:root{
  --navy:#071c3d;--navy-2:#0b2b56;--purple:#6d3ef1;--purple-2:#8a5cff;--purple-soft:#f2edff;
  --teal:#0b9b91;--teal-soft:#edf9f7;--ink:#0d1b3a;--muted:#61708f;--line:#dfe6f1;--line-2:#edf1f6;
  --surface:#fff;--bg:#f5f7fb;--danger:#b9314f;--success:#137e68;--shadow:0 14px 35px rgba(12,35,70,.06);
}
*{box-sizing:border-box}[hidden]{display:none!important}html,body{height:100%;margin:0}body{font-family:Inter,ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:var(--bg);color:var(--ink);overflow:hidden}.modal-open{overflow:hidden}
button,input,select{font:inherit}.app-shell{height:100%;display:flex;flex-direction:column}.topbar{height:66px;flex:0 0 66px;background:linear-gradient(90deg,#07182f,#082c55);color:#fff;display:grid;grid-template-columns:1fr auto 1fr auto;align-items:center;gap:28px;padding:0 28px;border-bottom:1px solid rgba(255,255,255,.08)}.brand{color:#fff;text-decoration:none;font-weight:850;font-size:23px;letter-spacing:-.8px}.top-context{justify-self:end;font-weight:600;font-size:14px}.profile-badge{width:40px;height:40px;border-radius:50%;border:0;background:#fff;color:var(--ink);font-weight:800}.top-progress{display:flex;align-items:center;gap:12px;font-size:13px;white-space:nowrap}.progress-track{width:190px;height:7px;border-radius:99px;background:rgba(255,255,255,.45);overflow:hidden}.progress-fill{height:100%;width:0;background:linear-gradient(90deg,#824ff7,#a579ff);border-radius:inherit;transition:width .3s ease}.top-progress strong{font-size:13px}
.learning-shell{display:grid;grid-template-columns:282px minmax(0,1fr);gap:18px;min-height:0;flex:1;padding:18px}.journey-panel{background:#fff;border:1px solid var(--line);border-radius:20px;padding:20px 14px;display:flex;flex-direction:column;min-height:0;box-shadow:0 8px 24px rgba(12,35,70,.03)}.journey-heading{text-transform:uppercase;letter-spacing:.13em;font-size:12px;font-weight:800;color:#4f6486;padding:4px 12px 16px}.journey-nav{display:flex;flex-direction:column;gap:7px}.journey-item{width:100%;border:0;background:transparent;display:grid;grid-template-columns:40px minmax(0,1fr) 30px;gap:10px;align-items:center;text-align:left;padding:13px 10px;border-radius:15px;color:var(--ink);cursor:pointer;transition:.18s ease}.journey-item:hover{background:#f7f8fc}.journey-item.active{background:linear-gradient(90deg,#f1ecff,#f8f6ff);box-shadow:inset 3px 0 0 var(--purple)}.journey-icon{width:36px;height:36px;border-radius:11px;background:#f7f8fb;display:grid;place-items:center;color:#193f7b}.journey-item.active .journey-icon{background:#ece3ff;color:var(--purple)}.journey-icon svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}.journey-copy{display:flex;flex-direction:column;min-width:0}.journey-copy strong{font-size:14px}.journey-copy small{font-size:11px;color:var(--muted);margin-top:5px}.journey-number{width:27px;height:27px;border-radius:50%;border:1px solid #c8d2e2;display:grid;place-items:center;font-size:11px;font-weight:800;color:#476084}.journey-item.active .journey-number{background:var(--purple);color:#fff;border-color:transparent}.journey-number.complete{background:var(--teal);color:#fff;border-color:transparent}.support-item{grid-template-columns:40px minmax(0,1fr);margin-top:2px}.help-card{margin-top:auto;border:1px solid var(--line);background:#fbfcff;border-radius:15px;padding:13px;display:flex;align-items:center;gap:12px;text-align:left;cursor:pointer}.help-card:hover{border-color:#c8b9ff}.help-icon{width:32px;height:32px;background:#eef1ff;color:var(--purple);border-radius:10px;display:grid;place-items:center;font-weight:900}.help-card span:last-child{display:flex;flex-direction:column}.help-card strong{font-size:13px}.help-card small{color:var(--muted);font-size:11px;margin-top:3px}
