:root{--learn-ink:var(--cat-ink);--learn-muted:var(--cat-muted);--learn-surface:var(--cat-surface);--learn-line:var(--cat-line);--learn-link:var(--cat-link);--learn-accent:var(--cat-accent);--learn-accent-ink:#fff;--learn-focus:var(--cat-focus);--learn-head:var(--cat-head);--learn-radius:var(--cat-radius,16px);--learn-shadow:var(--cat-shadow,none);--learn-tint:color-mix(in srgb, var(--learn-accent) 10%, var(--learn-surface));--learn-ok:#12703e;--learn-ok-bg:color-mix(in srgb, #1f9d5a 14%, var(--learn-surface));--learn-bad:#a1261c;--learn-bad-bg:color-mix(in srgb, #d6453a 13%, var(--learn-surface));--learn-warn:#8a4b00;--learn-warn-bg:color-mix(in srgb, #f5a524 16%, var(--learn-surface))}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--learn-ok:#7ee2a8;--learn-bad:#ffa59c;--learn-warn:#ffcf7a}}:root[data-theme=dark]{--learn-ok:#7ee2a8;--learn-bad:#ffa59c;--learn-warn:#ffcf7a}.learn-nav{border:1px solid var(--learn-line);background:var(--learn-surface);height:38px;color:var(--learn-ink);white-space:nowrap;border-radius:999px;flex:none;align-items:center;gap:.35rem;padding:0 .75rem;font-size:.9rem;font-weight:600;text-decoration:none;display:inline-flex}.learn-nav svg{fill:none;stroke:currentColor;stroke-width:2px;stroke-linecap:round;stroke-linejoin:round;flex:none;width:17px;height:17px}.learn-nav:hover{border-color:var(--learn-accent)}.learn-nav.is-current{box-shadow:inset 0 -3px 0 var(--learn-accent)}.learn-nav:focus-visible,.lsn a:focus-visible,.lh a:focus-visible,.lb a:focus-visible,.lq button:focus-visible,.lsn button:focus-visible,.lp button:focus-visible{outline:3px solid var(--learn-focus);outline-offset:2px}[dir=rtl] .lsn-arrow{display:inline-block;transform:scaleX(-1)}.lsn,.lh,.lb{overflow-wrap:anywhere;hyphens:auto}.lsn-prev,.lsn-next{min-width:0}.lsn-pn span{overflow-wrap:anywhere}.lb{border:1px solid var(--learn-line);border-inline-start:5px solid var(--learn-accent);border-radius:var(--learn-radius);background:var(--learn-surface);max-height:120px;box-shadow:var(--learn-shadow);color:var(--learn-ink);align-items:center;gap:.75rem 1rem;margin:.6rem 0 0;padding:.65rem .85rem;display:flex;overflow:hidden}.lb-main{min-width:0;color:inherit;flex:auto;align-items:center;gap:.7rem;text-decoration:none;display:flex}.lb-badge{text-transform:uppercase;letter-spacing:.06em;background:var(--learn-tint);color:var(--learn-link);border-radius:999px;flex:none;padding:.2rem .55rem;font-size:.72rem;font-weight:800}:lang(hi) .lb-badge,:lang(ar) .lb-badge{text-transform:none;letter-spacing:0;font-size:.8rem}.lb-txt{min-width:0;display:grid}.lb-title{font-family:var(--learn-head);text-overflow:ellipsis;white-space:nowrap;font-size:1.02rem;line-height:1.25;overflow:hidden}.lb-sub{color:var(--learn-muted);text-overflow:ellipsis;white-space:nowrap;font-size:.9rem;line-height:1.3;overflow:hidden}.lb-main:hover .lb-title{text-underline-offset:3px;text-decoration:underline}.lb-prog{flex:0 0 90px}.lb-bar{background:var(--learn-tint);border-radius:999px;height:8px;display:block;overflow:hidden}.lb-bar i{background:var(--learn-accent);width:0;height:100%;display:block}.lb-cta{background:var(--learn-accent);min-height:40px;color:var(--learn-accent-ink);white-space:nowrap;border-radius:999px;flex:none;align-items:center;padding:0 1rem;font-size:.92rem;font-weight:700;text-decoration:none;display:inline-flex}.lb-cta:hover{filter:brightness(1.08)}@media (width<=640px){.lb{flex-wrap:wrap;gap:.45rem .6rem;padding:.55rem .7rem}.lb-main{flex:1 1 0}.lb-title{white-space:normal;-webkit-line-clamp:2;-webkit-box-orient:vertical;font-size:.95rem;display:-webkit-box}.lb-sub{display:none}.lb[data-returning] .lb-sub{font-size:.82rem;display:block}.lb-prog{flex:100%;order:3}.lb-cta{min-height:36px;margin-inline-start:auto;padding:0 .85rem;font-size:.88rem}.lb-badge{display:none}}.lsn-btn{background:var(--learn-accent);min-height:44px;color:var(--learn-accent-ink);border-radius:999px;align-items:center;gap:.4rem;padding:0 1.15rem;font-weight:700;text-decoration:none;display:inline-flex}.lsn-btn:hover{filter:brightness(1.08)}.lsn-kicker{color:var(--learn-muted);margin:0 0 .4rem;font-size:.9rem;font-weight:600}.lsn-kicker a{color:var(--learn-link)}.lh{padding-bottom:2rem}.lh-head h1{font-size:clamp(2rem,5vw,3rem)}.lh-intro{max-width:68ch;font-size:1.1rem}.lh-promise{max-width:68ch;font-weight:700}.lp{border:1px solid var(--learn-line);border-radius:var(--learn-radius);background:var(--learn-surface);box-shadow:var(--learn-shadow);margin:1rem 0 .5rem;padding:.9rem 1rem}.lp-row{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.6rem 1rem;display:flex}.lp-label{margin:0}.lp-bar{background:var(--learn-tint);border-radius:999px;height:10px;margin-top:.7rem;overflow:hidden}.lp-bar i{background:var(--learn-accent);width:0;height:100%;transition:width .3s;display:block}.lp-reset{margin:.6rem 0 0}.lp-reset-btn{color:var(--learn-link);font:inherit;cursor:pointer;background:0 0;border:0;padding:0;font-size:.9rem;text-decoration:underline}.lh-mod{margin-top:1.8rem}.lh-mod h2{margin:0 0 .3rem}.lh-mn{text-transform:uppercase;letter-spacing:.06em;color:var(--learn-link);margin-bottom:.2rem;font-family:inherit;font-size:.8rem;font-weight:800;display:block}:lang(hi) .lh-mn,:lang(ar) .lh-mn{text-transform:none;letter-spacing:0;font-size:.9rem}.lh-blurb{color:var(--learn-muted);max-width:68ch}.lh-cards{grid-template-columns:repeat(auto-fill,minmax(min(280px,100%),1fr));gap:.75rem;margin:.6rem 0 0;padding:0;list-style:none;display:grid}.lh-card{border:1px solid var(--learn-line);border-top:4px solid var(--learn-accent);border-radius:var(--learn-radius);background:var(--learn-surface);height:100%;box-shadow:var(--learn-shadow);color:var(--learn-ink);grid-template-columns:auto 1fr;gap:.2rem .7rem;padding:.9rem 1rem;text-decoration:none;display:grid;position:relative}.lh-card:hover{border-color:var(--learn-accent)}.lh-n{background:var(--learn-tint);width:2rem;height:2rem;color:var(--learn-link);border-radius:50%;grid-row:span 3;place-items:center;font-weight:800;display:grid}.lh-t{font-family:var(--learn-head);font-size:1.05rem;font-weight:750;line-height:1.25}.lh-s{color:var(--learn-muted);font-size:.93rem;line-height:1.4}.lh-meta{color:var(--learn-muted);align-items:center;gap:.7rem;margin-top:.2rem;font-size:.82rem;font-weight:600;display:flex}.lh-read{color:var(--learn-ok);display:none}.lh-card[data-learn-read=true] .lh-read{display:inline}.lh-card[data-learn-read=true] .lh-n{background:var(--learn-ok-bg);color:var(--learn-ok)}.lsn{max-width:70ch;padding:.8rem 0 2rem}.lsn h1{font-size:clamp(1.9rem,5vw,2.8rem)}.lsn-intro{font-size:1.12rem}.lsn-sec h2{margin-top:1.8rem;font-size:1.4rem}.lsn-list{margin:0 0 1em;padding-inline-start:1.3rem}.lsn-list li{margin-bottom:.3rem}.lsn-box{border:1px solid var(--learn-line);background:var(--learn-tint);border-radius:12px;align-items:flex-start;gap:.7rem;margin:1rem 0;padding:.85rem 1rem;display:flex}.lsn-box p{margin:0}.lsn-box-t{font-weight:750;margin-bottom:.2rem!important}.lsn-box-i{fill:none;width:22px;height:22px;stroke:var(--learn-link);stroke-width:2px;stroke-linecap:round;stroke-linejoin:round;flex:none;margin-top:.1rem}.lsn-box-warning{background:var(--learn-warn-bg);border-color:color-mix(in srgb, #f5a524 45%, var(--learn-line))}.lsn-box-warning .lsn-box-i{stroke:var(--learn-warn)}.lsn-box-math .lsn-box-x{font-variant-numeric:tabular-nums;white-space:pre-line}.lsn-take{border-radius:var(--learn-radius);border:1px solid var(--learn-line);border-inline-start:5px solid var(--learn-accent);background:var(--learn-surface);box-shadow:var(--learn-shadow);margin:1.8rem 0 1.2rem;padding:1rem 1.1rem}.lsn-take h2{margin:0 0 .5rem;font-size:1.2rem}.lsn-take ul{margin:0;padding-inline-start:1.2rem}.lsn-take li{margin-bottom:.35rem}.lsn-try{border-radius:var(--learn-radius);background:var(--learn-tint);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.7rem 1rem;margin:1.4rem 0;padding:1rem 1.1rem;display:flex}.lsn-try p{flex:18rem;margin:0;font-weight:600}.lsn-done{flex-wrap:wrap;align-items:center;gap:.6rem 1rem;margin:1.2rem 0;display:flex}.lsn-mark{border:2px solid var(--learn-accent);background:var(--learn-surface);min-height:44px;color:var(--learn-ink);font:inherit;cursor:pointer;border-radius:999px;padding:0 1.1rem;font-weight:700}.lsn-mark[aria-pressed=true]{background:var(--learn-ok-bg);border-color:var(--learn-ok);color:var(--learn-ok)}.lsn-mark[aria-pressed=true]:before{content:"✓ "}.lsn-count{color:var(--learn-muted);font-size:.92rem;font-weight:600}.lsn-src{margin-top:1.6rem;font-size:.93rem}.lsn-src h2{margin:0 0 .4rem;font-size:1.05rem}.lsn-src ul{margin:0 0 .5rem;padding-inline-start:1.2rem}.lsn-src li{overflow-wrap:anywhere;margin-bottom:.25rem}.lsn-checked{color:var(--learn-muted);margin:0}.lsn-pn{border-top:1px solid var(--learn-line);grid-template-columns:1fr auto 1fr;align-items:stretch;gap:.6rem;margin-top:1.6rem;padding-top:1rem;display:grid}.lsn-pn a{color:var(--learn-link);text-decoration:none}.lsn-prev,.lsn-next{border:1px solid var(--learn-line);background:var(--learn-surface);border-radius:12px;gap:.1rem;padding:.6rem .8rem;display:grid}.lsn-next{text-align:end}.lsn-pn small{color:var(--learn-muted);font-weight:600}.lsn-pn span{font-weight:700;line-height:1.25}.lsn-all{align-self:center;padding:0 .4rem;font-weight:700}@media (width<=640px){.lsn-pn{grid-template-columns:1fr 1fr}.lsn-all{grid-area:2/1/auto/-1;justify-self:center}}.lq{border:1px solid var(--learn-line);border-radius:var(--learn-radius);background:var(--learn-surface);box-shadow:var(--learn-shadow);margin:1.6rem 0;padding:1rem 1.1rem 1.1rem}.lq h2{margin:0 0 .2rem;font-size:1.3rem}.lq-lede{color:var(--learn-muted);margin-bottom:.6rem}.lq-list{margin:0;padding-inline-start:1.3rem}.lq-q{margin:0 0 1rem}.lq-qt{margin:0 0 .45rem;font-weight:700}.lq-opts{gap:.4rem;display:grid}.lq-opt{text-align:start;border:1px solid var(--learn-line);background:var(--learn-surface);min-height:44px;color:var(--learn-ink);font:inherit;cursor:pointer;border-radius:10px;padding:.55rem .8rem;font-size:.97rem;line-height:1.35}.lq-opt:hover:not(:disabled){border-color:var(--learn-accent);background:var(--learn-tint)}.lq-opt:disabled{cursor:default;color:var(--learn-ink);opacity:1}.lq-opt[data-qc-state=ok]{border:2px solid var(--learn-ok);background:var(--learn-ok-bg)}.lq-opt[data-qc-state=ok]:before{content:"✓ ";color:var(--learn-ok);font-weight:800}.lq-opt[data-qc-state=bad]{border:2px solid var(--learn-bad);background:var(--learn-bad-bg)}.lq-opt[data-qc-state=bad]:before{content:"✗ ";color:var(--learn-bad);font-weight:800}.lq-opt[data-qc-state=dim]{opacity:.7}.lq-fb{border-radius:8px;margin:.45rem 0 0;padding:.5rem .7rem;font-size:.93rem}.lq-fb[data-qc-state=ok]{background:var(--learn-ok-bg);color:var(--learn-ok)}.lq-fb[data-qc-state=bad]{background:var(--learn-bad-bg);color:var(--learn-bad)}.lq-ans{margin-top:.4rem;font-size:.9rem}.lq-ans summary{cursor:pointer;color:var(--learn-link);font-weight:600}.lq-ans p{margin:.35rem 0 0}.lq-score{margin:.2rem 0 0;font-weight:800}@media print{.lb,.lq-opts,.lsn-done,.lp{display:none}}