/* 课件馆统一返回入口：静态链接不依赖课件脚本。 */
.oioi-course-return-bar {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  margin: 0;
  padding: 12px max(16px, calc((100% - 1160px) / 2));
  background: #eef5f3;
  border-bottom: 1px solid #cdded9;
  text-align: left;
  box-sizing: border-box;
}
.oioi-course-return-bar--bottom { border-top: 1px solid #cdded9; border-bottom: 0; }
a.oioi-course-return {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 7px 14px;
  border: 1px solid #9ebeb6;
  border-radius: 999px;
  background: #f6fbf9;
  color: #185d55;
  font: 600 14px/1.5 "PingFang SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
  text-decoration: none;
  white-space: nowrap;
  box-sizing: border-box;
}
a.oioi-course-return:hover { background: #e1f0e9; color: #12493f; }
a.oioi-course-return:focus-visible { outline: 3px solid #168375; outline-offset: 3px; }
a.oioi-course-return--floating {
  position: fixed;
  top: max(12px, env(safe-area-inset-top));
  left: max(14px, env(safe-area-inset-left));
  z-index: 70;
  box-shadow: 0 4px 16px #102a3820;
}
@media (max-width: 600px) {
  a.oioi-course-return { min-height: 40px; padding: 7px 12px; font-size: 12px; }
  .oioi-course-return-bar { padding: 8px 12px; }
}
@media print {
  .oioi-course-return-bar, a.oioi-course-return--floating { display: none !important; }
}