.UnitChain_unitChain__Mmfyd{--uc-quiet:color-mix(in srgb,var(--lx-ink) 62%,var(--lx-surface));--uc-ease:cubic-bezier(0.2,0.7,0.2,1);--uc-field:#f4f5f7;container-type:inline-size;margin:0;padding:0;font-family:var(--font-sans),system-ui,sans-serif;color:var(--lx-ink)}:where(.UnitChain_unitChain__Mmfyd p){margin:0}.UnitChain_layout__hjLBE{display:grid;grid-template-columns:minmax(0,2.15fr) minmax(18rem,1fr);gap:clamp(20px,3.4cqi,40px)}.UnitChain_field__0zk5U{display:flex;flex-direction:column;justify-content:center;gap:clamp(22px,3cqi,36px);min-width:0;min-height:min(25rem,50svh);padding:clamp(22px,3.4cqi,40px);border-radius:20px;background:var(--uc-field)}.UnitChain_facts__9oXfg{max-width:34em;color:var(--lx-ink);font:400 var(--type-read-serif)/1.45 var(--lx-reading);text-wrap:pretty}.UnitChain_stage__5cxid{container-type:inline-size;padding:.25em 0 2.4em}.UnitChain_afterPicture__TpQVW{display:flex;justify-content:center;animation:UnitChain_ucFade__kZOO0 .4s ease-out .3s backwards}.UnitChain_qa__EwOyy{display:flex;flex-direction:column;gap:16px;min-width:0;padding:8px 0}.UnitChain_question__fai0v{display:grid;gap:14px}@container (max-width: 600px){.UnitChain_layout__hjLBE{grid-template-columns:minmax(0,1fr);gap:16px}.UnitChain_field__0zk5U{min-height:0;padding:22px 16px}.UnitChain_qa__EwOyy{padding:0 2px 2px}}.UnitChain_top__ECMcC{display:flex;align-items:center;gap:10px;min-height:24px}.UnitChain_dots__pLk1j{display:flex;align-items:center;gap:2px;margin:0;padding:0;list-style:none}.UnitChain_dot__M1Lsh{display:grid;place-items:center;width:22px;height:24px;padding:0;border:0;background:transparent;cursor:pointer}.UnitChain_dot__M1Lsh:before{content:"";width:8px;height:8px;border-radius:999px;background:color-mix(in srgb,var(--lx-ink) 16%,transparent);transition:width var(--lx-med) var(--uc-ease),background-color var(--lx-med) var(--uc-ease)}.UnitChain_dot__M1Lsh[data-state=done]:before{background:var(--lx-right)}.UnitChain_dot__M1Lsh[data-state=current]:before{width:18px;background:var(--lx-subject)}.UnitChain_dot__M1Lsh:hover:before{background:color-mix(in srgb,var(--lx-subject) 75%,var(--lx-surface))}.UnitChain_dot__M1Lsh:focus-visible{outline:2px solid var(--lx-subject);outline-offset:1px;border-radius:6px}.UnitChain_count__qBPZm{color:var(--uc-quiet);font:600 var(--type-label)/1.3 var(--font-sans),sans-serif;font-variant-numeric:tabular-nums}.UnitChain_ask__Kz2uX{font:500 clamp(1.1875rem,2cqi,1.5rem)/1.3 var(--lx-serif);color:var(--lx-ink);text-wrap:pretty}.UnitChain_factors__s9PYh{display:flex;flex-wrap:wrap;gap:10px}.UnitChain_factor__LE9Al{display:inline-flex;align-items:center;gap:12px;min-height:72px;padding:8px 20px 8px 13px;border:1px solid color-mix(in srgb,var(--lx-ink) 16%,transparent);border-radius:14px;background:var(--lx-surface);color:var(--lx-ink);cursor:pointer;transition:border-color var(--lx-fast) var(--uc-ease),background-color var(--lx-fast) var(--uc-ease),transform .12s ease}.UnitChain_choices__wP_JE{display:grid;gap:8px}.UnitChain_choice__wgZgv{display:flex;align-items:center;gap:12px;width:100%;min-height:48px;padding:10px 16px 10px 13px;border:1px solid color-mix(in srgb,var(--lx-ink) 16%,transparent);border-radius:12px;background:var(--lx-surface);color:var(--lx-ink);font:500 var(--type-read)/1.3 var(--font-sans),sans-serif;text-align:left;cursor:pointer;transition:border-color var(--lx-fast) var(--uc-ease),background-color var(--lx-fast) var(--uc-ease),transform .12s ease}.UnitChain_choiceMark__ib09K{display:grid;flex:none;place-items:center;width:22px;height:22px;border:1.5px solid color-mix(in srgb,var(--lx-ink) 28%,transparent);border-radius:50%;color:#fff;transition:border-color var(--lx-fast) var(--uc-ease)}.UnitChain_choiceMark__ib09K svg{width:13px;height:13px;stroke-width:3}:is(.UnitChain_choice__wgZgv,.UnitChain_factor__LE9Al):not([data-state]):not([aria-disabled]):hover{border-color:color-mix(in srgb,var(--lx-ink) 55%,transparent);background:color-mix(in srgb,var(--lx-ink) 4%,var(--lx-surface))}:is(.UnitChain_choice__wgZgv,.UnitChain_factor__LE9Al):not([data-state]):not([aria-disabled]):hover .UnitChain_choiceMark__ib09K{border-color:color-mix(in srgb,var(--lx-ink) 55%,transparent)}:is(.UnitChain_choice__wgZgv,.UnitChain_factor__LE9Al):not([aria-disabled]):active{transform:scale(.99)}:is(.UnitChain_choice__wgZgv,.UnitChain_factor__LE9Al):focus-visible{outline:2px solid var(--lx-subject);outline-offset:2px}:is(.UnitChain_choice__wgZgv,.UnitChain_factor__LE9Al)[data-state=wrong]{border-color:color-mix(in srgb,var(--lx-wrong) 45%,transparent);background:var(--lx-wrong-soft);color:var(--lx-wrong);cursor:default}:is(.UnitChain_choice__wgZgv,.UnitChain_factor__LE9Al)[data-state=wrong] .UnitChain_choiceMark__ib09K{border-color:var(--lx-wrong);background:var(--lx-wrong)}.UnitChain_small__XmPfR{display:inline-grid;justify-items:center;gap:3px;font:400 var(--type-read-serif)/1.1 var(--lx-math)}.UnitChain_smallAmount__cCCma{white-space:nowrap}.UnitChain_smallBar__46SD3{justify-self:stretch;height:1.5px;background:currentColor}.UnitChain_after__rlIIZ{display:grid;gap:12px}.UnitChain_after__rlIIZ:empty{display:none}.UnitChain_feedback__9Lnqm{font:400 var(--type-read)/1.55 var(--font-sans),sans-serif;color:var(--lx-ink);animation:UnitChain_ucFade__kZOO0 .28s ease-out}.UnitChain_lead__PZiPF{display:inline-flex;align-items:center;gap:5px;font-weight:600}.UnitChain_lead__PZiPF[data-state=wrong]{color:var(--lx-wrong)}.UnitChain_lead__PZiPF svg{width:16px;height:16px;stroke-width:2.6}.UnitChain_answer__nWAVW{display:flex;align-items:center;gap:8px;color:var(--lx-right);font:650 var(--type-read)/1.4 var(--font-sans),sans-serif;animation:UnitChain_ucFade__kZOO0 .24s ease-out}.UnitChain_answer__nWAVW svg{flex:none;width:16px;height:16px;stroke-width:2.6}.UnitChain_showAnswer__tXNqu{display:inline-flex;align-items:center;gap:6px;width:fit-content;padding:6px 12px;border:1px solid var(--lx-rule);border-radius:999px;background:var(--lx-surface);color:var(--uc-quiet);font:500 var(--type-label)/1.3 var(--font-sans),sans-serif;cursor:pointer}.UnitChain_showAnswer__tXNqu:hover{border-color:var(--lx-subject);color:var(--lx-subject)}.UnitChain_showAnswer__tXNqu svg{width:15px;height:15px}.UnitChain_says___0S8r{display:grid;gap:12px;justify-items:start;animation:UnitChain_ucFade__kZOO0 .35s ease-out .45s backwards}.UnitChain_says___0S8r .UnitChain_feedback__9Lnqm{animation:none}.UnitChain_next__kchF6{display:inline-flex;align-items:center;gap:8px;min-height:44px;padding:10px 18px;border:0;border-radius:999px;background:var(--lx-subject);color:#fff;font:600 var(--type-read)/1.2 var(--font-sans),sans-serif;cursor:pointer;transition:transform .12s ease,filter .16s ease}.UnitChain_next__kchF6:hover{filter:brightness(1.08)}.UnitChain_next__kchF6:active{transform:scale(.98)}.UnitChain_next__kchF6:focus-visible{outline:2px solid var(--lx-subject);outline-offset:3px}.UnitChain_next__kchF6 