:root{color-scheme:light;--bg:#f6f4ef;--panel:#ffffff;--panel-strong:#faf8f4;--ink:#1f1d19;--muted:#646055;--line:#e7e2d7;--accent:#2d6a4f;--accent-soft:#dff0e8;--shadow:0 10px 28px rgba(27,25,19,0.06);--motif-book:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 64 64' fill='none'%3E%3Cpath d='M10 15c0-3.314 2.686-6 6-6h17c4.5 0 8 3.5 8 8v33H18c-4.418 0-8 3.582-8 8V15Z' stroke='%232d6a4f' stroke-width='2.5'/%3E%3Cpath d='M54 15c0-3.314-2.686-6-6-6H31c-4.5 0-8 3.5-8 8v33h23c4.418 0 8 3.582 8 8V15Z' stroke='%232d6a4f' stroke-width='2.5'/%3E%3C/svg%3E");--motif-cap:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 64 64' fill='none'%3E%3Cpath d='M8 24 32 14l24 10-24 10L8 24Z' stroke='%232d6a4f' stroke-width='2.5' stroke-linejoin='round'/%3E%3Cpath d='M18 30v10c0 3 7 8 14 8s14-5 14-8V30' stroke='%232d6a4f' stroke-width='2.5' stroke-linecap='round'/%3E%3Cpath d='M56 24v14' stroke='%232d6a4f' stroke-width='2.5' stroke-linecap='round'/%3E%3Cpath d='M56 38c-2 0-3.5 1.5-3.5 3.5S54 45 56 45s3.5-1.5 3.5-3.5S58 38 56 38Z' fill='%232d6a4f'/%3E%3C/svg%3E")}*{box-sizing:border-box}body,html{margin:0;padding:0;min-height:100%;background:var(--bg);color:var(--ink)}body{font-family:var(--font-body),sans-serif}button,input,select,textarea{font:inherit}.shell{max-width:1240px;margin:0 auto;padding:24px 20px 40px}.shell-study{max-width:none;padding-top:18px}.topbar{display:grid;grid-template-columns:minmax(0,1fr) auto;grid-gap:16px;gap:16px;align-items:center;margin-bottom:20px}.study-topbar{display:flex;justify-content:space-between;align-items:flex-start;gap:16px;margin:0 auto 28px;max-width:940px;padding:6px 0 18px;border-bottom:1px solid rgba(143,47,36,.12)}.card h2,.diagram-meta h3,.review-head h3,.study-topbar h1,.topbar h1{margin:0;font-family:var(--font-display),sans-serif;letter-spacing:-.025em}.study-topbar h1,.topbar h1{font-size:clamp(1.8rem,2.5vw,2.5rem);line-height:1.05}.subtle-copy{margin:8px 0 0;color:var(--muted);font-size:.98rem;line-height:1.5}.topbar-meta{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.eyebrow{margin:0 0 8px;text-transform:uppercase;letter-spacing:.22em;font-size:.72rem;color:var(--accent)}.workspace{display:grid;grid-template-columns:320px minmax(0,1fr);grid-gap:20px;gap:20px}.workspace-study{display:block}.control-column,.output-column,.stack{display:grid;grid-gap:18px;gap:18px}.output-column{align-content:start;align-items:start}.output-column-study{max-width:940px;margin:0 auto}.mini-metrics{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.card,.diagram-shell,.review-card{background:var(--panel);border:1px solid var(--line);box-shadow:var(--shadow);border-radius:18px}.card,.review-card{padding:20px}.card-head,.diagram-meta,.review-head{display:flex;justify-content:space-between;align-items:flex-start;gap:16px}.field{display:grid;grid-gap:8px;gap:8px}.field span{color:var(--muted);font-size:.95rem}.field input,.field select,.field textarea{width:100%;border:1px solid #d9d2c4;border-radius:12px;background:#fff;padding:12px 14px;color:var(--ink)}.field textarea{resize:vertical}.content-grid,.metric-grid,.range-grid{display:grid;grid-gap:14px;gap:14px}.input-type-tabs{display:grid;grid-template-columns:repeat(3,1fr);grid-gap:4px;gap:4px;padding:4px;background:var(--panel-strong);border-radius:10px}.input-type-tab{border:none;background:none;border-radius:7px;padding:7px 0;font-size:.85rem;font-weight:500;color:var(--muted);cursor:pointer;transition:background .12s,color .12s}.input-type-tab:hover{color:var(--ink)}.input-type-tab.is-active{background:#fff;color:var(--ink);font-weight:600;box-shadow:0 1px 4px rgba(0,0,0,.08)}.model-selector{display:grid;grid-template-columns:repeat(3,1fr);grid-gap:6px;gap:6px}.model-selector-btn{flex:1 1;padding:7px 0;border:1.5px solid #e3dccf;border-radius:10px;background:transparent;font-size:.85rem;font-weight:500;color:var(--muted);cursor:pointer;transition:background .12s,color .12s,border-color .12s}.model-selector-btn.is-active{background:#fff;box-shadow:0 1px 4px rgba(0,0,0,.07);font-weight:600}.model-selector-btn.is-active,.model-selector-btn:hover:not(.is-active){color:var(--ink);border-color:#c8bfb4}.range-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.metric-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.content-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.comparison-grid,.comparison-summary-grid{display:grid;grid-gap:16px;gap:16px}.comparison-grid{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}.diagram-meta p,.inline-message,.notice-box,.option-list,.ordered-list,.plain-list,.review-head