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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            color: #333;
        }

        .app-container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 20px;
            min-height: 100vh;
        }

        .header {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 20px;
            padding: 20px 30px;
            margin-bottom: 20px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .header h1 {
            font-size: 2.5rem;
            background: linear-gradient(45deg, #667eea, #764ba2);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            margin-bottom: 10px;
        }

        .header p {
            color: #666;
            font-size: 1.1rem;
        }

        .toolbar {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 15px;
            padding: 15px;
            margin-bottom: 20px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            align-items: center;
        }

        .btn {
            background: linear-gradient(45deg, #667eea, #764ba2);
            color: white;
            border: none;
            padding: 8px 16px;
            border-radius: 8px;
            cursor: pointer;
            font-size: 14px;
            transition: all 0.3s ease;
            white-space: nowrap;
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
        }

        .btn.secondary {
            background: linear-gradient(45deg, #764ba2, #667eea);
        }

        .btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none;
        }

        .editor-container {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 20px;
            height: 70vh;
        }

        .editor-panel, .preview-panel {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 15px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            overflow: hidden;
        }

        .panel-header {
            background: rgba(102, 126, 234, 0.1);
            padding: 15px 20px;
            font-weight: 600;
            color: #333;
            border-bottom: 1px solid rgba(102, 126, 234, 0.2);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .char-counter {
            font-size: 12px;
            color: #666;
        }

        .char-counter.warning {
            color: #ff6b6b;
            font-weight: bold;
        }

        .editor {
            width: 100%;
            height: calc(100% - 60px);
            border: none;
            padding: 20px;
            font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 14px;
            line-height: 1.6;
            resize: none;
            outline: none;
            background: transparent;
            color: #333;
        }

        .preview {
            height: calc(100% - 60px);
            padding: 20px;
            overflow-y: auto;
            line-height: 1.7;
        }

        .preview h1, .preview h2, .preview h3 {
            margin-top: 24px;
            margin-bottom: 16px;
            color: #333;
        }

        .preview p {
            margin-bottom: 16px;
        }

        .format-panel {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 15px;
            padding: 20px;
            margin-top: 20px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
        }

        .format-options {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 15px;
        }

        .format-btn {
            background: rgba(102, 126, 234, 0.1);
            border: 2px solid rgba(102, 126, 234, 0.3);
            padding: 15px;
            border-radius: 10px;
            cursor: pointer;
            transition: all 0.3s ease;
            text-align: center;
        }

        .format-btn:hover {
            background: rgba(102, 126, 234, 0.2);
            transform: translateY(-2px);
        }

        .format-btn.active {
            background: linear-gradient(45deg, #667eea, #764ba2);
            color: white;
            border-color: #667eea;
        }

        .format-btn.processing {
            opacity: 0.6;
            pointer-events: none;
        }

        .loading-spinner {
            display: inline-block;
            width: 20px;
            height: 20px;
            border: 3px solid #f3f3f3;
            border-top: 3px solid #667eea;
            border-radius: 50%;
            animation: spin 1s linear infinite;
            margin-right: 10px;
        }

        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }

        .stats {
            background: rgba(255, 255, 255, 0.9);
            padding: 10px 15px;
            border-radius: 8px;
            font-size: 12px;
            color: #666;
            margin-left: auto;
        }

        .error-message {
            background: #ff6b6b;
            color: white;
            padding: 10px 15px;
            border-radius: 8px;
            margin: 10px 0;
            display: none;
        }

        /* Settings Panel Styles */
        .settings-panel {
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border-radius: 15px;
            padding: 20px;
            margin-bottom: 20px;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .settings-options {
            display: flex;
            flex-direction: column;
            gap: 15px;
        }

        .setting-item {
            display: flex;
            align-items: center;
            gap: 10px;
            cursor: pointer;
            padding: 10px;
            background: rgba(255, 255, 255, 0.5);
            border-radius: 8px;
            transition: background-color 0.2s ease;
        }

        .setting-item:hover {
            background: rgba(255, 255, 255, 0.7);
        }

        .setting-item input[type="checkbox"] {
            width: 18px;
            height: 18px;
            cursor: pointer;
        }

        .setting-item span {
            font-size: 14px;
            color: #444;
        }

        @media (max-width: 768px) {
            .editor-container {
                grid-template-columns: 1fr;
                height: auto;
            }
            
            .editor-panel, .preview-panel {
                height: 400px;
            }
            
            .toolbar {
                justify-content: center;
            }
            
            .stats {
                margin: 10px 0 0 0;
            }

            .settings-options {
                gap: 10px;
            }

            .setting-item {
                padding: 8px;
                font-size: 13px;
            }
        }