:root{--bg:#f7f8f5;--panel:#fff;--ink:#242d27;--muted:#72796f;--line:#e2e5dc;--accent:#284936;--accent-soft:#edf2e9;--cream:#f0ecd9;--cream-ink:#665f40;--wrong:#a33e32;--wrong-bg:#faf0ec;--shadow:0 20px 80px #14241c20;--radius:10px;color-scheme:light;font-family:Arial,Helvetica,sans-serif;font-size:15px}
:root[data-theme=dark]{--bg:#19211c;--panel:#202a23;--ink:#e7ede5;--muted:#a5afa4;--line:#374238;--accent:#bbd6b2;--accent-soft:#2b3c2d;--cream:#393b28;--cream-ink:#e2ddba;--wrong:#f2aa9a;--wrong-bg:#3d2c28;--shadow:0 20px 80px #0006;color-scheme:dark}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);line-height:1.55}button,input,select{font:inherit}button{cursor:pointer;color:inherit}button:disabled{cursor:wait;opacity:.55}a{color:inherit}button,input,select,summary{outline-offset:4px}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:2px solid var(--accent)}button{border:0;background:none}h1,h2,h3,p{margin:0}h1,h2,h3{line-height:1.2;font-weight:500;letter-spacing:-.035em}h1{font-size:38px}h2{font-size:27px}h3{font-size:18px}small,.small{font-size:12px}.muted{color:var(--muted)}.eyebrow{font-size:10px;font-weight:700;letter-spacing:.17em;color:var(--muted);text-transform:uppercase}.icon{flex-shrink:0;vertical-align:middle}.skip-link{position:fixed;top:-70px;left:20px;z-index:100;background:var(--accent);color:var(--panel);padding:10px 18px}.skip-link:focus{top:12px}.loading-screen{padding:100px;text-align:center}.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:43px;padding:10px 18px;border:1px solid var(--line);border-radius:6px;background:var(--panel);font-size:13px;font-weight:600;line-height:1.35;transition:background .15s,border-color .15s}.btn:hover{border-color:var(--muted)}.btn.primary{background:var(--accent);color:var(--panel);border-color:var(--accent)}.btn.primary:hover{filter:brightness(1.1)}.btn.soft{background:var(--accent-soft);border-color:transparent;color:var(--accent)}.btn.small{padding:7px 12px;min-height:34px;font-size:12px}.btn.full{width:100%}.btn.danger{border-color:var(--wrong);color:var(--wrong)}.text-btn{color:var(--accent);padding:0;font-size:13px;font-weight:600;text-decoration:underline;text-underline-offset:4px}.icon-btn{display:inline-grid;place-items:center;width:36px;height:36px;border-radius:6px;color:var(--muted)}.icon-btn:hover,.icon-btn.active{background:var(--accent-soft);color:var(--accent)}.pill{display:inline-flex;gap:6px;align-items:center;font-size:11px;padding:5px 9px;border:1px solid var(--line);border-radius:4px;white-space:nowrap}.pill.soft{background:var(--accent-soft);color:var(--accent);border:0}.pill .icon{width:13px;height:13px}.app-shell{display:grid;grid-template-columns:232px 1fr;min-height:100vh}.sidebar{position:fixed;inset:0 auto 0 0;width:232px;background:var(--panel);border-right:1px solid var(--line);padding:34px 23px 22px;display:flex;flex-direction:column;z-index:5}.brand{display:flex;align-items:center;gap:12px;text-align:left;padding:0;margin-bottom:50px}.brand-mark{width:36px;height:41px;display:flex;align-items:center;justify-content:center;flex-shrink:0;background:var(--accent);color:var(--panel);border-radius:5px;font-family:Georgia,serif;font-size:22px}.brand-name{font-size:14px;line-height:1.35;font-weight:600;letter-spacing:-.015em}.brand-sub{font-size:9px;font-weight:400;letter-spacing:.09em;color:var(--muted);display:block;margin-top:4px;text-transform:uppercase}.nav-label{padding:0 11px;margin-bottom:12px}.nav{display:flex;flex-direction:column;gap:5px}.nav-item{display:flex;align-items:center;gap:11px;text-align:left;padding:12px 12px;border-radius:6px;font-size:13px;color:var(--muted);font-weight:500;width:100%}.nav-item .icon{width:18px;height:18px}.nav-item:hover{background:var(--bg);color:var(--ink)}.nav-item.selected{background:var(--accent-soft);color:var(--accent)}.nav-item .count{margin-left:auto;font-size:11px}.sidebar-bottom{margin-top:auto}.daily-card{margin:34px 5px 28px;padding:17px 0 0;border-top:1px solid var(--line)}.daily-card p{font-size:12px;color:var(--muted);margin:8px 0}.daily-title{display:flex;justify-content:space-between;font-size:12px}.daily-dots{display:flex;gap:4px;margin-top:12px}.daily-dots i{height:6px;flex:1;border-radius:2px;background:var(--line)}.daily-dots i.filled{background:var(--accent)}.author{font-size:10px;color:var(--muted);padding:17px 10px 0;line-height:1.7}.author strong{font-weight:500;color:var(--ink)}.main-wrap{grid-column:2}.topbar{height:85px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding:0 48px;gap:15px}.breadcrumb{font-size:12px;color:var(--muted);display:flex;gap:12px;align-items:center}.breadcrumb strong{font-weight:500;color:var(--ink)}.topbar-right{display:flex;align-items:center;gap:17px}.status-dot{height:6px;width:6px;border-radius:50%;background:var(--accent);display:inline-block;margin-right:6px}.saved-label{font-size:11px;color:var(--muted)}.avatar{width:28px;height:28px;border-radius:50%;background:var(--accent-soft);color:var(--accent);display:grid;place-items:center;font-size:11px}.user-menu{display:flex;align-items:center;gap:8px;font-size:12px}.mobile-menu{display:none}.main{padding:38px 48px 30px;max-width:1380px;margin:auto}.page-heading{display:flex;justify-content:space-between;align-items:flex-end;margin-bottom:29px;gap:20px}.page-heading h1{margin:7px 0 10px}.page-heading p{font-size:13px;color:var(--muted)}.date-label{font-size:11px;color:var(--muted);margin-bottom:5px;white-space:nowrap}.feature{display:grid;grid-template-columns:1.28fr 1fr;border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);overflow:hidden;margin-bottom:28px;min-height:207px}.feature-copy{padding:30px 31px}.feature-copy h2{font-size:28px;line-height:1.12;margin:11px 0 12px;max-width:390px}.feature-copy p{max-width:345px;font-size:12px;line-height:1.65;color:var(--muted);margin-bottom:17px}.feature-copy .text-btn{display:flex;align-items:center;gap:8px;text-decoration:none}.feature-art{position:relative;overflow:hidden;border-left:1px solid var(--line);background:var(--cream);display:flex;align-items:center;justify-content:center;padding:20px}.graph-grid{position:absolute;inset:0;opacity:.45;background-image:linear-gradient(#a99f7322 