p,.status-copy,.supporting-copy{color:var(--muted)}.phase-actions{display:grid;grid-gap:10px;gap:10px;margin-top:4px}.ghost-button,.primary-button,.secondary-button{border-radius:12px;border:1px solid transparent;padding:12px 16px;cursor:pointer;transition:background-color .12s ease,border-color .12s ease,color .12s ease}.ghost-button:hover,.primary-button:hover,.secondary-button:hover{border-color:#d3cbbe}.primary-button{background:var(--accent);color:white}.secondary-button{background:#fff}.ghost-button,.secondary-button{border-color:#d9d2c4;color:var(--ink)}.ghost-button{background:var(--panel-strong)}.ghost-button:disabled,.primary-button:disabled,.secondary-button:disabled{cursor:not-allowed;opacity:.5}.toggle{display:inline-flex;align-items:center;gap:10px;color:var(--muted)}.toggle input{accent-color:var(--accent)}.metric-pill{display:grid;grid-gap:4px;gap:4px;padding:12px 14px;border-radius:12px;background:var(--panel-strong);border:1px solid var(--line)}.metric-pill span{font-size:.76rem;text-transform:uppercase;letter-spacing:.15em;color:var(--muted)}.metric-pill strong{font-size:1rem}.step-pill{align-items:start}.step-pill.step-running{border-color:#d9c27d;background:#fff8df}.step-pill.step-success{border-color:#b9d7b2;background:#eef8ea}.step-pill.step-fallback{border-color:#d7c7b2;background:#f6efe8}.step-pill.step-failed{border-color:#e2b0b0;background:#fff0f0}.view-switcher{display:inline-flex;align-items:center;gap:6px;padding:4px;background:var(--panel);border:1px solid var(--line);border-radius:12px;width:auto;max-width:100%}.view-switcher-button{all:unset;display:inline-flex;align-items:center;justify-content:center;white-space:nowrap;padding:10px 14px;border-radius:10px;color:var(--muted);cursor:pointer;line-height:1}.view-switcher-button:hover{background:#f4f1ea}.view-switcher-button.is-active{background:var(--accent-soft);color:var(--accent)}.empty-state{width:100%;min-height:220px;padding:24px;background:var(--panel);border:1px solid var(--line);border-radius:18px;display:grid;align-content:start;grid-gap:8px;gap:8px}.empty-state h2{margin:0;font-family:var(--font-display),sans-serif}.option-list,.ordered-list,.plain-list{margin:0;padding-left:20px;display:grid;grid-gap:10px;gap:10px}.lesson-block,.mcq-card,.plain-list li{background:var(--panel-strong);border:1px solid var(--line);border-radius:14px;padding:24px}.plain-list li{list-style:none}.lesson-block p,.mcq-card p,.plain-list li p{margin:0;line-height:1.76}.lesson-block{position:relative;display:grid;grid-gap:18px;gap:18px;overflow:hidden}.lesson-block:after{content:"";position:absolute;top:20px;right:20px;width:56px;height:56px;background-image:var(--motif-book);background-repeat:no-repeat;background-size:contain;opacity:.06;pointer-events:none}.lesson-block:nth-of-type(2n):after{background-image:var(--motif-cap)}.lesson-block h3{margin:0;padding-right:56px;font-size:clamp(1.55rem,2.2vw,2.2rem);line-height:1.14;letter-spacing:-.03em}.lesson-block-analogy,.lesson-block-simplify{gap:20px}.lesson-block-simplify[id]{scroll-margin-top:40px}.lesson-lead{max-width:62ch;font-size:1.1rem;line-height:1.88;color:var(--ink)}.lesson-overview{max-width:64ch;font-size:clamp(1.08rem,1.45vw,1.2rem);line-height:1.84;color:#5d5649}.lesson-panel-label{margin:0 0 8px;color:var(--muted);font-size:.78rem;text-transform:uppercase;letter-spacing:.14em}.lesson-chip-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.lesson-chip{border:1px solid #e0b8ab;background:#dff0e8;color:#2d6a4f;font-weight:600;border-radius:999px;padding:8px 12px;font-size:.92rem;line-height:1.2;cursor:pointer;transition:border-color .12s ease,background-color .12s ease,transform .12s ease,color .12s ease}.lesson-chip:hover{border-color:#2d6a4f;transform:translateY(-1px)}.lesson-chip.is-open{background:#2d6a4f;border-color:#2d6a4f;color:#fff}.lesson-chip-shimmer{animation:chip-pulse 2.5s ease infinite}@keyframes chip-pulse{0%,to{border-color:#e0b8ab;box-shadow:none}50%{border-color:#2d6a4f;box-shadow:0 0 0 3px #dff0e8}}.lesson-reveal-panel{padding:16px 18px;border-radius:16px;border:1px solid #e3d0c2;border-left:3px solid rgba(143,47,36,.22);background:#fffaf5;box-shadow:inset 0 1px 0 rgba(255,255,255,.72)}.lesson-reveal-panel p{color:var(--ink)}.lesson-reveal-panel-muted{background:#fbf4ef;border-color:#e2d4c8 #e2d4c8 #e2d4c8 rgba(143,47,36,.16)}.lesson-reveal-panel-worked{background:#fff8f0}.ordered-list-tight{gap:8px;line-height:1.7}.mcq-header{display:flex;justify-content:space-between;align-items:center;gap:12px}.mcq-header h3{margin:0}.exam-takeaway,.inline-note,.notice-box{margin-top:14px;padding:18px 