.workspace-wrap{min-width:0;min-height:0;display:flex;flex-direction:column}.breadcrumbs{height:36px;display:flex;align-items:center;gap:9px;color:#61708f;font-size:13px;padding:0 4px}.breadcrumbs strong{color:var(--ink)}.workspace{min-height:0;overflow:auto;scrollbar-gutter:stable;padding-right:2px}.scene-card{background:#fff;border:1px solid var(--line);border-radius:20px;padding:24px 26px 20px;box-shadow:var(--shadow)}.scene-header{display:flex;justify-content:space-between;gap:20px;align-items:flex-start;margin-bottom:20px}.scene-heading{display:flex;gap:18px;min-width:0}.step-badge{width:46px;height:46px;border-radius:12px;background:linear-gradient(145deg,#8656ff,#5f31e9);color:#fff;display:grid;place-items:center;font-weight:850;font-size:20px;box-shadow:0 8px 18px rgba(109,62,241,.22);flex:0 0 auto}.eyebrow{text-transform:uppercase;letter-spacing:.1em;color:var(--purple);font-size:11px;font-weight:850}.eyebrow.light{color:#c6d6ef}.teal-text{color:var(--teal)}.scene-heading h1{font-size:26px;line-height:1.12;letter-spacing:-.55px;margin:5px 0 7px}.scene-heading p{margin:0;color:#405171;font-size:14px;line-height:1.55}.scene-tools{display:flex;align-items:center;gap:16px;white-space:nowrap}.listen-button{border:1px solid #d7dfeb;background:#fff;border-radius:10px;padding:10px 13px;color:#10203e;font-weight:700;cursor:pointer}.listen-button:hover{border-color:#a993ff;color:var(--purple)}.scene-count{font-size:12px;font-weight:700;color:#4d6180}.scene-content{min-height:0}.concept-grid{display:grid;grid-template-columns:minmax(310px,420px) minmax(0,1fr);gap:20px}.concept-column,.visual-column{min-width:0}.teaching-card,.graph-panel{border:1px solid var(--line);background:#fff;border-radius:16px}.teaching-card{padding:20px}.lead{font-size:15px;line-height:1.6;margin:8px 0 15px}.formula-box{border:1.5px solid #b899ff;background:linear-gradient(180deg,#fff,#fbf9ff);border-radius:13px;padding:17px;text-align:center}.large-formula{font-family:Cambria,"Times New Roman",serif;font-size:34px}.equation-formula{margin-top:10px}.purple{color:var(--purple)}.teal{color:var(--teal)}.equals{margin:0 9px}.frac{display:inline-flex;vertical-align:middle;flex-direction:column;text-align:center;line-height:1.05}.frac>span:first-child{border-bottom:1.5px solid currentColor;padding:0 .2em .11em}.frac>span:last-child{padding:.11em .2em 0}.formula-frac{font-size:.92em}.formula-legend{display:flex;gap:16px;flex-wrap:wrap;margin:11px 0 0;font-size:11px;color:#566783}.formula-legend span{display:flex;align-items:center;gap:6px}.purple-dot,.teal-dot{display:inline-block;width:8px;height:8px;border-radius:50%}.purple-dot{background:var(--purple)}.teal-dot{background:var(--teal)}.mini-heading{font-size:13px;font-weight:800;margin:18px 0 8px}.symbol-meaning{display:flex;flex-direction:column;gap:5px;font-size:12px;color:#526581;margin-top:10px}.vocab-block{border-top:1px solid var(--line-2);margin-top:17px;padding-top:14px}.chip-row{display:flex;gap:7px;flex-wrap:wrap;margin-top:8px}.vocab-chip{border:1px solid #dbe2ed;background:#fff;border-radius:99px;padding:6px 9px;color:#23385a;font-size:11px;cursor:pointer}.vocab-chip span{display:inline-grid;place-items:center;width:15px;height:15px;border-radius:50%;background:#f0eaff;color:var(--purple);font-size:9px;margin-left:4px}.keep-mind{margin-top:16px;border:1px solid #cfece6;background:var(--teal-soft);border-radius:12px;padding:13px;display:flex;flex-direction:column;gap:4px;color:#285f5d}.keep-mind strong{font-size:12px}.keep-mind span{font-size:11px;line-height:1.45}.graph-panel{position:relative;padding:14px 14px 0;height:100%;min-height:480px;overflow:hidden}.math-graph{width:100%;height:auto;display:block;touch-action:none}.gridline{stroke:#e8edf4;stroke-width:1}.axis{stroke:#1c2b47;stroke-width:1.7}.axis-arrow{fill:#1c2b47}.axis-label{fill:#263a5d;font-size:13px}.axis-name{fill:#101f3c;font-size:17px;font-weight:800}.main-line{stroke:#6d3ef1;stroke-width:4;stroke-linecap:round}.secondary-line{stroke:#0b9b91;stroke-width:3;stroke-dasharray:10 