:root {
            /* Light Theme Colors */
            --bg-primary: #f5f5f7;
            --bg-secondary: rgba(255, 255, 255, 0.85);
            --bg-tertiary: rgba(255, 255, 255, 0.6);
            --text-primary: #1d1d1f;
            --text-secondary: #86868b;
            --text-tertiary: #a1a1a6;
            --accent-blue: #007aff;
            --accent-green: #34c759;
            --accent-orange: #ff9500;
            --accent-red: #ff3b30;
            --accent-purple: #af52de;
            --accent-pink: #ff2d55;
            --accent-teal: #5ac8fa;
            --accent-indigo: #5856d6;
            --shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
            --border: rgba(0, 0, 0, 0.08);
            --glow: 0 0 20px rgba(0, 122, 255, 0.3);
            --glass-blur: 20px;
            --glass-saturation: 180%;
            --transition-fast: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-medium: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .dark-theme {
            /* Dark Theme Colors */
            --bg-primary: #000000;
            --bg-secondary: rgba(28, 28, 30, 0.85);
            --bg-tertiary: rgba(44, 44, 46, 0.6);
            --text-primary: #f5f5f7;
            --text-secondary: #98989d;
            --text-tertiary: #6e6e73;
            --accent-blue: #0a84ff;
            --accent-green: #30d158;
            --accent-orange: #ff9f0a;
            --accent-red: #ff453a;
            --accent-purple: #bf5af2;
            --accent-pink: #ff375f;
            --accent-teal: #64d2ff;
            --accent-indigo: #5e5ce6;
            --shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
            --border: rgba(255, 255, 255, 0.08);
            --glow: 0 0 20px rgba(10, 132, 255, 0.4);
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Poppins', 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
        }

        body {
            background: var(--bg-primary);
            color: var(--text-primary);
            min-height: 100vh;
            transition: background-color 0.5s ease, color 0.5s ease;
            overflow-x: hidden;
            font-weight: 400;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 1.5rem;
        }

        /* Enhanced Animated Background */
        .rgb-background {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: -1;
            overflow: hidden;
        }

        .rgb-light {
            position: absolute;
            border-radius: 50%;
            filter: blur(80px);
            opacity: 0.6;
            animation: float 20s infinite ease-in-out;
            mix-blend-mode: overlay;
        }

        .light-1 {
            width: 400px;
            height: 400px;
            background: linear-gradient(45deg, #ff0080, #ff8a00);
            top: 10%;
            left: 10%;
            animation-delay: 0s;
        }

        .light-2 {
            width: 500px;
            height: 500px;
            background: linear-gradient(45deg, #0080ff, #00ffaa);
            top: 60%;
            left: 70%;
            animation-delay: -5s;
        }

        .light-3 {
            width: 450px;
            height: 450px;
            background: linear-gradient(45deg, #80ff00, #ff0080);
            top: 30%;
            left: 80%;
            animation-delay: -10s;
        }

        .light-4 {
            width: 350px;
            height: 350px;
            background: linear-gradient(45deg, #ff8000, #8000ff);
            top: 70%;
            left: 20%;
            animation-delay: -7s;
        }

        .light-5 {
            width: 300px;
            height: 300px;
            background: linear-gradient(45deg, #ff0080, #0080ff);
            top: 20%;
            left: 50%;
            animation-delay: -12s;
        }

        .light-6 {
            width: 320px;
            height: 320px;
            background: linear-gradient(45deg, #00ff80, #ff0080);
            top: 80%;
            left: 40%;
            animation-delay: -15s;
        }

        @keyframes float {
            0%, 100% {
                transform: translate(0, 0) rotate(0deg) scale(1);
            }
            20% {
                transform: translate(100px, 50px) rotate(72deg) scale(1.1);
            }
            40% {
                transform: translate(50px, 100px) rotate(144deg) scale(1.2);
            }
            60% {
                transform: translate(-50px, 75px) rotate(216deg) scale(1.1);
            }
            80% {
                transform: translate(-100px, -50px) rotate(288deg) scale(0.9);
            }
        }

