/* Shared shell components override only the old independent shells. */
#nav.evolua-nav,.public-questions .catalog-tabs.evolua-nav{position:fixed;inset:auto 0 0;z-index:100;display:flex;align-items:stretch;justify-content:flex-start;gap:6px;padding:8px max(10px,env(safe-area-inset-left)) calc(8px + env(safe-area-inset-bottom,0px));width:100%;height:auto;border:0;border-top:1px solid var(--bd);background:var(--bg);box-sizing:border-box;overflow-x:auto;overflow-y:hidden;overscroll-behavior-x:contain;scrollbar-width:none;scroll-snap-type:x proximity}
.evolua-nav::-webkit-scrollbar{display:none}#nav.evolua-nav button,.public-questions .catalog-tabs.evolua-nav button{display:flex;flex:1 0 82px;flex-direction:column;align-items:center;justify-content:center;gap:6px;min-width:82px;min-height:58px;width:auto;padding:8px 6px;background:transparent;border:0;border-radius:12px;color:var(--mu);font:500 11.5px/1.35 Inter,system-ui,sans-serif;text-align:center;white-space:nowrap;cursor:pointer;scroll-snap-align:center}
#nav.evolua-nav button.on,.public-questions .catalog-tabs.evolua-nav button.on,#nav.evolua-nav button:hover,.public-questions .catalog-tabs.evolua-nav button:hover{color:var(--pr);background:var(--prl)}
.evolua-nav button svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;transition:transform .2s var(--ease)}.evolua-nav button:active svg{transform:scale(.88)}.evolua-nav button:focus-visible{outline:2px solid var(--pr);outline-offset:-2px}
.evolua-footer{max-width:1040px;margin:32px auto 0;padding:28px 24px 120px!important;border-top:1px solid var(--bd);font-size:13px;color:var(--mu);display:flex;align-items:center;justify-content:space-between;gap:24px;box-sizing:border-box}.evolua-footer .brand{font-size:22px;text-decoration:none}.evolua-footer p{margin:10px 0 0;line-height:1.6}.evolua-footer small{display:block;margin-top:6px;line-height:1.7}.evolua-footer nav{position:static!important;display:flex!important;flex-direction:row!important;align-items:center!important;justify-content:flex-start!important;flex-wrap:wrap;gap:12px 20px!important;inset:auto!important;width:auto!important;padding:0!important;border:0!important;background:transparent!important;box-shadow:none!important}.evolua-footer nav a{color:var(--mu);text-decoration:none;font-weight:500}.evolua-footer a:hover{color:var(--pr)}
.public-questions .catalog-header-links{display:grid!important;grid-template-columns:1fr 1fr;gap:10px!important;width:100%;margin-top:8px}.public-questions .catalog-header-links>a{display:flex;justify-content:center;align-items:center;min-height:46px;padding:10px 14px!important;border-radius:14px!important;font:600 13px var(--fb,Inter,system-ui,sans-serif)!important;text-align:center;text-decoration:none}.public-questions .catalog-header-links .catalog-nav{border:1px solid var(--bd);background:var(--card)}.public-questions .catalog-header-links .btn{border:1px solid var(--pr);color:var(--bg)}
[data-catalog-suspended],[data-native-inactive]{display:none!important}.catalog-native-surface{display:block;min-height:100dvh;background:var(--bg)}body.catalog-native-study{padding-left:0!important;padding-bottom:0!important;overflow-x:clip}.catalog-return{max-width:880px;margin:0 auto;padding:8px 20px 0}.catalog-return button{display:inline-flex;align-items:center;gap:8px;padding:8px 0;border:0;background:none;color:var(--mu);font:500 13px/1.4 Inter,system-ui,sans-serif;cursor:pointer}.catalog-return button:hover{color:var(--pr)}.catalog-return svg{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
/* Action bars stay inside the study column and leave the viewport before its footer. */
body.ins main,body.catalog-native-study.ins main{padding-bottom:24px!important}body.ins #nav{display:none!important}#app>.dock,#app>.dock2{position:sticky!important;inset:auto!important;bottom:0!important;left:auto!important;right:auto!important;width:100%!important;max-width:none!important;margin:24px 0 0!important;padding:12px 0 calc(12px + env(safe-area-inset-bottom,0px))!important;border-top:1px solid var(--bd);background:var(--bg);z-index:10;animation:none!important;transform:none!important}#app>.dock button,#app>.dock2 button{min-width:0}.catalog-native-study:not(.ins) #app{min-height:55dvh}
