/* question display kit (qkit.js) — used in practice, tests, homework, Daily 5, live tests and admin */
.qk-frac{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;font-size:.8em;line-height:1.1;margin:0 .15em}
.qk-frac>span:first-child{border-bottom:.08em solid currentColor;padding:0 .2em}
.qk-sqrt{border-top:.08em solid currentColor;padding:0 .1em}
.qk-blank{display:inline-block;min-width:4em;border-bottom:.12em solid currentColor;margin:0 .2em;vertical-align:baseline;opacity:.7}
sup,sub{font-size:.7em;line-height:0}
.qk-img{display:block;max-width:100%;max-height:300px;margin:0 auto;border-radius:12px;background:#fff;object-fit:contain}
.qk-emo{display:inline-block}
.qk-psg{text-align:left;font-size:.95rem;font-weight:500;line-height:1.55;padding:.7rem .85rem;border-radius:12px;background:rgba(249,115,22,.1);border-left:4px solid #f97316;margin:0 0 .8rem;white-space:normal}
.qk-psh{display:block;font-size:.78rem;font-weight:700;letter-spacing:.02em;color:#ea580c;margin-bottom:.3rem}
.qk-psg p{margin:0}.qk-psp{margin:.3rem 0 .5rem}
.qk-psp .qk-img{max-height:220px;margin:0}
.qk-ar{display:grid;gap:.5rem;text-align:left;white-space:normal}
.qk-ar>div{display:flex;gap:.6rem;align-items:flex-start;padding:.55rem .7rem;border-radius:10px;background:rgba(139,92,246,.1)}
.qk-ar b{flex:none;width:1.7rem;height:1.7rem;border-radius:.5rem;background:#8b5cf6;color:#fff;display:grid;place-items:center;font-size:.9rem}
.qk-ar small{display:block;font-size:.72rem;font-weight:700;opacity:.65;text-transform:uppercase;letter-spacing:.04em}
.qk-hint{font-size:.8rem;font-weight:600;opacity:.7;margin-top:.45rem}
.qk-in{display:grid;gap:.7rem;width:100%}
.qk-fill{font:inherit;font-size:1.25rem;font-weight:700;padding:.8rem 1rem;border-radius:12px;border:2px solid rgba(139,92,246,.45);background:rgba(255,255,255,.06);color:inherit;width:100%;min-width:0;text-align:center}
.qk-fill:focus{outline:none;border-color:#8b5cf6;box-shadow:0 0 0 3px rgba(139,92,246,.25)}
.qk-match{display:grid;gap:.5rem}
.qk-mrow{display:grid;grid-template-columns:minmax(0,1fr) 1.4rem minmax(0,1.2fr);gap:.5rem;align-items:center;padding:.45rem .6rem;border-radius:10px;background:rgba(139,92,246,.08);text-align:left;font-weight:600}
.qk-mrow i{font-style:normal;text-align:center;color:#10b981;font-weight:800}
.qk-mrow select{font:inherit;font-size:.95rem;padding:.5rem;border-radius:9px;border:1.5px solid rgba(139,92,246,.4);background:rgba(255,255,255,.06);color:inherit;min-width:0;width:100%}
.qk-mrow select option{color:#1e1145;background:#fff}
.qk-go{font:inherit;font-weight:700;font-size:1rem;padding:.75rem 1rem;border:0;border-radius:12px;background:linear-gradient(135deg,#8b5cf6,#ec4899);color:#fff;cursor:pointer}
.qk-go:disabled{opacity:.5;cursor:default}
.qk-in.ok .qk-fill,.qk-in.ok select{border-color:#10b981}
.qk-in.no .qk-fill,.qk-in.no select{border-color:#f43f5e}
@media (max-width:300px){.qk-mrow{grid-template-columns:1fr;gap:.3rem}.qk-mrow i{display:none}}
/* asked in earlier board exams */
.qk-board{display:flex;align-items:center;gap:.3em;width:fit-content;margin:0 0 .45em;padding:.2em .75em;border-radius:99px;background:linear-gradient(135deg,#fef3c7,#fde68a);border:1px solid #f59e0b;color:#92400e;font:700 .78rem/1.4 Inter,system-ui,sans-serif;letter-spacing:.01em;white-space:normal}
/* matrices [mat …] in round brackets and determinants [det …] between bars */
.qk-mat{display:inline-grid;vertical-align:middle;margin:.1em .25em;padding:.1em .45em;column-gap:.85em;row-gap:.1em;text-align:center;position:relative;line-height:1.35;white-space:nowrap}
.qk-mat.qk-br::before,.qk-mat.qk-br::after{content:"";position:absolute;top:0;bottom:0;width:.35em;border:.12em solid currentColor}
.qk-mat.qk-br::before{left:0;border-right:0;border-radius:.35em 0 0 .35em}
.qk-mat.qk-br::after{right:0;border-left:0;border-radius:0 .35em .35em 0}
.qk-mat.qk-det{border-left:.12em solid currentColor;border-right:.12em solid currentColor}
/* picture answers ("img:<file>") and pictures inside explanations ("[pic <file>]") */
.qk-oimg{display:block;width:100%;max-width:220px;max-height:150px;object-fit:contain;margin:0 auto;background:#fff;border-radius:10px;pointer-events:none}
.qk-xpic{max-height:260px;margin:.4rem auto;border:1px solid rgba(0,0,0,.08)}
.ts-opt .qk-oimg{margin:0;max-height:130px}