:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --background-color: #f8f9fa;
    --card-background: #ffffff;
    --text-color: #2c3e50;
    --text-muted: #6c757d;
    --border-color: #e9ecef;
    --border-radius: 8px;
    --box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    --transition: all 0.3s ease;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    background-color: var(--background-color);
    color: var(--text-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header Styles */
header {
    background: linear-gradient(135deg, var(--primary-color), #34495e);
    color: white;
    padding: 2rem 0;
    margin-bottom: 2rem;
    box-shadow: var(--box-shadow);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 12px;
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

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

.header-text {
    flex: 1;
}

.replit-link {
    display: flex;
    align-items: center;
    text-decoration: none;
    padding: 8px 12px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.replit-link:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.replit-logo {
    height: 32px;
    width: auto;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: rgba(255,255,255,0.9);
    text-decoration: none;
    font-size: 1rem;
    margin-bottom: 1rem;
    transition: var(--transition);
}

.back-link:hover {
    color: white;
    transform: translateX(-3px);
}

/* Search Styles */
.search-container {
    position: relative;
    margin-bottom: 2rem;
}

.search-container input {
    width: 100%;
    padding: 15px 50px 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--card-background);
}

.search-container input:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.search-icon {
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 1.2rem;
    line-height: 1;
    display: flex;
    align-items: center;
    height: 1.2rem;
}

.search-filters {
    display: flex;
    gap: 12px;
    margin-top: 12px;
    flex-wrap: wrap;
}

.search-filters select {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--card-background);
    color: var(--text-color);
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
}

.search-filters select:focus {
    outline: none;
    border-color: var(--secondary-color);
}

/* Category Grid */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-bottom: 3rem;
}

.category-card {
    background: var(--card-background);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary-color), var(--success-color));
    transform: scaleX(0);
    transition: var(--transition);
}

.category-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.category-card:hover::before {
    transform: scaleX(1);
}

.category-icon {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.category-image {
    width: 100%;
    height: 120px;
    margin-bottom: 1rem;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.category-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.category-card:hover .category-image img {
    transform: scale(1.05);
}

.category-card h3 {
    font-size: 1.5rem;
    margin-bottom: 0.8rem;
    color: var(--primary-color);
}

.category-card p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    line-height: 1.5;
}

.file-count {
    background: var(--secondary-color);
    color: white;
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 1.5rem;
}

.category-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    padding: 10px 20px;
    border: 2px solid var(--secondary-color);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.category-link:hover {
    background: var(--secondary-color);
    color: white;
    transform: translateX(3px);
}

/* Statistics Section */
.stats-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--card-background);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: center;
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-3px);
}

.stat-card i {
    font-size: 2rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Files List */
.files-section, .recent-files-section, .search-results-section {
    margin-bottom: 3rem;
}

.files-section h2, .recent-files-section h2, .search-results-section h2 {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.files-list {
    background: var(--card-background);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
    text-decoration: none;
    color: inherit;
}

.file-item:last-child {
    border-bottom: none;
}

.file-item:hover {
    background: var(--background-color);
    transform: translateX(5px);
}

.file-icon {
    font-size: 1.5rem;
    margin-right: 1rem;
    min-width: 40px;
    text-align: center;
}

.file-icon.pdf {
    color: var(--accent-color);
}

.file-icon.html {
    color: var(--warning-color);
}

.file-details {
    flex: 1;
}

.file-name {
    font-weight: 600;
    margin-bottom: 0.3rem;
    color: var(--primary-color);
}

.file-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.file-date, .file-size, .file-type {
    display: flex;
    align-items: center;
    gap: 4px;
}

.file-size {
    color: #888;
}

.file-location {
    color: #666;
    font-weight: 500;
}

.external-link-icon {
    margin-left: auto;
    color: var(--text-muted);
    font-size: 1rem;
}

/* Loading and Empty States */
.loading-placeholder {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.loading-placeholder i {
    margin-right: 8px;
}

