body{display: flex;justify-content: center;align-items: center;height: 100vh;margin: 0;background-color: #f0f0f0;}.upload-btn{display: inline-block;padding: 15px 30px;font-size: 18px;font-weight: bold;color: #fff;background-color: #007bff;border: none;border-radius: 5px;cursor: pointer;transition: background-color 0.3s ease;}.upload-btn:hover{background-color: #0056b3;}.loading-overlay{position: fixed;top: 0;left: 0;width: 100%;height: 100%;background-color: rgba(0,0,0,0.5);display: none;justify-content: center;align-items: center;z-index: 9999;}.loading-window{background-color: #fff;padding: 50px;text-align: center;border-radius: 10px;box-shadow: 0 0 10px rgba(0,0,0,0.3);width: 250px;width: 250px;}.loading-spinner{border: 4px solid rgba(0,123,255,0.3);
border-radius: 50%;border-top: 4px solid #007bff;width: 50px;height: 50px;animation: spin 1s linear infinite;margin: 0 auto;}.loading-tips{padding-top: 20px;}@keyframes spin{0%{transform: rotate(0deg);}100%{transform: rotate(360deg);}}.back-link{text-decoration: none;color: #007bff;}.back-link-right{text-decoration: none;color: #007bff;padding-right:20px;}.footer{position: absolute;bottom: 20px;}