/* practical sums: solved examples and interactive practice */
.layout>main,.layout>.side{min-width:0}
.pr-sec{margin:22px 0 16px;padding-top:4px;border-top:1px solid var(--line)}
.pr-sec>h3:first-child{margin-top:16px}
.pr-jump{margin:-4px 0 6px}
.pr-jumpbtn{padding:6px 12px;font-size:.86rem;border-color:var(--brand);color:var(--brand);font-weight:600}
.pr-intro{color:var(--muted);margin:4px 0 12px}
.pr-ex{border:1px solid var(--line);border-radius:14px;margin:0 0 10px;background:var(--card);overflow:hidden}
.pr-ex>summary{cursor:pointer;padding:12px 14px;font-weight:600;list-style:none;display:flex;gap:10px;align-items:center}
.pr-ex>summary::-webkit-details-marker{display:none}
.pr-ex>summary::after{content:"+";margin-left:auto;font-size:1.2rem;color:var(--muted)}
.pr-ex[open]>summary::after{content:"\2013"}
.pr-ex[open]>summary{border-bottom:1px solid var(--line)}
.pr-num{font-size:.72rem;text-transform:uppercase;letter-spacing:.08em;background:var(--brand-soft);color:var(--brand);padding:2px 8px;border-radius:999px}
.pr-ex .pr-q,.pr-ex .pr-sol{padding:4px 14px 10px}
.pr-sol{border-top:1px dashed var(--line)}
.pr-sol h4{margin:10px 0 6px;font-family:"Bricolage Grotesque",Figtree,sans-serif;color:var(--brand)}
.pr-q p{margin:8px 0}
.pr-data{font-family:ui-monospace,Consolas,monospace;background:var(--bg);padding:8px 10px;border-radius:10px;word-spacing:4px}
.pr-tx{margin:6px 0 10px;padding-left:22px}.pr-tx li{margin:3px 0}
.pr-tw{overflow-x:auto;margin:6px 0 10px;border:1px solid var(--line);border-radius:10px;-webkit-overflow-scrolling:touch}
.pr-t{border-collapse:collapse;width:100%;font-size:.88rem;min-width:420px}
.pr-t th,.pr-t td{border-bottom:1px solid var(--line);padding:6px 8px;text-align:left;vertical-align:top}
.pr-t th{background:var(--bg);font-weight:600;white-space:nowrap}
.pr-t td.n,.pr-t th.n{text-align:right}
.pr-t td.n{white-space:nowrap;font-variant-numeric:tabular-nums}
.pr-t tr.pr-tot td{border-top:2px solid var(--text);border-bottom:2px solid var(--text);background:var(--bg)}
.pr-ta4 td:nth-child(2),.pr-ta4 th:nth-child(2),.pr-ta6 td:nth-child(3),.pr-ta6 th:nth-child(3){border-right:2px solid var(--line)}
.pr-jt .pr-dr{float:right;color:var(--muted);font-size:.8rem;margin-left:10px}
.pr-jt .pr-to{padding-left:22px;display:inline-block}
.pr-jt .pr-nar{color:var(--muted);font-size:.84rem}
.pr-cap{margin:12px 0 2px;display:flex;justify-content:center;gap:12px;align-items:baseline;text-align:center}
.pr-side{color:var(--muted);font-size:.8rem;font-weight:600}
.pr-steps{padding-left:22px;margin:8px 0}.pr-steps li{margin:5px 0}
.pr-list{padding-left:20px;margin:6px 0}.pr-list li{margin:4px 0}
.pr-note{background:var(--brand-soft);border-radius:10px;padding:8px 12px;font-size:.9rem;margin:8px 0}
.pr-types{display:flex;flex-wrap:wrap;gap:8px;margin:4px 0 12px}
.pr-type[aria-pressed="true"]{background:var(--brand);color:var(--on-brand);border-color:var(--brand)}
.pr-box{border:1px solid var(--line);border-radius:14px;padding:4px 14px 12px;background:var(--bg)}
.pr-form{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:10px 14px;margin-top:8px}
.pr-form .row,.pr-form .pr-fb,.pr-form .pr-jn{grid-column:1/-1}
.pr-f{display:flex;flex-direction:column;gap:4px;font-size:.88rem;font-weight:600;padding:8px;border-radius:10px;border:1px solid transparent}
.pr-f input,.pr-f select,.pr-line select,.pr-line input{font:inherit;font-weight:400;padding:8px 10px;border-radius:9px;border:1px solid var(--line);background:var(--card);color:var(--text);width:100%;min-width:0}
.pr-f.ok,.pr-je.ok{border-color:var(--ok);background:var(--ok-bg)}
.pr-f.bad,.pr-je.bad{border-color:var(--bad);background:var(--bad-bg)}
.pr-jn-h{margin:6px 0;color:var(--muted);font-size:.88rem}
.pr-je{border:1px solid var(--line);border-radius:12px;padding:8px 10px;margin:0 0 10px;background:var(--card)}
.pr-je-t{margin:2px 0 8px}
.pr-line{display:grid;grid-template-columns:70px minmax(0,1fr) 120px 38px;gap:6px;margin-bottom:6px}
.pr-line .pr-rm{padding:6px 0}
.pr-je-foot{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.pr-add{padding:5px 10px;font-size:.85rem}
.pr-je-fb{font-size:.88rem;font-weight:600}
.pr-je.ok .pr-je-fb{color:var(--ok)}.pr-je.bad .pr-je-fb{color:var(--bad)}
.pr-fb{margin:4px 0 0;min-height:1.2em}
.pr-fb.ok{color:var(--ok)}.pr-fb.bad{color:var(--bad)}
.pr-box .pr-sol{margin-top:10px;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:4px 12px 10px}
.pr-score{color:var(--muted);font-size:.88rem;margin:8px 0 0}
@media (max-width:560px){
  .pr-line{grid-template-columns:62px minmax(0,1fr) 34px;grid-template-areas:"s a r" "m m m"}
  .pr-line .pr-side-s{grid-area:s}.pr-line .pr-acc{grid-area:a}.pr-line .pr-amt{grid-area:m}.pr-line .pr-rm{grid-area:r}
  .pr-form{grid-template-columns:1fr}
}
@media print{.pr-sec,.pr-jump{display:none}}
.pr-tabs{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px;margin:0 0 12px}
.pr-tablist{display:flex;gap:4px;background:var(--bg);border:1px solid var(--line);border-radius:12px;padding:4px}
.pr-tab{border:0;background:transparent;padding:7px 14px;border-radius:9px;font-weight:600;color:var(--muted)}
.pr-tab[aria-selected="true"]{background:var(--brand);color:var(--on-brand)}
.pr-count{display:inline-block;min-width:1.5em;padding:0 6px;margin-left:4px;border-radius:999px;background:rgba(127,127,127,.18);font-size:.75rem}
.pr-allbtns{display:flex;gap:6px}
.pr-all{padding:6px 10px;font-size:.84rem}
.pr-num.cx,.pr-type.cx{border-color:var(--gold)}
.pr-num.cx{background:#fff3d6;color:#8a5a00}
.pr-exname{flex:1}
.pr-grp{margin:10px 0 4px;font-size:.72rem;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);font-weight:600}
.pr-exbody:empty::before{content:"Loading...";display:block;padding:10px 14px;color:var(--muted)}
.pr-exbody .pr-q,.pr-exbody .pr-sol{padding:4px 14px 10px}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) .pr-num.cx{background:#3a2c0c;color:#ffcf6b}}
:root[data-theme="dark"] .pr-num.cx{background:#3a2c0c;color:#ffcf6b}