20px;border-radius:16px;background:var(--accent-soft);border:1px solid #ead0c8}.analogy-panel{font-size:1.04rem;line-height:1.78;background:linear-gradient(180deg,#f9ece7,#f6e6e0)}.analogy-panel p:last-child{color:var(--ink)}.exam-takeaway{background:linear-gradient(180deg,#f8e9e3,#f5ddd5);font-size:1.02rem;line-height:1.76}.lesson-takeaway-compact{margin-top:0;padding:14px 16px;border-left:4px solid #a43b2d;background:linear-gradient(180deg,#f9ece6,#f6e1d8)}.lesson-takeaway-compact p:last-child{font-weight:600;color:#542117}.lesson-footnote{font-size:.94rem;line-height:1.7;color:var(--muted);font-style:italic;border-top:1px solid #efe4d8;padding-top:14px}.section-intro{display:grid;grid-gap:6px;gap:6px}.section-intro h3{margin:0;font-size:1.3rem;line-height:1.2}.mcq-card,.mcq-options{display:grid;grid-gap:10px;gap:10px}.mcq-option{width:100%;display:grid;grid-template-columns:24px 1fr;grid-gap:10px;gap:10px;align-items:start;text-align:left;border:1px solid #d9d2c4;border-radius:12px;background:#fff;color:var(--ink);padding:12px 14px;cursor:pointer;transition:background-color .12s ease,border-color .12s ease,transform .12s ease,color .12s ease}.mcq-option:hover:not(:disabled){border-color:#cbbba8;transform:translateY(-1px)}.mcq-option:disabled{cursor:default}.mcq-option.is-correct{background:#eef8ea;border-color:#b9d7b2}.mcq-option.is-wrong{background:#fff0f0;border-color:#e2b0b0}.mcq-option.is-dimmed{opacity:.72}.mcq-feedback{margin-top:4px;padding:12px 14px;border-radius:12px;border:1px solid #d9d2c4}.mcq-feedback.is-correct{background:#eef8ea;border-color:#b9d7b2}.mcq-feedback.is-wrong{background:#fff0f0;border-color:#e2b0b0}.review-actions{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.json-pane{margin:0;padding:18px;border-radius:12px;overflow:auto;background:#181613;color:#f3ede3;font-size:.88rem;line-height:1.6}.summary-toggle{cursor:pointer;margin:14px 0 0;color:var(--accent);font-weight:600}.diagram-shell{overflow:hidden}.diagram-meta{padding:18px 18px 0}.visual-card-meta{align-items:center}.visual-card-actions{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.diagram-canvas{height:520px}.diagram-canvas,.study-diagram{margin-top:12px;border-top:1px solid var(--line)}.study-diagram{background:linear-gradient(180deg,#fffdf8,#faf6ef)}.study-diagram-inline{padding:20px}.study-diagram-expanded{padding:24px}.study-table-shell{overflow-x:auto}.study-table{width:100%;min-width:560px;border-collapse:collapse}.study-table td,.study-table th{padding:14px 16px;border:1px solid #e3dccf;text-align:left;vertical-align:top}.study-table th{background:#f5efe6;font-family:var(--font-display),sans-serif;font-size:.98rem}.study-table td{background:#fffdf9;color:var(--muted);line-height:1.55}.study-table tr.is-emphasis td{background:#fdf0eb}.study-axis-label,.study-label{margin:0 0 14px;color:var(--muted);font-size:.82rem;text-transform:uppercase;letter-spacing:.14em}.formula-shell,.threshold-shell{display:grid;grid-gap:18px;gap:18px}.threshold-band-list{display:grid;grid-gap:14px;gap:14px}.threshold-band-card{display:grid;grid-template-columns:minmax(0,1fr) auto;grid-gap:16px;gap:16px;align-items:start;padding:16px 18px;border-radius:16px;border:1px solid #e3dccf;background:#fffdf9}.threshold-note,.threshold-range{margin:0}.threshold-range{font-family:var(--font-display),sans-serif;font-size:1.05rem}.threshold-note{margin-top:8px;color:var(--muted);line-height:1.55}.threshold-value{display:inline-flex;align-items:center;justify-content:center;min-width:110px;padding:10px 14px;border-radius:999px;background:#fdf0eb;color:var(--accent);font-size:1rem}.formula-component-card,.formula-expression-card,.formula-worked-example{padding:18px;border-radius:16px;border:1px solid #e3dccf;background:#fffdf9}.formula-expression{font-family:var(--font-display),sans-serif;font-size:clamp(1.3rem,2vw,1.8rem);line-height:1.25;letter-spacing:-.02em}.formula-components-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));grid-gap:14px;gap:14px}.formula-component-head,.formula-result-row,.formula-step-row{display:flex;justify-content:space-between;align-items:flex-start;gap:12px}.formula-component-card p{margin:10px 0 0;color:var(--muted);line-height:1.55}.formula-example-chip{display:inline-flex;align-items:center;padding:6px 10px;border-radius:999px;background:#f5efe6;color:var(--muted);font-size:.88rem}.formula-worked-steps{display:grid;grid-gap:12px;gap:12px}.formula-result-row,.formula-step-row{padding:12px 0;border-bottom:1px solid #eee6d8}.formula-result-row span,.formula-step-row