.u1-page{--u1-muted:color-mix(in srgb,var(--ink)72%,var(--ground));--u1-line:color-mix(in srgb,var(--fine)48%,var(--ground));background:var(--surface);color:var(--ink);font-family:Instrument Sans,Arial,sans-serif;line-height:1.7}.u1-page *{box-sizing:border-box}.u1-page button{font:inherit;color:inherit}.u1-page a{color:inherit}.u1-page h1,.u1-page h2,.u1-page h3{font-family:Instrument Serif,Georgia,serif;font-weight:400;line-height:1.12}.u1-shell{grid-template-columns:270px minmax(0,1fr);max-width:1440px;margin:0 auto;display:grid}.u1-sidebar{background:var(--ground);border-right:1px solid var(--u1-line);padding:30px 22px}.u1-sidebar-inner{scrollbar-width:thin;max-height:calc(100dvh - 118px);padding:0 5px 22px 0;position:sticky;top:98px;overflow-y:auto}.u1-eyebrow{text-transform:uppercase;letter-spacing:1.65px;font-size:11px;font-weight:600;text-decoration:none}.u1-course-name{margin:16px 0 24px;font:30px/1.1 Instrument Serif,Georgia,serif;text-decoration:none;display:block}.u1-progress-heading{justify-content:space-between;font-size:12px;display:flex}.u1-page progress{appearance:none;background:var(--wash);border:0;border-radius:4px;width:100%;height:5px;margin:11px 0;display:block;overflow:hidden}.u1-page progress::-webkit-progress-bar{background:var(--wash)}.u1-page progress::-webkit-progress-value{background:var(--red)}.u1-page progress::-moz-progress-bar{background:var(--red)}.u1-small{color:var(--u1-muted);line-height:1.6;font-size:12px!important}.u1-text-button{text-underline-offset:4px;background:0 0;border:0;padding:4px 0;text-decoration:underline;font-size:12px!important}.u1-unit{border-top:1px solid var(--u1-line);margin-top:22px;padding-top:16px}.u1-unit summary{cursor:pointer;justify-content:space-between;gap:10px;font-size:13px;font-weight:600;list-style:none;display:flex}.u1-unit summary small{white-space:nowrap;font-size:11px}.u1-unit summary:before{content:"+";font-weight:400}.u1-unit[open] summary:before{content:"−"}.u1-module{margin-top:15px}.u1-module-title{color:var(--u1-muted);margin-bottom:4px;padding:4px 8px;font-size:11px;display:block}.u1-lesson-link,.u1-coming{border-radius:4px;align-items:flex-start;gap:9px;padding:9px 8px;font-size:12px;line-height:1.5;text-decoration:none;display:flex}.u1-lesson-link:hover{background:var(--surface)}.u1-lesson-link.u1-current{background:var(--surface);color:var(--red);box-shadow:inset 2px 0 var(--red);font-weight:600}.u1-status-dot{border:1px solid var(--fine);border-radius:50%;flex-shrink:0;place-items:center;width:15px;height:15px;margin-top:2px;display:grid}.u1-current .u1-status-dot{border-color:var(--red)}.u1-status-dot>span{background:var(--red);border-radius:50%;width:5px;height:5px}.u1-done{background:var(--deep);border-color:var(--deep);color:var(--on-deep)}.u1-coming{color:var(--u1-muted)}.u1-coming small{font-size:10px;display:block}.u1-main{min-width:0;padding:28px clamp(22px,4vw,64px) 60px}.u1-breadcrumb{color:var(--u1-muted);flex-wrap:wrap;gap:8px;margin-bottom:42px;font-size:11px;display:flex}.u1-breadcrumb a{text-decoration:none}.u1-intro{max-width:820px}.u1-intro h1{letter-spacing:-1.3px;max-width:730px;margin:18px 0 20px;font-size:clamp(40px,4.6vw,64px)}.u1-lead{color:var(--u1-muted);max-width:710px;font-size:17px}.u1-kicker{color:var(--red);margin-top:20px;font-family:Instrument Serif,Georgia,serif;font-size:23px;font-style:italic}.u1-goals{border-bottom:1px