:root {
            --primary-color: #3a86ff;
            --secondary-color: #8338ec;
            --accent-color: #ff006e;
            --dark-color: #1a1a2e;
            --light-color: #f8f9fa;
            --gray-color: #6c757d;
            --success-color: #28a745;
            --danger-color: #dc3545;
            --warning-color: #fd7e14;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        body {
            background-color: #f5f5f5;
            color: var(--dark-color);
            padding-bottom: 60px;
        }

        /* Authentication Pages */
        .auth-container {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            padding: 20px;
        }

        .auth-card {
            background-color: white;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
            width: 100%;
            max-width: 400px;
            padding: 30px;
        }

        .auth-title {
            text-align: center;
            margin-bottom: 30px;
            color: var(--primary-color);
        }

        .auth-form .form-group {
            margin-bottom: 20px;
        }

        .auth-form label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
        }

        .auth-form input {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #ddd;
            border-radius: 5px;
            font-size: 16px;
            transition: all 0.3s;
        }

        .auth-form input:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(58, 134, 255, 0.2);
            outline: none;
        }

        .auth-btn {
            width: 100%;
            padding: 12px;
            background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
            color: white;
            border: none;
            border-radius: 5px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
        }

        .auth-btn:hover {
            opacity: 0.9;
            transform: translateY(-2px);
        }

        .auth-toggle {
            text-align: center;
            margin-top: 20px;
            color: var(--gray-color);
        }

        .auth-toggle a {
            color: var(--primary-color);
            text-decoration: none;
            font-weight: 600;
        }

        .auth-error {
            color: var(--danger-color);
            margin-bottom: 20px;
            text-align: center;
            font-size: 14px;
        }

        /* Main App */
        #app-container {
            display: none;
        }

        .container {
            display: flex;
            min-height: 100vh;
        }

        /* Sidebar - Desktop */
        .sidebar {
            width: 250px;
            background-color: white;
            box-shadow: 2px 0 10px rgba(0, 0, 0, 0.1);
            padding: 20px 0;
            position: fixed;
            height: 100vh;
            z-index: 100;
            display: none;
        }

        .logo {
            font-size: 24px;
            font-weight: bold;
            color: var(--primary-color);
            text-align: center;
            margin-bottom: 30px;
            padding: 0 20px;
        }

        .logo span {
            color: var(--secondary-color);
        }

        .nav-menu {
            list-style: none;
        }

        .nav-item {
            margin-bottom: 5px;
        }

        .nav-link {
            display: flex;
            align-items: center;
            padding: 12px 20px;
            color: var(--dark-color);
            text-decoration: none;
            transition: all 0.3s;
        }

        .nav-link:hover, .nav-link.active {
            background-color: rgba(58, 134, 255, 0.1);
            color: var(--primary-color);
            border-left: 3px solid var(--primary-color);
        }

        .nav-link i {
            margin-right: 10px;
            font-size: 20px;
        }

        .create-post-btn {
            background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
            color: white;
            border: none;
            border-radius: 30px;
            padding: 12px 20px;
            margin: 20px;
            width: calc(100% - 40px);
            font-weight: bold;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s;
        }

        .create-post-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(58, 134, 255, 0.3);
        }

        .create-post-btn i {
            margin-right: 8px;
        }

        /* Main Content */
        .main-content {
            flex: 1;
            padding: 20px;
        }

        .header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            background-color: white;
            padding: 15px 20px;
            border-radius: 10px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
        }

        .search-bar {
            position: relative;
            width: 40%;
        }

        .search-bar input {
            width: 100%;
            padding: 10px 15px 10px 40px;
            border: 1px solid #ddd;
            border-radius: 30px;
            outline: none;
            transition: all 0.3s;
        }

        .search-bar input:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(58, 134, 255, 0.2);
        }

        .search-bar i {
            position: absolute;
            left: 15px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--gray-color);
        }

        .user-actions {
            display: flex;
            align-items: center;
        }

        .notification-icon, .message-icon {
            position: relative;
            margin-right: 20px;
            cursor: pointer;
        }

        .notification-icon i, .message-icon i {
            font-size: 20px;
            color: var(--gray-color);
        }

        .notification-count, .message-count {
            position: absolute;
            top: -5px;
            right: -5px;
            background-color: var(--danger-color);
            color: white;
            border-radius: 50%;
            width: 18px;
            height: 18px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 10px;
            font-weight: bold;
        }

