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

:root {
    --primary-color: #4f46e5;
    --primary-dark: #3730a3;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 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);
    --gradient: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --border-color: #334155;
}

body {
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: all 0.3s ease;
    overflow-x: hidden;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header Styles */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    border-bottom: 1px solid var(--border-color);
}

[data-theme="dark"] .header {
    background: rgba(30, 41, 59, 0.95);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.75rem;
    font-weight: 800;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    cursor: pointer;
}

.logo-icon {
    font-size: 2rem;
    color: var(--primary-color);
}

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

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.75rem;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.95rem;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

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

.btn-icon {
    background: none;
    border: none;
    padding: 0.75rem;
    border-radius: 50%;
    cursor: pointer;
    color: var(--text-color);
    transition: all 0.3s ease;
    position: relative;
}

.btn-icon:hover {
    background: var(--border-color);
    transform: scale(1.1);
}

/* Language Selector */
.language-selector {
    position: relative;
    display: inline-block;
}

.language-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.flag-icon {
    width: 20px;
    height: 15px;
    border-radius: 2px;
    object-fit: cover;
}

.language-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-lg);
    min-width: 150px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    z-index: 1000;
}

.language-dropdown.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: background 0.3s ease;
}

.language-option:hover {
    background: var(--border-color);
}

.language-option.active {
    background: var(--primary-color);
    color: white;
}

/* Main Content */
.main {
    padding: 2rem 0;
    min-height: calc(100vh - 200px);
}

.hero {
    text-align: center;
    margin-bottom: 4rem;
    padding: 3rem 0;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 900;
    margin-bottom: 1.5rem;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.hero p {
    color: var(--text-muted);
    max-width: 700px;
    margin: 0 auto;
    font-size: 1.25rem;
    line-height: 1.7;
}

/* Category Filter */
.category-filter {
    margin-bottom: 3rem;
}

.filter-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.filter-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
}

.category-tabs {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    background: var(--card-bg);
    color: var(--text-muted);
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    border: 2px solid transparent;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.tab-btn.active {
    background: var(--gradient);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.tab-btn:hover:not(.active) {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Search and Sort */
.search-sort {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

.search-box {
    position: relative;
    flex: 1;
    min-width: 250px;
}

.search-input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 3rem;
    border: 2px solid var(--border-color);
    border-radius: 0.75rem;
    background: var(--card-bg);
    color: var(--text-color);
    transition: all 0.3s ease;
    font-size: 1rem;
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
}

.sort-select {
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.75rem;
    background: var(--card-bg);
    color: var(--text-color);
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 150px;
}

.sort-select:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Wallpaper Grid */
.wallpaper-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.wallpaper-card {
    background: var(--card-bg);
    border-radius: 1.5rem;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    border: 1px solid var(--border-color);
}

.wallpaper-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.wallpaper-img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    transition: transform 0.3s ease;
}

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

.wallpaper-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(to bottom, transparent 0%, rgba(0,0,0,0.7) 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
    display: flex;
    align-items: flex-end;
    padding: 1.5rem;
}

.wallpaper-card:hover .wallpaper-overlay {
    opacity: 1;
}

.overlay-actions {
    display: flex;
    gap: 0.75rem;
    width: 100%;
}

.overlay-btn {
    background: rgba(255, 255, 255, 0.9);
    border: none;
    padding: 0.75rem;
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--text-color);
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-weight: 600;
}

.overlay-btn:hover {
    background: white;
    transform: scale(1.05);
}

.overlay-btn.download:hover {
    background: var(--secondary-color);
    color: white;
}

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

.wallpaper-info {
    padding: 1.5rem;
}

.wallpaper-title {
    font-weight: 700;
    font-size: 1.1rem;
    margin-bottom: 0.75rem;
    color: var(--text-color);
}

.wallpaper-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.wallpaper-category {
    background: var(--gradient);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.8rem;
    font-weight: 600;
}

.wallpaper-stats {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin: 3rem 0;
    flex-wrap: wrap;
}

.page-btn {
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    background: var(--card-bg);
    color: var(--text-color);
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    min-width: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.page-btn:hover, .page-btn.active {
    background: var(--gradient);
    color: white;
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    backdrop-filter: blur(5px);
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--card-bg);
    border-radius: 1.5rem;
    padding: 2.5rem;
    max-width: 600px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: var(--shadow-xl);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.modal-title {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--text-color);
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
    padding: 0.5rem;
    border-radius: 50%;
    transition: all 0.3s ease;
}

.close-btn:hover {
    color: var(--text-color);
    background: var(--border-color);
}

