@font-face{unicode-range:u+00??,u+0131,u+0152-0153,u+02bb-02bc,u+02c6,u+02da,u+02dc,u+0304,u+0308,u+0329,u+2000-206f,u+20ac,u+2122,u+2191,u+2193,u+2212,u+2215,u+feff,u+fffd;font-family:inter;src:url(/_next/static/media/5678e9b0dc22dee2-s.p.woff2) format("woff2");font-display:swap;font-weight:100 900;font-style:normal}@font-face{font-family:inter Fallback;src:local("Arial");ascent-override:89.79%;descent-override:22.36%;line-gap-override:0.00%;size-adjust:107.89%}.__className_cc277d{font-family:inter,inter Fallback,Segoe UI,Arial,sans-serif;font-style:normal}.__variable_cc277d{--font-inter:"inter","inter Fallback",Segoe UI,Arial,sans-serif}@font-face{unicode-range:u+0370-0377,u+037a-037f,u+0384-038a,u+038c,u+038e-03a1,u+03a3-03ff;font-family:interGreek;src:url(/_next/static/media/a94d318eedf07730.woff2) format("woff2");font-display:swap;font-weight:100 900;font-style:normal}.__className_0c460b{font-family:interGreek;font-style:normal}.__variable_0c460b{--font-inter-greek:"interGreek"}:root{--font-inter-stack:var(--font-inter-greek),var(--font-inter),"Inter",-apple-system,"Segoe UI",Roboto,Arial,sans-serif;--font-display:var(--font-inter-stack);--font-text:var(--font-inter-stack);--w-read:440;--w-quiet:440;--w-ui:470;--w-ui-on:580;--w-button:520;--w-strong:540;--w-title:560;--w-figure:600;--w-label:460;--tr-read:-0.005em;--tr-button:0em;--tr-ui:0em;--tr-trail:0em;--tr-title:-0.03em;--tr-name:-0.035em;--tr-figure:0em;--tr-read-phone:-0.012em;--fs-read:0.94;--fs-trail:0.975;--fs-nav:0.956;--fs-small:0.97;--fs-quiet:0.958;--fs-hint:0.986;--fs-title:1;--text-xs:12px;--text-sm:14px;--text-md:15.5px;--text-body:17.5px;--text-title:36px;--text-name:46px;--leading-body:1.52;--ink:#1d2b36;--ink-2:#3d4b57;--ink-3:#55636f;--sign:#fdfdfb;--calculus:#1e6aa0;--physics:#e8a317;--physics-ink:#8a5a00;--wagon:#c8302a;--rule:rgba(29,43,54,0.16);--wash:rgba(29,43,54,0.06);--value:#2b6fd6;--space-1:4px;--space-2:8px;--space-3:12px;--space-4:16px;--space-5:20px;--space-6:24px;--space-7:28px;--r-sign:4px;--r-control:4px;--r-plate:3px;--r-blaze:2px;--edge:0 2px 0 rgba(29,43,54,0.24);--ease:cubic-bezier(0.2,0.7,0,1);--ease-move:cubic-bezier(0.6,0,0,1);--dur-press:120ms;--dur-hover:150ms;--dur-state:320ms;--dur-reveal:700ms;--stagger:70ms}[data-trail=calculus]{--trail:var(--calculus);--trail-ink:var(--calculus);--trail-edge:var(--calculus);--on-trail:var(--sign)}[data-trail=physics]{--trail:var(--physics);--trail-ink:var(--physics-ink);--trail-edge:var(--physics-ink);--on-trail:var(--ink)}[data-trail=books]{--trail:var(--ink);--trail-ink:var(--ink);--trail-edge:var(--ink);--on-trail:var(--sign)}*{box-sizing:border-box}body,html{margin:0;padding:0;background:#cfe6f1;color:var(--ink);font-family:var(--font-text);font-size:16px;font-weight:var(--w-read);line-height:1.3125;font-optical-sizing:auto;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizeLegibility;font-feature-settings:"kern" 1}html.lenis,html.lenis body{height:auto}.lenis.lenis-smooth{scroll-behavior:auto!important}.lenis.lenis-stopped{overflow:hidden}body{overflow-x:hidden}a,button{font:inherit;color:inherit}a{text-decoration:none}button{cursor:pointer}:focus-visible{outline:2.5px solid var(--ink);outline-offset:2px;box-shadow:0 0 0 6.5px var(--sign)}.experience{position:fixed;inset:0;z-index:0;background:linear-gradient(#5c9edb,#cfe6f1 55%,#8fbf6c 56%)}.experience canvas{display:block;width:100%;height:100%;touch-action:pan-y}.scroll-spacer{position:relative;z-index:-1;pointer-events:none}.btn{--h:44px;position:relative;display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:var(--h);padding:0 18px;border-radius:var(--r-control);border:1.5px