:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --secondary: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --dark: #1f2937;
    --gray: #6b7280;
    --light: #f3f4f6;
    --white: #ffffff;
    --border: #e5e7eb;
    --shadow: 0 2px 8px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.15);
    --radius: 12px;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--light);
    color: var(--dark);
    line-height: 1.6;
    padding-bottom: 80px;
}

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

/* Header */
.header {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 15px 0;
}

.header-content {
    display: flex;
    align-items: center;
    gap: 30px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 28px;
    font-weight: bold;
    color: var(--primary);
    cursor: pointer;
    white-space: nowrap;
}

.logo i {
    font-size: 32px;
}

.search-bar {
    flex: 1;
    display: flex;
    align-items: center;
    background: var(--light);
    border-radius: var(--radius);
    padding: 12px 20px;
    gap: 10px;
    max-width: 600px;
}

.search-bar i {
    color: var(--gray);
    font-size: 18px;
}

.search-bar input {
    flex: 1;
    border: none;
    background: none;
    font-size: 16px;
    outline: none;
}

.search-btn {
    background: var(--primary);
    color: var(--white);
    border: none;
    padding: 8px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.search-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.icon-btn {
    position: relative;
    background: var(--light);
    border: none;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: var(--dark);
    transition: var(--transition);
}

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

.badge {
    position: absolute;
    top: -5px;
    right: -5px;
    background: var(--danger);
    color: var(--white);
    font-size: 11px;
    font-weight: bold;
    padding: 2px 6px;
    border-radius: 10px;
    min-width: 20px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: var(--white);
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 15px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
    box-shadow: var(--shadow);
    white-space: nowrap;
}

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

.btn-secondary {
    background: var(--light);
    color: var(--dark);
    border: 2px solid var(--border);
    padding: 12px 24px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 15px;
    cursor: pointer;
    transition: var(--transition);
}

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

/* Categories Bar */
.categories-bar {
    background: var(--white);
    padding: 15px 0;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 75px;
    z-index: 99;
}

.categories-scroll {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.categories-scroll::-webkit-scrollbar {
    display: none;
}

.category-btn {
    background: var(--light);
    border: 2px solid transparent;
    padding: 10px 20px;
    border-radius: 25px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    font-size: 14px;
    color: var(--dark);
    transition: var(--transition);
    white-space: nowrap;
}

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

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

/* Filters Section */
.filters-section {
    background: var(--white);
    padding: 20px 0;
    border-bottom: 1px solid var(--border);
}

.filters-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.filters-left {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.filter-btn {
    background: var(--light);
    border: 2px solid var(--border);
    padding: 10px 18px;
    border-radius: var(--radius);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    font-size: 14px;
    color: var(--dark);
    transition: var(--transition);
}

.filter-btn:hover,
.filter-btn.active {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(99, 102, 241, 0.1);
}

.sort-select {
    background: var(--light);
    border: 2px solid var(--border);
    padding: 10px 18px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 14px;
    color: var(--dark);
    cursor: pointer;
    outline: none;
}

.active-filters {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 15px;
}

.filter-tag {
    background: var(--primary);
    color: var(--white);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-tag button {
    background: none;
    border: none;
    color: var(--white);
    cursor: pointer;
    font-size: 14px;
}

/* Main Content */
.main-content {
    padding: 30px 0;
}

.section-title {
    font-size: 24px;
    font-weight: bold;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.results-count {
    color: var(--gray);
    font-size: 14px;
}

/* Featured Section */
.featured-section {
    margin-bottom: 50px;
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 25px;
}

/* Products Grid */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

/* Product Card */
.product-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
    position: relative;
}

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

.product-card.featured {
    border: 2px solid var(--warning);
}

.featured-badge {
    position: absolute;
    top: 10px;
    left: 10px;
    background: var(--warning);
    color: var(--white);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: bold;
    z-index: 2;
    display: flex;
    align-items: center;
    gap: 5px;
}