1px,transparent 1px),linear-gradient(90deg,#a99f7322 1px,transparent 1px);background-size:24px 24px}.feature-math{position:relative;transform:rotate(-4deg);display:flex;align-items:center;gap:16px;font-family:Georgia,serif;font-size:44px;color:var(--cream-ink);padding-bottom:20px}.feature-math math{font-size:45px}.pencil-note{position:absolute;bottom:35px;font-family:Georgia,serif;font-style:italic;font-size:14px;color:var(--cream-ink);transform:rotate(-4deg);border-bottom:1px solid #9b9378;padding:0 10px 5px}.stat-strip{display:grid;grid-template-columns:repeat(4,1fr);padding:5px 0 27px;border-bottom:1px solid var(--line);margin-bottom:29px;gap:15px}.stat-item{padding-left:23px;border-left:1px solid var(--line)}.stat-item:first-child{padding-left:0;border-left:0}.stat-label{font-size:11px;color:var(--muted);display:flex;align-items:center;gap:7px}.stat-label .icon{width:14px;height:14px}.stat-value{font-size:27px;letter-spacing:-.04em;margin-top:7px;line-height:1.2}.stat-value span{font-size:12px;font-weight:400;color:var(--muted);letter-spacing:0;margin-left:6px}.section-title{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:17px}.section-title h2{font-size:21px}.section-title p{font-size:11px;color:var(--muted);margin-top:4px}.search-box{display:flex;align-items:center;gap:9px;border:1px solid var(--line);border-radius:6px;background:var(--panel);padding:9px 12px;color:var(--muted);width:254px}.search-box input{width:100%;border:0;outline:0;background:transparent;font-size:12px;color:var(--ink)}.search-box .icon{width:16px;height:16px}.topic-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.topic-card{border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);padding:24px;display:flex;flex-direction:column;transition:border .15s,transform .15s}.topic-card:hover{border-color:#a5b29e;transform:translateY(-1px)}.topic-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}.topic-number{font-family:Georgia,serif;font-size:16px;color:var(--muted)}.topic-symbol{height:58px;display:flex;align-items:center;font-family:Georgia,serif;font-size:32px;color:var(--accent);margin-bottom:18px}.topic-symbol math{font-size:30px}.topic-symbol .icon{width:65px;height:58px;stroke-width:.8}.topic-card h3{font-size:19px;line-height:1.25;max-width:300px;margin-bottom:10px}.topic-card .topic-description{font-size:12px;color:var(--muted);line-height:1.75;min-height:44px;margin-bottom:18px}.topic-meta{display:flex;gap:12px;align-items:center;color:var(--muted);font-size:10px;margin-bottom:20px}.tiny-dot{height:3px;width:3px;background:var(--muted);border-radius:50%}.topic-progress{border-top:1px solid var(--line);padding-top:16px;margin-top:auto}.progress-label{display:flex;align-items:center;justify-content:space-between;font-size:11px;margin-bottom:9px;gap:12px}.progress-label span{color:var(--muted)}.progress-track{height:4px;border-radius:2px;background:var(--line);overflow:hidden}.progress-fill{height:100%;background:var(--accent)}.topic-actions{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-top:18px}.topic-actions .text-btn{font-size:11px}.topic-actions .btn{font-size:12px;min-height:38px;padding:9px 12px}.bottom-note{display:flex;align-items:center;gap:12px;border-top:1px solid var(--line);padding-top:22px;margin-top:28px;color:var(--muted);font-size:11px}.bottom-note .icon{height:18px;width:18px}.bottom-note button{font-size:11px;color:var(--ink);text-decoration:underline;text-underline-offset:3px}.page-footer{display:flex;justify-content:space-between;gap:20px;color:var(--muted);font-size:10px;margin-top:35px}.banner{background:var(--cream);color:var(--cream-ink);border:1px solid var(--line);border-radius:6px;padding:14px 17px;font-size:12px;display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:22px}.banner.network{background:var(--wrong-bg);color:var(--wrong)}.empty-state{padding:45px 22px;text-align:center;border:1px dashed var(--line);border-radius:var(--radius);color:var(--muted)}.empty-state .icon{width:29px;height:29px;margin-bottom:12px}.empty-state h3{color:var(--ink);margin-bottom:8px}.empty-state p{font-size:13px;max-width:400px;margin:0 auto 18px}.empty-search{grid-column:1/-1}.panel{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:24px;margin-bottom:20px}.panel>h2{font-size:23px;margin-bottom:10px}.panel>p{font-size:13px;color:var(--muted);margin-bottom:15px}.progress-overview{display:grid;grid-template-columns:1fr 1fr;gap:20px}.grade-row{display:flex;align-items:flex-end;gap:18px;margin:24px 0}.grade-number{font-size:43px;letter-spacing:-.05em;line-height:1}.grade-number small{font-size:20px;margin-left:4px;color:var(--muted)}.grade-meta{font-size:12px;color:var(--muted)}.grade-meta strong{display:block;color:var(--ink);font-size:14px;margin-bottom:3px}.topic-stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;padding:17px 0;margin:15px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.topic-stat-grid b{display:block;font-size:18px;font-weight:500}.topic-stat-grid small{font-size:10px;color:var(--muted)}.skill-row{display:grid;grid-template-columns:minmax(120px,1fr) 100px 42px;gap:12px;align-items:center;font-size:11px;margin:13px 0}.skill-row>span:last-child{text-align:right;color:var(--muted)}.sparkline{width:100%;height:100px;display:block;margin:15px 0}.sparkline .axis{stroke:var(--line);stroke-width:1}.sparkline .trend{fill:none;stroke:var(--accent);stroke-width:2}.sparkline text{font-size:10px;fill:var(--muted)}.activity-grid{display:flex;gap:9px;height:105px;align-items:flex-end;margin:25px 0}.activity-day{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:flex-end;height:100%;gap:6px}.activity-bar{width:100%;max-width:35px;background:var(--accent-soft);border-top:2px solid var(--accent);min-height:3px}.activity-day small{font-size:9px;color:var(--muted)}.activity-day b{font-size:10px;font-weight:400}.recent-row{display:flex;justify-content:space-between;align-items:center;padding:13px 0;border-top:1px solid var(--line);gap:16px;font-size:12px}.recent-label{display:flex;align-items:center;gap:12px}.recent-label .icon{color:var(--accent);width:17px;height:17px}.recent-label .wrong-icon{color:var(--wrong)}.recent-label