.install-guide{width:min(560px,calc(100% - 28px));max-height:85dvh;padding:24px;box-sizing:border-box;border:1px solid var(--bd);border-radius:20px;background:var(--card);color:var(--tx)}.install-guide::backdrop{background:rgba(0,0,0,.6);backdrop-filter:blur(4px)}.install-head{display:flex;align-items:center;gap:14px}.install-head img{border-radius:14px}.install-head h2{font-size:22px;margin:4px 0}.install-head .ib{margin-left:auto;flex-shrink:0}.install-tabs{display:flex;gap:6px;margin:20px 0 14px}.install-tabs button{flex:1;padding:10px 6px;border:1px solid var(--bd);border-radius:10px;background:var(--bg);color:var(--tx);font:inherit;font-size:12px;cursor:pointer}.install-tabs button[aria-selected=true]{border-color:var(--pr);color:var(--pr);background:var(--prl)}.install-guide li{line-height:1.7;margin:14px 0}.install-note{font-size:12px;line-height:1.6}.sound-switch svg{animation:sound-switch .3s var(--ease)}@keyframes sound-switch{50%{transform:scale(.75) rotate(-12deg)}}@keyframes workspace-in{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.sb-price{display:flex;align-items:baseline;gap:5px;flex-wrap:wrap}.sb-was{display:inline-flex;position:relative;margin-left:16px;font:700 clamp(26px,7vw,36px)/1.1 var(--fd);color:var(--mu);text-decoration-line:line-through;text-decoration-thickness:3px;text-decoration-color:var(--ac);white-space:nowrap}.sb-was small{font:500 12px Inter,system-ui,sans-serif;margin-left:3px}.sb-reference{display:none}.community-approved.solution-comment{padding:18px;margin:18px 0;background:var(--prl);border-color:var(--bd)}.solution-comment h3{font-size:14px;margin:0 0 12px;color:var(--pr)}.solution-comment .solution-author{margin:0 0 12px}.solution-comment .student-avatar{width:38px;height:38px;border-radius:50%}.solution-comment .solution-author b{font-size:14px}.solution-comment .solution-author small{font-size:11px}.solution-comment .solution-body{font-size:15px;line-height:1.7;margin-left:50px}.solution-comment .solution-attachment{max-width:calc(100% - 50px);margin-left:50px}
@media(min-width:900px){#nav.evolua-nav,.public-questions .catalog-tabs.evolua-nav{padding-left:max(24px,calc((100vw - 960px)/2));padding-right:max(24px,calc((100vw - 960px)/2));gap:10px}}
@media(max-width:600px){.evolua-footer{align-items:flex-start;flex-direction:column;gap:20px;padding:24px 20px 120px!important}.install-guide{padding:18px}.install-head h2{font-size:19px}.install-head img{width:44px;height:44px}}
@media(prefers-reduced-motion:reduce){.sound-switch svg,.shell-tap{animation:none}.evolua-nav button svg{transition:none}}
/* Header touch targets must not stretch the circular portrait. */
body .profile-header-avatar{box-sizing:border-box!important;display:inline-flex!important;align-items:center;justify-content:center;flex:0 0 40px!important;width:40px!important;height:40px!important;min-width:40px!important;max-width:40px!important;min-height:40px!important;max-height:40px!important;aspect-ratio:1!important;border-radius:50%!important;padding:0!important;overflow:hidden!important;line-height:0!important}body .profile-header-avatar>img,body .profile-header-avatar>svg{display:block!important;width:100%!important;height:100%!important;max-width:none!important;object-fit:cover!important;flex-shrink:0}
.solution-contribution{margin-top:24px!important;margin-bottom:24px!important;padding:20px!important}.solution-contribution .solution-callout{gap:16px}.solution-contribution>button{margin-top:18px!important}.solution-contribution [data-solution-status]:empty{display:none}

/* Portrait colors must not inherit the white stroke of toolbar line icons. */
.student-avatar>svg,.avatar-choice>svg,.profile-header-avatar>svg,.admin-avatar-grid button>svg{stroke:none!important;filter:none!important;outline:none;border:0}
.shell-tap{animation:shell-tap .22s var(--ease)}@keyframes shell-tap{50%{transform:scale(.96)}}.install-tabs button,.avatar-choice,[data-solution-open],[data-close-workspace]{transition:background-color .18s,color .18s,border-color .18s,box-shadow .18s}.install-tabs button:hover,.avatar-choice:hover,[data-solution-open]:hover{border-color:var(--pr)}
@media(min-width:900px){#nav.evolua-nav button,.public-questions .catalog-tabs.evolua-nav button{flex-basis:96px;min-width:96px}.evolua-nav{justify-content:center}}
