/* CSS styles remain unchanged... */
        :root {
            --primary-color: #4A69E2;
            --primary-gradient: linear-gradient(135deg, #4A69E2 0%, #3A55B6 100%);
            --success-color: #28a745;
            --success-alt-color: #20c997;
            --secondary-color: #f5a623;
            --danger-color: #d9534f;
            --light-bg: #f4f6f9;
            --dark-text: #212529;
            --light-text: #ffffff;
            --border-color: #dee2e6;
            --radius-md: 8px;
            --radius-lg: 12px;
            --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
            --shadow-md: 0 5px 15px rgba(0,0,0,0.08);
            --shadow-lg: 0 10px 30px rgba(0,0,0,0.1);
            --transition-speed: 0.3s;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            background-color: var(--light-bg);
            color: var(--dark-text);
            margin: 0;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        /* 헤더 스타일 */
        .app-header {
            background-color: var(--light-text);
            padding: 16px 32px;
            border-bottom: 1px solid var(--border-color);
            display: flex;
            align-items: center;
            gap: 24px;
            box-shadow: var(--shadow-sm);
        }

        .app-header .logo img {
            height: 32px;
            display: block;
            transition: transform var(--transition-speed) ease;
        }

        .app-header .logo:hover img {
            transform: scale(1.05);
        }

        .app-header .intro-text {
            font-size: 14px;
            color: #495057;
            line-height: 1.6;
        }

        .sns-growth-button {
            display: inline-block;
            padding: 12px 20px;
            background-image: var(--primary-gradient);
            color: white;
            text-align: center;
            text-decoration: none;
            border-radius: var(--radius-md);
            font-weight: bold;
            margin-left: auto;
            box-shadow: var(--shadow-sm);
            transition: all 0.2s ease-in-out;
            white-space: nowrap;
        }

        .sns-growth-button:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }

        /* 메인 컨테이너 */
        .app-container {
            display: flex;
            padding: 32px;
            gap: 32px;
            max-width: 1400px;
            margin: 0 auto;
        }

        /* 메인 작업 영역 */
        .workspace {
            flex: 1;
            background-color: var(--light-text);
            border-radius: var(--radius-lg);
            box-shadow: var(--shadow-md);
            padding: 32px;
        }

        /* 사이드바 */
        .sidebar {
            width: 350px;
            position: sticky;
            top: 32px;
            height: fit-content;
        }

        .sidebar-section {
            background-color: var(--light-text);
            border-radius: var(--radius-lg);
            box-shadow: var(--shadow-md);
            padding: 24px;
            margin-bottom: 24px;
        }

        /* 제목 스타일 */
        h1 {
            margin-top: 0;
            margin-bottom: 12px;
            font-size: 28px;
            font-weight: 600;
            color: var(--primary-color);
        }

        h2 {
            margin-top: 0;
            border-bottom: 1px solid #e9ecef;
            padding-bottom: 16px;
            font-size: 22px;
            font-weight: 600;
            color: var(--dark-text);
        }

        /* 단계별 안내 */
        .steps {
            display: flex;
            gap: 16px;
            margin-bottom: 32px;
            flex-wrap: wrap;
        }

        .step {
            flex: 1;
            min-width: 200px;
            background: var(--light-bg);
            padding: 16px;
            border-radius: var(--radius-md);
            text-align: center;
            border: 2px solid transparent;
            transition: all var(--transition-speed) ease;
        }

        .step.active {
            border-color: var(--primary-color);
            background: linear-gradient(135deg, rgba(74, 105, 226, 0.1) 0%, rgba(58, 85, 182, 0.1) 100%);
        }

        .step-number {
            display: inline-block;
            width: 32px;
            height: 32px;
            line-height: 32px;
            background: var(--primary-gradient);
            color: var(--light-text);
            border-radius: 50%;
            font-weight: bold;
            margin-bottom: 8px;
        }

        .step-title {
            font-weight: 500;
            color: var(--dark-text);
        }

        /* 입력 영역 */
        .input-section {
            margin-bottom: 24px;
        }

        .input-methods {
            display: flex;
            gap: 16px;
            margin-bottom: 16px;
        }

