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

        :root {
            --primary-color: #667eea;
            --primary-dark: #5a6fd8;
            --secondary-color: #764ba2;
            --background-light: #f8fafc;
            --background-dark: #1a202c;
            --card-light: #ffffff;
            --card-dark: #2d3748;
            --text-light: #2d3748;
            --text-dark: #f7fafc;
            --border-light: #e2e8f0;
            --border-dark: #4a5568;
            --success: #48bb78;
            --warning: #ed8936;
            --error: #f56565;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            transition: all 0.3s ease;
            min-height: 100vh;
        }

        body.light {
            background: linear-gradient(135deg, var(--background-light) 0%, #e3f2fd 100%);
            color: var(--text-light);
        }

        body.dark {
            background: linear-gradient(135deg, var(--background-dark) 0%, #1e1e2e 100%);
            color: var(--text-dark);
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
        }

        header {
            text-align: center;
            margin-bottom: 40px;
            padding: 20px 0;
        }

        h1 {
            font-size: 2.5rem;
            margin-bottom: 10px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .subtitle {
            font-size: 1.1rem;
            opacity: 0.8;
            margin-bottom: 30px;
        }

        .theme-toggle {
            position: fixed;
            top: 20px;
            right: 20px;
            background: var(--primary-color);
            border: none;
            border-radius: 50%;
            width: 50px;
            height: 50px;
            cursor: pointer;
            font-size: 1.5rem;
            color: white;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
            z-index: 1000;
        }

        .theme-toggle:hover {
            transform: scale(1.1);
            background: var(--primary-dark);
        }

        .card {
            border-radius: 15px;
            padding: 30px;
            margin-bottom: 30px;
            backdrop-filter: blur(10px);
            border: 1px solid;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            transition: all 0.3s ease;
        }

        .light .card {
            background: rgba(255, 255, 255, 0.9);
            border-color: var(--border-light);
        }

        .dark .card {
            background: rgba(45, 55, 72, 0.9);
            border-color: var(--border-dark);
        }

        .card:hover {
            transform: translateY(-5px);
            box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
        }

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

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

        input, textarea, select {
            width: 100%;
            padding: 12px 16px;
            border: 2px solid;
            border-radius: 10px;
            font-size: 1rem;
            transition: all 0.3s ease;
            outline: none;
        }

        .light input, .light textarea, .light select {
            background: white;
            border-color: var(--border-light);
            color: var(--text-light);
        }

        .dark input, .dark textarea, .dark select {
            background: var(--card-dark);
            border-color: var(--border-dark);
            color: var(--text-dark);
        }

        input:focus, textarea:focus, select:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        textarea {
            resize: vertical;
            min-height: 80px;
        }

        .btn {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            border: none;
            padding: 12px 24px;
            border-radius: 10px;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            text-decoration: none;
            display: inline-block;
            text-align: center;
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 25px rgba(102, 126, 234, 0.4);
        }

        .btn-full {
            width: 100%;
        }

        .btn-secondary {
            background: linear-gradient(135deg, #6b7280, #4b5563);
        }

        .todo-stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
        }

        .stat-card {
            text-align: center;
            padding: 20px;
            border-radius: 12px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
        }

        .stat-number {
            font-size: 2rem;
            font-weight: bold;
            display: block;
        }

        .stat-label {
            font-size: 0.9rem;
            opacity: 0.9;
        }

        .navigation {
            text-align: center;
            margin-bottom: 30px;
        }

        .nav-links {
            display: flex;
            gap: 15px;
            justify-content: center;
            flex-wrap: wrap;
        }

        .quote-section {
            text-align: center;
            padding: 30px;
            margin-bottom: 30px;
            border-radius: 15px;
            background: linear-gradient(135deg, rgba(102, 126, 234, 0.1), rgba(118, 75, 162, 0.1));
            border: 2px dashed var(--primary-color);
        }

        .quote-text {
            font-size: 1.3rem;
            font-style: italic;
            margin-bottom: 15px;
            line-height: 1.8;
        }

        .quote-author {
            font-weight: 600;
            color: var(--primary-color);
        }

        .loading {
            text-align: center;
            padding: 20px;
        }

        .spinner {
            display: inline-block;
            width: 30px;
            height: 30px;
            border: 3px solid rgba(102, 126, 234, 0.3);
            border-radius: 50%;
            border-top-color: var(--primary-color);
            animation: spin 1s ease-in-out infinite;
        }

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

        .error {
            background: rgba(245, 101, 101, 0.1);
            color: var(--error);
            border: 1px solid var(--error);
        }

        /* Responsive Design */
        @media (max-width: 768px) {
            .container {
                padding: 15px;
            }
            
            h1 {
                font-size: 2rem;
            }
            
            .card {
                padding: 20px;
            }
            
            .theme-toggle {
                top: 15px;
                right: 15px;
                width: 45px;
                height: 45px;
                font-size: 1.3rem;
            }
            
            .nav-links {
                flex-direction: column;
                align-items: center;
            }
            
            .quote-text {
                font-size: 1.1rem;
            }
        }

        @media (max-width: 480px) {
            h1 {
                font-size: 1.8rem;
            }
            
            .card {
                padding: 15px;
            }
            
            .btn {
                padding: 10px 20px;
                font-size: 0.9rem;
            }
        }

        /* Animations */
        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(20px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .fade-in {
            animation: fadeIn 0.6s ease-out;
        }

        /* Todo List Styles */
        .todo-item {
            display: flex;
            align-items: center;
            padding: 15px;
            margin-bottom: 15px;
            border-radius: 10px;
            border: 1px solid;
            transition: all 0.3s ease;
        }

        .light .todo-item {
            background: white;
            border-color: var(--border-light);
        }

        .dark .todo-item {
            background: var(--card-dark);
            border-color: var(--border-dark);
        }

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

        .todo-item.completed .todo-title {
            text-decoration: line-through;
        }

        .todo-checkbox {
            margin-right: 15px;
            width: 20px;
            height: 20px;
            cursor: pointer;
        }

        .todo-content {
            flex: 1;
        }

        .todo-title {
            font-weight: 600;
            margin-bottom: 5px;
        }

        .todo-description {
            font-size: 0.9rem;
            opacity: 0.8;
            margin-bottom: 5px;
        }

        .todo-date {
            font-size: 0.8rem;
            opacity: 0.6;
        }

        .todo-actions {
            display: flex;
            gap: 10px;
        }

        .btn-small {
            padding: 6px 12px;
            font-size: 0.8rem;
            border-radius: 6px;
        }

        .btn-danger {
            background: var(--error);
        }

        .btn-danger:hover {
            background: #e53e3e;
        }

        .empty-state {
            text-align: center;
            padding: 60px 20px;
            opacity: 0.6;
        }

        .empty-state-icon {
            font-size: 4rem;
            margin-bottom: 20px;
        }