hero p {
                font-size: 1.125rem;
                color: var(--gray-600);
                max-width: 800px;
                margin: 0 auto 1.5rem;
            }

            .features {
                display: grid;
                grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
                gap: 1.5rem;
                margin-bottom: 2rem;
            }

            .feature-card {
                background: white;
                border-radius: var(--border-radius);
                padding: 1.5rem;
                box-shadow: var(--shadow);
                transition: transform 0.2s, box-shadow 0.2s;
            }

            .feature-card:hover {
                transform: translateY(-5px);
                box-shadow: var(--shadow-lg);
            }

            .feature-card h3 {
                margin-top: 0;
                color: var(--primary);
                font-size: 1.25rem;
            }

            .feature-card p {
                color: var(--gray-600);
                margin-bottom: 0;
            }

            .feature-card a {
                text-decoration: none;
            }
            .section-title {
                margin-bottom: 1.5rem;
                padding-bottom: 0.75rem;
                border-bottom: 1px solid var(--gray-300);
            }

            .section-title h2 {
                margin: 0;
                color: var(--dark);
                font-size: 1.5rem;
            }

            .section-title p {
                margin: 0.5rem 0 0;
                color: var(--gray-600);
            }

            .program-builder {
                background: white;
                border-radius: var(--border-radius);
                padding: 2rem;
                box-shadow: var(--shadow);
                margin-bottom: 2rem;
            }

            /* PANELS */
            .grid {
                display: grid;
                grid-template-columns: 1fr 1fr;
                gap: 1.25rem;
            }

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

            .panel {
                background: var(--surface);
                border: 1px solid var(--border);
                padding: 1.2rem;
                border-radius: 12px;
            }

            .panel h2 {
                font-size: 1.2rem;
                margin-bottom: 1rem;
                border-bottom: 2px solid var(--primary);
                padding-bottom: .5rem;
            }

            /* MODULES LIST - DRAGGABLE */
            .modules-list {
                min-height: 100px;
                max-height: 500px;
                overflow-y: auto;
                border: 2px dashed var(--gray-300);
                border-radius: 8px;
                padding: 10px;
                background-color: var(--gray-100);
                transition: all 0.3s ease;
            }

            .modules-list.dragover {
                border-color: var(--primary);
                background-color: rgba(44, 123, 229, 0.05);
            }

            .module-item {
                background: white;
                border: 1px solid var(--border);
                border-radius: 8px;
                padding: 12px;
                margin-bottom: 8px;
                display: flex;
                align-items: flex-start;
                gap: 12px;
                cursor: grab;
                transition: all 0.2s ease;
                box-shadow: 0 1px 3px rgba(0,0,0,0.05);
            }

            .module-item:hover {
                box-shadow: 0 2px 6px rgba(0,0,0,0.1);
                transform: translateY(-1px);
            }

            .module-item.sortable-ghost {
                opacity: 0.4;
                background-color: var(--gray-200);
            }

            .module-item.sortable-chosen {
                box-shadow: 0 4px 12px rgba(0,0,0,0.15);
            }

            .module-item:last-child {
                margin-bottom: 0;
            }

            .module-drag-handle {
                color: var(--gray-500);
                font-size: 1.2rem;
                cursor: grab;
                padding-top: 2px;
                user-select: none;
            }

            .module-details {
                flex: 1;
            }

            .module-name {
                font-weight: 600;
                color: var(--dark);
                margin-bottom: 4px;
                font-size: 0.95rem;
            }

            .module-meta {
                font-size: 0.85rem;
                color: var(--gray-600);
                margin-bottom: 4px;
            }

            .prerequisites {
                font-size: 0.75rem;
                color: var(--gray-500);
                font-style: italic;
            }

            .module-checkbox {
                margin-top: 3px;
            }

            /* Module counter */
            .module-counter {
                font-size: 0.9rem;
                color: var(--gray-600);
                margin-bottom: 10px;
                font-weight: 500;
            }

            /* Module filter/search */
            .module-filter {
                margin-bottom: 15px;
            }

            .filter-input {
                width: 100%;
                padding: 8px 12px;
                border: 1px solid var(--gray-300);
                border-radius: 6px;
                font-size: 0.9rem;
            }