7;stroke-linecap:round}.run-line{stroke:#0b9b91;stroke-width:2.4;stroke-dasharray:9 7}.rise-line{stroke:#2688d7;stroke-width:2.4;stroke-dasharray:9 7}.run-text{fill:#0a8f85;font-size:16px;font-weight:800}.rise-text{fill:#1473c7;font-size:16px;font-weight:800}.graph-point{fill:#6d3ef1;stroke:#fff;stroke-width:3;filter:drop-shadow(0 3px 7px rgba(109,62,241,.25))}.graph-point-group[data-draggable=true]{cursor:grab}.graph-point-group[data-draggable=true]:active{cursor:grabbing}.point-label{fill:#6d3ef1;font-size:15px;font-weight:800}.c-point{fill:#0b9b91;stroke:#fff;stroke-width:3}.c-label{fill:#0b9b91;font-size:16px;font-weight:900}.expand-graph{position:absolute;right:14px;top:14px;z-index:2;width:38px;height:38px;border:1px solid var(--line);border-radius:10px;background:#fff;color:#3d5576;cursor:pointer;box-shadow:0 4px 14px rgba(12,35,70,.08)}.graph-summary{display:grid;grid-template-columns:1fr 1fr;border-top:1px solid var(--line);margin:4px -14px 0;background:#fbfcfe}.graph-summary>div{padding:14px 16px;display:flex;flex-direction:column;gap:7px}.graph-summary>div+div{border-left:1px solid var(--line)}.graph-summary span{font-size:11px;color:#50637f}.graph-summary strong{font-size:19px;color:#18355d}.math-expression{font-family:Cambria,"Times New Roman",serif;font-style:italic}.scene-footer{height:78px;background:#fff;border:1px solid var(--line);border-radius:17px;margin-top:14px;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;padding:0 18px;box-shadow:0 5px 18px rgba(12,35,70,.03)}.secondary-button,.primary-button{border-radius:11px;padding:12px 18px;font-weight:800;cursor:pointer}.secondary-button{justify-self:start;border:1px solid var(--line);background:#fff;color:#1b2b48}.primary-button{justify-self:end;border:0;background:linear-gradient(145deg,#7d4df6,#5d2fe8);color:#fff;min-width:112px;box-shadow:0 8px 20px rgba(109,62,241,.2)}.primary-button:disabled{opacity:.42;cursor:not-allowed;box-shadow:none}.dot-row{display:flex;gap:8px;justify-content:center}.progress-dot{width:9px;height:9px;border-radius:50%;border:0;background:#dfe5ee;padding:0;cursor:pointer}.progress-dot.active{background:var(--purple);transform:scale(1.1)}
.interactive-layout,.learn-layout,.example-layout,.try-layout,.challenge-layout{display:grid;grid-template-columns:minmax(300px,370px) minmax(0,1fr);gap:20px}.values-card{display:flex;flex-direction:column}.value-stack{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:13px}.value-stack>div{border:1px solid var(--line-2);border-radius:12px;padding:13px;background:#fbfcfe}.value-stack span{display:block;font-size:11px;color:#60718d}.value-stack strong{display:block;margin-top:5px;font-size:20px}.live-equation{margin-top:12px;border:1px solid #cbb8ff;background:#faf8ff;border-radius:12px;padding:15px;text-align:center;font-size:26px}.interaction-hint{margin-top:auto;background:var(--teal-soft);color:#27625f;border-radius:12px;padding:12px;font-size:12px;line-height:1.5}.lesson-step-card{font-size:14px}.worked-line{font-family:Cambria,"Times New Roman",serif;font-size:27px;margin:18px 0;padding:15px;border-radius:12px;background:#faf8ff;border:1px solid #d8caff;text-align:center}.worked-stack{display:flex;flex-direction:column;gap:12px;font-family:Cambria,"Times New Roman",serif;font-size:22px;margin:18px 0}.worked-stack>div{border-bottom:1px solid var(--line-2);padding-bottom:10px}.focus-callout{background:#f1f4f9;border-left:3px solid var(--purple);padding:12px 13px;border-radius:0 10px 10px 0;font-size:12px;line-height:1.5}.focus-callout.success{background:var(--teal-soft);border-left-color:var(--teal);color:#24605c}.final-answer{font-family:Cambria,"Times