span{color:var(--muted);line-height:1.5}.formula-result-row{border-bottom:none;padding-bottom:0}.diagram-canvas-expanded{height:calc(100vh - 170px);min-height:760px}.diagram-shell-expanded{border:none;box-shadow:none}.diagram-shell-expanded .diagram-meta{display:none}.illustration-shell{overflow:hidden}.illustration-shell-expanded{background:transparent}.illustration-viewport{position:relative;margin-top:12px;border-top:1px solid var(--line);background:linear-gradient(180deg,#fffdf8,#faf6ef)}.illustration-viewport-inline{padding:18px;min-height:520px}.illustration-viewport-expanded{margin-top:0;min-height:calc(100vh - 170px);padding:10px 0 0;border-top:none;background:transparent}.illustration-image,.illustration-viewport-expanded .illustration-image,.illustration-viewport-inline .illustration-image{object-fit:contain}.diagram-modal-backdrop{position:fixed;inset:0;background:rgba(23,20,16,.7);display:grid;place-items:center;padding:24px;z-index:80}.diagram-modal{width:min(1480px,100%);max-height:calc(100vh - 48px);overflow:auto;padding:18px 20px 20px;background:var(--panel);border:1px solid var(--line);border-radius:22px;box-shadow:0 30px 80px rgba(20,18,15,.25)}.diagram-modal-toolbar{display:flex;justify-content:space-between;align-items:center;gap:16px;margin-bottom:16px}.diagram-modal-status{display:grid;grid-gap:6px;gap:6px}.visual-modal-title{color:var(--muted);line-height:1.45}.diagram-modal-actions{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.visual-note-backdrop{position:fixed;inset:0;background:rgba(23,20,16,.42);display:grid;place-items:center;padding:24px;z-index:90}.visual-note-popover{width:min(460px,100%);padding:22px;border-radius:20px;background:var(--panel);border:1px solid var(--line);box-shadow:0 30px 80px rgba(20,18,15,.22);display:grid;grid-gap:12px;gap:12px}.visual-note-popover h3{margin:0;font-size:1.35rem}.visual-note-popover p:last-of-type{color:var(--muted);line-height:1.7}.fallback-note{margin:0 0 14px;padding:12px 14px;border-radius:12px;background:#f6efe8;border:1px solid #d7c7b2;color:var(--muted)}.error-copy{color:#a01010;font-weight:600}.decision-tree-shell{display:grid;grid-gap:14px;gap:14px;padding:20px;border-radius:16px;border:1px solid #e3dccf;background:#fffdf9}.decision-node-question{font-size:1.05rem;line-height:1.6}.decision-node-outcome{font-family:var(--font-display);font-size:1.1rem;color:var(--accent)}.decision-node-rule{color:var(--muted);font-size:.95rem;margin-top:6px}.dt-header{display:flex;align-items:center;justify-content:space-between;gap:10px;min-height:22px}.dt-crumbs{display:flex;gap:6px;flex-wrap:wrap}.dt-crumb{font-size:.78rem;font-weight:600;padding:2px 9px;border-radius:20px;letter-spacing:.02em}.dt-crumb-yes{background:#e8f4ec;color:#1a6b3c}.dt-crumb-no{background:#fdf3e8;color:#8a4e00}.dt-map-btn{background:none;border:none;cursor:pointer;font-size:.82rem;color:var(--muted);white-space:nowrap;padding:0;transition:color .12s}.dt-map-btn:hover{color:var(--ink)}.dt-choice-grid{display:grid;grid-template-columns:1fr 1fr;grid-gap:12px;gap:12px}.dt-choice-card{display:flex;flex-direction:column;gap:6px;text-align:left;padding:18px 16px;border-radius:14px;border:1.5px solid #e3dccf;background:#fff;cursor:pointer;transition:transform .12s ease,box-shadow .12s ease,border-color .12s ease,background .12s ease}.dt-choice-card:hover{transform:translateY(-2px);box-shadow:0 4px 14px rgba(0,0,0,.07)}.dt-choice-yes:hover{border-color:#9ecfb0;background:#f4faf6}.dt-choice-no:hover{border-color:#e8c98a;background:#fdf8f0}.dt-choice-arrow{font-size:1.3rem;line-height:1}.dt-choice-yes .dt-choice-arrow{color:#1a7a3c}.dt-choice-no .dt-choice-arrow{color:#9a5c00}.dt-choice-label{font-size:1rem;font-weight:700;color:var(--ink)}.dt-choice-preview{font-size:.82rem;color:var(--muted);line-height:1.45;margin-top:2px}.dt-restart-btn{background:none;border:none;cursor:pointer;font-size:.88rem;color:var(--muted);padding:0;text-align:left;transition:color .12s}.dt-restart-btn:hover{color:var(--ink)}.worked-example-shell{display:grid;grid-gap:14px;gap:14px;padding:18px;border-radius:16px;border:1px solid #e3dccf;background:#fffdf9}.worked-example-expression{font-family:var(--font-display);font-size:clamp(1.1rem,1.8vw,1.5rem);letter-spacing:-.02em}.worked-example-steps{display:grid;grid-gap:10px;gap:10px}.worked-example-row{display:flex;justify-content:space-between;gap:12px;padding:10px 0;border-bottom:1px solid #eee6d8;font-feature-settings:"tnum";font-variant-numeric:tabular-nums}.worked-example-row:last-child{border-bottom:none;font-weight:600}.fill-in-input{border:1px solid #d9d2c4;border-radius:8px;padding:8px 