solid transparent;font-family:var(--font-text);font-size:var(--text-md);font-weight:var(--w-button);letter-spacing:var(--tr-button);line-height:1;white-space:nowrap;transition:transform var(--dur-press) var(--ease),background-color var(--dur-hover) linear,color var(--dur-hover) linear,border-color var(--dur-hover) linear,box-shadow var(--dur-press) var(--ease);-webkit-tap-highlight-color:transparent}.btn:active{transform:translateY(1px);transition-duration:60ms}.btn:before{content:"";position:absolute;inset:calc(min(0px, (var(--h) - 44px) / 2) - 1.5px) -1.5px}.btn-small{--h:36px;padding:0 14px;font-size:calc(var(--text-sm) * var(--fs-small))}.btn-ink{background:var(--ink);color:var(--sign);box-shadow:0 2px 0 #0b141b}.btn-ink:hover{background:#2a3c4a}.btn-ink:active,.btn-red:active{box-shadow:0 1px 0 #0b141b}.btn-red{background:var(--wagon);color:#fff;box-shadow:0 2px 0 #7e1c18}.btn-red:hover{background:#b12923}.btn-outline{background:var(--sign);color:var(--ink);border-color:var(--ink)}.btn-outline:hover{background:#eef0ee}.btn-plate{background:var(--sign);color:var(--ink);box-shadow:var(--edge)}.btn-plate:hover{background:#eef0ee}.btn-quiet{background:var(--sign);color:var(--ink);font-weight:var(--w-ui);box-shadow:var(--edge)}.btn-quiet:hover{text-decoration:underline;text-underline-offset:3px}.btn-icon{margin-right:-2px;opacity:.7}.btn-icon-lead{margin-left:-3px}.icon-btn{position:relative;display:grid;place-items:center;width:40px;height:40px;border-radius:var(--r-control);border:1.5px solid var(--rule);background:var(--sign);color:var(--ink);transition:background-color var(--dur-hover) linear,transform var(--dur-press) var(--ease)}.icon-btn:before{content:"";position:absolute;inset:-3px}.icon-btn:hover{background:#eef0ee}.icon-btn:active{transform:translateY(1px);transition-duration:60ms}.link-btn{border:0;background:none;padding:0;color:var(--ink);font-weight:var(--w-button);text-decoration:underline;text-underline-offset:3px}@keyframes rise{0%{opacity:0;translate:0 12px}}.overlay:not(.is-ready) :is(.topbar,.hud:not(.is-probe),.rail){opacity:0}.overlay.is-ready :is(.topbar,.hud:not(.is-probe),.rail){animation:rise var(--dur-reveal) var(--ease) backwards;animation-delay:calc(.42s + var(--step-k, 0) * var(--stagger))}.overlay.is-ready .hud{--step-k:0}.is-handover .hud:not(.is-probe) .site-name{visibility:hidden}.overlay.is-ready .topbar{--step-k:2}.overlay.is-ready .rail{--step-k:3}.topbar{position:fixed;z-index:50;top:14px;left:20px;right:20px;display:flex;justify-content:center;align-items:center;pointer-events:none}.topbar>*{pointer-events:auto}.nav{display:flex;gap:2px;padding:0 8px;border-radius:var(--r-sign);background:var(--sign);box-shadow:var(--edge)}.nav,.nav button{position:relative;height:44px}.nav button{z-index:1;display:inline-flex;align-items:center;gap:7px;padding:0 10px;border:0;background:transparent;font-family:var(--font-text);font-size:calc(var(--text-sm) * var(--fs-nav));font-weight:var(--w-ui);letter-spacing:var(--tr-ui);color:var(--ink);-webkit-tap-highlight-color:transparent;transition:color var(--dur-state) var(--ease-move),transform var(--dur-press) var(--ease)}.trail-mark{flex:none;width:5px;height:13px;border-radius:1px;background:var(--trail);box-shadow:inset 0 0 0 1px var(--trail-edge)}.nav button[data-trail=books] .trail-mark{display:none}.nav button:hover .trail-name{text-decoration:underline;text-decoration-thickness:1.5px;text-underline-offset:4px}.nav button:active{transform:translateY(1px);transition-duration:60ms}.nav button.is-active{font-weight:var(--w-ui-on);color:var(--trail-ink)}.nav button.is-active:hover .trail-name{text-decoration:none}.nav-bar{position:absolute;left:0;bottom:5px;width:0;height:3px;border-radius:1px;background:var(--trail-ink);transition:transform var(--dur-state) var(--ease-move),width var(--dur-state) var(--ease-move),background-color var(--dur-state) var(--ease-move)}.nav-bar.is-instant{transition:none}.top-actions{position:absolute;right:0;display:flex;gap:8px}.show-md{display:none!important}.hud{position:fixed;z-index:20;inset:0}.hud,.hud.is-probe{pointer-events:none}.hud.is-probe{visibility:hidden;z-index:-1}.panel{--sign-gap:clamp(28px,3.2vw,52px);position:absolute;left:var(--sign-gap);bottom:var(--sign-gap);display:flex;flex-direction:column;width:clamp(440px,29vw,468px);max-height:calc(100vh - 92px - var(--sign-gap));border-radius:var(--r-sign);background:var(--sign);color:var(--ink);box-shadow:var(--edge);pointer-events:auto}.panel-scroll{flex:0 1 auto;min-height:0;overflow:auto;padding:24px 28px 22px;border-radius:inherit;scrollbar-width:thin}.sign-trail{gap:10px;margin:0 0 12px;font-family:var(--font-text);font-size:calc(var(--text-sm) * var(--fs-trail));font-weight:var(--w-strong);line-height:1;letter-spacing:var(--tr-trail);color:var(--trail-ink)}.sign-trail,.sign-trail .rise{display:flex;align-items:center}.sign-trail .rise{gap:inherit}.blaze{display:inline-grid;flex:none;place-items:center;width:22px;height:32px;padding-top:1px;border-radius:var(--r-blaze);background:var(--trail);box-shadow:inset 0 0 0 1.5px var(--trail-edge);color:var(--on-trail);font-family:var(--font-display);font-size:17px;font-weight:var(--w-figure);line-height:1;letter-spacing:var(--tr-figure);font-feature-settings:lining-nums tabular-nums;font-variant-numeric:lining-nums tabular-nums}.panel h1{margin:0 0 12px;font-family:var(--font-display);--title:clamp(30px,2.5vw,38px);font-size:calc(var(--title) * var(--fs-title));font-weight:var(--w-title);line-height:calc(var(--title) * 1.06);letter-spacing:var(--tr-title);color:var(--ink);text-wrap:balance}.panel h1 span{display:block}.panel h1:not(.site-name){padding-right:17%}.body{margin:0;font-family:var(--font-text);font-size:calc(var(--text-body) * var(--fs-read));font-weight:var(--w-read);line-height:calc(var(--text-body) * var(--leading-body));letter-spacing:var(--tr-read);color:var(--ink-2);text-wrap:pretty}.point{color:var(--trail-ink);font-weight:var(--w-strong);-webkit-text-decoration:underline dotted;text-decoration:underline dotted;text-decoration-thickness:2px;text-underline-offset:4px}.point:hover{text-decoration-style:solid}.todo{display:flex;flex-direction:column;align-items:stretch;gap:8px;margin-top:18px}.instruction{position:relative;display:flex;align-items:center;gap:12px;width:100%;min-height:48px;margin:0;padding:7px 14px 7px 8px;border:1.5px solid rgba(29,43,54,.24);border-radius:var(--r-control);background:var(--sign);box-shadow:0 2px 0 rgba(29,43,54,.16);text-align:left;font-family:var(--font-text);font-size:var(--text-md);font-weight:var(--w-button);line-height:1.3;letter-spacing:var(--tr-button);color:var(--ink);-webkit-tap-highlight-color:transparent;transition:transform var(--dur-press) var(--ease),box-shadow var(--dur-press) var(--ease),border-color var(--dur-hover) linear,background-color var(--dur-hover) linear}.push{flex:none;display:grid;place-items:center;width:30px;height:30px;border-radius:var(--r-plate);background:var(--trail);color:var(--on-trail);box-shadow:inset 0 0 0 1.5px var(--trail-edge),inset 0 -2px 0 rgba(0,0,0,.22);transition:opacity var(--dur-hover) linear}button.instruction:not([aria-disabled=true]):hover{border-color:var(--trail);background:#f3f5f4}button.instruction:not([aria-disabled=true]):active{transform:translateY(2px);box-shadow:0 