/* iPad layout (touch devices >= 768px, html.pad) and the Apple Pencil drawing layer. Phone and mouse desktop are unchanged. */
.ink-wrap{position:relative}
.ink-cv{position:absolute;left:0;top:0;pointer-events:none;z-index:5;border-radius:inherit}
.ink-wrap.ink-on{outline:2px dashed color-mix(in srgb,var(--pri) 55%,transparent);outline-offset:3px;border-radius:var(--r)}
.ink-wrap.ink-on .ink-cv{cursor:crosshair}
.ink-bar{display:flex;flex-wrap:wrap;align-items:center;gap:6px 10px;margin:0 0 8px}
.ink-bar:not(.on):not(.always) .ink-tools,.ink-bar:not(.on):not(.always) .ink-hint{display:none}
.ink-bar.on:not(.always){position:sticky;top:70px;z-index:20;background:var(--s1);border:1px solid var(--bd);border-radius:14px;padding:6px 10px;box-shadow:var(--sh)}
.ink-bar.always{padding:0 0 6px}
.ink-ttl{font-weight:600;font-size:15px}
.ink-tools{display:flex;flex-wrap:wrap;align-items:center;gap:4px 12px}
.ink-g{display:inline-flex;align-items:center;gap:2px}
.ink-t{min-width:44px;min-height:44px;border-radius:12px;border:1px solid transparent;background:transparent;color:var(--tx);font:inherit;font-size:20px;display:inline-flex;flex-direction:column;align-items:center;justify-content:center;line-height:1.05;padding:2px 6px;cursor:pointer}
.ink-t .ink-l{display:none}
.ink-bar.on:not(.always) .ink-hint{display:none}
.ink-wrap.ink-on,.ink-wrap.ink-on *{-webkit-user-select:none;user-select:none;-webkit-touch-callout:none}
.ink-bar.on:not(.always){gap:2px 8px}
.ink-bar.on:not(.always) .ink-tools{gap:0 8px}
.ink-t[aria-pressed=true]{background:color-mix(in srgb,var(--pri) 16%,var(--s1));border-color:var(--pri)}
.ink-t:disabled{opacity:.35}
.ink-sw{width:44px;height:44px;border:0;background:transparent;position:relative;cursor:pointer;padding:0}
.ink-sw::after{content:"";position:absolute;inset:10px;border-radius:50%;background:var(--ic,#5b4bdb);border:2px solid var(--bd)}
.ink-sw[aria-pressed=true]::after{border-color:var(--pri);box-shadow:0 0 0 3px color-mix(in srgb,var(--pri) 35%,transparent)}
.ink-fg{display:inline-flex;align-items:center;gap:8px;font-size:13px;color:var(--mu);min-height:44px}
.ink-fg input{width:22px;height:22px;accent-color:var(--pri)}
.ink-hint{font-size:12.5px}
.ink-draw.btn{min-height:44px}
.ink-draw[aria-pressed=true]{background:var(--pri);border-color:var(--pri);color:#fff}
.ink-draw.has{border-color:var(--pri)}
.ink-padbox{margin:12px 0}
.ink-pad{height:220px;border:1px solid var(--bd);border-radius:12px;background-color:var(--s2);background-image:repeating-linear-gradient(to bottom,transparent 0 31px,color-mix(in srgb,var(--mu) 28%,transparent) 31px 32px);overflow:hidden}
.ink-pad .ink-cv{touch-action:none}
.pad-split{display:block}
@media (min-width:768px){
 html.pad main{max-width:1000px;padding-left:20px;padding-right:20px}
 /* large touch targets */
 html.pad .btn,html.pad .chip,html.pad .qb-chip,html.pad .lnk,html.pad .hlink,html.pad select,html.pad nav button{min-height:48px}
 html.pad .mini,html.pad .qb-x,html.pad .pn-x,html.pad .pn-sg{min-height:44px;min-width:44px}
 html.pad .mini{padding:8px 14px;font-size:14px}
 html.pad .qb-opt{min-height:56px}
 html.pad label.ck{min-height:48px;align-items:center}
 html.pad label.ck input{width:24px;height:24px}
 html.pad details.tcard>summary{min-height:64px}
 /* master / detail panes */
 html.pad .pad-split{display:grid;grid-template-columns:minmax(250px,300px) minmax(0,1fr);gap:16px;align-items:start}
 html.pad .pad-l{position:sticky;top:72px;max-height:calc(100vh - 92px);overflow-y:auto;overscroll-behavior:contain;padding:2px 4px 8px 2px;margin:-2px}
 html.pad .pad-r{min-width:0}
 html.pad .pad-topics .tlist{display:block;grid-template-columns:none}
 html.pad .pad-topics .tcard{margin-bottom:10px;cursor:pointer}
 html.pad .pad-topics .tcard.sel{outline:2px solid var(--pri);outline-offset:-1px;background:color-mix(in srgb,var(--pri) 8%,var(--s1))}
 html.pad .pad-topics .tcard>summary::after{transform:none!important}
 html.pad .pad-topics .tcard .tbody{display:none}
 html.pad .pad-r .tbody{display:block;padding:0}
 html.pad .pad-dh{display:flex;gap:14px;align-items:center;margin:0 0 14px;padding:14px 16px;border:1px solid var(--bd);border-left:5px solid var(--c,var(--pri));border-radius:var(--r);background:var(--s1)}
 html.pad .pad-dh h2{margin:0;font-size:22px}
 html.pad .pad-notes{grid-template-columns:minmax(0,1fr) minmax(250px,320px)}
 html.pad .pad-notes .pad-l{position:static;max-height:none;overflow:visible}
 html.pad .pad-notes .pad-r{position:sticky;top:72px}
 /* practice: question left, notes + figure right */
 html.pad #qb:has(>.qb-side){display:grid;grid-template-columns:minmax(0,1fr) minmax(240px,300px);gap:12px 16px;max-width:none;align-items:start}
 html.pad #qb:has(>.qb-side)>.qb-bar,html.pad #qb:has(>.qb-side)>.qb-prog{grid-column:1/-1}
 html.pad #qb:has(>.qb-side)>:not(.qb-bar):not(.qb-prog):not(.qb-side){grid-column:1}
 html.pad #qb:has(>.qb-side)>.qb-side{grid-column:2;grid-row:3/span 4;position:sticky;top:72px}
 html.pad .qb-side .qs-n{background:var(--s2);border-radius:10px;padding:8px 10px;margin:6px 0;font-size:14px;white-space:pre-wrap;overflow-wrap:anywhere}
 html.pad .qb-side .qs-act{margin:10px 0}
 html.pad .qb-side .qs-h{margin-top:16px}
 html.pad .v-practice .card{max-width:none}
 html.pad .pn-ink{padding:0 16px}
}
@media (min-width:768px) and (max-width:1023px){
 html.pad .pad-split{grid-template-columns:minmax(230px,270px) minmax(0,1fr)}
 html.pad .pad-notes{grid-template-columns:minmax(0,1fr) minmax(230px,280px)}
}
@media (min-width:1100px){html.pad main{max-width:1200px}}
@media (max-width:1279px){html.pad #sp-tab{display:none!important}}