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

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
            overflow-x: hidden;
        }

        .container {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(20px);
            border-radius: 24px;
            box-shadow: 0 25px 50px rgba(0, 0, 0, 0.15);
            padding: 40px;
            width: 100%;
            max-width: 480px;
            position: relative;
            border: 1px solid rgba(255, 255, 255, 0.3);
        }

        .container::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 4px;
            background: linear-gradient(90deg, #ff6b6b, #4ecdc4, #45b7d1, #96ceb4, #feca57);
            border-radius: 24px 24px 0 0;
            animation: rainbow 3s ease-in-out infinite;
        }

        @keyframes rainbow {
            0%, 100% { transform: translateX(0); }
            50% { transform: translateX(10px); }
        }

        .header {
            text-align: center;
            margin-bottom: 40px;
        }

        .title {
            font-size: 2.5rem;
            font-weight: 700;
            background: linear-gradient(135deg, #667eea, #764ba2);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            margin-bottom: 10px;
            animation: titlePulse 2s ease-in-out infinite alternate;
        }

        @keyframes titlePulse {
            0% { transform: scale(1); }
            100% { transform: scale(1.05); }
        }

        .subtitle {
            color: #666;
            font-size: 1rem;
            opacity: 0;
            animation: fadeInUp 0.8s ease-out 0.3s forwards;
        }

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

        .input-section {
            margin-bottom: 30px;
            position: relative;
        }

        .input-container {
            position: relative;
            display: flex;
            gap: 12px;
        }

        #todoInput {
            flex: 1;
            padding: 16px 20px;
            border: 2px solid #e1e8ed;
            border-radius: 16px;
            font-size: 1rem;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            outline: none;
            background: rgba(255, 255, 255, 0.8);
        }

        #todoInput:focus {
            border-color: #667eea;
            transform: translateY(-2px);
            box-shadow: 0 8px 25px rgba(102, 126, 234, 0.2);
        }

        #addBtn {
            padding: 16px 24px;
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            border: none;
            border-radius: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            position: relative;
            overflow: hidden;
        }

        #addBtn:hover {
            transform: translateY(-2px) scale(1.05);
            box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
        }

        #addBtn:active {
            transform: translateY(0) scale(0.98);
        }

        #addBtn::before {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 0;
            height: 0;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.3);
            transition: all 0.6s;
            transform: translate(-50%, -50%);
        }

        #addBtn:active::before {
            width: 300px;
            height: 300px;
        }

        .stats {
            display: flex;
            justify-content: space-around;
            margin-bottom: 30px;
            padding: 20px;
            background: linear-gradient(135deg, rgba(255, 255, 255, 0.4), rgba(255, 255, 255, 0.2));
            border-radius: 16px;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255, 255, 255, 0.3);
        }

        .stat-item {
            text-align: center;
            animation: statSlide 0.6s ease-out;
        }

        @keyframes statSlide {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .stat-number {
            font-size: 1.5rem;
            font-weight: 700;
            color: #667eea;
        }

        .stat-label {
            font-size: 0.8rem;
            color: #666;
            margin-top: 4px;
        }

        .todo-list {
            max-height: 400px;
            overflow-y: auto;
            padding-right: 8px;
        }

        .todo-list::-webkit-scrollbar {
            width: 6px;
        }

        .todo-list::-webkit-scrollbar-track {
            background: rgba(255, 255, 255, 0.2);
            border-radius: 3px;
        }

        .todo-list::-webkit-scrollbar-thumb {
            background: linear-gradient(135deg, #667eea, #764ba2);
            border-radius: 3px;
        }

        .todo-item {
            display: flex;
            align-items: center;
            padding: 20px;
            margin-bottom: 12px;
            background: rgba(255, 255, 255, 0.7);
            border-radius: 16px;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255, 255, 255, 0.3);
            transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            animation: slideIn 0.5s ease-out;
            position: relative;
            overflow: hidden;
        }

        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateX(-100px) scale(0.8);
            }
            to {
                opacity: 1;
                transform: translateX(0) scale(1);
            }
        }

        .todo-item::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
            transition: left 0.5s;
        }

        .todo-item:hover::before {
            left: 100%;
        }

        .todo-item:hover {
            transform: translateY(-4px) scale(1.02);
            box-shadow: 0 15px 40px rgba(0, 0, 0, 0.1);
        }

        .todo-item.completed {
            opacity: 0.6;
            transform: scale(0.98);
        }

        .todo-item.completed .todo-text {
            text-decoration: line-through;
            color: #888;
        }

        .todo-checkbox {
            width: 20px;
            height: 20px;
            margin-right: 16px;
            position: relative;
            cursor: pointer;
        }

        .todo-checkbox input {
            display: none;
        }

        .checkmark {
            position: absolute;
            top: 0;
            left: 0;
            height: 20px;
            width: 20px;
            background: transparent;
            border: 2px solid #667eea;
            border-radius: 50%;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .checkmark::after {
            content: '';
            position: absolute;
            display: none;
            left: 6px;
            top: 2px;
            width: 6px;
            height: 12px;
            border: solid white;
            border-width: 0 2px 2px 0;
            transform: rotate(45deg);
        }

        .todo-checkbox input:checked ~ .checkmark {
            background: linear-gradient(135deg, #667eea, #764ba2);
            transform: scale(1.1);
        }

        .todo-checkbox input:checked ~ .checkmark::after {
            display: block;
            animation: checkAnim 0.3s ease-out;
        }

        @keyframes checkAnim {
            0% {
                transform: rotate(45deg) scale(0);
            }
            50% {
                transform: rotate(45deg) scale(1.3);
            }
            100% {
                transform: rotate(45deg) scale(1);
            }
        }

        .todo-text {
            flex: 1;
            font-size: 1rem;
            color: #333;
            transition: all 0.3s ease;
        }

        .todo-time {
            font-size: 0.8rem;
            color: #888;
            margin-right: 12px;
            opacity: 0.7;
        }

        .delete-btn {
            padding: 8px 12px;
            background: linear-gradient(135deg, #ff6b6b, #ee5a52);
            color: white;
            border: none;
            border-radius: 10px;
            cursor: pointer;
            font-size: 0.8rem;
            font-weight: 600;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            opacity: 0;
            transform: translateX(20px);
        }

        .todo-item:hover .delete-btn {
            opacity: 1;
            transform: translateX(0);
        }

        .delete-btn:hover {
            transform: scale(1.1);
            box-shadow: 0 5px 15px rgba(255, 107, 107, 0.4);
        }

        .empty-state {
            text-align: center;
            padding: 60px 20px;
            color: #888;
            animation: fadeIn 0.8s ease-out;
        }

        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }

        .empty-icon {
            font-size: 4rem;
            margin-bottom: 20px;
            opacity: 0.3;
            animation: float 3s ease-in-out infinite;
        }

        @keyframes float {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-10px); }
        }

        .filter-tabs {
            display: flex;
            justify-content: center;
            margin-bottom: 20px;
            gap: 8px;
        }

        .filter-tab {
            padding: 8px 16px;
            border: none;
            background: transparent;
            color: #888;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s ease;
            font-weight: 500;
        }

        .filter-tab.active {
            background: linear-gradient(135deg, #667eea, #764ba2);
            color: white;
            transform: scale(1.05);
        }

        @media (max-width: 480px) {
            .container {
                margin: 10px;
                padding: 20px;
                max-width: none;
            }
            
            .title {
                font-size: 2rem;
            }
            
            .input-container {
                flex-direction: column;
            }
            
            #addBtn {
                width: 100%;
            }
        }