        /* Particle Background */
        .particles {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: -1;
            pointer-events: none;
        }

        .particle {
            position: absolute;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.1);
            animation: particle-float 15s infinite linear;
        }

        @keyframes particle-float {
            0% {
                transform: translateY(100vh) rotate(0deg);
                opacity: 0;
            }
            10% {
                opacity: 1;
            }
            90% {
                opacity: 1;
            }
            100% {
                transform: translateY(-100px) rotate(360deg);
                opacity: 0;
            }
        }

        /* Enhanced Glass Morphism Effect */
        .glass-card {
            background: var(--bg-secondary);
            backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturation));
            -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturation));
            border: 1px solid var(--border);
            border-radius: 24px;
            box-shadow: var(--shadow);
            position: relative;
            overflow: hidden;
            transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
        }

        .glass-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: linear-gradient(135deg, 
                rgba(255, 0, 128, 0.1) 0%, 
                rgba(0, 128, 255, 0.1) 50%, 
                rgba(128, 255, 0, 0.1) 100%);
            z-index: -1;
            opacity: 0;
            transition: opacity 0.5s ease;
        }

        .glass-card:hover {
            transform: translateY(-8px);
            box-shadow: var(--shadow), var(--glow);
        }

        .glass-card:hover::before {
            opacity: 1;
        }

        /* App Container */
        .app-container {
            width: 95%;
            max-width: 850px;
            height: 90vh;
            max-height: 900px;
            border-radius: 24px;
            overflow: hidden;
            display: flex;
            flex-direction: column;
            position: relative;
            opacity: 0;
            transform: translateY(20px);
            transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .app-container.loaded {
            opacity: 1;
            transform: translateY(0);
        }

        /* Header */
        .app-header {
            padding: 1.5rem 2.5rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            border-bottom: 1px solid rgba(255, 255, 255, 0.18);
            transition: all var(--transition-medium);
            position: relative;
            overflow: hidden;
        }

        .app-header::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 100%;
            background: linear-gradient(90deg, 
                rgba(10, 132, 255, 0.15) 0%, 
                rgba(191, 90, 242, 0.15) 50%, 
                rgba(10, 132, 255, 0.15) 100%);
            background-size: 200% 100%;
            animation: shimmer 4s infinite linear;
            z-index: -1;
        }

        @keyframes shimmer {
            0% {
                background-position: -200% 0;
            }
            100% {
                background-position: 200% 0;
            }
        }

        .app-title {
            font-size: 2.2rem;
            font-weight: 800;
            display: flex;
            align-items: center;
            gap: 0.75rem;
            letter-spacing: -0.5px;
        }

        .app-icon {
            width: 52px;
            height: 52px;
            border-radius: 16px;
            background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-weight: bold;
            font-size: 24px;
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
            animation: gentlePulse 3s infinite;
        }

        @keyframes gentlePulse {
            0%, 100% {
                transform: scale(1);
            }
            50% {
                transform: scale(1.03);
            }
        }

        .header-actions {
            display: flex;
            gap: 0.75rem;
        }

        .icon-button {
            width: 44px;
            height: 44px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            background: var(--bg-tertiary);
            border: none;
            color: var(--text-primary);
            cursor: pointer;
            transition: all var(--transition-fast);
            position: relative;
            overflow: hidden;
        }

        .icon-button::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 0;
            height: 0;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.4);
            transform: translate(-50%, -50%);
            transition: width 0.3s, height 0.3s;
        }

        .icon-button:hover::after {
            width: 100%;
            height: 100%;
        }

        .icon-button:hover {
            transform: scale(1.08);
        }

        /* Main Content */
        .app-main {
            flex: 1;
            padding: 1.5rem 2.5rem;
            overflow-y: auto;
            display: flex;
            flex-direction: column;
        }