        .method-tab {
            padding: 10px 20px;
            background: var(--light-bg);
            border: 2px solid var(--border-color);
            border-radius: var(--radius-md);
            cursor: pointer;
            transition: all var(--transition-speed) ease;
        }

        .method-tab.active {
            background: var(--primary-gradient);
            color: var(--light-text);
            border-color: var(--primary-color);
        }

        /* 파일 업로드 영역 */
        .file-upload-area {
            border: 2px dashed var(--primary-color);
            border-radius: var(--radius-lg);
            padding: 40px;
            text-align: center;
            background: var(--light-bg);
            transition: all var(--transition-speed) ease;
            cursor: pointer;
        }

        .file-upload-area:hover {
            background: rgba(74, 105, 226, 0.05);
            border-color: #3A55B6;
        }

        .file-upload-area.drag-over {
            background: rgba(74, 105, 226, 0.1);
            border-color: #3A55B6;
        }

        #file-input {
            display: none;
        }

        .upload-icon {
            font-size: 48px;
            color: var(--primary-color);
            margin-bottom: 16px;
        }

        /* 텍스트 입력 영역 */
        .text-input-area {
            display: none;
        }

        .text-input-area.active {
            display: block;
        }

        textarea {
            width: 100%;
            box-sizing: border-box;
            height: 300px;
            padding: 16px;
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, Courier, monospace;
            font-size: 14px;
            resize: vertical;
            background-color: #f8f9fa;
            transition: all var(--transition-speed) ease;
        }

        textarea:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 4px rgba(74, 105, 226, 0.2);
        }

        /* 버튼 스타일 */
        .button {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 12px 24px;
            color: var(--light-text);
            border: none;
            border-radius: var(--radius-md);
            cursor: pointer;
            font-weight: 500;
            font-size: 16px;
            transition: all 0.2s ease-in-out;
            background: var(--primary-gradient);
            box-shadow: var(--shadow-sm);
        }

        .button:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }

        .button:active {
            transform: translateY(0);
            box-shadow: var(--shadow-sm);
        }

        .button.success {
            background: var(--success-color);
        }

        .button:disabled {
            opacity: 0.6;
            cursor: not-allowed;
        }

        .button-group {
            display: flex;
            gap: 12px;
            margin-top: 16px;
        }

        /* 결과 영역 */
        .result-section {
            margin-top: 32px;
            padding-top: 32px;
            border-top: 2px solid var(--light-bg);
        }

        #result-area {
            background-color: #2d3748;
            color: #e2e8f0;
            border: 1px solid #4a5568;
        }

        /* 에러 메시지 */
        .error-message {
            display: none;
            background-color: #fee;
            color: var(--danger-color);
            padding: 12px;
            border-radius: var(--radius-md);
            border: 1px solid #fcc;
            margin-top: 16px;
        }

        /* 성공 메시지 */
        .success-message {
            display: none;
            background-color: #d4edda;
            color: #155724;
            padding: 12px;
            border-radius: var(--radius-md);
            border: 1px solid #c3e6cb;
            margin-top: 16px;
        }

        /* 광고 영역 */
        .ad-container {
            background: #e9ecef;
            height: 250px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #868e96;
            border-radius: var(--radius-md);
            margin-bottom: 24px;
        }

        /* 푸터 */
        footer {
            background-color: var(--light-text);
            border-top: 1px solid var(--border-color);
            padding: 24px 32px;
            text-align: center;
            margin-top: 64px;
            color: #6c757d;
        }

        footer a {
            color: #6c757d;
            text-decoration: none;
            margin: 0 12px;
        }

        footer a:hover {
            color: var(--primary-color);
        }

        /* 반응형 디자인 */
        @media (max-width: 1024px) {
            .app-container {
                flex-direction: column;
            }

            .sidebar {
                width: 100%;
                position: static;
            }

            .steps {
                flex-direction: column;
            }

            .step {
                min-width: auto;
            }
        }

        @media (max-width: 768px) {
            .app-header {
                flex-direction: column;
                text-align: center;
                gap: 16px;
            }

            .sns-growth-button {
                margin-left: 0;
            }

            .input-methods {
                flex-direction: column;
            }

            .method-tab {
                text-align: center;
            }

            .button-group {
                flex-direction: column;
            }
        }