small{display:block;color:var(--muted);font-size:10px}.recent-row time{font-size:10px;color:var(--muted)}.grading-note{font-size:12px;color:var(--muted)}.grading-note p{margin:12px 0}.grading-note summary{font-size:14px;color:var(--ink);cursor:pointer}.saved-row{display:flex;align-items:center;justify-content:space-between;padding:17px 0;border-top:1px solid var(--line);gap:18px}.saved-row:first-of-type{border-top:0}.saved-row h3{font-size:14px;margin-bottom:6px}.saved-row small{color:var(--muted);font-size:10px}.saved-expression{font-size:20px;max-width:250px;overflow:auto}.saved-buttons{display:flex;gap:8px;align-items:center}.settings-grid{display:grid;grid-template-columns:1fr 1fr;gap:23px}.settings-grid label{display:block;font-size:12px;margin-bottom:7px}.field-input,select{border:1px solid var(--line);background:var(--panel);border-radius:5px;min-height:43px;padding:10px 12px;color:var(--ink);width:100%;font-size:13px}.settings-actions{display:flex;justify-content:flex-end;margin-top:20px}.check-label{display:flex!important;align-items:flex-start;gap:9px;line-height:1.5}.check-label input{accent-color:var(--accent);margin-top:3px}.account-actions{display:flex;gap:10px;flex-wrap:wrap}.settings-warning{margin-top:15px;font-size:11px;color:var(--muted)}
/* Dialogs and the problem workspace */
dialog{color:var(--ink);background:var(--panel);border:1px solid var(--line);box-shadow:var(--shadow);padding:0;border-radius:12px;max-height:calc(100dvh - 48px);overflow:auto}dialog::backdrop{background:#14251db3;backdrop-filter:blur(3px)}.workspace-dialog{width:min(1100px,calc(100vw - 44px))}.dialog-header{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:22px 28px;border-bottom:1px solid var(--line);background:var(--panel)}.dialog-header h2{font-size:19px;letter-spacing:-.02em;margin-top:4px}.dialog-header .eyebrow{font-size:9px}.dialog-header-right{display:flex;align-items:center;gap:11px}.workspace-body{display:grid;grid-template-columns:minmax(0,1fr) 247px;min-height:540px}.problem-pane{padding:27px 34px 32px;min-width:0}.problem-meta{display:flex;align-items:center;justify-content:space-between;gap:12px;color:var(--muted);font-size:10px;margin-bottom:25px}.problem-pane h3{font-size:25px;margin:0 0 11px}.problem-prompt{font-size:13px;color:var(--muted);max-width:590px;line-height:1.7;margin-bottom:20px}.main-expression{padding:24px 10px 29px;font-size:39px;min-height:105px;overflow-x:auto;text-align:center}.main-expression math{font-size:39px}.choice-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:24px}.choice{display:flex;align-items:center;gap:15px;min-height:82px;padding:17px;border:1px solid var(--line);border-radius:7px;cursor:pointer;font-size:23px;overflow-x:auto}.choice input{position:absolute;opacity:0;width:1px;height:1px}.choice-box{display:grid;place-items:center;min-width:23px;height:23px;border:1px solid var(--line);border-radius:4px;font-size:12px;font-family:Arial,sans-serif;color:var(--muted)}.choice:has(input:checked){border-color:var(--accent);background:var(--accent-soft)}.choice:has(input:checked) .choice-box{background:var(--accent);color:var(--panel);border-color:var(--accent)}.choice:has(input:focus-visible){outline:2px solid var(--accent);outline-offset:3px}.choice.correct-option{border-color:var(--accent);background:var(--accent-soft)}.choice.wrong-option{border-color:var(--wrong);background:var(--wrong-bg)}.choice.math-large math{font-size:20px}.choice-hint{font-size:11px;color:var(--muted);margin:0 0 12px}.answer-fields{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:19px}.answer-field>label{display:block;font-size:12px;font-weight:600;margin-bottom:8px}.math-input-shell{border:1px solid var(--line);border-radius:7px;background:var(--panel);overflow:hidden}.math-input-shell:focus-within{border-color:var(--accent);box-shadow:0 0 0 1px var(--accent)}.math-toolbar{display:flex;align-items:center;border-bottom:1px solid var(--line);background:var(--bg);padding:4px;gap:2px}.math-toolbar button{font-family:Georgia,serif;font-size:17px;height:30px;min-width:30px;flex:1;border-radius:3px;line-height:1}.math-toolbar button:hover{background:var(--accent-soft);color:var(--accent)}.math-toolbar button sup,.math-toolbar button sub{font-size:11px}.input-with-unit{display:flex;align-items:center;padding-right:12px}.math-entry{min-width:0;width:100%;padding:15px 12px;border:0;outline:0;background:none;color:var(--ink);font-family:Consolas,monospace;font-size:15px}.math-entry:focus-visible{outline:0}.math-entry::placeholder{font-family:Arial,sans-serif;font-size:12px;color:var(--muted)}.answer-unit{font-size:12px;color:var(--muted);white-space:nowrap}.math-preview{padding:9px 12px 13px;border-top:1px dashed var(--line);min-height:52px;color:var(--accent);display:flex;align-items:center;font-size:21px;overflow-x:auto}.math-preview>span{font-family:Georgia,serif;font-size:12px;font-style:italic;color:var(--muted)}.input-help{display:block;color:var(--muted);font-size:10px;line-height:1.6;margin-top:8px}.input-help code{font-size:10px;color:var(--ink)}.field-feedback{font-size:11px;margin-top:8px;color:var(--wrong)}.field-feedback.good{color:var(--accent)}.problem-actions{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-top:25px}.keyboard-note{font-size:10px;color:var(--muted)}.form-error{padding:11px 14px;color:var(--wrong);background:var(--wrong-bg);border-radius:5px;font-size:12px;margin-top:15px}.form-error:empty{display:none}.study-rail{background:var(--bg);border-left:1px solid var(--line);padding:27px 22px;display:flex;flex-direction:column;gap:24px}.rail-section .eyebrow{display:block;margin-bottom:12px}.rail-section p{font-size:11px;line-height:1.7;color:var(--muted);margin-top:10px}.difficulty-label{display:flex;align-items:center;justify-content:space-between;font-size:12px}.difficulty-bars{display:flex;gap:4px;margin-top:10px}.difficulty-bars i{height:7px;flex:1;background:var(--line);border-radius:1px}.difficulty-bars i.active{background:var(--accent)}.rail-tally{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:12px 0}.rail-tally b{display:block;font-size:24px;font-weight:400;letter-spacing:-.04em}.rail-tally