@media(prefers-reduced-motion:reduce){.shell-tap{animation:none}.install-tabs button,.avatar-choice,[data-solution-open],[data-close-workspace]{transition:none}}
/* Only the open dialog scrolls; gestures do not reach the page beneath it. */
html:has(.pf,.sb,.dn,#ev-ban,dialog[open]){overflow:hidden;overscroll-behavior:none}.pf,.pf-box,.sb,.sb-box,.dn,.dc,#ev-ban,.bn-card,dialog[open]{overscroll-behavior:contain}
body.ins .evolua-footer{padding-bottom:24px!important}

.install-guide{overflow-y:auto;animation:workspace-in .24s var(--ease)}.install-step-list{list-style:none;margin:0;padding:0}.install-step-list li{display:flex;gap:12px;padding:14px 0;margin:0;border-bottom:1px solid var(--bd);line-height:1.5}.install-step-number{flex:0 0 28px;width:28px;height:28px;border-radius:50%;display:grid;place-items:center;color:var(--pr);background:var(--prl);font-size:13px;font-weight:700}.install-step-list b{display:flex;align-items:center;gap:8px;font-size:14px}.install-step-list p{margin:6px 0 0;color:var(--mu);font-size:13px;line-height:1.6}.install-guide svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex-shrink:0}.install-ready{display:flex;align-items:center;gap:10px;padding:14px;border:1px solid var(--bd);border-radius:12px;background:var(--prl);color:var(--pr);font-size:13px;line-height:1.6}.install-copy{display:flex;flex-direction:column;gap:10px;margin-top:20px;font-size:12px;color:var(--mu)}.install-copy small:empty{display:none}.install-guide .btn,.solution-notice .btn{width:100%;min-height:46px;box-sizing:border-box;transition:transform .18s var(--ease),background-color .18s}.install-guide .btn:active,.solution-notice .btn:active{transform:scale(.98)}
.solution-notice{position:fixed;width:min(520px,calc(100% - 28px));max-height:85dvh;overflow-y:auto;padding:28px;box-sizing:border-box;border:1px solid var(--bd);border-radius:22px;background:var(--card);color:var(--tx);text-align:center;animation:workspace-in .28s var(--ease)}.solution-notice::backdrop{background:rgba(0,0,0,.65);backdrop-filter:blur(5px)}.solution-notice>[data-close-notice]{position:absolute;right:12px;top:12px}.solution-notice h2{font-size:24px;margin:18px 0 12px;line-height:1.25}.solution-notice>.mu{line-height:1.7;font-size:14px;margin:12px 0 20px}.solution-notice-emblem{display:grid;place-items:center;width:68px;height:68px;border-radius:22px;margin:12px auto;color:var(--pr);background:var(--prl);font-size:36px;animation:solution-celebrate .65s var(--ease)}.solution-notice-state{display:block;color:var(--pr);font-size:12px;font-weight:600;margin:18px 0}.solution-notice>.btn{margin-top:10px}.solution-earned-xp{color:var(--pr);font:700 52px/1.1 var(--fd);margin:24px 0;animation:workspace-in .4s var(--ease)}.solution-earned-xp span{display:block;font:500 13px/1.5 var(--fb,Inter,system-ui,sans-serif);margin-top:8px;color:var(--mu)}.solution-preview-content{text-align:left;overflow-wrap:anywhere}.solution-preview-content .question-statement{font-size:14px;line-height:1.7;max-height:240px;overflow:auto;padding:14px;border:1px solid var(--bd);border-radius:12px}.solution-preview-content .question-statement img{max-width:100%}.solution-preview-content .solution-body{margin-left:0}.solution-preview-content .solution-attachment{margin-left:0;max-width:100%}.solution-preview-content .solution-author>div{min-width:0}.solution-preview-content .solution-author b{overflow-wrap:anywhere}.solution-preview-content .btn{display:flex;align-items:center;justify-content:center;text-decoration:none}
@keyframes solution-celebrate{0%{opacity:0;transform:scale(.7) rotate(-15deg)}65%{transform:scale(1.08) rotate(8deg)}100%{opacity:1;transform:none}}@media(max-width:400px){.solution-notice{padding:24px 18px}.install-head{gap:10px}}@media(prefers-reduced-motion:reduce){.install-guide,.solution-notice,.solution-notice-emblem,.solution-earned-xp{animation:none}.install-guide .btn,.solution-notice .btn{transition:none;transform:none}}