        /* Task Input Section */
        .task-input-section {
            margin-bottom: 2rem;
        }

        .task-form {
            display: flex;
            gap: 1rem;
            margin-bottom: 1.5rem;
        }

        .task-input {
            flex: 1;
            padding: 1.2rem 1.5rem;
            border-radius: 18px;
            background: var(--bg-tertiary);
            border: none;
            color: var(--text-primary);
            font-size: 1.1rem;
            transition: all var(--transition-fast);
            font-weight: 500;
        }

        .task-input:focus {
            outline: none;
            background: var(--bg-secondary);
            box-shadow: 0 0 0 3px rgba(10, 132, 255, 0.3);
        }

        .task-input::placeholder {
            color: var(--text-tertiary);
            font-weight: 400;
        }

        .add-task-btn {
            padding: 1.2rem 2rem;
            border-radius: 18px;
            background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
            color: white;
            border: none;
            font-weight: 600;
            font-size: 1rem;
            cursor: pointer;
            transition: all var(--transition-fast);
            position: relative;
            overflow: hidden;
        }

        .add-task-btn::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
            transition: left 0.6s;
        }

        .add-task-btn:hover::before {
            left: 100%;
        }

        .add-task-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 25px rgba(10, 132, 255, 0.4);
        }

        .task-options {
            display: flex;
            gap: 1.5rem;
            align-items: center;
        }

        .priority-selector {
            display: flex;
            gap: 0.5rem;
            background: var(--bg-tertiary);
            border-radius: 14px;
            padding: 0.5rem;
        }

        .priority-option {
            padding: 0.5rem 1rem;
            border-radius: 10px;
            font-size: 0.9rem;
            font-weight: 600;
            cursor: pointer;
            transition: all var(--transition-fast);
            opacity: 0.7;
        }

        .priority-option.active {
            opacity: 1;
            background: var(--bg-secondary);
        }

        .priority-low.active {
            color: var(--accent-green);
        }

        .priority-medium.active {
            color: var(--accent-orange);
        }

        .priority-high.active {
            color: var(--accent-red);
        }

        .category-selector {
            flex: 1;
            padding: 0.75rem 1rem;
            border-radius: 14px;
            background: var(--bg-tertiary);
            border: none;
            color: var(--text-primary);
            font-size: 0.9rem;
            font-weight: 500;
        }

        /* Filter Section */
        .filter-section {
            display: flex;
            gap: 0.75rem;
            margin-bottom: 2rem;
            overflow-x: auto;
            padding-bottom: 0.5rem;
        }

        .filter-option {
            padding: 0.75rem 1.5rem;
            border-radius: 14px;
            background: var(--bg-tertiary);
            border: none;
            color: var(--text-secondary);
            font-size: 0.9rem;
            font-weight: 600;
            cursor: pointer;
            white-space: nowrap;
            transition: all var(--transition-fast);
            position: relative;
        }

        .filter-option.active {
            background: var(--accent-blue);
            color: white;
        }

        .filter-option.active::after {
            content: '';
            position: absolute;
            bottom: -6px;
            left: 50%;
            transform: translateX(-50%);
            width: 6px;
            height: 6px;
            border-radius: 50%;
            background: white;
            animation: bounce 0.5s ease;
        }

        @keyframes bounce {
            0%, 100% {
                transform: translateX(-50%) scale(1);
            }
            50% {
                transform: translateX(-50%) scale(1.3);
            }
        }

        /* Task List */
        .task-list {
            display: flex;
            flex-direction: column;
            gap: 0.75rem;
            flex: 1;
            overflow-y: auto;
            padding-right: 0.5rem;
        }

        /* Custom Scrollbar */
        .task-list::-webkit-scrollbar {
            width: 8px;
        }

        .task-list::-webkit-scrollbar-track {
            background: transparent;
        }

        .task-list::-webkit-scrollbar-thumb {
            background: var(--bg-tertiary);
            border-radius: 10px;
        }