svg{width:18px;height:18px}@keyframes UnitChain_ucFade__kZOO0{0%{opacity:0}}@media (prefers-reduced-motion:reduce){.UnitChain_unitChain__Mmfyd *,.UnitChain_unitChain__Mmfyd :after,.UnitChain_unitChain__Mmfyd :before{animation:none!important;transition:none!important}}.Glossary_term__ESXpE{cursor:help;border-radius:2px;text-decoration-line:underline;text-decoration-style:dotted;text-decoration-thickness:1.5px;text-decoration-color:color-mix(in srgb,var(--subject-color,currentColor) 70%,transparent);text-underline-offset:.24em;text-decoration-skip-ink:auto;-webkit-tap-highlight-color:transparent;transition:background-color .16s ease,box-shadow .16s ease,text-decoration-color .16s ease}.Glossary_term__ESXpE:hover,.Glossary_term__ESXpE[data-glossary-active]{text-decoration-style:solid;text-decoration-color:var(--subject-color,currentColor);background-color:var(--subject-soft,rgb(0 0 0/.05));box-shadow:0 0 0 2px var(--subject-soft,rgb(0 0 0/.05))}.Glossary_term__ESXpE:focus-visible{outline:2px solid var(--fg-accent,currentColor);outline-offset:3px}.Glossary_card__Doy14{--tooltip-surface:var(--fg-surface,#ffffff);--tooltip-border:var(--fg-border,#e2e4e8);--tooltip-text:var(--fg-ink,rgb(26 28 24));--tooltip-muted:var(--fg-muted,#65675f);--tooltip-accent:var(--subject-color,var(--fg-accent,#a54a32));--tooltip-shadow:0 18px 40px -20px rgb(40 35 25/.45),0 2px 8px -3px rgb(40 35 25/.14);--tooltip-shift:4px;--tooltip-plate:color-mix(in srgb,var(--subject-soft,#f1f3f5) 72%,var(--tooltip-surface));box-sizing:border-box;width:max-content;max-width:min(320px,calc(100vw - 24px));border:1px solid var(--tooltip-border);border-radius:8px;background:var(--tooltip-surface);box-shadow:var(--tooltip-shadow);color:var(--tooltip-text);font:16px/1.55 var(--font-sans),sans-serif;letter-spacing:0;text-align:left}.Glossary_card__Doy14[data-figure]{width:min(340px,calc(100vw - 24px));max-width:none}.Glossary_tooltip__DlLyU{position:fixed;top:0;left:0;z-index:90;visibility:hidden;opacity:0;transform:translateY(var(--tooltip-shift));transition:opacity .14s ease,transform .2s cubic-bezier(.2,.8,.2,1)}.Glossary_tooltip__DlLyU[data-placement=bottom]{--tooltip-shift:-4px}.Glossary_tooltip__DlLyU[data-ready]{opacity:1;transform:none}.Glossary_plate__YHDBO{display:grid;place-items:center;min-height:112px;padding:16px 14px 14px;border-bottom:1px solid color-mix(in srgb,var(--tooltip-accent) 14%,var(--tooltip-border));border-radius:7px 7px 0 0;background:radial-gradient(70% 90% at 50% 100%,color-mix(in srgb,var(--tooltip-surface) 70%,transparent),transparent 75%),var(--tooltip-plate)}.Glossary_body__LOCqq{padding:13px 16px 14px}.Glossary_card__Doy14[data-figure] .Glossary_body__LOCqq{padding-top:12px}.Glossary_name__iXZIF{margin:0 0 3px;color:var(--tooltip-accent);font:400 20px/1.25 var(--fg-serif,var(--font-serif)),Georgia,serif;font-variant-numeric:lining-nums;letter-spacing:-.01em}.Glossary_definition__pBzVt{margin:0}.Glossary_example__hP_gI{margin:10px 0 0;padding-top:9px;border-top:1px solid var(--tooltip-border);color:var(--tooltip-muted);font-size:15px;line-height:1.5}.Glossary_exampleLabel__GwAx3{display:block;margin-bottom:1px;color:var(--tooltip-muted);font:600 12px/1.5 var(--font-sans),sans-serif;letter-spacing:.1em;text-transform:uppercase}.Glossary_arrow__Dl9El{position:absolute;width:10px;height:10px;background:var(--tooltip-surface);transform:rotate(45deg)}.Glossary_tooltip__DlLyU[data-placement=top] .Glossary_arrow__Dl9El{bottom:-6px;border-right:1px