0 0 rgba(29,43,54,.16);transition-duration:60ms}button.instruction[aria-disabled=true]{cursor:default}button.instruction[aria-disabled=true] .push{opacity:.55}.instruction-row{display:flex;align-items:center;gap:12px;width:100%}.instruction.is-text{flex:1 1;min-height:0;padding:6px 0;border:0;background:none;box-shadow:none;font-weight:var(--w-button);color:var(--ink-2)}.slide-nav{display:flex;flex:none;gap:6px}.slide-btn{position:relative;display:grid;place-items:center;width:40px;height:40px;padding:0;border:1.5px solid var(--ink);border-radius:var(--r-control);background:var(--sign);color:var(--ink);-webkit-tap-highlight-color:transparent;transition:background-color var(--dur-hover) linear,color var(--dur-hover) linear,opacity var(--dur-hover) linear,transform var(--dur-press) var(--ease)}.slide-btn:before{content:"";position:absolute;inset:-2px}.slide-btn:not([aria-disabled=true]):hover{background:var(--ink);color:var(--sign)}.slide-btn:not([aria-disabled=true]):active{transform:translateY(1px);transition-duration:60ms}.slide-btn[aria-disabled=true]{opacity:.35;cursor:default}.cta-row{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}.way-back{display:inline-flex;align-items:center;min-height:44px;margin-top:8px;padding:0;border:0;background:none;font-family:var(--font-text);font-size:var(--text-md);font-weight:var(--w-button);letter-spacing:var(--tr-button);color:var(--ink);text-decoration:underline;text-decoration-thickness:1.5px;text-underline-offset:4px}.way-back:hover{text-decoration-thickness:2.5px}.sr-only{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}.panel.is-trailhead .panel-scroll{padding:28px 30px 24px}.site-name{margin:0;font-family:var(--font-display);font-size:clamp(38px,3.2vw,48px);font-weight:var(--w-title);line-height:1.02;letter-spacing:var(--tr-name);color:var(--ink)}.site-name span{display:block}.site-byline{margin:10px 0 0;font-family:var(--font-text);font-size:calc(15px * var(--fs-quiet));font-weight:var(--w-quiet);line-height:20px;color:var(--ink-3)}.trailhead .body{margin-top:22px}.start-row{display:flex;flex-wrap:wrap;align-items:center;gap:10px 18px;margin-top:20px}.scroll-hint{display:inline-flex;align-items:center;gap:8px;margin:0;font-family:var(--font-text);font-size:calc(var(--text-sm) * var(--fs-hint));font-weight:var(--w-quiet);color:var(--ink-3);opacity:0;transition:opacity var(--dur-reveal) linear}.scroll-hint.is-shown{opacity:1}.hint-icon{flex:none}.hint-icon.is-wheel .hint-dot{animation:wheel-dot 1.8s var(--ease) infinite}.hint-icon.is-swipe .hint-dot{animation:swipe-dot 1.8s var(--ease) infinite}@keyframes wheel-dot{0%{transform:translateY(-1px);opacity:0}20%{opacity:1}70%,to{transform:translateY(6px);opacity:0}}@keyframes swipe-dot{0%{transform:translateY(2px);opacity:0}20%{opacity:1}75%,to{transform:translateY(-9px);opacity:0}}@media (min-width:1700px){.panel{--text-body:18.5px}.panel h1{--title:40px}}@media (prefers-reduced-motion:reduce){.hint-icon .hint-dot{animation:none}}.panel-scroll{--step:min(55ms,calc(900ms / max(1, var(--n, 1) - 1)))}.piece,.w,.wi{--at:calc(140ms + var(--i, 0) * var(--step))}.li{--at:calc(140ms + (var(--n, 1) - 1) * var(--step) + var(--k, 0) * 75ms)}.panel[data-arrive] .sign-trail,.panel[data-arrive] h1>span{overflow:clip;overflow-clip-margin:.14em}.panel[data-arrive] .w{display:inline-block}.panel[data-arrive=wait] .rise{translate:0 calc(100% + .2em)}.panel[data-arrive=wait] :is(.w,.wi,.piece,.li){opacity:0}.panel[data-arrive=play] .rise{animation:arrive-line 1.3s var(--ease) backwards;animation-delay:calc((var(--l, -1) + 1) * 