/* 打开课次后的页面样式；目录卡片样式由 exercise-shell.css 保持不变。 */
.exercise-open .hero{padding:28px 0 20px;border-bottom:1px solid #dce4dd}
.exercise-open #teacherManagePanel{display:none}
.exercise-open .hero h1{font-size:clamp(34px,4.8vw,56px);letter-spacing:.04em}
.exercise-open .hero .stats{gap:20px}
.exercise-open .controls{position:relative;top:auto;backdrop-filter:none;background:#fff;padding:13px 0;border-bottom:1px solid #dce4dd}
.exercise-open .exercise-view-nav{display:flex!important}
.exercise-open .bank{padding:30px 0}
.exercise-open .unit-heading{margin:0 0 5px;padding:0 0 13px;border-bottom:2px solid #315e4b}
.exercise-open .unit-heading h2{font-size:clamp(25px,3vw,34px);letter-spacing:.04em}
.exercise-open .q{padding:25px 0 28px;border-bottom:1px solid #dce4dd;scroll-margin-top:18px}
.exercise-open .q-head{gap:12px;margin-bottom:10px}
.exercise-open .q-no{font-size:15px;color:#8b6840}
.exercise-open .q-stem{max-width:1060px;font-size:clamp(17px,1.7vw,20px);line-height:1.9;font-weight:400}
.exercise-open .options{gap:7px 20px}
.exercise-open .option{border-color:transparent;border-bottom-color:#dce4dd;border-radius:2px;background:#fff;padding:11px 13px;line-height:1.9}
.exercise-open .option:hover{border-color:#dce4dd;background:#fafbf7}
.exercise-open .feedback,.exercise-open .feedback.ok,.exercise-open .feedback.bad{background:transparent;padding:11px 0 11px 16px;line-height:1.9}
.exercise-open footer{padding-bottom:30px}
@media(max-width:760px){
  .exercise-open .hero{padding:22px 0 16px}
  .exercise-open .bank{padding-top:22px;padding-bottom:24px}
  .exercise-open .q{padding:21px 0 23px}
  .exercise-open .q-stem{font-size:17px}
  .exercise-open footer{padding-bottom:24px}
}