small{font-size:10px;color:var(--muted)}.hint-box{font-size:12px;line-height:1.75;padding:14px;border:1px solid var(--line);border-radius:5px;background:var(--cream);color:var(--cream-ink);margin-top:12px}.rail-select{font-size:11px;min-height:35px;padding:7px 8px;margin-bottom:8px}.rail-bottom{margin-top:auto;font-size:10px;color:var(--muted);line-height:1.7}.feedback-panel{margin-top:25px;padding:19px 20px;background:var(--accent-soft);border:1px solid var(--line);border-radius:7px}.feedback-panel.wrong{background:var(--wrong-bg)}.feedback-heading{display:flex;align-items:center;gap:9px;font-size:15px;font-weight:600;margin-bottom:9px}.feedback-panel.wrong .feedback-heading{color:var(--wrong)}.feedback-panel p{font-size:12px;line-height:1.8}.solution{margin-top:14px}.solution summary{cursor:pointer;font-size:12px;font-weight:600}.solution-steps{list-style:none;counter-reset:steps;margin:15px 0 0;padding:0}.solution-steps li{position:relative;padding:0 0 16px 32px;font-size:12px;line-height:1.75;counter-increment:steps}.solution-steps li:before{content:counter(steps);position:absolute;left:0;top:2px;border:1px solid var(--line);border-radius:50%;width:20px;height:20px;display:grid;place-items:center;font-size:10px;background:var(--panel)}.solution-math{padding:7px 0;font-size:18px;overflow-x:auto}.takeaway{border-top:1px solid var(--line);margin-top:5px;padding-top:12px;font-size:11px!important}.choice-reason{border-top:1px solid var(--line);padding:12px 0;display:grid;grid-template-columns:25px 1fr;gap:8px}.choice-reason b{font-size:12px;color:var(--accent)}.choice-reason p{font-size:12px}.choice-reason math{font-size:19px;margin-bottom:7px}.geometry-diagram{width:100%;height:auto;display:block;margin:-3px auto 12px;max-height:300px;overflow:visible;color:var(--muted)}.geometry-diagram .shape{fill:var(--accent-soft);stroke:var(--ink);stroke-width:2.2;stroke-linejoin:round}.geometry-diagram .guide{stroke:var(--muted);stroke-width:1.3;stroke-dasharray:5 5}.geometry-diagram .dimension,.geometry-diagram .tick{stroke:var(--muted);stroke-width:1}.geometry-diagram .radius{stroke:var(--accent);stroke-width:1.5}.geometry-diagram .right-angle{stroke:var(--muted);stroke-width:1.2;fill:none}.geometry-diagram .center-dot{fill:var(--accent)}.geometry-diagram .dim-label{fill:var(--ink);font-size:14px;font-family:Arial,sans-serif;paint-order:stroke;stroke:var(--panel);stroke-width:5px;stroke-linejoin:round}.session-progress{height:3px;background:var(--line)}.session-progress>div{height:100%;background:var(--accent)}.session-summary{padding:45px 42px;max-width:730px;margin:auto;text-align:center}.summary-check{display:grid;place-items:center;width:55px;height:55px;margin:0 auto 22px;background:var(--accent-soft);color:var(--accent);border-radius:50%}.summary-check .icon{width:27px;height:27px}.session-summary h2{font-size:33px;margin:10px 0}.session-summary>p{font-size:13px;color:var(--muted);margin-bottom:24px}.summary-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:15px;padding:22px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line);margin:23px 0}.summary-stats b{display:block;font-size:28px;font-weight:400}.summary-stats small{color:var(--muted);font-size:11px}.summary-buttons{display:flex;justify-content:center;gap:12px;flex-wrap:wrap}.test-intro{text-align:left;margin:25px 0;background:var(--bg);border:1px solid var(--line);padding:20px;border-radius:7px}.test-intro p{font-size:13px;color:var(--muted);margin:9px 0}.diagnostic-review{text-align:left;border-top:1px solid var(--line);margin-top:28px;padding-top:22px}.diagnostic-review>details{border:1px solid var(--line);padding:14px 16px;border-radius:5px;margin-bottom:9px}.diagnostic-review summary{cursor:pointer;font-size:12px}.diagnostic-review .geometry-diagram{max-height:230px}
/* Account and reference windows */
.account-dialog{width:min(455px,calc(100vw - 32px));}.account-inner{padding:29px 33px 32px}.account-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:26px}.account-top .brand-mark{width:31px;height:35px;font-size:20px}.account-inner h2{font-size:27px;margin:8px 0 10px}.account-inner>p{font-size:12px;color:var(--muted);margin-bottom:20px;line-height:1.8}.auth-tabs{display:flex;gap:4px;padding:4px;background:var(--bg);border:1px solid var(--line);border-radius:6px;margin:21px 0}.auth-tabs button{flex:1;font-size:12px;padding:8px;border-radius:4px;color:var(--muted)}.auth-tabs .selected{background:var(--panel);box-shadow:0 1px 3px #0001;color:var(--ink)}.account-form label:not(.check-label){display:block;font-size:12px;font-weight:600;margin:17px 0 7px}.account-form .check-label{font-size:11px;color:var(--muted);margin:17px 0}.account-form>.btn{margin-top:6px}.auth-footer{border-top:1px solid var(--line);padding-top:17px;margin-top:20px;text-align:center;font-size:11px;color:var(--muted)}.auth-footer .text-btn{font-size:11px}.auth-fine{font-size:10px;color:var(--muted);margin-top:17px;line-height:1.7}.recovery-code{font-family:Consolas,monospace;word-break:break-all;padding:18px;background:var(--bg);border:1px dashed var(--accent);font-size:17px;margin:18px 0;letter-spacing:.03em}.reference-dialog{width:min(860px,calc(100vw - 36px))}.reference-body{padding:28px 35px 35px}.reference-tabs{display:flex;gap:12px;border-bottom:1px solid var(--line);padding-bottom:15px;margin-bottom:23px}.reference-tabs button{font-size:12px;color:var(--muted);padding:7px 12px;border-radius:4px}.reference-tabs button.selected{background:var(--accent-soft);color:var(--accent)}.formula-intro .eyebrow{display:block;margin-bottom:10px}.formula-intro h2{font-size:28px;margin-bottom:13px}.formula-intro p{font-size:12px;color:var(--muted);margin-bottom:25px;line-height:1.8}.formula-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}.formula-row{border:1px solid var(--line);border-radius:7px;padding:18px}.formula-row h3{font-size:17px;margin-bottom:17px}.formula-row>div{display:flex;align-items:center;gap:12px;margin:10px 0;font-size:19px;overflow-x:auto}.formula-row>div>span{font-size:8px;letter-spacing:.07em;color:var(--muted);width:63px;flex-shrink:0}.formula-row>p{font-size:11px;color:var(--muted);line-height:1.7;margin-top:15px}.reference-notes{display:grid;grid-template-columns:1fr 