.product-image {
    width: 100%;
    height: 220px;
    object-fit: cover;
    background: var(--light);
}

.product-favorite {
    position: absolute;
    top: 10px;
    right: 10px;
    background: var(--white);
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: var(--gray);
    transition: var(--transition);
    z-index: 2;
}

.product-favorite:hover,
.product-favorite.active {
    color: var(--danger);
    transform: scale(1.2);
}

.product-info {
    padding: 15px;
}

.product-title {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.product-price {
    font-size: 22px;
    font-weight: bold;
    color: var(--primary);
    margin-bottom: 10px;
}

.product-details {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 13px;
    color: var(--gray);
    margin-bottom: 8px;
}

.product-details i {
    margin-right: 5px;
}

.product-condition {
    display: inline-block;
    background: var(--secondary);
    color: var(--white);
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 11px;
    font-weight: 600;
    margin-bottom: 10px;
}

/* No Results */
.no-results {
    text-align: center;
    padding: 60px 20px;
}

.no-results i {
    font-size: 64px;
    color: var(--gray);
    margin-bottom: 20px;
}

.no-results h3 {
    font-size: 24px;
    margin-bottom: 10px;
}

.no-results p {
    color: var(--gray);
}

/* Footer */
.footer {
    background: var(--dark);
    color: var(--white);
    padding: 50px 0 20px;
    margin-top: 60px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-col .logo {
    color: var(--white);
    margin-bottom: 15px;
}

.footer-col p {
    color: var(--light);
    margin-bottom: 20px;
    line-height: 1.8;
}

.footer-col h4 {
    margin-bottom: 15px;
    font-size: 18px;
}

.footer-col a {
    display: block;
    color: var(--light);
    text-decoration: none;
    margin-bottom: 10px;
    transition: var(--transition);
}

.footer-col a:hover {
    color: var(--primary);
    padding-left: 5px;
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    width: 40px;
    height: 40px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary);
    transform: translateY(-3px);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: var(--light);
}

/* Mobile Bottom Nav */
.mobile-bottom-nav {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--white);
    box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
    z-index: 100;
}

.nav-item {
    flex: 1;
    background: none;
    border: none;
    padding: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    cursor: pointer;
    color: var(--gray);
    font-size: 20px;
    transition: var(--transition);
}

.nav-item span {
    font-size: 11px;
    font-weight: 600;
}

.nav-item.active {
    color: var(--primary);
}

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

/* Modals */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.6);
    backdrop-filter: blur(5px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
    overflow-y: auto;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--white);
    border-radius: var(--radius);
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    animation: modalSlideIn 0.3s ease;
}

.modal-large {
    max-width: 900px;
}

@keyframes modalSlideIn {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid var(--border);
}

.modal-header h2 {
    font-size: 24px;
}

.close-btn {
    background: var(--light);
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: var(--dark);
    transition: var(--transition);
}

.close-btn:hover {
    background: var(--danger);
    color: var(--white);
    transform: rotate(90deg);
}

.modal-body {
    padding: 20px;
}

/* Form Styles */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--dark);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 15px;
    font-family: inherit;
    transition: var(--transition);
    outline: none;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.image-upload-area {
    border: 3px dashed var(--border);
    border-radius: var(--radius);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.image-upload-area:hover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.05);
}

.image-upload-area i {
    font-size: 48px;
    color: var(--gray);
    margin-bottom: 10px;
}

.image-upload-area p {
    font-weight: 600;
    margin-bottom: 5px;
}

.image-upload-area span {
    font-size: 13px;
    color: var(--gray);
}

.image-preview {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    gap: 10px;
    margin-top: 15px;
}

.preview-item {
    position: relative;
    width: 100%;
    height: 100px;
    border-radius: var(--radius);
    overflow: hidden;
}

.preview-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.preview-remove {
    position: absolute;
    top: 5px;
    right: 5px;
    background: var(--danger);
    color: var(--white);
    border: none;
    width: 25px;
    height: 25px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.checkbox-group label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}