80ms)}.panel[data-arrive=play] :is(.w,.piece){animation:arrive-fade .7s linear backwards,arrive-word 1s var(--ease) backwards;animation-delay:var(--at)}.panel[data-arrive=play] .wi{animation:arrive-fade .7s linear backwards;animation-delay:var(--at)}.panel[data-arrive=play] .body{animation:arrive-blur .9s var(--ease) .14s backwards}.panel[data-arrive=play] .li{animation:arrive-fade .9s linear backwards,arrive-item 1.1s var(--ease) backwards;animation-delay:var(--at)}@keyframes arrive-line{0%{translate:0 calc(100% + .2em)}}@keyframes arrive-fade{0%{opacity:0}}@keyframes arrive-blur{0%{filter:blur(8px)}}@keyframes arrive-word{0%{translate:0 .32em}}@keyframes arrive-item{0%{translate:0 12px}}.panel[data-arrive][data-fits] .panel-scroll{overflow-y:hidden}.panel[data-arrive=play]:not([data-fits]) .li{animation:arrive-fade .9s linear backwards;animation-delay:var(--at)}.rail{position:fixed;z-index:30;right:18px;top:50%;width:34px;height:min(440px,calc(100vh - 190px));transform:translateY(-50%)}.rail-track{position:absolute;left:0;right:0;top:12px;bottom:12px}.rail-line{top:-11px;bottom:-11px;width:12px;margin-left:-6px;border-radius:var(--r-blaze);background:var(--sign);box-shadow:var(--edge);overflow:hidden}.rail-fill,.rail-line{position:absolute;left:50%}.rail-fill{top:11px;bottom:11px;width:2px;margin-left:-1px;background:var(--ink);transform-origin:top;transform:scaleY(0);will-change:transform}.rail-stop{position:absolute;left:0;right:0;height:22px;margin-top:-11px;padding:0;border:0;background:transparent;display:grid;place-items:center;-webkit-tap-highlight-color:transparent}.rail-blaze{width:8px;height:14px;border-radius:1.5px;background:var(--trail);box-shadow:inset 0 0 0 1px var(--trail-edge);transition:transform var(--dur-hover) var(--ease)}.rail-stop:hover .rail-blaze{transform:scale(1.3)}.rail-stop:active .rail-blaze{transform:scale(1.1);transition-duration:60ms}.rail-stop:focus-visible{outline:none;box-shadow:none}.rail-stop:focus-visible .rail-blaze{box-shadow:0 0 0 2px var(--sign),0 0 0 4.5px var(--ink),0 0 0 6.5px var(--sign)}.rail-wagon-track{position:absolute;inset:0;pointer-events:none;will-change:transform}.rail-wagon{position:absolute;left:50%;top:0;width:34px;height:22px;margin:-13px 0 0 -17px}.rail-wagon-icon{display:block;overflow:visible}.rail.is-complete .rail-fill{transform:scaleY(1)!important}.rail-tip{position:absolute;right:44px;top:50%;display:flex;flex-direction:column;align-items:flex-end;gap:3px;padding:7px 11px;border-radius:var(--r-plate);background:var(--sign);box-shadow:var(--edge);font-family:var(--font-text);font-size:calc(var(--text-sm) * var(--fs-trail));color:var(--ink);white-space:nowrap;opacity:0;transform:translate(6px,-50%);pointer-events:none;transition:opacity var(--dur-hover) linear,transform var(--dur-hover) var(--ease)}.rail-tip,.rail-tip small{font-weight:var(--w-strong)}.rail-tip small{font-size:var(--text-xs);color:var(--trail-ink)}.rail-stop:focus-visible .rail-tip,.rail-stop:hover .rail-tip{opacity:1;transform:translateY(-50%)}.sheet-backdrop{position:fixed;inset:0;z-index:120;background:rgba(13,22,29,.36);display:flex;align-items:flex-end;justify-content:center;animation:fadeIn var(--dur-state) linear both}.sheet-backdrop.is-closing{animation:fadeOut var(--dur-state) linear both;pointer-events:none}.sheet{width:min(560px,100%);max-height:80vh;display:flex;flex-direction:column;border-radius:var(--r-sign) var(--r-sign) 0 0;background:var(--sign);animation:sheetIn var(--dur-reveal) var(--ease) both;padding-bottom:env(safe-area-inset-bottom)}.sheet-backdrop.is-closing .sheet{animation:sheetOut