1fr;gap:23px;margin:28px 0;padding-top:22px;border-top:1px solid var(--line)}.reference-notes h3{font-size:17px;margin-bottom:12px}.reference-notes p{font-size:12px;color:var(--muted);line-height:1.8;margin:12px 0}.reference-equation{font-size:23px;display:flex;align-items:center;flex-wrap:wrap;gap:10px;margin:18px 0;overflow-x:auto}.formula-footnote{font-size:11px;color:var(--muted);padding-top:17px;border-top:1px solid var(--line)}.rule-card{margin:20px 0;padding:21px;border:1px solid var(--line);border-radius:7px}.rule-card p{font-size:13px;color:var(--muted);line-height:1.9}.rule-card h3{font-size:18px}.toast{position:fixed;bottom:24px;left:50%;transform:translate(-50%,15px);background:var(--ink);color:var(--panel);padding:13px 20px;box-shadow:var(--shadow);border-radius:6px;font-size:12px;opacity:0;pointer-events:none;transition:opacity .2s,transform .2s;z-index:999;max-width:calc(100vw - 30px)}.toast.visible{opacity:1;transform:translate(-50%,0)}.notice-inline{font-size:11px;color:var(--muted);margin:12px 0}.no-margin{margin:0}.readonly-note{font-size:10px;letter-spacing:.03em;color:var(--muted)}.plain-math{font-family:Georgia,serif}math{font-family:math,"Cambria Math","STIX Two Math",serif}input[type=checkbox]{accent-color:var(--accent)}[hidden]{display:none!important}
:root[data-large=true] .problem-prompt,:root[data-large=true] .solution-steps li,:root[data-large=true] .choice-reason p,:root[data-large=true] .feedback-panel p{font-size:16px}:root[data-large=true] .dim-label{font-size:16px}:root[data-reduce-motion=true] *{transition:none!important;animation:none!important}
@media(min-width:1450px){.main{padding-top:48px}.feature{min-height:235px}.feature-copy{padding:35px}.topic-card{padding:28px}}
@media(max-width:1150px){.app-shell{grid-template-columns:205px 1fr}.sidebar{width:205px;padding:28px 17px}.topbar{padding:0 30px}.main{padding:30px}.feature-copy{padding:26px}.feature-copy h2{font-size:25px}.topic-card{padding:20px}.topic-actions{align-items:flex-start;flex-direction:column}.topic-actions .btn{width:100%}.topic-description{min-height:65px!important}.workspace-body{grid-template-columns:minmax(0,1fr) 225px}.problem-pane{padding:26px}.study-rail{padding:25px 18px}.answer-fields{grid-template-columns:1fr}.math-preview{min-height:49px}}
@media(max-width:850px){.app-shell{grid-template-columns:176px 1fr}.sidebar{width:176px;padding:25px 12px}.brand{gap:8px}.brand-name{font-size:12px}.brand-sub{font-size:8px}.brand-mark{width:30px;height:36px}.nav-item{font-size:12px;gap:8px;padding:11px 8px}.nav-item .icon{width:17px;height:17px}.main{padding:27px 23px}.topbar{padding:0 23px;height:73px}.saved-label{display:none}.page-heading{margin-bottom:24px}.date-label{display:none}.feature{grid-template-columns:1fr}.feature-art{display:none}.feature-copy p{max-width:100%}.feature-copy h2{max-width:100%}.topic-grid{grid-template-columns:1fr}.topic-description{min-height:0!important}.topic-symbol{float:right;position:absolute;right:20px;top:50px;opacity:.3}.topic-card{position:relative}.topic-card h3{max-width:85%}.topic-actions{flex-direction:row;align-items:center}.topic-actions .btn{width:auto}.stat-item{padding-left:14px}.stat-value{font-size:24px}.stat-value span{display:block;margin-left:0;font-size:10px}.stat-label{font-size:10px}.stat-label .icon{display:none}.page-heading h1{font-size:33px}.section-title{align-items:flex-start;flex-direction:column;gap:12px}.search-box{width:100%}.progress-overview{grid-template-columns:1fr}.settings-grid{gap:17px}.workspace-body{grid-template-columns:1fr 200px}.study-rail{padding:24px 15px}.choice-grid{grid-template-columns:1fr}.choice{min-height:70px}.choice math{font-size:23px}.problem-pane{padding:25px}.geometry-diagram .dim-label{font-size:16px}.page-footer{flex-direction:column;gap:7px}}
@media(max-width:620px){.app-shell{display:block}.sidebar{display:none}.sidebar.open{display:flex;width:235px;box-shadow:0 0 0 100vmax #12231999;z-index:30}.main-wrap{width:100%}.topbar{height:65px;padding:0 18px}.mobile-menu{display:inline-grid}.breadcrumb{gap:8px;font-size:11px}.topbar-right{gap:8px}.topbar-right .btn{font-size:11px;min-height:35px;padding:8px 11px}.main{padding:25px 18px}.page-heading h1{font-size:31px}.page-heading .eyebrow{font-size:9px}.page-heading p{font-size:12px}.feature{margin-bottom:25px}.feature-copy{padding:23px}.feature-copy h2{font-size:26px}.feature-copy p{font-size:12px}.stat-strip{gap:8px;margin-bottom:24px;padding-bottom:23px}.stat-item{padding-left:9px}.stat-label{font-size:9px}.stat-value{font-size:23px}.stat-value span{font-size:9px}.topic-card{padding:22px}.topic-card h3{font-size:20px;max-width:84%}.topic-symbol{right:25px}.topic-actions .btn{padding:9px 14px}.bottom-note{align-items:flex-start;font-size:10px}.page-footer{font-size:9px}.banner{align-items:flex-start;font-size:11px;gap:10px}.banner .btn{white-space:nowrap;padding:7px 9px}.panel{padding:20px}.settings-grid{grid-template-columns:1fr}.grade-number{font-size:39px}.activity-grid{gap:5px}.activity-day small{font-size:8px}.saved-expression{display:none}.saved-row h3{font-size:12px}.saved-buttons .btn{font-size:10px}.recent-row time{max-width:70px;text-align:right}.account-actions .btn{width:100%}.workspace-dialog{width:100%;height:100dvh;max-height:100dvh;border:0;border-radius:0;margin:0}.dialog-header{padding:16px 18px;gap:10px}.dialog-header h2{font-size:15px;max-width:240px}.dialog-header .eyebrow{font-size:8px}.dialog-header-right .pill{display:none}.workspace-body{display:flex;flex-direction:column;min-height:0}.problem-pane{padding:22px 19px}.problem-pane h3{font-size:23px}.problem-prompt{font-size:12px;margin-bottom:12px}.problem-meta{margin-bottom:17px}.main-expression{padding:20px 0;font-size:32px;min-height:90px}.main-expression math{font-size:33px}.choice-grid{grid-template-columns:1fr 1fr;gap:9px}.choice{padding:11px;gap:9px;font-size:20px;min-height:75px}.choice math{font-size:20px}.choice-box{width:20px;min-width:20px;height:20px;font-size:10px}.choice.math-large math{font-size:18px}.study-rail{border-left:0;border-top:1px solid var(--line);padding:22px 19px;display:grid;grid-template-columns:1fr 