solid var(--tooltip-border);border-bottom:1px solid var(--tooltip-border)}.Glossary_tooltip__DlLyU[data-placement=bottom] .Glossary_arrow__Dl9El{top:-6px;background:var(--tooltip-surface);border-top:1px solid var(--tooltip-border);border-left:1px solid var(--tooltip-border)}.Glossary_tooltip__DlLyU[data-figure][data-placement=bottom] .Glossary_arrow__Dl9El{background:var(--tooltip-plate);border-color:color-mix(in srgb,var(--tooltip-accent) 14%,var(--tooltip-border))}@media (prefers-reduced-motion:reduce){.Glossary_term__ESXpE,.Glossary_tooltip__DlLyU{transition:none}.Glossary_tooltip__DlLyU{transform:none}}.InstructorLetter_letter__xP593{--letter-ink:rgb(var(--home-ink));--letter-muted:rgb(var(--home-muted));--letter-accent:rgb(var(--home-ember-deep));--letter-tint:rgb(var(--home-ember)/0.07);--letter-panel:#ffffff;--letter-edge:#d6d4ca;--letter-hairline:#e4e1d7;--letter-control-edge:#b9b1a6;--letter-radius:22px;--letter-shadow:0 24px 60px -24px rgb(60 40 24/0.4);--letter-portrait-shadow:0 1px 2px rgb(60 40 24/0.07),0 18px 36px -20px rgb(60 40 24/0.32);--letter-serif:var(--font-serif);--letter-sans:var(--font-sans);display:grid;align-items:center;max-width:1352px;margin:0 auto;color:var(--letter-ink);font-family:var(--letter-sans),sans-serif}.InstructorLetter_card__c5z6C,.InstructorLetter_portrait__7Dw2m{grid-area:1/1}.InstructorLetter_portrait__7Dw2m{position:relative;justify-self:end;align-self:stretch;width:66%;min-height:var(--letter-portrait-height,clamp(560px,46vw,700px));overflow:hidden;border-radius:var(--letter-radius);background:#f1f3f5;box-shadow:var(--letter-portrait-shadow)}.InstructorLetter_portrait__7Dw2m img{position:absolute;display:block;width:100%;height:100%;object-fit:cover;object-position:44% 28%}.InstructorLetter_card__c5z6C{position:relative;z-index:1;justify-self:start;display:grid;justify-items:start;width:min(600px,47%);margin-block:var(--letter-card-inset,48px);padding:var(--letter-card-padding,clamp(28px,3vw,48px));border:1px solid var(--letter-edge);border-radius:var(--letter-radius);background:var(--letter-panel);box-shadow:var(--letter-shadow)}.InstructorLetter_hello__ZAMOB{margin:0;font:400 var(--type-heading)/1.2 var(--letter-serif),Georgia,serif;font-variant-numeric:lining-nums;color:var(--letter-muted)}.InstructorLetter_letter__xP593 .InstructorLetter_name__fJD0S{margin:4px 0 0;font:400 clamp(52px,4.8vw,72px)/1 var(--letter-serif),Georgia,serif;font-size:var(--letter-name-size,clamp(52px,4.8vw,72px));font-variant-numeric:lining-nums;letter-spacing:-.035em;color:var(--letter-ink)}.InstructorLetter_name__fJD0S span{color:var(--letter-accent)}.InstructorLetter_role__f_OWB{display:flex;align-items:center;gap:12px;margin:12px 0 0;font-size:var(--type-label);font-weight:600;line-height:1.4;letter-spacing:.14em;text-transform:uppercase;color:var(--letter-accent)}.InstructorLetter_role__f_OWB:before{content:"";width:28px;height:1px;flex:none;background:currentColor}.InstructorLetter_lede__N5Sfs{width:100%;margin:var(--letter-rhythm,24px) 0 0;padding-top:var(--letter-rhythm,24px);border-top:1px solid var(--letter-hairline);font:400 var(--type-heading)/1.3 var(--letter-serif),Georgia,serif;text-wrap:pretty;font-variant-numeric:lining-nums;letter-spacing:-.01em}.InstructorLetter_facts__c4mYu{display:grid;grid-template-columns:repeat(3,minmax(0,auto));justify-content:start;gap:16px 