New Roman",serif;font-size:32px;margin:20px 0;border:1.5px solid #b99cff;background:#faf8ff;border-radius:13px;padding:18px;text-align:center}.example-card p{color:#53647f;font-size:13px}.final-example{color:var(--purple);font-size:24px!important;border:0!important;padding:13px!important;background:#faf8ff;border-radius:11px}.try-card,.challenge-card{display:flex;flex-direction:column}.answer-form{margin-top:18px}.answer-form label{font-weight:800;font-size:14px}.answer-row{display:flex;gap:8px;margin-top:8px}.answer-row input,.multi-answer-form input,.support-step input{width:100%;border:1px solid #cbd5e4;border-radius:10px;padding:12px;background:#fff;color:var(--ink);outline:none}.answer-row input:focus,.multi-answer-form input:focus,.support-step input:focus{border-color:#9271f8;box-shadow:0 0 0 3px #f0ebff}.answer-row button,.multi-answer-form>button{border:0;border-radius:10px;padding:12px 16px;background:var(--purple);color:#fff;font-weight:800;cursor:pointer}.feedback{display:none;margin-top:12px;padding:11px 12px;border-radius:10px;font-size:12px;line-height:1.45}.feedback.show{display:block}.feedback.success{background:var(--teal-soft);color:#17665c}.feedback.error{background:#fff0f4;color:#8f2641}.feedback.hint{background:#f2efff;color:#5940a6}.hint-button{border:0;background:transparent;color:var(--purple);font-weight:800;margin-top:10px;padding:4px 0;cursor:pointer}.multi-answer-form{display:flex;flex-direction:column;gap:12px;margin-top:16px}.multi-answer-form label{display:flex;flex-direction:column;gap:6px;font-size:12px;font-weight:800}.challenge-problem{background:#f7f8fc;border:1px solid var(--line-2);border-radius:12px;padding:12px 14px;font-size:13px;line-height:1.5}.challenge-problem p{margin:3px 0}.secondary-point{margin-top:10px;background:#f4f1ff;border:1px solid #ddd2ff;border-radius:12px;padding:12px 14px;display:flex;flex-direction:column;gap:4px}.secondary-point strong{font-size:12px}.secondary-point span{font-size:11px;color:#60718d}
.drawer-backdrop{position:fixed;inset:66px 0 0;background:rgba(4,14,33,.24);z-index:40;backdrop-filter:blur(2px)}.support-drawer{position:fixed;top:66px;right:0;bottom:0;width:min(440px,94vw);background:linear-gradient(180deg,#08264c,#071b36);color:#fff;z-index:50;transform:translateX(101%);transition:transform .25s ease;box-shadow:-20px 0 45px rgba(4,14,33,.24);display:flex;flex-direction:column}.support-drawer.open{transform:translateX(0)}.drawer-header{display:flex;justify-content:space-between;gap:14px;padding:22px 20px 17px;border-bottom:1px solid rgba(255,255,255,.12)}.drawer-header h2{margin:4px 0 0;font-size:21px}.icon-button{width:38px;height:38px;border-radius:10px;border:1px solid var(--line);background:#fff;cursor:pointer;font-size:24px}.light-button{border-color:rgba(255,255,255,.25);background:rgba(255,255,255,.07);color:#fff}.drawer-body{padding:18px 20px 28px;overflow:auto}.support-problem{background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.12);border-radius:14px;padding:15px}.support-problem p{font-size:13px;line-height:1.55;margin:8px 0 0}.support-graph{background:#fff;border-radius:14px;padding:8px;margin-top:14px}.support-step{margin-top:16px}.step-pill{display:inline-block;background:#7650e9;border-radius:99px;padding:5px 9px;font-size:10px;font-weight:800}.support-step h3{font-size:18px;line-height:1.4}.support-step form{display:flex;flex-direction:column;gap:9px}.support-step