/* 交互页壳：全屏工作区 */

.pt-app {
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--c-bg-page);
}
.pt-app__bar {
  height: var(--h-header);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: var(--sp-4);
  padding: 0 var(--sp-4);
  background: var(--c-bg);
  border-bottom: 1px solid var(--c-border);
  z-index: var(--z-header);
}
.pt-app__back {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--c-text-sub);
  font-size: var(--fs-sm);
  font-weight: 500;
  text-decoration: none;
  flex-shrink: 0;
}
.pt-app__back:hover { color: var(--c-primary); text-decoration: none; }
.pt-app__back-ico {
  transform: rotate(90deg);
  width: 14px;
  height: 14px;
}
.pt-app__brand { margin-right: auto; }
.pt-app__user {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  flex-shrink: 0;
}
.pt-app__nick {
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--c-text);
  max-width: 120px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.pt-app__workspace {
  flex: 1;
  min-height: 0;
  overflow: auto;
  position: relative;
}
/* 内嵌老页面时尽量铺满 */
.pt-app__workspace > .container,
.pt-app__workspace > .main-content,
.pt-app__workspace > form,
.pt-app__workspace > .pt-challenge-app,
.pt-app__workspace > .pt-exam-app,
.pt-app__workspace > .pt-learn-app {
  max-width: none;
  height: 100%;
}
.pt-app--immersive .pt-app__workspace {
  height: 100vh;
  overflow: hidden;
}
.pt-app--learn .pt-app__workspace,
.pt-app--exam .pt-app__workspace {
  overflow: auto;
}