36px;margin:var(--letter-rhythm,24px) 0 0}.InstructorLetter_facts__c4mYu div{display:grid;gap:8px}.InstructorLetter_facts__c4mYu dt{font-size:var(--type-label);font-weight:500;line-height:1.3;color:var(--letter-muted)}.InstructorLetter_facts__c4mYu dd{margin:0;font:400 var(--type-title)/1 var(--letter-serif),Georgia,serif;font-variant-numeric:lining-nums;letter-spacing:-.02em;color:var(--letter-ink)}.InstructorLetter_close__QYVnk{margin:20px 0 0;font-size:var(--type-read);line-height:1.6;text-wrap:pretty;color:var(--letter-muted)}.InstructorLetter_action__bgAGD{display:inline-flex;align-items:center;gap:10px;min-height:48px;margin-top:var(--letter-rhythm,24px);padding:10px 20px;border:1px solid var(--letter-control-edge);border-radius:10px;color:var(--letter-ink);background:transparent;font-size:var(--type-read);font-weight:500;line-height:1.2;text-decoration:none;transition:border-color .16s ease-out,background-color .16s ease-out,transform .2s ease-out}.InstructorLetter_action__bgAGD svg{flex:none;width:17px;height:17px;transition:transform .2s ease-out}.InstructorLetter_action__bgAGD:active{transform:scale(.985)}.InstructorLetter_postscript__Js40A{width:100%;margin-top:calc(var(--letter-rhythm, 24px) + 4px);padding-top:calc(var(--letter-rhythm, 24px) - 4px);border-top:1px solid var(--letter-hairline);font-size:var(--type-read);line-height:1.6;color:var(--letter-muted)}.InstructorLetter_postscript__Js40A a{white-space:nowrap;color:var(--letter-ink);font-weight:500;text-decoration:underline;text-decoration-color:var(--letter-control-edge);text-decoration-thickness:1px;text-underline-offset:4px;transition:color .16s ease-out,text-decoration-color .16s ease-out}.InstructorLetter_postscript__Js40A a svg{display:inline-block;width:15px;height:15px;margin-left:2px;vertical-align:-2px;transition:transform .2s ease-out}.InstructorLetter_letter__xP593 a:focus-visible{outline:2px solid var(--letter-accent);outline-offset:4px;border-radius:4px}.InstructorLetter_letter__xP593 .InstructorLetter_action__bgAGD:focus-visible{border-radius:10px}@media (hover:hover){.InstructorLetter_action__bgAGD:hover{border-color:var(--letter-accent);background:var(--letter-tint)}.InstructorLetter_action__bgAGD:hover svg{transform:translateX(3px)}.InstructorLetter_postscript__Js40A a:hover{color:var(--letter-accent);text-decoration-color:currentColor}.InstructorLetter_postscript__Js40A a:hover svg{transform:translate(2px,-2px)}}@media (prefers-reduced-motion:reduce){.InstructorLetter_action__bgAGD,.InstructorLetter_action__bgAGD svg,.InstructorLetter_postscript__Js40A a svg{transition:none}.InstructorLetter_action__bgAGD:active,.InstructorLetter_action__bgAGD:hover svg,.InstructorLetter_postscript__Js40A a:hover svg{transform:none}}@media (max-width:1200px){.InstructorLetter_portrait__7Dw2m img{object-position:36% 28%}}@media (max-width:900px){.InstructorLetter_letter__xP593{display:block}.InstructorLetter_portrait__7Dw2m{width:100%;min-height:0;height:clamp(340px,62vw,520px)}.InstructorLetter_portrait__7Dw2m img{object-position:58% 22%}.InstructorLetter_card__c5z6C{width:auto;margin:-64px 12px 0}}@media (max-width:720px){.InstructorLetter_letter__xP593{--letter-radius:16px}.InstructorLetter_portrait__7Dw2m{height:340px}.InstructorLetter_card__c5z6C{margin:-48px 8px 0;padding:24px}.InstructorLetter_letter__xP593 .InstructorLetter_name__fJD0S{font-size:var(--letter-name-size,48px)}.InstructorLetter_facts__c4mYu{gap:16px 24px}}