.container{max-width:500px;margin:0 auto;padding:40px;background-color:#e6e9f1;border-radius:12px;box-shadow:0 4px 12px #0000001a;box-sizing:border-box;position:relative}.back-link{position:absolute;top:20px;right:20px;padding:8px 16px;font-size:14px;text-decoration:none;color:#9598e3;font-weight:500;border:2px solid #2C3096;border-radius:6px;transition:background-color .3s ease,color .3s ease}.back-link:hover{background-color:#3f34ba;color:#fff}.main-title{text-align:center;margin-bottom:32px;font-size:28px;font-weight:700;color:#264580}#datetime-picker,button[data-start]{display:block;width:100%;padding:12px;font-size:16px;font-family:inherit;border-radius:6px;border:1px solid #b0bec5;margin-bottom:24px;box-sizing:border-box}button[data-start]{background-color:#3f34ba;color:#fff;font-weight:600;border:none;cursor:pointer;transition:background-color .3s ease}button[data-start]:hover:not(:disabled){background-color:#2c2391}button[data-start]:disabled{background-color:#b0aec5;cursor:not-allowed}.timer{display:flex;justify-content:space-between;gap:12px;text-align:center;margin-top:16px}.timer .field{flex:1;background-color:#fff;border:1px solid #b0bec5;border-radius:6px;padding:12px}.timer .value{display:block;font-size:24px;font-weight:700;color:#264580}.timer .label{display:block;font-size:14px;color:#595959;margin-top:4px}button[type=submit]:hover{background-color:#242742}