var(--dur-state) var(--ease-move) both}.sheet-head{display:flex;align-items:center;justify-content:space-between;padding:14px 14px 12px 22px;border-bottom:1px solid var(--rule);font-family:var(--font-display);font-size:22px;font-weight:var(--w-title);line-height:37px;letter-spacing:var(--tr-title)}.sheet-body{overflow:auto;padding:4px 12px 18px}.sheet-group+.sheet-group{border-top:1px solid var(--rule)}.sheet-section{margin:14px 10px 4px;font-size:calc(var(--text-sm) * var(--fs-nav));font-weight:var(--w-ui-on);line-height:18px;color:var(--trail-ink)}.sheet-item,.sheet-section{font-family:var(--font-text)}.sheet-item{position:relative;display:flex;align-items:center;gap:12px;width:100%;min-height:48px;padding:0 10px;border:0;border-radius:var(--r-control);background:transparent;text-align:left;font-size:calc(17px * var(--fs-nav));font-weight:var(--w-ui);color:var(--ink);transition:background-color var(--dur-hover) linear,transform var(--dur-press) var(--ease)}.sheet-item .blaze{width:18px;height:26px;font-size:14px}.sheet-item .blaze:empty{visibility:hidden}.sheet-item:hover{background:var(--wash)}.sheet-item:active{transform:translateY(1px);transition-duration:60ms}.sheet-item.is-active{font-weight:var(--w-ui-on)}.sheet-item.is-active:after{content:"";position:absolute;left:0;top:8px;bottom:8px;width:3px;border-radius:1px;background:var(--ink)}@keyframes fadeIn{0%{opacity:0}}@keyframes fadeOut{to{opacity:0}}@keyframes sheetIn{0%{transform:translateY(40px);opacity:0}}@keyframes sheetOut{to{transform:translateY(32px);opacity:0}}.label-above{display:flex;transform:translate(-50%,-100%)}.world-label{display:inline-flex;flex-direction:column;align-items:center;gap:2px;padding:8px 14px;border-radius:var(--r-plate);background:var(--sign);box-shadow:var(--edge);font-family:var(--font-text);line-height:1.33;color:var(--ink);white-space:nowrap;text-align:center;font-feature-settings:tabular-nums lining-nums;font-variant-numeric:tabular-nums lining-nums;opacity:clamp(0,calc((var(--card-opacity, 1) - .2) / .8),1);-webkit-user-select:none;user-select:none}.world-label small{font-size:var(--text-xs);font-weight:var(--w-label);letter-spacing:.005em;color:var(--ink-3)}.world-label b{letter-spacing:-.005em;line-height:1.1}.world-label b,.world-label.is-equation{font-size:22px;font-weight:var(--w-figure)}.world-label.is-equation{flex-direction:row;gap:8px}.world-label.is-equation .op{color:var(--ink-3)}.world-label.is-equation b{color:var(--value)}.world-label.is-area{flex-direction:row;gap:14px}.world-label.is-area>span{display:flex;flex-direction:column;align-items:center}.world-label.is-area>span:first-child b{color:var(--value)}.world-label .sep{align-self:stretch;width:1px;background:var(--rule)}.world-label.is-ants{flex-direction:row;gap:8px;font-size:15px;font-weight:var(--w-figure)}.world-label.is-stack{flex-direction:column;align-items:flex-start;gap:3px}.world-label.is-stack>span{display:flex;align-items:baseline;gap:8px}.world-label.is-result{align-items:flex-start;gap:3px}.world-label.is-result>span{display:flex;align-items:baseline;gap:6px;font-size:14px;font-weight:var(--w-figure)}.world-label .label-time{margin-top:2px;color:var(--ink-2)}.world-label.is-mass b{font-size:18px}.world-label.is-speed b{color:var(--value)}.world-label.is-limit b{color:var(--ink)}.world-label.is-energy{align-items:stretch;gap:6px;min-width:190px;padding:10px 14px}.energy-row{display:grid;grid-template-columns:56px 1fr;align-items:center;gap:8px}.energy-row small{text-align:left}.energy-track{height:10px;border-radius:1px;background:rgba(29,43,54,.1);overflow:hidden}.energy-fill{display:block;height:100%;border-radius:1px;transform-origin:left}.is-stored .energy-fill{background:#2b6fd6}.is-moving .energy-fill{background:#e0782a}.is-heat .energy-fill{background:#d23b2a}.loading{position:fixed;inset:0;z-index:200;display:grid;place-items:center;overflow:hidden}.loading:before{content:"";position:absolute;inset:0;background:linear-gradient(180deg,#4a95d9,#9cc9ea 48%,#d5ebf3 70%)}.loading-scene,.loading:before{transition:opacity var(--dur-reveal) linear .22s,transform .9s var(--ease) .22s}.loading.is-leaving{pointer-events:none}.loading.is-leaving .loading-scene,.loading.is-leaving:before{opacity:0;transform:scale(1.03)}.loading.is-leaving .loading-block>:not(.loading-title){opacity:0;translate:0 -10px;transition:opacity .36s linear,translate .36s var(--ease)}.loading.is-leaving .loading-title:not([style*=transform]){opacity:0;transition:opacity .36s linear}.loading-scene{position:absolute;left:0;right:0;bottom:0;width:100%;height:62%}.loading-block{position:relative;width:min(560px,calc(100vw - 32px));margin-bottom:16vh;text-align:center}.loading-title{display:inline-block;margin:0;text-align:left;font-family:var(--font-display);font-size:clamp(38px,4.6vw,60px);font-weight:var(--w-title);line-height:1.02;letter-spacing:var(--tr-name);color:var(--ink)}.loading-title span{display:block}.loading-byline{margin:14px 0 0;font-family:var(--font-text);font-size:calc(16px * var(--fs-quiet));font-weight:var(--w-quiet);color:var(--ink-2)}.loading-trail{position:relative;width:min(340px,72vw);height:40px;margin:30px auto 0}.loading-bar{position:absolute;left:0;right:0;bottom:3px;height:0;border-top:3px dotted rgba(29,43,54,.45)}.loading-bar span{position:absolute;left:0;top:-3px;width:100%;height:3px;border-radius:1px;background:var(--ink);transform-origin:left}.loading-wagon{position:absolute;left:-26px;bottom:4px;display:block;width:52px;height:32px}.loading-wagon-icon{display:block;overflow:visible}.loading-stage{display:flex;justify-content:center;gap:8px;margin:12px 0 0;font-family:var(--font-text);font-size:calc(var(--text-sm) * var(--fs-hint));font-weight:var(--w-quiet);color:var(--ink-2)}.loading-percent{min-width:3.2ch;text-align:left;font-feature-settings:"tnum";font-variant-numeric:tabular-nums;font-weight:var(--w-figure)}.loading-note{margin:14px 0 0;font-size:var(--text-sm)}.loading-note,.loading-problem p{font-family:var(--font-text);color:var(--ink-2)}.loading-problem p{margin:22px auto 16px;max-width:46ch;font-size:16px;line-height:1.5}.loading-actions{display:flex;flex-wrap:wrap;justify-content:center;gap:10px}.page{min-height:100vh;display:grid;place-items:center;padding:24px;background:linear-gradient(180deg,#4a95d9,#9cc9ea 42%,#d5ebf3 58%,#8fbf6c 58.2%,#6fae4f)}.page-card{width:min(640px,100%);padding:clamp(26px,5.4vw,48px);border-radius:var(--r-sign);background:var(--sign);box-shadow:var(--edge);animation:pageIn var(--dur-reveal) var(--ease) both}@keyframes pageIn{0%{opacity:0;transform:translateY(10px)}}.page-kicker{font-size:17px;font-weight:var(--w-strong);color:var(--ink-3)}.page-card h1,.page-kicker{margin:0 0 14px;font-family:var(--font-display)}.page-card h1{font-size:clamp(32px,5vw,44px);font-weight:var(--w-title);line-height:1.06;letter-spacing:var(--tr-title);color:var(--ink)}.page-card p{font-family:var(--font-text);font-size:calc(var(--text-body) * var(--fs-read));font-weight:var(--w-read);line-height:calc(var(--text-body) * var(--leading-body));letter-spacing:var(--tr-read);color:var(--ink-2)}.page-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:26px}.form{display:grid;gap:16px;margin-top:22px}.form label{display:grid;gap:6px;font-family:var(--font-text);font-size:var(--text-sm);font-weight:var(--w-strong);color:var(--ink)}.form