12px;font:inherit;font-feature-settings:"tnum";font-variant-numeric:tabular-nums;width:120px}.fill-in-correct{color:#2a6e23;border-color:#b9d7b2;background:#eef8ea}.fill-in-wrong{color:#8a1c1c;border-color:#e2b0b0;background:#fff0f0}.recall-shell{display:flex;flex-direction:column;gap:20px}.recall-progress{text-align:center;color:var(--muted);font-size:.88rem;margin:0}.recall-card{display:flex;flex-direction:column;gap:18px;background:var(--panel);border:1px solid var(--line);border-radius:18px;padding:32px}.recall-concept{margin:0;font-family:var(--font-display),sans-serif;font-size:clamp(1.3rem,2vw,1.8rem);letter-spacing:-.03em}.recall-prompt{margin:0;color:var(--muted);font-size:.9rem}.recall-textarea{width:100%;min-height:120px;resize:vertical;border:1px solid var(--line);border-radius:10px;padding:12px 14px;font-size:1rem;font-family:inherit;background:var(--bg);color:var(--ink);transition:opacity .3s;box-sizing:border-box}.recall-textarea:focus{outline:2px solid var(--accent);outline-offset:2px}.recall-textarea:disabled{opacity:.6;background:var(--surface);cursor:default}.recall-reference{background:var(--surface);border-radius:12px;padding:20px 22px;display:flex;flex-direction:column;gap:10px;border-left:4px solid var(--accent)}.recall-reference-label{margin:0;font-size:.65rem;text-transform:uppercase;letter-spacing:.2em;color:var(--muted)}.recall-takeaway{margin:0;font-weight:600;line-height:1.5}.recall-explanation{margin:0;color:var(--muted);font-size:.95rem;line-height:1.65}.recall-steps{margin:6px 0 0;padding-left:18px;display:flex;flex-direction:column;gap:4px;font-size:.9rem;line-height:1.5}.recall-score{display:flex;align-items:baseline;gap:10px;padding:10px 14px;border-radius:10px;border:1px solid}.recall-score-label{font-size:.92rem;font-weight:600}.recall-score-sub{font-size:.8rem;opacity:.7}.recall-score-not-quite{color:var(--muted);border-color:var(--line)}.recall-score-on-track{color:#865a00;border-color:#e8d39a;background:#fdf9ef}.recall-score-almost{color:#1a4f7a;border-color:#aacde8;background:#eef5fb}.recall-score-nailed{color:#1a7a3c;border-color:#b7dfc5;background:#edf7f1}.recall-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.recall-done{margin:0;color:var(--muted);font-size:.9rem}.recall-nav{display:flex;gap:10px;justify-content:center}.dt-canvas-backdrop{position:fixed;inset:0;background:rgba(23,20,16,.65);display:grid;place-items:center;padding:24px;z-index:80}.dt-canvas-modal{width:min(1200px,94%);max-height:calc(100vh - 48px);display:flex;flex-direction:column;background:var(--panel);border:1px solid var(--line);border-radius:22px;box-shadow:0 30px 80px rgba(20,18,15,.25);overflow:hidden}.dt-canvas-header{display:flex;justify-content:space-between;align-items:center;gap:16px;padding:16px 20px;border-bottom:1px solid var(--line);flex-shrink:0}.dt-canvas-scroll{overflow:auto;flex:1 1;padding:24px;background:#faf8f4}.dt-canvas-scroll canvas{display:block}.step-answer-cell{justify-content:flex-end;flex:1 1;min-width:0}.step-answer-cell,.step-blank{display:flex;align-items:center}.step-blank{gap:6px}.step-answer{font-size:inherit;line-height:1.5}.step-answer.is-correct{color:#1a7a3c;font-weight:600}.step-answer.is-wrong{display:flex;gap:8px;align-items:center;flex-wrap:wrap;color:#2d6a4f}.step-answer.is-revealed{animation:step-reveal .28s cubic-bezier(.34,1.56,.64,1);transform-origin:left center}@keyframes step-reveal{0%{opacity:0;transform:scaleX(.6)}to{opacity:1;transform:scaleX(1)}}.fillin-blank-list{display:flex;flex-direction:column;gap:14px}.fillin-blank-row{font-size:.95rem;line-height:1.7}.fillin-sentence{display:inline}.fillin-answer{display:inline-flex;align-items:center;gap:8px;font-weight:600;padding:0 4px}.fillin-answer.is-correct{color:#1a7a3c}.fillin-answer.is-wrong{color:#2d6a4f;font-weight:400}.fillin-answer.is-revealed{color:#5a4a2f;animation:step-reveal .28s cubic-bezier(.34,1.56,.64,1);transform-origin:left center}.study-layout{display:flex;align-items:stretch;min-height:100vh;gap:0}.study-ambient-panel{position:-webkit-sticky;position:sticky;top:0;width:22%;flex-shrink:0;height:100vh;background:#0f0e14;border-radius:20px;overflow:hidden}.study-ambient-panel:before{content:"";position:absolute;inset:0;z-index:0;background-image:repeating-linear-gradient(0deg,rgba(255,255,255,.05),rgba(255,255,255,.05) 1px,transparent 0,transparent 32px),repeating-linear-gradient(90deg,rgba(255,255,255,.05),rgba(255,255,255,.05) 1px,transparent 0,transparent 32px);pointer-events:none}.study-ambient-orb{position:absolute;border-radius:50%;pointer-events:none;filter:blur(80px)}.study-ambient-orb-1{width:260px;height:260px;top:-60px;left:-80px;background:radial-gradient(circle,rgba(120,60,200,.55) 