.checkbox-group input {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.form-actions {
    display: flex;
    gap: 15px;
    justify-content: flex-end;
    margin-top: 30px;
}

/* Chat Styles */
.chat-container {
    display: grid;
    grid-template-columns: 300px 1fr;
    height: 500px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.chat-sidebar {
    border-right: 1px solid var(--border);
    overflow-y: auto;
}

.chat-item {
    padding: 15px;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    transition: var(--transition);
}

.chat-item:hover,
.chat-item.active {
    background: var(--light);
}

.chat-main {
    display: flex;
    flex-direction: column;
}

.chat-empty {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--gray);
}

.chat-empty i {
    font-size: 64px;
    margin-bottom: 15px;
}

/* Profile Tabs */
.profile-tabs {
    display: flex;
    gap: 10px;
    border-bottom: 2px solid var(--border);
    margin-bottom: 20px;
}

.tab-btn {
    background: none;
    border: none;
    padding: 12px 20px;
    cursor: pointer;
    font-weight: 600;
    color: var(--gray);
    border-bottom: 3px solid transparent;
    transition: var(--transition);
}

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

.tab-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

/* Toast Notifications */
.toast {
    position: fixed;
    bottom: 100px;
    right: 20px;
    background: var(--dark);
    color: var(--white);
    padding: 15px 25px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    z-index: 2000;
    display: none;
    animation: toastSlideIn 0.3s ease;
}

.toast.show {
    display: block;
}

@keyframes toastSlideIn {
    from {
        transform: translateX(400px);
    }
    to {
        transform: translateX(0);
    }
}

/* Responsive Design */
@media (max-width: 1024px) {
    .search-bar {
        max-width: 400px;
    }
    
    .featured-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }
    
    .products-grid {
        grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    }
}

@media (max-width: 768px) {
    body {
        padding-bottom: 70px;
    }
    
    .header {
        padding: 10px 0;
    }
    
    .header-content {
        flex-wrap: wrap;
        gap: 10px;
    }
    
    .logo {
        font-size: 22px;
    }
    
    .logo i {
        font-size: 26px;
    }
    
    .search-bar {
        order: 3;
        width: 100%;
        max-width: 100%;
        padding: 10px 15px;
    }
    
    .header-actions {
        margin-left: auto;
        gap: 8px;
    }
    
    .icon-btn {
        width: 40px;
        height: 40px;
        font-size: 18px;
    }
    
    .header-actions .btn-primary {
        display: none;
    }
    
    .categories-bar {
        top: 90px;
        padding: 10px 0;
    }
    
    .category-btn {
        padding: 8px 16px;
        font-size: 13px;
    }
    
    .filters-section {
        padding: 15px 0;
    }
    
    .filter-btn {
        padding: 8px 14px;
        font-size: 13px;
    }
    
    .sort-select {
        padding: 8px 14px;
        font-size: 13px;
    }
    
    .mobile-bottom-nav {
        display: flex;
    }
    
    .main-content {
        padding: 20px 0;
    }
    
    .section-title {
        font-size: 20px;
        margin-bottom: 15px;
    }
    
    .featured-grid,
    .products-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    .product-card {
        border-radius: 10px;
    }
    
    .product-image {
        height: 140px;
    }
    
    .product-info {
        padding: 12px;
    }
    
    .product-title {
        font-size: 13px;
        margin-bottom: 6px;
    }
    
    .product-price {
        font-size: 18px;
        margin-bottom: 8px;
    }
    
    .product-condition {
        font-size: 10px;
        padding: 2px 8px;
    }
    
    .product-details {
        font-size: 11px;
        gap: 8px;
        flex-direction: column;
        align-items: flex-start;
    }
    
    .product-favorite {
        width: 35px;
        height: 35px;
        font-size: 16px;
    }
    