solid var(--u1-line);padding:15px 0;font-size:13px}.u1-goals summary{cursor:pointer}.u1-goals ul{margin:12px 0;padding-left:22px}.u1-prediction{padding:26px 0 20px}.u1-prediction p{margin:7px 0 0;font-size:14px}.u1-lab{border:1px solid var(--u1-line);background:var(--ground);border-radius:10px;padding:22px;overflow:hidden}.u1-lab-heading{border-bottom:1px solid var(--u1-line);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:10px;margin-bottom:19px;padding-bottom:15px;display:flex}.u1-experiment-grid{grid-template-columns:minmax(0,1.1fr) minmax(0,1fr);align-items:center;gap:26px;display:grid}.u1-experiment-grid>div{min-width:0}.u1-figure{width:100%;height:auto;max-height:300px;display:block;overflow:visible}.u1-figure text{fill:var(--ink);font:17px Instrument Sans,Arial,sans-serif}.u1-outline{fill:none;stroke:var(--hero-line);stroke-width:2px}.u1-boundary{fill:none;stroke:var(--red);stroke-width:2px;stroke-dasharray:6 5}.u1-flow{stroke-dasharray:10 8;animation:2.5s linear infinite u1-flow}@keyframes u1-flow{to{stroke-dashoffset:-54px}}html[data-motion=paused] .u1-flow{animation-play-state:paused}.u1-choice{flex-wrap:wrap;gap:9px;margin:10px 0 20px;display:flex}.u1-choice button{background:var(--surface);border:1px solid var(--u1-line);border-radius:4px;min-height:38px;padding:8px 11px;font-size:12px}.u1-choice button[aria-pressed=true]{background:var(--deep);color:var(--on-deep);border-color:var(--deep)}.u1-slider{margin:16px 0;font-size:12px;display:block}.u1-slider>span{justify-content:space-between;align-items:flex-start;gap:12px;display:flex}.u1-slider strong{white-space:nowrap;font-variant-numeric:tabular-nums;font-weight:600}.u1-slider input{width:100%;accent-color:var(--red);cursor:ew-resize;height:20px;margin:12px 0;display:block}.u1-button{border:1px solid var(--u1-line);background:var(--surface);border-radius:5px;justify-content:center;align-items:center;gap:7px;min-height:40px;padding:9px 15px;display:inline-flex;font-size:12px!important}.u1-primary{background:var(--deep);border-color:var(--deep);color:var(--on-deep)!important}.u1-readout{margin:18px 0 6px}.u1-readout>span{color:var(--u1-muted);font-size:12px;display:block}.u1-readout>strong{color:var(--red);overflow-wrap:anywhere;margin:5px 0;font:32px/1.25 Instrument Serif,Georgia,serif;display:block}.u1-readout p,.u1-experiment-grid p{margin:10px 0;font-size:13px}.u1-assumption{color:var(--u1-muted);margin-bottom:0;padding-top:15px;font-size:12px!important}.u1-bars{gap:13px;margin:20px 0;display:grid}.u1-bar-label{justify-content:space-between;gap:12px;margin-bottom:5px;font-size:12px;display:flex}.u1-bar-label strong{white-space:nowrap;font-variant-numeric:tabular-nums}.u1-track{background:var(--wash);border-radius:2px;height:6px;overflow:hidden}.u1-track>span{height:100%;transition:width .2s;display:block}.u1-crossing-list p{border-bottom:1px solid var(--u1-line);justify-content:space-between;gap:14px;padding:10px 0;display:flex}.u1-crossing-list span{text-align:right}.u1-reading{padding:30px 0 8px}.u1-reading section{grid-template-columns:40px minmax(0,1fr);gap:14px;margin:22px 0 32px;display:grid}.u1-section-number{color:var(--red);padding-top:8px;font:italic 23px Instrument Serif,Georgia,serif}.u1-reading h2,.u1-worked h2,.u1-practice h2,.u1-finish h2{margin:0 0 14px;font-size:32px}.u1-reading