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

        :root {
            --primary: #3B82F6;
            --primary-dark: #2563EB;
            --gray-100: #F3F4F6;
            --gray-200: #E5E7EB;
            --gray-300: #D1D5DB;
            --gray-500: #6B7280;
            --gray-700: #374151;
            --gray-900: #111827;
            --red-100: #FEE2E2;
            --red-500: #EF4444;
            --green-100: #D1FAE5;
            --green-500: #10B981;
            --yellow-100: #FEF3C7;
            --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
            --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
            --radius: 0.75rem;
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: #F9FAFB;
            color: var(--gray-900);
            padding: 1.5rem;
            margin: 0;
        }

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

        .card {
            background: white;
            border-radius: var(--radius);
            box-shadow: var(--shadow-lg);
            overflow: hidden;
        }

        .card-header {
            background: linear-gradient(135deg, #1F2937, #111827);
            padding: 1.5rem;
            color: white;
        }

        .card-header h1 {
            font-size: 1.8rem;
            margin-bottom: 0.5rem;
        }

        .card-header p {
            opacity: 0.8;
            font-size: 0.95rem;
        }

        .textarea-container {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            padding: 1.5rem;
        }

        .textarea-box {
            flex: 1;
            min-width: 250px;
        }

        .textarea-box label {
            display: block;
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--gray-700);
        }

        textarea {
            width: 100%;
            height: 250px;
            padding: 0.75rem;
            font-family: 'Courier New', monospace;
            font-size: 0.9rem;
            border: 1px solid var(--gray-200);
            border-radius: 0.5rem;
            resize: vertical;
            transition: 0.2s;
        }

        textarea:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 2px rgba(59,130,246,0.2);
        }

        .controls {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            padding: 1rem 1.5rem;
            justify-content: space-between;
            align-items: center;
            border-top: 1px solid var(--gray-200);
            border-bottom: 1px solid var(--gray-200);
            background: var(--gray-100);
        }

        .btn-group {
            display: flex;
            flex-wrap: wrap;
            gap: 0.75rem;
        }

        .btn {
            padding: 0.5rem 1rem;
            border-radius: 2rem;
            font-weight: 500;
            border: none;
            cursor: pointer;
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            transition: all 0.2s;
            background: white;
            border: 1px solid var(--gray-200);
        }

        .btn-primary {
            background: var(--primary);
            color: white;
            border: none;
        }

        .btn-primary:hover {
            background: var(--primary-dark);
            transform: translateY(-1px);
        }

        .btn-outline {
            border: 1px solid var(--primary);
            color: var(--primary);
        }

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

        .btn-danger {
            background: var(--red-500);
            color: white;
        }

        .btn-danger:hover {
            background: #DC2626;
        }

        .options {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            align-items: center;
        }

        .option {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .diff-results {
            padding: 1.5rem;
            overflow-x: auto;
        }

        .diff-table {
            width: 100%;
            border-collapse: collapse;
            font-family: 'Courier New', monospace;
            font-size: 0.85rem;
        }

        .diff-table th {
            background: var(--gray-100);
            padding: 0.5rem;
            text-align: left;
            font-weight: 600;
            border-bottom: 2px solid var(--gray-200);
        }

        .diff-table td {
            padding: 0.5rem;
            vertical-align: top;
            border-bottom: 1px solid var(--gray-200);
        }

        .diff-line-num {
            background: var(--gray-100);
            color: var(--gray-500);
            text-align: right;
            width: 50px;
            padding-right: 1rem;
            user-select: none;
        }

        .diff-line-content {
            white-space: pre-wrap;
            word-break: break-word;
        }

        .line-removed {
            background: var(--red-100);
            text-decoration: line-through;
            color: var(--red-500);
        }

        .line-added {
            background: var(--green-100);
            color: var(--green-500);
        }

        .word-diff {
            background: var(--yellow-100);
            color: #B45309;
            font-weight: 500;
        }

        .toast {
            position: fixed;
            bottom: 1.5rem;
            right: 1.5rem;
            background: var(--gray-900);
            color: white;
            padding: 0.75rem 1.25rem;
            border-radius: 2rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            opacity: 0;
            transform: translateY(1rem);
            transition: opacity 0.3s, transform 0.3s;
            z-index: 1000;
            pointer-events: none;
        }

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

        @media (max-width: 768px) {
            body {
                padding: 1rem;
            }
            .controls {
                flex-direction: column;
                align-items: stretch;
            }
            .btn-group, .options {
                justify-content: center;
            }
            .diff-table th, .diff-table td {
                font-size: 0.75rem;
            }
        }