1fr;gap:20px}.rail-bottom{grid-column:1/-1}.rail-section>p{font-size:10px}.rail-tally b{font-size:22px}.answer-fields{grid-template-columns:1fr;gap:17px}.geometry-diagram{margin:0 auto 10px;max-height:250px}.geometry-diagram .dim-label{font-size:16px}.keyboard-note{display:none}.problem-actions{justify-content:flex-end;margin-top:21px}.problem-actions .btn{flex:1}.feedback-panel{padding:17px 15px}.session-summary{padding:35px 22px}.session-summary h2{font-size:29px}.summary-stats b{font-size:25px}.summary-stats small{font-size:10px}.summary-buttons .btn{width:100%}.reference-dialog{width:calc(100vw - 20px);max-height:calc(100dvh - 20px)}.reference-body{padding:22px 19px}.formula-grid{grid-template-columns:1fr}.reference-notes{grid-template-columns:1fr;gap:10px}.formula-row>div{font-size:21px}.formula-row p{font-size:12px}.formula-intro h2{font-size:25px}.account-inner{padding:25px}.account-inner h2{font-size:26px}.account-top{margin-bottom:22px}.recovery-code{font-size:15px}.toast{bottom:15px;font-size:11px;text-align:center;width:max-content}.search-box{padding:11px 12px}.input-help{font-size:10px}.math-entry{font-size:16px}.math-toolbar button{min-height:34px}.math-preview{font-size:23px}.saved-label{display:none}.user-menu>span:not(.avatar){max-width:105px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.check-label{font-size:12px}.progress-overview .panel{margin-bottom:0}.progress-overview{margin-bottom:20px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important;scroll-behavior:auto!important}}

.topic-link{font:inherit;letter-spacing:inherit;text-align:left;padding:0;line-height:inherit}.topic-link:hover{text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:4px}

@media(max-width:620px){.workspace-dialog{max-width:100vw}.geometry-diagram .dim-label{font-size:22px}}
/* Expanded study workspace. Kept deliberately quiet: paper, readable type, useful controls. */
:root[data-accent=ink]{--accent:#354d68;--accent-soft:#eaf0f7}:root[data-accent=clay]{--accent:#87533e;--accent-soft:#f4eae3}:root[data-accent=plum]{--accent:#69516e;--accent-soft:#f1eaf3}
:root[data-theme=dark][data-accent=ink]{--accent:#b0cce8;--accent-soft:#29384b}:root[data-theme=dark][data-accent=clay]{--accent:#e5baa0;--accent-soft:#46322b}:root[data-theme=dark][data-accent=plum]{--accent:#d1b6d7;--accent-soft:#3c2d43}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}.sidebar{overflow-y:auto}.sidebar .nav-item{min-height:38px}.sidebar-bottom{padding-top:16px}.account-count{font-size:12px;color:var(--muted);border-bottom:1px dashed var(--line);white-space:nowrap}.topic-symbol{min-height:42px}.topic-meta{flex-wrap:wrap}.topic-card{display:flex;flex-direction:column}.topic-progress{margin-top:auto}.topic-description{min-height:66px}.topic-actions{gap:12px}.topic-actions .text-btn{max-width:48%;text-align:left}.section-controls{display:flex;justify-content:space-between;align-items:center;gap:12px;margin:18px 0}.button-row{display:flex;flex-wrap:wrap;gap:12px;align-items:center}.deck-topic-grid{border:0;padding:0;margin:20px 0;display:grid;grid-template-columns:1fr 1fr;gap:12px}.deck-topic{display:flex;gap:12px;align-items:flex-start;border:1px solid var(--line);border-radius:6px;padding:14px;cursor:pointer;background:var(--bg)}.deck-topic:has(input:checked){border-color:var(--accent);background:var(--accent-soft)}.deck-topic input{margin-top:5px;accent-color:var(--accent)}.deck-topic span{font-size:13px;font-weight:600}.deck-topic small{display:block;font-weight:400;color:var(--muted);margin-top:4px}.deck-options{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:20px;margin:24px 0}.deck-options fieldset{border:0;padding:0;margin:0}.deck-options label,.deck-options legend{font-size:12px;color:var(--muted)}.deck-options legend{margin-bottom:10px}.deck-options select{margin-top:10px;display:block;width:100%}.level-check{display:inline-flex;align-items:center;gap:5px;white-space:nowrap}.simple-list{margin-top:20px}.simple-list>div{display:flex;gap:16px;justify-content:space-between;padding:14px 0;border-bottom:1px solid var(--line);font-size:13px}.simple-list small{display:block;color:var(--muted)}.reward-hero{display:grid;grid-template-columns:270px 1fr;gap:48px;align-items:center;margin:28px 0 36px}.notebook-preview{height:310px;background:var(--accent-soft);color:var(--accent);border:1px solid var(--accent);border-left-width:10px;border-radius:3px 12px 12px 3px;padding:28px;display:flex;flex-direction:column;align-items:flex-start;box-shadow:5px 5px 0 var(--line)}.notebook-preview h2{font-size:26px;font-weight:600;margin:16px 0}.notebook-preview small{margin-top:auto}.notebook-mark{font-size:44px;line-height:1}.ink-balance{font-size:62px;line-height:1.2;margin:10px 0 15px;font-variant-numeric:tabular-nums}.ink-balance small{display:inline-block;font-size:13px;color:var(--muted);margin-left:12px}.ink-summary p+p{margin-top:14px}.badge-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:24px}.badge-card{display:flex;gap:14px;border:1px solid var(--line);padding:16px;border-radius:6px}.badge-card p{font-size:12px;color:var(--muted);margin:5px 0}.badge-card strong{font-size:13px}.badge-card small{font-size:11px}.badge-card.earned{border-color:var(--accent);background:var(--accent-soft)}.badge-symbol{font-size:24px;color:var(--accent)}.catalog-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin-top:24px}.catalog-item{display:flex;flex-direction:column;gap:10px;border:1px solid var(--line);border-radius:6px;padding:16px}.catalog-item strong{font-size:13px}.catalog-item p{font-size:12px;color:var(--muted);flex:1}.catalog-item .btn{font-size:11px;padding:8px}.item-swatch{height:72px;display:flex;align-items:center;justify-content:center;font-size:30px;background:var(--accent-soft);color:var(--accent);border-radius:4px;border:1px solid var(--line)}[data-swatch=forest]{background:#284936}[data-swatch=ink]{background:#354d68}[data-swatch=clay]{background:#87533e}[data-swatch=plum]{background:#69516e}[data-cover=grid].notebook-preview,[data-cover=grid].item-swatch{background-image:linear-gradient(90deg,#72847320 1px,transparent 1px),linear-gradient(#72847320 1px,transparent 1px);background-size:16px 