p{margin:0 0 12px;font-size:15px}.u1-equation{background:var(--ground);border-left:2px solid var(--red);overflow-wrap:anywhere;padding:14px 18px;font-size:16px}.u1-worked{background:var(--ground);border-radius:7px;padding:28px}.u1-worked h2{margin-top:13px}.u1-worked ol{margin:0;padding-left:22px}.u1-worked li{margin:14px 0;padding-left:8px;font-size:14px}.u1-worked li::marker{color:var(--red);font-weight:600}.u1-pitfall{border-bottom:1px solid var(--u1-line);margin:10px 0 34px;padding:22px 0 28px}.u1-pitfall p{margin:7px 0 0;font-size:14px}.u1-practice h2{margin-top:12px}.u1-practice>p{color:var(--u1-muted);font-size:14px}.u1-problem{border-bottom:1px solid var(--u1-line);padding:25px 0}.u1-problem h3{margin:10px 0;font-size:26px}.u1-problem>p{font-size:14px}.u1-hint{margin:14px 0;font-size:13px}.u1-hint summary{cursor:pointer;color:var(--u1-muted)}.u1-hint p{padding:8px 0}.u1-solution>summary{cursor:pointer;color:var(--red);justify-content:space-between;padding:12px 0;font-size:13px;font-weight:600;list-style:none;display:flex}.u1-solution>summary:after{content:"+"}.u1-solution[open]>summary:after{content:"−"}.u1-solution-body{background:var(--ground);border-radius:7px;padding:22px}.u1-solution-grid{grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);align-items:center;gap:25px;display:grid}.u1-solution-grid>div{min-width:0}.u1-solution-visual>p{font-size:13px}.u1-worked-solution{border-top:1px solid var(--u1-line);margin-top:20px;padding-top:20px}.u1-worked-solution>p{min-height:70px;font-size:14px}.u1-step-nav{justify-content:space-between;gap:12px;display:flex}.u1-takeaway{border-left:2px solid var(--red);margin:22px 0 0;padding-left:14px;font-size:13px}.u1-energy-split{border-radius:5px;width:100%;height:32px;display:flex;overflow:hidden}.u1-energy-split span:first-child{background:var(--red)}.u1-energy-split span:last-child{background:var(--hero-line)}.u1-finish{margin-top:44px}.u1-finish h2{margin-top:12px}.u1-finish>p{font-size:14px}.u1-footer-nav{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:14px;margin:23px 0;display:flex}.u1-footer-nav a{align-items:center;gap:6px;font-size:12px;text-decoration:none;display:flex}.u1-mobile-menu{display:none}.u1-page button:disabled{opacity:.5}.u1-page summary::-webkit-details-marker{display:none}@media (min-width:1450px){.u1-shell{border-left:1px solid var(--u1-line);border-right:1px solid var(--u1-line)}}@media (max-width:1100px){.u1-shell{grid-template-columns:230px minmax(0,1fr)}.u1-sidebar{padding:26px 15px}.u1-main{padding:25px}.u1-experiment-grid,.u1-solution-grid{grid-template-columns:1fr}.u1-figure{max-height:270px}.u1-experiment-grid{gap:6px}.u1-solution-grid{gap:8px}.u1-experiment-grid>div:has(>.u1-slider){grid-template-columns:1fr 1fr;gap:0 20px;display:grid}.u1-experiment-grid .u1-readout,.u1-experiment-grid p{grid-column:1/-1}}@media (max-width:760px){.u1-shell{display:block}.u1-mobile-menu{background:var(--ground);border:0;border-bottom:1px solid var(--u1-line);align-items:center;gap:10px;width:100%;padding:14px 20px;display:flex;font-size:13px!important}.u1-mobile-menu span{margin-left:auto}.u1-sidebar{border-right:0;border-bottom:1px solid var(--u1-line);display:none}.u1-sidebar.u1-open{display:block}.u1-sidebar-inner{max-height:none;position:static;overflow:visible}.u1-main{padding:24px 20px 45px}.u1-breadcrumb{margin-bottom:30px}.u1-intro