            .filter-input:focus {
                outline: none;
                border-color: var(--primary);
                box-shadow: 0 0 0 2px rgba(44, 123, 229, 0.2);
            }

            .no-modules {
                text-align: center;
                padding: 20px;
                color: var(--gray-500);
                font-style: italic;
            }

            .drag-instruction {
                font-size: 0.85rem;
                color: var(--gray-500);
                margin-bottom: 10px;
                padding: 8px 12px;
                background-color: var(--gray-100);
                border-radius: 6px;
                border-left: 3px solid var(--primary);
            }

            .form-group {
                margin-bottom: 1.5rem;
            }

            .form-label {
                display: block;
                margin-bottom: 0.5rem;
                font-weight: 500;
                color: var(--dark);
            }

            .form-control {
                display: block;
                width: 100%;
                padding: 0.5rem 0.75rem;
                font-size: 0.875rem;
                line-height: 1.5;
                color: var(--gray-800);
                background-color: white;
                background-clip: padding-box;
                border: 1px solid var(--gray-400);
                border-radius: var(--border-radius);
                transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
            }

            .form-control:focus {
                color: var(--gray-800);
                background-color: white;
                border-color: var(--primary);
                outline: 0;
                box-shadow: 0 0 0 0.2rem rgba(44, 123, 229, 0.25);
            }

            textarea.form-control {
                min-height: 100px;
                resize: vertical;
            }

            .alert {
                position: relative;
                padding: 0.75rem 1.25rem;
                margin-bottom: 1rem;
                border: 1px solid transparent;
                border-radius: var(--border-radius);
            }

            .alert-warning {
                color: #856404;
                background-color: #fff3cd;
                border-color: #ffeaa7;
            }

            .alert-success {
                color: #155724;
                background-color: #d4edda;
                border-color: #c3e6cb;
            }

            .alert-danger {
                color: #721c24;
                background-color: #f8d7da;
                border-color: #f5c6cb;
            }

            .planning-results {
                margin-top: 2rem;
            }

            .planning-summary {
                background: var(--gray-100);
                border-radius: var(--border-radius);
                padding: 1rem;
                margin-bottom: 1.5rem;
                border-left: 4px solid var(--primary);
            }

            .table {
                width: 100%;
                margin-bottom: 1rem;
                background-color: transparent;
                border-collapse: collapse;
            }

            .table th,
            .table td {
                padding: 0.75rem;
                vertical-align: top;
                border-top: 1px solid var(--gray-300);
            }

            .table thead th {
                vertical-align: bottom;
                border-bottom: 2px solid var(--gray-300);
                color: var(--dark);
                font-weight: 600;
            }

            .table tbody tr:nth-of-type(odd) {
                background-color: rgba(0, 0, 0, 0.02);
            }

            .table tbody tr:hover {
                background-color: rgba(0, 0, 0, 0.04);
            }

            .calendar {
                display: grid;
                grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
                gap: 0.5rem;
                margin-top: 1rem;
            }

            .week {
                border: 1px solid var(--gray-300);
                border-radius: var(--border-radius);
                padding: 0.5rem;
                text-align: center;
                font-size: 0.75rem;
                background: white;
                transition: transform 0.2s;
            }

            .week:hover {
                transform: scale(1.05);
                box-shadow: var(--shadow);
            }

            .week-number {
                font-weight: 600;
                color: var(--dark);
            }

            .week-module {
                font-size: 0.625rem;
                color: var(--gray-600);
                margin-top: 0.25rem;
                white-space: nowrap;
                overflow: hidden;
                text-overflow: ellipsis;
            }

            footer {
                background: var(--dark);
                color: white;
                padding: 2rem 0;
                margin-top: 3rem;
            }

            .footer-content {
                display: flex;
                justify-content: space-between;
                align-items: center;
            }

            .footer-links {
                display: flex;
                gap: 1.5rem;
            }

            .footer-links a {
                color: var(--gray-400);
                text-decoration: none;
                transition: color 0.2s;
            }

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

            .copyright {
                color: var(--gray-500);
                font-size: 0.875rem;
            }