16px}[data-cover=dots].notebook-preview,[data-cover=dots].item-swatch{background-image:radial-gradient(#72847350 1px,transparent 1px);background-size:12px 12px}[data-cover=lines].notebook-preview,[data-cover=lines].item-swatch{background-image:repeating-linear-gradient(transparent 0px,transparent 23px,#72847330 23px,#72847330 24px)}:root[data-cover=grid] .feature-art .graph-grid{opacity:.7}:root[data-cover=dots] .feature-art .graph-grid{background-image:radial-gradient(var(--accent) 1px,transparent 1px);background-size:16px 16px}:root[data-cover=lines] .feature-art .graph-grid{background-image:repeating-linear-gradient(transparent 0,transparent 23px,#72847340 23px,#72847340 24px)}.community-stats{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--line);border-radius:8px;margin:24px 0;background:var(--panel)}.community-stats>div{padding:24px;border-right:1px solid var(--line)}.community-stats>div:last-child{border:0}.community-stats strong{display:block;font-size:32px;font-weight:500}.community-stats span{font-size:12px;color:var(--muted)}.metric-tabs{display:flex;flex-wrap:wrap;gap:6px;margin:20px 0}.metric-tabs button{padding:9px 12px;border-radius:5px;font-size:12px;color:var(--muted);border:1px solid var(--line)}.metric-tabs button.selected{background:var(--accent-soft);color:var(--accent);border-color:var(--accent)}.table-scroll{overflow:auto}.leaderboard{width:100%;border-collapse:collapse;margin:24px 0 0;text-align:left;font-size:13px}.leaderboard th{font-size:11px;color:var(--muted);font-weight:400;padding:12px;border-bottom:1px solid var(--line)}.leaderboard td{padding:15px 12px;border-bottom:1px solid var(--line)}.leaderboard td:nth-child(2){display:flex;align-items:center;gap:12px}.leaderboard td:last-child,.leaderboard th:last-child{text-align:right;font-variant-numeric:tabular-nums}.leaderboard small{display:block;color:var(--muted);font-size:11px}.leader-mark{font-size:25px;width:32px;text-align:center}.leaderboard .my-row{background:var(--accent-soft)}.formula-card{padding:22px;border:1px solid var(--line);border-radius:5px}.formula-card h3{font-size:17px;margin-bottom:15px}.formula-card p{font-size:13px;color:var(--muted);margin-top:15px}.formula-value{font-size:22px}.formula-grid{margin-top:24px}.shape-givens{display:flex;gap:8px 20px;flex-wrap:wrap;margin:0 0 20px;padding:12px 16px;border:1px solid var(--line);border-radius:4px;font-size:12px;color:var(--muted);line-height:1.8}.shape-givens span{display:block}.diagram-wrap{margin:10px 0 20px}.diagram-expand{font-size:11px;display:block;margin-left:auto}.expanded-diagram .geometry-diagram{width:100%;max-height:none;height:auto}.expanded-diagram p{margin:12px 0}.compound-diagram .shape{fill:var(--accent-soft);stroke:var(--accent);stroke-width:2.4;stroke-linejoin:round}.compound-diagram .guide{stroke:var(--muted);stroke-width:1.5;stroke-dasharray:5 5;fill:none}.compound-diagram .dimension,.compound-diagram .tick{stroke:var(--muted);stroke-width:1;fill:none}.compound-diagram .dim-label{font:13px Arial,Helvetica,sans-serif;fill:var(--ink)}.number-line{width:100%;display:block;margin:12px 0;color:var(--accent)}.number-line text{font:13px Arial,Helvetica,sans-serif;fill:var(--ink)}.number-axis{stroke:var(--muted);stroke-width:1}.number-solution{stroke:var(--accent);stroke-width:4}.number-dot{stroke:var(--accent);stroke-width:2;fill:var(--panel)}.number-dot.closed{fill:var(--accent)}.number-arrow{stroke:var(--accent);stroke-width:3;fill:none}.math-toolbar{flex-wrap:wrap}.choice:has(.choice-box){min-width:0}.choice math{max-width:100%;overflow-x:auto}.choice-reason math{max-width:100%;overflow-x:auto}.main-expression{overflow-x:auto;max-width:100%}.reference-tabs{flex-wrap:wrap}.study-rail .btn+.btn{margin-top:10px}.study-rail .text-btn{margin-top:12px}.problem-pane{min-width:0}.diagram-wrap svg{overflow:visible}.topic-grid .topic-card h3{min-height:44px}
@media(min-width:1200px){.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.app-shell{grid-template-columns:240px minmax(0,1fr)}.sidebar{width:240px}}
@media(max-width:900px){.catalog-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.deck-options{grid-template-columns:1fr 1fr}.deck-options fieldset{grid-column:1/-1}.reward-hero{gap:24px;grid-template-columns:220px 1fr}.notebook-preview{height:290px;padding:20px}.notebook-preview h2{font-size:24px}.saved-label{display:none}}
@media(max-width:600px){.deck-topic-grid,.badge-grid{grid-template-columns:1fr}.reward-hero{grid-template-columns:1fr}.notebook-preview{max-width:260px;justify-self:center;width:100%;height:280px}.ink-summary{text-align:left}.ink-balance{font-size:48px}.community-stats>div{padding:16px 10px}.community-stats strong{font-size:26px}.community-stats span{font-size:10px}.section-controls{align-items:flex-start}.account-count{font-size:10px}.topbar-right{gap:8px}.catalog-grid{gap:10px}.catalog-item{padding:12px}.panel{padding:20px}.topic-description{min-height:0}.topic-actions{align-items:center}.topic-actions .btn{padding:9px 10px}.choice-grid{grid-template-columns:1fr}.shape-givens{padding:10px;font-size:11px;gap:5px 12px}.compound-diagram .dim-label{font-size:15px}.diagram-wrap{overflow:hidden}.numberline-preview{margin:0 -4px}.leaderboard td,.leaderboard th{padding:12px 7px}.topic-grid .topic-card h3{min-height:0}}
.diagram-caption{color:var(--muted);font-size:12px;line-height:1.6;margin:0 0 10px}.diagram-expand{margin-top:8px}

.main-wrap{min-width:0}.breadcrumb{min-width:0}.breadcrumb strong{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}@media(max-width:620px){.breadcrumb>span{display:none}.user-menu>span:not(.avatar){display:none}.topbar{gap:10px}.topbar-right{flex-shrink:0}.account-count{max-width:80px;overflow:hidden;text-overflow:ellipsis}}

/* Version 3: quiet study controls and a detailed, collectible notebook shelf. */
.community-stats .community-topics{border:0;background:none;text-align:left;font:inherit;color:inherit;cursor:pointer;border-radius:10px;padding:0}
.community-stats .community-topics:hover strong,.community-stats .community-topics:focus-visible strong{color:var(--accent)}
.community-stats .community-topics:focus-visible{outline:2px solid var(--accent);outline-offset:8px}