0,transparent 70%)}.study-ambient-orb-2{width:200px;height:200px;top:40%;left:10%;background:radial-gradient(circle,rgba(180,60,50,.45) 0,transparent 70%)}.study-ambient-orb-3{width:220px;height:220px;bottom:80px;right:-60px;background:radial-gradient(circle,rgba(40,80,200,.4) 0,transparent 70%)}.study-ambient-orb-4{width:160px;height:160px;bottom:20%;left:50%;background:radial-gradient(circle,rgba(80,160,120,.3) 0,transparent 70%)}.study-toc-window{position:absolute;top:0;left:0;right:0;z-index:1;padding:24px 16px 40px;background:linear-gradient(180deg,rgba(15,14,20,.97) 60%,transparent);display:flex;flex-direction:column;gap:8px;max-height:72%}.study-toc-heading{margin:0;font-size:.63rem;text-transform:uppercase;letter-spacing:.22em;color:rgba(255,255,255,.28);flex-shrink:0}.study-toc-list{display:flex;flex-direction:column;gap:1px;overflow-y:auto;scrollbar-width:none}.study-toc-list::-webkit-scrollbar{display:none}.study-toc-item{display:block;width:100%;background:none;border:none;text-align:left;padding:6px 8px;border-radius:6px;font-size:.78rem;line-height:1.35;color:rgba(255,255,255,.48);cursor:pointer;transition:color .15s,background .15s}.study-toc-item:hover{color:rgba(255,255,255,.88);background:rgba(255,255,255,.06)}.study-reading-column{flex:1 1;min-width:0;padding:48px 64px;font-size:1.12rem;line-height:1.92}.study-reading-column .stack{gap:64px}.study-reading-column .lesson-block .stack{gap:18px}.study-reading-column .lesson-block{background:transparent;border:none;box-shadow:none;padding:0;gap:28px;overflow:visible}.study-reading-column .lesson-block:after{display:none}.study-reading-column .lesson-block h3{font-size:clamp(1.6rem,2.4vw,2.4rem);letter-spacing:-.04em;padding-right:0}.study-reading-column .lesson-takeaway-compact{background:transparent;border-radius:0;border:none;border-left:4px solid #a43b2d;padding:4px 0 4px 16px;margin-top:0}.study-reading-column .lesson-lead{font-size:1.12rem;line-height:1.92;max-width:70ch}.study-reading-column .analogy-panel{border-radius:0;border:none;border-left:3px solid rgba(143,47,36,.3);background:rgba(249,236,231,.4);padding:16px 20px;margin-top:0}.study-reading-column .lesson-overview{font-size:clamp(1.12rem,1.5vw,1.25rem);line-height:1.92;color:var(--muted);max-width:72ch}.study-reading-column.is-full-width{max-width:900px;margin:0 auto}.revise-section{display:flex;flex-direction:column;gap:32px}.revise-tab-bar{display:flex;gap:6px;flex-wrap:wrap;border-bottom:1px solid var(--line);padding-bottom:16px}.revise-tab{background:none;border:1px solid transparent;border-radius:8px;padding:7px 14px;font-size:.88rem;color:var(--muted);cursor:pointer;transition:color .15s,border-color .15s,background .15s}.revise-tab:hover{color:var(--ink);background:var(--surface)}.revise-tab.is-active{color:var(--ink);border-color:var(--line);background:var(--panel);font-weight:600}.revise-tab.is-disabled{opacity:.35;text-decoration:line-through;cursor:not-allowed;pointer-events:none}.revise-panel{min-height:200px}.revise-aid-block{display:flex;flex-direction:column;gap:12px}.revise-aid-label{margin:0;font-size:.82rem;font-weight:600;text-transform:uppercase;letter-spacing:.1em;color:var(--muted)}.revise-empty{margin:0;color:var(--muted);font-size:.95rem;padding:32px 0}@media (max-width:1080px){.comparison-summary-grid,.content-grid,.study-topbar,.topbar,.workspace{grid-template-columns:1fr}.control-column{order:2}.output-column{order:1}.topbar-meta{justify-content:flex-start}.view-switcher{flex-wrap:wrap}.study-topbar{max-width:100%}.study-layout{flex-direction:column}.study-ambient-panel{position:static;width:100%;height:auto;min-height:140px;border-radius:16px}.study-toc-window{max-height:60%;padding:20px 14px 32px}.study-reading-column{padding:32px 24px}}@media (max-width:680px){.shell{padding:24px 16px 40px}.metric-grid,.range-grid{grid-template-columns:1fr}.card-head,.diagram-meta,.review-head{flex-direction:column}.diagram-modal-actions,.visual-card-actions{justify-items:start;justify-content:flex-start}.diagram-modal{padding:16px}.diagram-canvas{height:420px}.diagram-canvas-expanded{height:calc(100vh - 240px);min-height:520px}.study-diagram-expanded,.study-diagram-inline{padding:16px}.threshold-band-card{grid-template-columns:1fr}.study-table{min-width:480px}.diagram-modal-toolbar,.mcq-header{flex-direction:column;align-items:stretch}.illustration-viewport-expanded{min-height:calc(100vh - 220px)}.dt-choice-grid{grid-template-columns:1fr}.recall-actions{flex-direction:column;align-items:stretch}.study-reading-column{padding:24px 