.stn-converter-wrapper { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; position: relative; }
                    .stn-intro { background: linear-gradient(135deg, #f5f7fa 0%, #e8eef5 100%); border-left: 4px solid #667eea; padding: 16px 20px; margin-top: 16px; border-radius: 0 8px 8px 0; color: #555; font-size: 14px; line-height: 1.8; }
                    .stn-converter-body { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 20px; }
                    .stn-textarea-container { display: flex; flex-direction: column; }
                    .stn-textarea-label { font-size: 14px; color: #555; margin-bottom: 8px; font-weight: 500; }
                    .stn-textarea { width: 100%; height: 320px; border: 1px solid #e0e0e0; border-radius: 8px; padding: 12px; font-size: 14px; line-height: 1.6; resize: vertical; outline: none; transition: border-color 0.2s, box-shadow 0.2s; box-sizing: border-box; }
                    .stn-textarea:focus { border-color: #4a90e2; box-shadow: 0 0 0 3px rgba(74,144,226,0.1); }
                    .stn-textarea::placeholder { color: #bbb; }
                    .stn-actions { display: flex; gap: 12px; justify-content: center; margin-top: 20px; flex-wrap: wrap; }
                    .stn-btn { padding: 12px 28px; border: none; border-radius: 8px; font-size: 15px; font-weight: 500; cursor: pointer; display: inline-flex; align-items: center; gap: 8px; transition: all 0.2s; }
                    .stn-btn-primary { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: #fff; }
                    .stn-btn-primary:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(102,126,234,0.4); }
                    .stn-btn-secondary { background: #f5f5f5; color: #333; }
                    .stn-btn-secondary:hover { background: #e8e8e8; }
                    .stn-btn-success { background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%); color: #fff; }
                    .stn-btn-success:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(17,153,142,0.4); }
                    .stn-toast { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); background: rgba(0,0,0,0.75); color: #fff; padding: 14px 28px; border-radius: 8px; font-size: 14px; z-index: 10000; opacity: 0; transition: opacity 0.3s; pointer-events: none; }
                    .stn-toast.show { opacity: 1; }
                    @media (max-width: 768px) {
                        .stn-converter-body { grid-template-columns: 1fr; }
                        .stn-textarea { height: 200px; }
                        .stn-btn { padding: 10px 20px; font-size: 14px; }
                    }