.workspace-dialog.question-fullscreen{position:fixed;inset:0;margin:0;width:100vw;max-width:100vw;height:100dvh;max-height:100dvh;border:0;border-radius:0;box-sizing:border-box;overscroll-behavior:contain}
.question-fullscreen .workspace-body{max-width:1560px;margin:0 auto;min-height:calc(100dvh - 110px)}
.question-fullscreen .dialog-header{position:sticky;top:0;z-index:5;background:var(--panel,#fff);padding-top:max(18px,env(safe-area-inset-top));}
.question-fullscreen .problem-pane{padding-top:34px;padding-bottom:max(32px,env(safe-area-inset-bottom))}
.fullscreen-toggle{white-space:nowrap;flex-shrink:0;gap:5px}
.fullscreen-toggle>span:first-child{font-size:20px;line-height:1}
.confetti-layer{position:absolute;left:0;right:0;height:500px;max-height:100%;overflow:hidden;z-index:20;pointer-events:none;contain:layout paint}
.confetti-piece{position:absolute;left:var(--x);top:14px;width:6px;height:10px;opacity:0;animation:answer-confetti 1.35s ease-out both}
@keyframes answer-confetti{0%{opacity:0;transform:translate(0,0) rotate(0)}10%{opacity:.9}70%{opacity:.8}100%{opacity:0;transform:translate(var(--drift),var(--fall)) rotate(var(--spin))}}
[data-reduce-motion="true"] .confetti-layer{display:none}
@media (prefers-reduced-motion:reduce){.confetti-layer{display:none}.cover-preview{transition:none!important}.feedback-panel{scroll-behavior:auto}}
.cover-preview{position:relative;isolation:isolate;width:144px;aspect-ratio:3/4;overflow:hidden;border-radius:3px 10px 10px 3px;background:#f3eddd;color:var(--cover-text,#294331);box-shadow:3px 4px 0 -1px #c5c1b3,6px 9px 15px -7px #13282a40;border:1px solid #192c282b;flex-shrink:0}
.cover-preview-large{width:240px;max-width:100%;transform:rotate(-3deg);box-shadow:4px 5px 0 -1px #ccc7b5,12px 15px 25px -12px #13282a66;justify-self:center}
.notebook-art{position:absolute;inset:0;width:100%;height:100%;z-index:-1}
.cover-lettering{position:absolute;left:12%;right:9%;top:34.5%;height:32.5%;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;text-align:center;padding:4px;box-sizing:border-box}
.cover-mark{font-family:Georgia,serif;font-size:16px;font-weight:400}
.cover-lettering strong{font-family:Georgia,serif;font-size:12px;font-weight:500;line-height:1.2;max-width:110px}
.cover-preview-large .cover-mark{font-size:27px}
.cover-preview-large .cover-lettering strong{font-size:23px;max-width:145px}
.cover-preview-large .cover-lettering small{font-size:9px;letter-spacing:.06em;line-height:1.2;max-width:160px}
.book-spine{position:absolute;top:0;bottom:0;left:0;width:9px;border-right:1px solid #0002;background:linear-gradient(90deg,#0003,transparent)}
.cover-preview[data-cover="grid"]{background-color:#f6f3df;background-image:linear-gradient(#acb7aa44 1px,transparent 1px),linear-gradient(90deg,#acb7aa44 1px,transparent 1px);background-size:14px 14px}
.cover-preview[data-cover="dots"]{background-color:#f6f3df;background-image:radial-gradient(#93a190 1px,transparent 1px);background-size:12px 12px}
.cover-preview[data-cover="lines"]{background-color:#f6f3df;background-image:repeating-linear-gradient(transparent 0 16px,#adbbaa 17px,transparent 18px)}
.cover-preview:not(.cover-illustrated) .cover-lettering{background:#f6f3dfdf;border:1px solid #c8b89055}
.catalog-grid.cover-catalog,.edition-grid{grid-template-columns:repeat(auto-fit,minmax(185px,1fr));gap:20px}
.catalog-item.cover-shop-card{padding:20px 16px 16px;align-items:center;display:flex;flex-direction:column;gap:14px}
.catalog-item.cover-shop-card .catalog-copy{width:100%}
.catalog-copy strong{display:block;line-height:1.35}
.catalog-copy p{font-size:12px;line-height:1.5}
.catalog-copy .ink-price{font-size:11px;font-weight:600;color:var(--muted,#58675d);display:block;margin-top:8px}
.cover-shop-card>.btn{margin-top:auto;width:100%;white-space:normal;line-height:1.4;min-height:40px}
.collector-panel{border-top:3px solid #ad9154}
.owned-editions{margin-top:24px;padding-top:20px;border-top:1px solid var(--border,#dce1d9)}
.owned-editions summary{cursor:pointer;font-weight:600;margin-bottom:16px}
.owned-editions .button-row{margin:12px 0 20px}.owned-editions select{max-width:370px;min-width:0}
.reward-hero{align-items:center}.ink-summary .notice-inline{margin:18px 0}
@media(min-width:1500px){.question-fullscreen .main-expression{font-size:36px}.question-fullscreen .problem-pane{padding-left:54px;padding-right:54px}}
@media(max-width:650px){.dialog-header-right{gap:4px;flex-wrap:wrap;justify-content:flex-end}.fullscreen-toggle{padding:6px 8px}.fullscreen-toggle>span:last-child{font-size:11px}.dialog-header>div:first-child{min-width:0}.dialog-header h2{font-size:18px}.question-fullscreen .workspace-body{min-height:0}.question-fullscreen .dialog-header{padding-left:14px;padding-right:10px}.cover-preview-large{width:190px;margin:12px auto 26px}.cover-preview-large .cover-lettering strong{font-size:19px}.cover-preview-large .cover-mark{font-size:21px}.catalog-grid.cover-catalog,.edition-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.catalog-item.cover-shop-card{padding:14px 9px 12px}.cover-shop-card .cover-preview{width:125px;max-width:100%}.cover-lettering strong{font-size:11px}.catalog-copy strong{font-size:13px}.catalog-copy p{font-size:11px}.catalog-item.cover-shop-card .btn{font-size:11px}.reward-hero{grid-template-columns:1fr}.community-stats{gap:14px}.confetti-layer{height:380px}}
@media(max-width:359px){.catalog-grid.cover-catalog,.edition-grid{grid-template-columns:1fr}.dialog-header .pill{display:none}}

.community-stats .community-topics{padding:24px;border:1px solid var(--line);background:var(--panel);border-radius:10px}.community-topics strong,.community-topics>span{display:block}.community-topics>span{font-size:12px;color:var(--muted)}#topics{scroll-margin-top:25px}
@media(max-width:600px){.community-stats .community-topics{padding:16px 10px}}

.ink-summary{min-width:0}.reward-hero{grid-template-columns:270px minmax(0,1fr)}.ink-summary .notice-inline{display:block;white-space:normal}.cover-shop-card{min-width:0}@media(max-width:900px){.reward-hero{grid-template-columns:220px minmax(0,1fr)}}@media(max-width:600px){.reward-hero{grid-template-columns:minmax(0,1fr)}}