.image-nav{
  display:flex;
  align-items:center;
  gap:8px;
  flex-wrap:wrap;
}

.image-nav button{
  padding:6px 9px;
  border-radius:8px;
  font-size:12px;
}

.image-page{
  width:100%;
}

.image-page[hidden]{
  display:none;
}

.image-scroll{
  position:relative;
}

.source-text-panel{
  margin-top:14px;
}

.source-text-card{
  margin:0;
  border:1px solid #dbe4f0;
  border-radius:12px;
  background:#fff;
  overflow:hidden;
}

.source-text-scroll{
  position:relative;
  min-height:360px;
  max-height:min(72vh, 820px);
  overflow:auto;
  background:#fff;
}

.source-text-page{
  padding:28px 34px;
}

.source-text-page[hidden]{
  display:none;
}

.source-text-content{
  line-height:1.78;
  color:#111827;
}

.source-text-content .math-block{
  margin:18px 0;
}

.source-text-page pre{
  margin:0;
  white-space:pre-wrap;
  word-break:keep-all;
  overflow-wrap:anywhere;
  font:16px/1.78 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  color:#111827;
}

.source-text-card .source-text-caption{
  margin:0;
  padding:7px 10px;
  border-top:1px solid #edf2f7;
  background:#fff;
}

.source-empty{
  border:1px dashed #cbd5e1;
  border-radius:12px;
  background:#fff;
}

.problem-source-combo{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:14px;
  align-items:start;
}

.problem-source-combo.image-open{
  grid-template-columns:minmax(0,1fr) minmax(340px,.82fr);
}

.question-grid:has(.problem-source-combo.image-open){
  grid-template-columns:minmax(0,1.65fr) minmax(320px,.65fr);
}

.problem-source-main,
.problem-source-aside{
  min-width:0;
}

.source-action-row{
  display:flex;
  justify-content:flex-end;
  margin:0 0 10px;
}

.source-image-toggle{
  padding:7px 10px;
  border-radius:8px;
  font-size:12px;
}

.problem-source-aside{
  position:sticky;
  top:58px;
  max-height:calc(100vh - 82px);
  overflow:auto;
  border:1px solid #dbe4f0;
  border-radius:12px;
  background:#fff;
}

.problem-source-aside[hidden]{
  display:none;
}

.source-aside-head{
  position:sticky;
  top:0;
  z-index:3;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  padding:9px 10px;
  border-bottom:1px solid #edf2f7;
  background:#fff;
}

.source-aside-head strong{
  font-size:13px;
}

.source-aside-head button{
  padding:5px 8px;
  border-radius:8px;
  font-size:12px;
}

.problem-source-aside .image-panel{
  margin-top:0;
}

.problem-source-aside .problem-image-card{
  border:0;
  border-radius:0;
}

.image-overlay-nav{
  position:absolute;
  top:50%;
  z-index:4;
  display:flex;
  align-items:center;
  justify-content:center;
  width:42px;
  height:68px;
  padding:0;
  border:1px solid rgba(148,163,184,.38);
  border-radius:999px;
  background:rgba(15,23,42,.48);
  color:#fff;
  font-size:34px;
  line-height:1;
  opacity:0;
  transform:translateY(-50%);
  transition:opacity .16s ease, background .16s ease;
}

.image-overlay-prev{
  left:14px;
}

.image-overlay-next{
  right:14px;
}

.problem-image-card:hover .image-overlay-nav:not(:disabled),
.source-text-card:hover .image-overlay-nav:not(:disabled),
.image-overlay-nav:focus-visible{
  opacity:.8;
}

.image-overlay-nav:hover{
  background:rgba(15,23,42,.68);
}

.image-overlay-nav:disabled{
  display:none;
}

.problem-image-card .image-caption{
  margin:0;
  padding:7px 10px;
  border-top:1px solid #edf2f7;
  background:#fff;
  word-break:break-all;
}

.problem-image-card:fullscreen .image-page{
  width:100%;
}

.problem-image-card:fullscreen .image-scroll{
  display:block;
}

@media(max-width:760px){
  .image-nav{
    width:100%;
    justify-content:space-between;
  }

  .image-nav button{
    flex:1;
  }

  .image-counter{
    min-width:52px;
    text-align:center;
  }

  .source-text-page{
    padding:20px 18px;
  }

  .source-text-page pre,
  .source-text-content{
    font-size:15px;
  }

  .problem-source-combo.image-open{
    grid-template-columns:1fr;
  }

  .problem-source-aside{
    position:relative;
    top:auto;
    max-height:none;
  }
}