        .user-profile {
            display: flex;
            align-items: center;
            cursor: pointer;
        }

        .user-profile img {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            object-fit: cover;
            margin-right: 10px;
        }

        .user-profile span {
            font-weight: 600;
        }

        /* Content Area */
        .content-area {
            display: flex;
            gap: 20px;
        }

        .feed {
            flex: 2;
        }

        .sidebar-right {
            flex: 1;
        }

        /* Empty State */
        .empty-state {
            background-color: white;
            border-radius: 10px;
            padding: 40px 20px;
            text-align: center;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
        }

        .empty-state i {
            font-size: 50px;
            color: var(--gray-color);
            margin-bottom: 20px;
        }

        .empty-state h3 {
            margin-bottom: 10px;
            color: var(--dark-color);
        }

        .empty-state p {
            color: var(--gray-color);
            margin-bottom: 20px;
        }

        .empty-state-btn {
            background-color: var(--primary-color);
            color: white;
            border: none;
            border-radius: 5px;
            padding: 10px 20px;
            font-weight: 600;
            cursor: pointer;
        }

        /* Bottom Navigation - Mobile */
        .bottom-nav {
            position: fixed;
            bottom: 0;
            left: 0;
            width: 100%;
            background-color: white;
            display: flex;
            justify-content: space-around;
            align-items: center;
            padding: 10px 0;
            box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
            z-index: 1000;
        }

        .nav-icon {
            display: flex;
            flex-direction: column;
            align-items: center;
            color: var(--gray-color);
            text-decoration: none;
            font-size: 12px;
        }

        .nav-icon i {
            font-size: 20px;
            margin-bottom: 5px;
        }

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

        .plus-button {
            background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
            color: white;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 24px;
            margin-top: -25px;
            box-shadow: 0 5px 15px rgba(58, 134, 255, 0.3);
        }

        /* Create Post Modal */
        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.5);
            z-index: 1000;
            justify-content: center;
            align-items: center;
        }

        .modal-content {
            background-color: white;
            border-radius: 10px;
            width: 500px;
            max-width: 90%;
            max-height: 90vh;
            overflow-y: auto;
        }

        .modal-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px;
            border-bottom: 1px solid #eee;
        }

        .modal-title {
            font-weight: 600;
        }

        .close-modal {
            background: none;
            border: none;
            font-size: 20px;
            cursor: pointer;
            color: var(--gray-color);
        }

        .modal-body {
            padding: 15px;
        }

        .post-form textarea {
            width: 100%;
            border: none;
            outline: none;
            resize: none;
            min-height: 100px;
            font-size: 16px;
            margin-bottom: 15px;
        }

        .post-options-bar {
            display: flex;
            justify-content: space-between;
            border-top: 1px solid #eee;
            border-bottom: 1px solid #eee;
            padding: 10px 0;
            margin-bottom: 15px;
        }

        .add-to-post {
            display: flex;
            gap: 15px;
        }

        .add-option {
            display: flex;
            align-items: center;
            color: var(--gray-color);
            cursor: pointer;
        }

        .add-option i {
            margin-right: 5px;
        }

        .post-submit-btn {
            background-color: var(--primary-color);
            color: white;
            border: none;
            border-radius: 5px;
            padding: 8px 15px;
            font-weight: 600;
            cursor: pointer;
            opacity: 0.5;
            transition: all 0.3s;
        }

        .post-submit-btn.active {
            opacity: 1;
        }

        .preview-container {
            margin-bottom: 15px;
            position: relative;
        }

        .preview-image {
            width: 100%;
            border-radius: 8px;
            max-height: 300px;
            object-fit: contain;
            background-color: #f5f5f5;
        }

        .remove-preview {
            position: absolute;
            top: 10px;
            right: 10px;
            background-color: rgba(0, 0, 0, 0.5);
            color: white;
            border: none;
            border-radius: 50%;
            width: 30px;
            height: 30px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
        }

        /* Responsive */
        @media (min-width: 992px) {
            .sidebar {
                display: block;
            }
            
            .main-content {
                margin-left: 250px;
            }
            
            .bottom-nav {
                display: none;
            }
            
            body {
                padding-bottom: 0;
            }
        }

        @media (max-width: 768px) {
            .search-bar {
                display: none;
            }
            
            .content-area {
                flex-direction: column;
            }
            
            .sidebar-right {
                display: none;
            }
        }