        .task-list::-webkit-scrollbar-thumb:hover {
            background: var(--text-tertiary);
        }

        /* Task Item */
        .task-item {
            padding: 1.5rem;
            border-radius: 18px;
            background: var(--bg-secondary);
            display: flex;
            align-items: flex-start;
            gap: 1.5rem;
            transition: all var(--transition-medium);
            animation: slideIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            position: relative;
            overflow: hidden;
        }

        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(15px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .task-item.completed {
            opacity: 0.7;
        }

        .task-item.priority-high {
            border-left: 5px solid var(--accent-red);
        }

        .task-item.priority-medium {
            border-left: 5px solid var(--accent-orange);
        }

        .task-item.priority-low {
            border-left: 5px solid var(--accent-green);
        }

        .task-checkbox {
            width: 24px;
            height: 24px;
            border-radius: 50%;
            border: 2px solid var(--text-tertiary);
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all var(--transition-fast);
            flex-shrink: 0;
            margin-top: 2px;
        }

        .task-checkbox.checked {
            background: var(--accent-blue);
            border-color: var(--accent-blue);
        }

        .task-checkbox.checked::after {
            content: '✓';
            color: white;
            font-size: 14px;
            font-weight: bold;
        }

        .task-content {
            flex: 1;
            display: flex;
            flex-direction: column;
            gap: 0.5rem;
        }

        .task-title {
            font-size: 1.1rem;
            font-weight: 600;
            transition: all var(--transition-fast);
            line-height: 1.4;
        }

        .task-item.completed .task-title {
            text-decoration: line-through;
            color: var(--text-tertiary);
        }

        .task-meta {
            display: flex;
            gap: 1.5rem;
            font-size: 0.9rem;
            color: var(--text-secondary);
        }

        .task-category {
            background: var(--bg-tertiary);
            padding: 4px 0.75rem;
            border-radius: 10px;
            font-weight: 500;
        }

        .task-actions {
            display: flex;
            gap: 0.5rem;
            opacity: 0;
            transition: all var(--transition-fast);
        }

        .task-item:hover .task-actions {
            opacity: 1;
        }

        .task-action-btn {
            width: 32px;
            height: 32px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            background: var(--bg-tertiary);
            border: none;
            color: var(--text-primary);
            cursor: pointer;
            transition: all var(--transition-fast);
        }

        .task-action-btn:hover {
            background: var(--bg-secondary);
            transform: scale(1.1);
        }

        .delete-btn:hover {
            background: var(--accent-red);
            color: white;
        }

        /* Empty State */
        .empty-state {
            text-align: center;
            padding: 3rem;
            color: var(--text-secondary);
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            flex: 1;
        }

        .empty-icon {
            font-size: 4rem;
            margin-bottom: 1.5rem;
            opacity: 0.5;
            animation: bounce 2s infinite;
        }

        /* Enhanced Footer */
        .app-footer {
            padding: 1.5rem 2.5rem;
            border-top: 1px solid rgba(255, 255, 255, 0.18);
            display: flex;
            justify-content: space-between;
            align-items: center;
            background: var(--bg-primary);
            transition: all var(--transition-medium);
        }

        .stats {
            display: flex;
            gap: 1.5rem;
            font-size: 0.9rem;
            color: var(--text-secondary);
        }

        .stat-item {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            font-weight: 500;
        }

        .footer-actions {
            display: flex;
            gap: 0.75rem;
        }

        .footer-btn {
            padding: 0.75rem 1.5rem;
            border-radius: 14px;
            background: linear-gradient(135deg, var(--accent-teal), var(--accent-indigo));
            color: white;
            border: none;
            font-weight: 600;
            font-size: 0.9rem;
            cursor: pointer;
            transition: all var(--transition-fast);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .footer-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(90, 200, 250, 0.4);
        }