16px}.study-reading-column .stack{gap:40px}}.login-gate{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:60vh;gap:20px}.login-gate-heading{font-size:1.25rem;color:var(--ink);font-family:var(--font-display),sans-serif;font-weight:500;margin:0}.login-gate-spinner{display:block;width:32px;height:32px;border:3px solid var(--line);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(1turn)}}.login-shell{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px 20px}.login-card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:40px 36px;width:100%;max-width:400px}.login-title{font-family:var(--font-display),sans-serif;font-size:1.5rem;font-weight:700;color:var(--ink);margin:0 0 6px}.login-subtitle{font-size:.9rem;color:var(--ink);opacity:.6;margin:0 0 28px}.login-form{gap:16px}.login-field,.login-form{display:flex;flex-direction:column}.login-field{gap:6px}.login-label{font-size:.85rem;font-weight:500;color:var(--ink)}.login-input{padding:10px 12px;border:1px solid var(--line);border-radius:6px;background:var(--bg);color:var(--ink);font-size:.95rem;font-family:var(--font-body),sans-serif;transition:border-color .15s}.login-input:focus{outline:none;border-color:var(--accent)}.login-error{font-size:.85rem;color:var(--accent);margin:0}.login-submit{margin-top:4px;width:100%}.login-toggle{margin:20px 0 0;font-size:.875rem;color:var(--ink);opacity:.7;text-align:center}.login-toggle-btn{background:none;border:none;padding:0;color:var(--accent);font-size:inherit;font-family:inherit;cursor:pointer;text-decoration:underline}.login-success{font-size:.875rem;color:#2d8a4e;margin:0}.login-resend-sent{font-size:.85rem;color:var(--ink);opacity:.6;margin:0}.login-forgot-link{font-size:.8rem;color:var(--ink);opacity:.6;text-decoration:underline;align-self:flex-end}.login-forgot-link:hover{opacity:1}.login-otp-input{font-family:IBM Plex Mono,Courier New,monospace;font-size:1.75rem;font-weight:700;letter-spacing:.45em;text-align:center;text-transform:uppercase;padding:16px 12px}.login-back-btn{background:none;border:none;cursor:pointer;color:var(--muted);font-size:.875rem;padding:0;margin-bottom:16px;display:block;font-family:inherit}.login-back-btn:hover{color:var(--ink)}.rate-limit-card{background:var(--accent-soft);border:1px solid var(--line);border-radius:8px;padding:16px;display:flex;flex-direction:column;gap:8px;margin-top:8px}.rate-limit-heading{font-weight:600;color:var(--ink);margin:0;font-size:.9rem}.rate-limit-reset{color:var(--ink);opacity:.7;margin:0;font-size:.85rem}.rate-limit-feedback-btn{align-self:flex-start;font-size:.85rem;padding:4px 0}.quota-display{font-size:.8rem;color:var(--ink);opacity:.55;margin:8px 0 0}.feedback-prompt{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:20px;display:flex;flex-direction:column;gap:12px;margin-top:12px}.feedback-heading{font-size:.95rem;font-weight:600;color:var(--ink);margin:0}.feedback-stars{display:flex;gap:8px}.feedback-star-btn{width:36px;height:36px;border-radius:50%;border:1px solid var(--line);background:var(--panel-strong);cursor:pointer;font-size:.9rem;font-weight:600;color:var(--ink);transition:background .12s,border-color .12s,color .12s}.feedback-star-btn.is-selected{background:var(--accent);color:white;border-color:var(--accent)}.feedback-note{resize:vertical;min-height:60px;padding:8px 10px;border:1px solid var(--line);border-radius:6px;background:var(--bg);font-family:var(--font-body),sans-serif;font-size:.875rem;color:var(--ink)}.feedback-note:focus{outline:none;border-color:var(--accent)}.feedback-actions{display:flex;gap:8px}.landing-nav{position:-webkit-sticky;position:sticky;top:0;z-index:100;background:var(--bg);border-bottom:1px solid var(--line)}.landing-nav-inner{max-width:960px;margin:0 auto;padding:0 24px;height:56px;display:flex;align-items:center;justify-content:space-between}.landing-logo{font-family:var(--font-display);font-weight:700;font-size:1.05rem;color:var(--ink)}.landing-nav-links{display:flex;gap:10px;align-items:center}.landing-hero{padding:96px 24px 80px}.landing-eyebrow{font-size:.8rem;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin:0 0 16px}.landing-headline{font-family:var(--font-display);font-size:clamp(2.4rem,6vw,3.8rem);font-weight:700;color:var(--ink);line-height:1.1;margin:0 0 20px}.landing-subline{font-size:1.1rem;color:var(--muted);max-width:560px;margin:0 auto 36px;line-height:1.65}.landing-hero-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}.landing-cta{padding:12px 24px;font-size:1rem}.landing-section{padding:72px 