/* 全站统一：桌面端采用第五关的窄版阅读宽度；手机端保留各页面原有布局。 */
@media (min-width: 781px) {
  body > main,
  body > .wrap,
  body > .lc,
  body > .page,
  body > .container,
  body > .shell,
  body > #app > main,
  body > #app > .wrap,
  body > #app > .lc,
  .course-header > .header-inner,
  header.course-header > .header-inner {
    width: min(560px, calc(100% - 32px)) !important;
    max-width: 560px !important;
    margin-left: auto !important;
    margin-right: auto !important;
  }
}