/* Image Viewer Modal */
.image-viewer {
    background: rgba(0, 0, 0, 0.95);
}

.image-viewer .modal-content {
    background: transparent;
    max-width: 95%;
    max-height: 95%;
    padding: 0;
    border-radius: 1rem;
    overflow: hidden;
}

.viewer-image {
    width: 100%;
    height: auto;
    max-height: 90vh;
    object-fit: contain;
    border-radius: 0.5rem;
}

.viewer-controls {
    position: absolute;
    top: 1rem;
    right: 1rem;
    display: flex;
    gap: 0.75rem;
}

.viewer-btn {
    background: rgba(0, 0, 0, 0.8);
    border: none;
    color: white;
    padding: 0.75rem;
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.viewer-btn:hover {
    background: rgba(0, 0, 0, 0.9);
    transform: scale(1.1);
}

/* Form Styles */
.form-group {
    margin-bottom: 2rem;
}

.form-label {
    display: block;
    margin-bottom: 0.75rem;
    font-weight: 600;
    color: var(--text-color);
}

.form-input, .form-select, .form-textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.75rem;
    background: var(--card-bg);
    color: var(--text-color);
    transition: all 0.3s ease;
    font-size: 1rem;
}

.form-input:focus, .form-select:focus, .form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

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

.file-upload {
    border: 3px dashed var(--border-color);
    border-radius: 1rem;
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--bg-color);
}

.file-upload:hover {
    border-color: var(--primary-color);
    background: rgba(79, 70, 229, 0.05);
}

.file-upload.dragover {
    border-color: var(--primary-color);
    background: rgba(79, 70, 229, 0.1);
    transform: scale(1.02);
}

.upload-icon {
    font-size: 3rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.upload-text {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.upload-hint {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Image Preview */
.image-preview {
    margin-top: 1.5rem;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.preview-img {
    width: 100%;
    height: auto;
    max-height: 300px;
    object-fit: cover;
}

.preview-info {
    padding: 1rem;
    background: var(--card-bg);
    border-top: 1px solid var(--border-color);
}

.preview-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}

.stat-card {
    background: var(--bg-color);
    padding: 0.75rem;
    border-radius: 0.5rem;
    text-align: center;
}

.stat-value {
    font-weight: 700;
    color: var(--primary-color);
    font-size: 1.1rem;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Admin Panel */
.admin-panel {
    background: var(--card-bg);
    border-radius: 1.5rem;
    padding: 2rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow);
    border: 2px solid var(--accent-color);
}

.admin-toggle {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.admin-label {
    font-weight: 700;
    color: var(--accent-color);
    font-size: 1.1rem;
}

.toggle-switch {
    position: relative;
    width: 60px;
    height: 30px;
    background: var(--border-color);
    border-radius: 15px;
    cursor: pointer;
    transition: background 0.3s ease;
}

.toggle-switch.active {
    background: var(--accent-color);
}

.toggle-slider {
    position: absolute;
    top: 3px;
    left: 3px;
    width: 24px;
    height: 24px;
    background: white;
    border-radius: 50%;
    transition: transform 0.3s ease;
    box-shadow: var(--shadow);
}

.toggle-switch.active .toggle-slider {
    transform: translateX(30px);
}

.admin-info {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Footer */
.footer {
    background: var(--card-bg);
    padding: 3rem 0 2rem;
    margin-top: 5rem;
    border-top: 1px solid var(--border-color);
}

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

.footer-section h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-links a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 24px;
    height: 24px;
    border: 3px solid var(--border-color);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

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

/* Notification */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--primary-color);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-xl);
    transform: translateX(100%);
    transition: transform 0.3s ease;
    z-index: 1001;
    max-width: 400px;
    backdrop-filter: blur(10px);
}

.notification.show {
    transform: translateX(0);
}

.notification.error {
    background: #ef4444;
}

.notification.success {
    background: var(--secondary-color);
}

.notification.warning {
    background: var(--accent-color);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero h1 {
        font-size: 3rem;
    }
    
    .wallpaper-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
        gap: 1.5rem;
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }
    
    .wallpaper-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        gap: 1rem;
    }
    
    .category-tabs {
        justify-content: center;
    }
    
    .search-sort {
        flex-direction: column;
        align-items: stretch;
    }
    
    .nav {
        flex-wrap: wrap;
        gap: 1rem;
    }
    
    .nav-actions {
        order: 3;
        width: 100%;
        justify-content: center;
    }
    
    .modal-content {
        padding: 1.5rem;
        margin: 1rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .wallpaper-grid {
        grid-template-columns: 1fr;
    }
    
    .btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .tab-btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
}

/* 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-up {
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from { transform: translateY(100%); }
    to { transform: translateY(0); }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.hidden { display: none; }
.visible { display: block; }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }

.w-full { width: 100%; }
.h-full { height: 100%; }