form>button,.drawer-next{border:0;border-radius:10px;background:#8055ef;color:#fff;padding:12px;font-weight:800;cursor:pointer}.drawer-feedback{display:none;border-radius:10px;padding:11px;font-size:12px;line-height:1.45}.drawer-feedback.success,.drawer-feedback.error,.drawer-feedback.hint{display:block}.drawer-feedback.success{background:rgba(47,199,167,.15);color:#bff2e8}.drawer-feedback.error{background:rgba(255,116,150,.14);color:#ffd1dc}.drawer-feedback.hint{background:rgba(180,150,255,.15);color:#e3d8ff}.drawer-next{width:100%;margin-top:10px;background:#15a797}.drawer-hint{border:0;background:transparent;color:#cbbfff;font-weight:800;padding:10px 0;cursor:pointer}.graph-overlay{position:fixed;inset:0;background:rgba(3,14,34,.72);z-index:80;padding:32px;display:grid;place-items:center}.graph-overlay-card{position:relative;width:min(1100px,95vw);max-height:93vh;background:#fff;border-radius:20px;padding:20px;overflow:auto}.overlay-close{position:absolute;right:14px;top:14px;z-index:2}.toast{position:fixed;left:50%;bottom:24px;transform:translate(-50%,20px);background:#102a51;color:#fff;padding:11px 16px;border-radius:10px;box-shadow:0 12px 30px rgba(5,20,45,.25);font-size:12px;opacity:0;pointer-events:none;transition:.2s;z-index:100;max-width:min(520px,90vw);text-align:center}.toast.show{opacity:1;transform:translate(-50%,0)}.mobile-stagebar{display:none}
@media(max-width:1100px){.learning-shell{grid-template-columns:230px minmax(0,1fr)}.journey-panel{padding-left:10px;padding-right:10px}.journey-copy small{display:none}.concept-grid,.interactive-layout,.learn-layout,.example-layout,.try-layout,.challenge-layout{grid-template-columns:320px minmax(0,1fr)}.top-context{display:none}.topbar{grid-template-columns:1fr auto auto}.graph-panel{min-height:420px}.scene-heading h1{font-size:23px}}
@media(max-width:850px){body{overflow:auto}.app-shell{min-height:100%;height:auto}.topbar{height:60px;flex-basis:60px;padding:0 16px;grid-template-columns:1fr auto}.brand{font-size:20px}.top-progress{display:none}.profile-badge{width:36px;height:36px}.learning-shell{display:block;padding:10px}.journey-panel{display:none}.mobile-stagebar{display:flex;align-items:center;gap:9px;padding:10px;background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}.mobile-stagebar label{font-size:11px;font-weight:800;color:#62738d}.mobile-stagebar select{flex:1;border:1px solid var(--line);background:#fff;border-radius:9px;padding:9px}.mobile-stagebar button{border:0;background:var(--navy);color:#fff;border-radius:9px;padding:9px 12px;font-weight:800}.workspace{overflow:visible}.breadcrumbs{height:auto;min-height:34px;overflow:auto;white-space:nowrap;padding:5px 2px 9px}.scene-card{padding:18px 15px 14px}.scene-header{flex-direction:column}.scene-tools{width:100%;justify-content:space-between}.scene-heading h1{font-size:22px}.step-badge{width:40px;height:40px;font-size:17px}.concept-grid,.interactive-layout,.learn-layout,.example-layout,.try-layout,.challenge-layout{grid-template-columns:1fr}.graph-panel{min-height:0}.scene-footer{position:sticky;bottom:0;z-index:15;margin-left:0;margin-right:0}.drawer-backdrop{inset:60px 0 0}.support-drawer{top:60px}.graph-summary{grid-template-columns:1fr}.graph-summary>div+div{border-left:0;border-top:1px solid var(--line)}.graph-overlay{padding:10px}.graph-overlay-card{padding:10px}.large-formula{font-size:30px}}
@media(max-width:520px){.learning-shell{padding:7px}.scene-card{border-radius:15px;padding:15px 12px}.scene-heading{gap:12px}.scene-heading p{font-size:13px}.scene-tools{gap:8px}.listen-button{padding:8px 10px}.concept-column .teaching-card,.teaching-card{padding:15px}.value-stack{grid-template-columns:1fr 1fr}.scene-footer{height:66px;padding:0 9px}.secondary-button,.primary-button{padding:10px 12px;min-width:auto;font-size:12px}.dot-row{gap:6px}.progress-dot{width:7px;height:7px}.point-label,.run-text,.rise-text{font-size:13px}.axis-label{font-size:11px}.formula-legend{flex-direction:column;gap:5px}.large-formula{font-size:27px}.answer-row{flex-direction:column}.scene-count{font-size:11px}}