.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

/* Upload Instructions */
.upload-instructions {
    background: var(--card-background);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--box-shadow);
    border-left: 4px solid var(--secondary-color);
}

.upload-instructions h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.upload-instructions ol, .upload-instructions ul {
    margin-bottom: 1rem;
    padding-left: 2rem;
}

.upload-instructions li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.upload-instructions code {
    background: var(--background-color);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

/* Footer */
footer {
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

footer a {
    color: var(--secondary-color);
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

/* Error States */
.error-message {
    background: #ffe6e6;
    border: 1px solid #ffb3b3;
    border-radius: var(--border-radius);
    padding: 1rem;
    margin: 1rem 0;
    color: #d63031;
    text-align: center;
}

.error-message i {
    margin-right: 8px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }

    header h1 {
        font-size: 2rem;
    }

    .header-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .replit-link {
        align-self: flex-end;
    }

    .category-grid {
        grid-template-columns: 1fr;
    }

    .stats-section {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }

    .search-filters {
        flex-direction: column;
    }

    .search-filters select {
        width: 100%;
    }

    .file-meta {
        flex-direction: column;
        gap: 0.3rem;
    }

    .file-item {
        padding: 1rem;
    }

    .upload-instructions {
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    header {
        padding: 1.5rem 0;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .category-card {
        padding: 1.5rem;
    }

    .stat-card {
        padding: 1rem;
    }

    .stat-number {
        font-size: 2rem;
    }
}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.slide-in-left {
    animation: slideInLeft 0.5s ease-out;
}

@keyframes slideInLeft {
    from { opacity: 0; transform: translateX(-30px); }
    to { opacity: 1; transform: translateX(0); }
}

/* Search Results Highlighting */
.search-highlight {
    background: #fff3cd;
    padding: 2px 4px;
    border-radius: 3px;
    font-weight: 600;
}

/* File Type Specific Styles */
.file-item.pdf .file-icon {
    color: var(--accent-color);
}

.file-item.html .file-icon {
    color: var(--warning-color);
}

.file-item.doc .file-icon {
    color: var(--secondary-color);
}

/* Accessibility Improvements */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.focus-visible:focus {
    outline: 2px solid var(--secondary-color);
    outline-offset: 2px;
}

/* Projects Section */
.projects-section {
    margin-bottom: 3rem;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
    margin-bottom: 2rem;
}

.project-card {
    background: var(--card-background);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    position: relative;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.project-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--background-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 3rem;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.project-content {
    padding: 1.5rem;
}

.project-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.project-description {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    padding: 8px 16px;
    border: 2px solid var(--secondary-color);
    border-radius: var(--border-radius);
    transition: var(--transition);
    font-size: 0.9rem;
}

.project-link:hover {
    background: var(--secondary-color);
    color: white;
}

.project-type-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--secondary-color);
    color: white;
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background: var(--card-background);
    margin: 5% auto;
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    animation: slideIn 0.3s ease;
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    margin: 0;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.close {
    color: var(--text-muted);
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    transition: var(--transition);
}

.close:hover {
    color: var(--primary-color);
}

.modal-body {
    padding: 1.5rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

.form-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 2rem;
}

.form-actions button {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.form-actions button[type="submit"] {
    background: var(--secondary-color);
    color: white;
}

.form-actions button[type="submit"]:hover {
    background: #2980b9;
}

.form-actions button[type="button"] {
    background: var(--border-color);
    color: var(--text-color);
}

.form-actions button[type="button"]:hover {
    background: #bdc3c7;
}

/* Floating Action Button */
.fab {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 56px;
    height: 56px;
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
    transition: var(--transition);
    z-index: 100;
}

.fab:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(52, 152, 219, 0.4);
}

/* Animations */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Print Styles */
@media print {
    header, footer, .search-container, .upload-instructions, .fab {
        display: none;
    }

    .file-item, .project-card {
        break-inside: avoid;
    }

    body {
        background: white;
    }

    .files-list, .category-card, .project-card {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}