24px}.landing-section-alt{background:var(--panel)}.landing-section-inner{max-width:960px;margin:0 auto}.landing-section-title{font-family:var(--font-display);font-size:1.6rem;font-weight:700;color:var(--ink);margin:0 0 6px}.landing-section-sub{color:var(--muted);margin:0 0 36px;font-size:.95rem}.landing-vision-text{font-size:1rem;line-height:1.8;color:var(--ink);max-width:700px}.landing-steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));grid-gap:16px;gap:16px}.landing-step-card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:28px 24px}.landing-step-num{font-family:var(--font-display);font-size:1.6rem;font-weight:700;color:var(--accent);margin:0 0 12px}.landing-step-title{font-weight:600;color:var(--ink);margin:0 0 8px}.landing-step-desc{font-size:.88rem;color:var(--muted);margin:0;line-height:1.6}.landing-audience{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));grid-gap:14px;gap:14px}.landing-audience-card{background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:20px}.landing-audience-name{font-family:var(--font-display);font-weight:700;font-size:1.05rem;color:var(--ink);margin:0 0 6px}.landing-audience-desc{font-size:.83rem;color:var(--muted);margin:0;line-height:1.5}.landing-pricing{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));grid-gap:16px;gap:16px;max-width:560px}.landing-pricing-card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:32px 28px}.landing-pricing-card.is-coming-soon{opacity:.65}.landing-plan-name{font-size:1.1rem;color:var(--ink);margin:0 0 4px}.landing-plan-name,.landing-plan-price{font-family:var(--font-display);font-weight:700}.landing-plan-price{font-size:2rem;color:var(--accent);margin:10px 0 20px}.landing-plan-features{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:8px}.landing-plan-features li{font-size:.88rem;color:var(--ink);padding-left:18px;position:relative}.landing-plan-features li:before{content:"✓";position:absolute;left:0;color:var(--accent);font-weight:700}.landing-badge{display:inline-block;background:var(--accent-soft);color:var(--accent);font-size:.75rem;font-weight:600;padding:4px 10px;border-radius:20px;margin-top:20px}.landing-roadmap{display:flex;flex-direction:column;gap:14px;max-width:520px}.landing-roadmap-item{display:flex;align-items:flex-start;gap:12px;font-size:.93rem;color:var(--ink);line-height:1.5}.landing-roadmap-dot{width:8px;height:8px;border-radius:50%;background:var(--accent);flex-shrink:0;margin-top:6px}.landing-contact-form{display:flex;flex-direction:column;gap:16px;max-width:520px}.landing-contact-field{display:flex;flex-direction:column;gap:6px}.landing-contact-label{font-size:.88rem;font-weight:500;color:var(--ink)}.landing-contact-input,.landing-contact-textarea{padding:10px 12px;border:1px solid var(--line);border-radius:6px;background:var(--panel);color:var(--ink);font-family:var(--font-body);font-size:.93rem;outline:none;transition:border-color .15s}.landing-contact-input:focus,.landing-contact-textarea:focus{border-color:var(--accent)}.landing-contact-textarea{resize:vertical;min-height:120px}.landing-contact-success{color:#2d8a4e;font-size:.93rem}.landing-footer{padding:28px 24px;border-top:1px solid var(--line)}.landing-footer-inner{max-width:960px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}.landing-footer-copy{font-size:.83rem;color:var(--muted);margin:0}.landing-footer-links{display:flex;gap:20px}.landing-footer-link{font-size:.83rem;color:var(--muted);text-decoration:none}.landing-footer-link:hover{color:var(--ink)}.landing-nav-text-link{font-size:.9rem;color:var(--muted);text-decoration:none;padding:4px 8px}.landing-nav-text-link:hover{color:var(--ink)}.landing-construction-badge{display:inline-block;font-size:.72rem;font-weight:600;color:var(--muted);background:var(--bg);border:1px solid var(--line);border-radius:20px;padding:3px 10px;margin-top:10px}.landing-vision-quote{font-family:var(--font-display);font-size:clamp(1.25rem,3vw,1.75rem);font-weight:700;color:var(--ink);line-height:1.4;border-left:4px solid var(--accent);padding-left:24px;margin:0 0 52px;max-width:680px}.landing-vision-split{display:grid;grid-template-columns:1fr 1px 1fr;grid-gap:40px;gap:40px;align-items:start}@media (max-width:640px){.landing-vision-split{grid-template-columns:1fr}.landing-vision-divider{display:none}}.landing-vision-divider{background:var(--line);align-self:stretch}.landing-vision-col-label{font-size:.75rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin:0 0 16px}.landing-vision-col-body{display:flex;flex-direction:column;gap:14px}.landing-vision-col-body p{font-size:.95rem;line-height:1.75;color:var(--ink);margin:0}