        /* Toast Notification */
        .toast {
            position: fixed;
            bottom: 20px;
            right: 20px;
            padding: 1rem 1.5rem;
            background: var(--bg-secondary);
            border-radius: 12px;
            box-shadow: var(--shadow);
            display: flex;
            align-items: center;
            gap: 0.75rem;
            transform: translateY(100px);
            opacity: 0;
            transition: all 0.3s ease;
            z-index: 1000;
            backdrop-filter: blur(var(--glass-blur));
            -webkit-backdrop-filter: blur(var(--glass-blur));
        }

        .toast.show {
            transform: translateY(0);
            opacity: 1;
        }

        .toast-icon {
            width: 24px;
            height: 24px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 0.8rem;
        }

        .toast.success .toast-icon {
            background: var(--accent-green);
        }

        .toast.error .toast-icon {
            background: var(--accent-red);
        }

        .toast.warning .toast-icon {
            background: var(--accent-orange);
        }

        /* Confetti */
        .confetti-canvas {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            z-index: 999;
        }

        /* Enhanced Loading Screen */
        .loading-screen {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: var(--bg-primary);
            display: flex;
            justify-content: center;
            align-items: center;
            z-index: 1000;
            transition: opacity 0.8s ease;
        }

        .loading-content {
            text-align: center;
            max-width: 400px;
            padding: 3rem;
        }

        .loading-icon {
            display: flex;
            justify-content: center;
            gap: 1.5rem;
            margin-bottom: 2.5rem;
        }

        .loading-icon div {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            animation: bounce 1.5s infinite;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
        }

        .loading-icon .task {
            background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
            animation-delay: 0s;
        }

        .loading-icon .list {
            background: linear-gradient(135deg, var(--accent-green), var(--accent-blue));
            animation-delay: 0.2s;
        }

        .loading-icon .done {
            background: linear-gradient(135deg, var(--accent-orange), var(--accent-red));
            animation-delay: 0.4s;
        }

        .loading-bar {
            width: 100%;
            height: 6px;
            background: var(--border);
            border-radius: 3px;
            overflow: hidden;
            margin-top: 2rem;
        }

        .loading-progress {
            height: 100%;
            background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple), var(--accent-pink));
            border-radius: 3px;
            animation: loading 2.5s ease-in-out infinite;
            width: 40%;
        }

        @keyframes loading {
            0% { transform: translateX(-100%); }
            100% { transform: translateX(250%); }
        }

        .hidden {
            display: none !important;
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            body {
                padding: 0;
            }
            
            .app-container {
                width: 100%;
                height: 100vh;
                border-radius: 0;
            }
            
            .app-header {
                padding: 1.5rem;
            }
            
            .app-main {
                padding: 1.5rem;
            }
            
            .task-form {
                flex-direction: column;
            }
            
            .add-task-btn {
                width: 100%;
            }
            
            .task-options {
                flex-direction: column;
                align-items: flex-start;
            }
            
            .category-selector {
                width: 100%;
            }
            
            .app-footer {
                flex-direction: column;
                gap: 1rem;
                padding: 1.5rem;
            }
            
            .stats {
                justify-content: center;
            }
        }

        /* Animation for task completion */
        @keyframes completeTask {
            0% {
                transform: scale(1);
            }
            50% {
                transform: scale(1.03);
            }
            100% {
                transform: scale(1);
            }
        }

        .task-item.completing {
            animation: completeTask 0.4s ease;
        }

        /* Animation for task deletion */
        @keyframes deleteTask {
            to {
                opacity: 0;
                transform: translateX(100px);
            }
        }

        .task-item.deleting {
            animation: deleteTask 0.3s ease forwards;
        }

        /* Focus mode animation */
        .focus-mode .task-item:not(.priority-high) {
            opacity: 0.3;
            filter: blur(1px);
        }

        .focus-mode .task-item.priority-high {
            transform: scale(1.02);
            box-shadow: 0 4px 16px rgba(255, 69, 58, 0.2);
        }