input,.form textarea{width:100%;padding:11px 13px;border-radius:var(--r-control);border:1.5px solid rgba(29,43,54,.4);background:#fff;color:var(--ink);font:var(--w-read) 16px/1.45 var(--font-text);resize:vertical}.form input:focus-visible,.form textarea:focus-visible{border-color:var(--ink)}.help{font-size:var(--text-sm)!important;color:var(--ink-3)!important}@media (max-width:1180px){.nav button{padding:0 8px}}@media (max-width:1060px){.nav{display:none}.show-md{display:inline-flex!important}.topbar{justify-content:flex-end;top:max(12px,env(safe-area-inset-top));left:12px;right:12px}.top-actions{position:static}.rail{right:12px}.panel{width:min(380px,40vw)}.panel-scroll,.panel.is-trailhead .panel-scroll{padding:20px 22px 18px}.panel h1{--title:clamp(28px,3.4vw,34px)}.site-name{font-size:clamp(32px,4vw,40px)}}@media (max-width:1060px) and (orientation:portrait),(max-width:700px){.rail{display:none}.topbar.is-end .top-actions>:not(.show-md){visibility:hidden}.panel{left:12px;right:12px;top:auto;bottom:max(12px,env(safe-area-inset-bottom));width:auto;max-height:46vh}.panel-scroll,.panel.is-trailhead .panel-scroll{padding:16px 18px 14px}.sign-trail{margin-bottom:8px}.blaze{width:19px;height:28px;font-size:15px}.panel h1{--title:clamp(26px,6.6vw,32px);margin-bottom:8px}.body{--text-body:16px;--leading-body:1.48;--fs-read:1;--tr-read:var(--tr-read-phone)}.todo{margin-top:10px;padding-top:4px}.cta-row{margin-top:14px}.site-name{font-size:clamp(30px,8vw,38px)}.site-byline{margin-top:6px;font-size:calc(14px * var(--fs-quiet));line-height:18px}.start-row,.trailhead .body{margin-top:14px}}@media (min-width:701px) and (max-width:1060px) and (orientation:portrait){.panel[data-stop="3"]{min-height:38vh}.panel[data-stop="3"] .panel-scroll{display:flex;flex:1 1 auto;flex-direction:column}.panel[data-stop="3"] .todo{margin-top:auto;padding-top:18px}}@media (max-height:520px) and (orientation:landscape){.rail{display:none}.panel{left:max(16px,env(safe-area-inset-left));right:auto;top:60px;bottom:auto;width:min(340px,42vw);max-height:calc(100vh - 72px)}.panel-scroll,.panel.is-trailhead .panel-scroll{padding:14px 16px 12px}.sign-trail{margin-bottom:8px}.blaze{width:18px;height:26px;font-size:14px}.panel h1{--title:23px;margin-bottom:6px}.body{--text-body:16px;--leading-body:1.42;--fs-read:1;--tr-read:var(--tr-read-phone)}.todo{margin-top:8px;padding-top:2px}.instruction{min-height:40px;font-size:14px}.slide-btn{width:36px;height:36px}.slide-btn:before{inset:-4px}.cta-row{margin-top:12px}.btn{--h:38px;padding:0 14px;font-size:var(--text-sm)}.btn.btn-small{font-size:calc(var(--text-sm) * var(--fs-small))}.cta-row .btn{padding:0 11px}.way-back{min-height:40px;margin-top:2px}.topbar.is-end .top-actions>:not(.show-md){visibility:hidden}.site-name{font-size:26px}.site-byline{margin-top:6px;font-size:calc(13px * var(--fs-quiet));line-height:17px}.start-row,.trailhead .body{margin-top:12px}.world-label{padding:6px 11px}.world-label small{font-size:10px}.world-label b{font-size:17px}.world-label.is-ants,.world-label.is-equation{font-size:13px}.world-label.is-energy{min-width:160px}}@media (max-width:560px){.hide-sm{display:none!important}.btn{--h:42px;padding:0 16px}.instruction{font-size:14.5px}.world-label{padding:6px 11px}.world-label small{font-size:10px}.world-label b{font-size:17px}.world-label.is-ants,.world-label.is-equation{font-size:13px}.world-label.is-energy{min-width:160px}}@media (prefers-reduced-motion:reduce){*,:after,:before{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}}.capture *,.capture :after,.capture :before{animation:none!important;transition:none!important}