.solution-celebration{padding-top:34px}.solution-celebration-label{margin:20px 0 8px;color:var(--pr);font:600 11px/1.5 Inter,system-ui,sans-serif;letter-spacing:1.8px}.solution-celebration h2{margin-top:8px;font-size:25px;letter-spacing:-.5px}.solution-celebration .solution-notice-emblem{width:64px;height:64px;border-radius:50%;border:1px solid var(--bd);background:var(--prl)}.solution-notice-emblem svg{width:32px;height:32px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}.solution-celebration .solution-earned-xp{padding:20px 0;margin:20px 0;border-top:1px solid var(--bd);border-bottom:1px solid var(--bd);font-size:48px}.solution-confetti{position:absolute;inset:0;overflow:hidden;border-radius:inherit;pointer-events:none}.solution-confetti i{position:absolute;top:-12px;left:var(--confetti-x);width:6px;height:11px;border-radius:2px;background:var(--pr);opacity:0;animation:solution-confetti-fall 1.8s var(--confetti-delay) cubic-bezier(.2,.65,.35,1) forwards}.solution-confetti i:nth-child(3n){background:var(--ac);width:7px;height:7px}.solution-confetti i:nth-child(4n){background:var(--mu);width:4px;height:9px}@keyframes solution-confetti-fall{0%{opacity:0;transform:translate(0,-10px) rotate(0)}12%{opacity:.85}80%{opacity:.7}100%{opacity:0;transform:translate(var(--confetti-drift),350px) rotate(calc(var(--confetti-spin)*300deg))}}@media(prefers-reduced-motion:reduce){.solution-confetti{display:none}}

/* Equal tab widths prevent long labels from changing the gaps beside short labels. */
#nav.evolua-nav button,.public-questions .catalog-tabs.evolua-nav button{box-sizing:border-box;flex:0 0 96px;width:96px;min-width:96px;max-width:96px;margin:0!important}#nav.evolua-nav button span,.public-questions .catalog-tabs.evolua-nav button span{display:block;width:100%;text-align:center;margin:0;padding:0;line-height:1.35}
.evolua-nav-hints{position:fixed;inset:auto 0 calc(24px + env(safe-area-inset-bottom,0px));height:30px;z-index:101;display:flex;justify-content:space-between;pointer-events:none;padding:0 3px}.evolua-nav-hints[hidden],.evolua-nav-hints button[hidden]{display:none!important}.evolua-nav-hints button{pointer-events:auto;display:grid;place-items:center;width:23px;height:30px;padding:0;border:1px solid var(--bd);border-radius:8px;background:var(--card);color:var(--pr);font:500 25px/1 Inter,system-ui,sans-serif;box-shadow:0 0 12px 5px var(--bg);cursor:pointer;transition:background .18s,transform .18s}.evolua-nav-hints button:active{transform:scale(.92)}.evolua-nav-hints button:last-child{margin-left:auto}body.ins .evolua-nav-hints,body.au-lock .evolua-nav-hints,body.lp .evolua-nav-hints{display:none!important}
.public-questions .breadcrumb{gap:8px;margin-bottom:22px;font:500 12px/1.4 Inter,system-ui,sans-serif}.public-questions .breadcrumb a{display:inline-flex;align-items:center;gap:7px;padding:7px 10px;border:1px solid var(--bd);border-radius:9px;color:var(--mu);background:var(--card);text-decoration:none;transition:color .18s,border-color .18s,background .18s}.public-questions .breadcrumb a:hover{color:var(--pr);border-color:var(--pr);background:var(--prl);text-decoration:none}.public-questions .breadcrumb svg{width:14px;height:14px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}.breadcrumb-separator{font-size:17px;color:var(--mu)}
.solution-approved-count{font-size:14px;color:var(--mu);margin:18px 0}.solution-approved-count b{color:var(--tx)}.solution-approved-list{text-align:left;margin:20px 0 12px}.solution-approved-list[hidden],.solution-celebration button[hidden]{display:none!important}.solution-approved-choice{display:flex;align-items:center;justify-content:space-between;gap:12px;width:100%;padding:14px;margin:10px 0;border:1px solid var(--bd);border-radius:12px;background:var(--bg);color:var(--tx);text-align:left;transition:border-color .18s,background .18s,transform .18s}.solution-approved-choice b{font-size:13px;line-height:1.6;display:block}.solution-approved-choice small{display:block;font-size:11px;color:var(--mu);margin-top:6px}.solution-approved-choice:hover{border-color:var(--pr);background:var(--prl)}.solution-approved-choice:active{transform:scale(.98)}
@media(min-width:900px){#nav.evolua-nav button,.public-questions .catalog-tabs.evolua-nav button{flex:1 0 96px;width:auto;max-width:none}.evolua-nav-hints{display:none}}@media(prefers-reduced-motion:reduce){.solution-approved-choice,.evolua-nav-hints button,.public-questions .breadcrumb a{transition:none}}

.solution-choice-excerpt{display:block;color:var(--mu);font-size:12px;line-height:1.6;margin-top:8px}.solution-approved-list{max-height:320px;overflow-y:auto;overscroll-behavior:contain}