/* Vector structure layout for examination chemical formula questions. */
.chemical-svg{display:block;width:100%;height:auto;overflow:visible;color:#172d37}
.chemical-bond{stroke:currentColor;stroke-width:2.25;stroke-linecap:round;fill:none;vector-effect:non-scaling-stroke}
.chemical-atom{fill:currentColor;font-family:Georgia,"Times New Roman",serif;font-weight:500;user-select:none}
.chemical-figure{border:1px solid #dce5e2;background:#fff;border-radius:14px;padding:12px 14px;margin:16px 0 18px;min-width:0}
.chemical-scroll{overflow-x:auto;overflow-y:hidden;overscroll-behavior-x:contain;touch-action:pan-x pan-y;scrollbar-width:thin}
.chemical-scroll .polymer-svg{width:100%;min-width:780px;max-width:1100px;margin-inline:auto}
.chemical-scroll-hint{display:none;font-size:11px;color:#708b86;margin-top:6px}
.chemical-option-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.chemical-option{display:grid;grid-template-columns:30px minmax(0,1fr);align-items:center;gap:8px;width:100%;min-width:0;min-height:176px;padding:15px 12px;background:#fff;color:#172d37;border:1.5px solid #dce8e2;border-radius:14px;text-align:left;cursor:pointer;transition:border-color .18s,background .18s,transform .18s}
.chemical-option .alkene-svg{max-width:320px;margin:0 auto}
.chemical-letter{align-self:start;display:grid;place-items:center;width:30px;height:30px;border-radius:9px;background:#edf4f1;color:#416c66;font-size:14px;font-weight:800}
.chemical-option:hover:not(:disabled){border-color:#68ac97;transform:translateY(-1px)}
.chemical-option:focus-visible{outline:3px solid #5ac4ac;outline-offset:2px}
.chemical-option.correct{border-color:#098766;background:#effbf4}
.chemical-option.wrong{border-color:#d27767;background:#fff3f1}
.chemical-option.dimmed{color:#879c94}
.chemical-option:disabled{opacity:1;cursor:default}
.chemical-option.correct .chemical-letter{background:#098766;color:white}
.chemical-option.wrong .chemical-letter{background:#d27767;color:white}
@media(max-width:620px){
  .chemical-option-grid{grid-template-columns:1fr;gap:10px}
  .chemical-option{min-height:145px;padding:10px 12px}
  .chemical-option .alkene-svg{max-width:260px}
  .chemical-figure{padding:12px 10px}
  .chemical-scroll-hint{display:block}
}
@media(prefers-reduced-motion:reduce){.chemical-option{transition:none}}

/* 2024 Q33: solid and hashed stereochemical bonds, retained at any zoom. */
.chemical-scroll .stereo-pair-svg{width:100%;min-width:760px;max-width:920px;margin-inline:auto}
.chemical-stereo-wedge{fill:currentColor;stroke:none}
.chemical-terminal{font-weight:500}
.chemical-statements{list-style:none;display:grid;gap:6px;padding:0;margin:15px 0 22px;color:var(--ink);font-size:clamp(14px,1.6vw,16px);line-height:1.6}
.chemical-statements li{display:grid;grid-template-columns:42px minmax(0,1fr);gap:4px;align-items:start}
.statement-index{font-variant-numeric:tabular-nums;white-space:nowrap}
@media(max-width:620px){
 .chemical-scroll .stereo-pair-svg{min-width:730px}
 .chemical-statements li{grid-template-columns:34px minmax(0,1fr)}
}