    .featured-badge {
        font-size: 10px;
        padding: 4px 10px;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        margin: 10px;
        max-height: 85vh;
    }
    
    .modal-header {
        padding: 15px;
    }
    
    .modal-header h2 {
        font-size: 20px;
    }
    
    .modal-body {
        padding: 15px;
    }
    
    .chat-container {
        grid-template-columns: 1fr;
        height: 400px;
    }
    
    .chat-sidebar {
        display: none;
    }
    
    .footer {
        padding: 30px 0 15px;
        margin-top: 40px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 25px;
    }
    
    .footer-col h4 {
        font-size: 16px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 12px;
    }
    
    .logo {
        font-size: 20px;
    }
    
    .logo i {
        font-size: 24px;
    }
    
    .search-bar {
        padding: 8px 12px;
    }
    
    .search-bar input {
        font-size: 14px;
    }
    
    .icon-btn {
        width: 36px;
        height: 36px;
        font-size: 16px;
    }
    
    .categories-bar {
        padding: 8px 0;
    }
    
    .category-btn {
        padding: 6px 12px;
        font-size: 12px;
    }
    
    .filters-content {
        flex-direction: column;
        align-items: stretch;
    }
    
    .filters-left {
        width: 100%;
        justify-content: space-between;
    }
    
    .filters-right {
        width: 100%;
    }
    
    .sort-select {
        width: 100%;
    }
    
    .section-title {
        font-size: 18px;
        margin-bottom: 12px;
    }
    
    .featured-grid,
    .products-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }
    
    .product-card {
        border-radius: 8px;
    }
    
    .product-image {
        height: 120px;
    }
    
    .product-info {
        padding: 10px;
    }
    
    .product-title {
        font-size: 12px;
        margin-bottom: 5px;
    }
    
    .product-price {
        font-size: 16px;
        margin-bottom: 6px;
    }
    
    .product-condition {
        font-size: 9px;
        padding: 2px 6px;
        margin-bottom: 6px;
    }
    
    .product-details {
        font-size: 10px;
        gap: 6px;
    }
    
    .product-favorite {
        width: 32px;
        height: 32px;
        font-size: 14px;
        top: 8px;
        right: 8px;
    }
    
    .featured-badge {
        font-size: 9px;
        padding: 3px 8px;
        top: 8px;
        left: 8px;
    }
    
    .modal-content {
        max-width: 100%;
        max-height: 100vh;
        border-radius: 0;
        margin: 0;
    }
    
    .modal-header {
        padding: 12px 15px;
    }
    
    .modal-header h2 {
        font-size: 18px;
    }
    
    .modal-body {
        padding: 12px 15px;
    }
    
    .form-group label {
        font-size: 14px;
    }
    
    .form-group input,
    .form-group select,
    .form-group textarea {
        font-size: 14px;
        padding: 10px;
    }
    
    .image-upload-area {
        padding: 30px 15px;
    }
    
    .image-upload-area i {
        font-size: 36px;
    }
    
    .btn-primary,
    .btn-secondary {
        padding: 10px 20px;
        font-size: 14px;
    }
    
    .nav-item {
        padding: 10px;
        font-size: 18px;
    }
    
    .nav-item span {
        font-size: 10px;
    }
    
    .toast {
        right: 10px;
        left: 10px;
        bottom: 80px;
        font-size: 14px;
        padding: 12px 20px;
    }
    
.footer {
    padding: 25px 0 15px;
}

.product-detail-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

.product-detail-info {
    display: flex;
    flex-direction: column;
}

.product-detail-grid .btn-primary,
.product-detail-grid .btn-secondary {
    width: 100%;
    justify-content: center;
}

@media (min-width: 769px) {
    .product-detail-grid {
        grid-template-columns: 1fr 1fr;
        gap: 30px;
    }
    
    .product-detail-grid .btn-primary,
    .product-detail-grid .btn-secondary {
        width: auto;
    }
}
}