h1{font-size:43px}.u1-lead{font-size:16px}.u1-lab,.u1-solution-body{padding:16px}.u1-reading section{grid-template-columns:27px minmax(0,1fr);gap:8px}.u1-reading h2,.u1-worked h2,.u1-practice h2,.u1-finish h2{font-size:29px}.u1-worked{padding:22px}.u1-experiment-grid>div:has(>.u1-slider){grid-template-columns:1fr}.u1-figure{max-height:280px}.u1-choice button{min-height:44px}.u1-footer-nav{justify-content:flex-start}.u1-small{font-size:12px!important}}@media (prefers-reduced-motion:reduce){.u1-flow{animation:none}.u1-track>span{transition:none}}.u1-page{--water:#677e90}html[data-theme=dark] .u1-page{--water:#91a8bc}.u1-water-stream{animation:2s linear infinite u1-water}.u1-pump-rotor{animation:4s linear infinite u1-rotor}@keyframes u1-water{to{stroke-dashoffset:-36px}}@keyframes u1-rotor{to{transform:rotate(360deg)}}html[data-motion=paused] .u1-water-stream,html[data-motion=paused] .u1-pump-rotor{animation-play-state:paused}.thermal-math-display{max-width:100%;padding:8px 0;display:block;overflow-x:auto}.thermal-math-display .katex-display{text-align:left;margin:.5em 0}.thermal-math-inline{font-size:.98em}.u1-equation .katex{font-size:1.08em}.u1-worked-solution .thermal-math-display{margin:12px 0}.thermal-reference-table{border-collapse:collapse;width:100%;font-size:12px}.thermal-reference-table th,.thermal-reference-table td{border-bottom:1px solid var(--u1-line);text-align:right;padding:10px}.thermal-reference-table th:first-child,.thermal-reference-table td:first-child{text-align:left}.thermal-reference-table .selected-row{background:var(--wash)}.thermal-table-wrap{margin:16px 0;overflow-x:auto}.thermal-note{color:var(--u1-muted);padding:12px 0;font-size:12px}@media (prefers-reduced-motion:reduce){.u1-water-stream,.u1-pump-rotor{animation:none}}.thermal-visuals{grid-template-columns:1fr 1fr;align-items:center;gap:20px;display:grid}.thermal-controls{grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:24px;margin:24px 0;display:grid}.thermal-live-answer{border-top:1px solid var(--fine);padding:20px 0}.thermal-table-wrap{margin:25px 0;overflow:auto}.thermal-table{border-collapse:collapse;width:100%;font-size:14px}.thermal-table th,.thermal-table td{text-align:left;border-bottom:1px solid var(--fine);white-space:nowrap;padding:12px}.thermal-table caption{text-align:left;padding:10px 0;font-weight:600}.thermal-dome{border-top:1px solid var(--fine);margin-top:35px;padding-top:25px}.thermal-dome .u1-figure{max-width:600px;margin:auto}.thermal-mixture{border:2px solid var(--hero-line);background:var(--wash);flex-direction:column-reverse;max-width:220px;height:220px;margin:auto;display:flex;position:relative}.thermal-mixture>div{background:var(--water);min-height:2px}.thermal-mixture>span{font-size:13px;position:absolute;top:20px;left:12px}.thermal-guess{flex-wrap:wrap;align-items:center;gap:12px;margin:20px 0;display:flex}.thermal-guess input{border:1px solid var(--fine);background:var(--surface);max-width:200px;color:inherit;font:inherit;border-radius:6px;padding:10px 12px}.thermal-explorer .u1-figure text{fill:var(--hero-line)}@media (max-width:680px){.thermal-visuals,.thermal-controls{grid-template-columns:1fr}.thermal-guess input{width:100%;max-width:100%}}.thermal-mixture>div{min-height:0}.thermal-visuals>div{min-width:0}.u1-page .thermal-math-display .katex{font-size:1.08em}.thermal-visuals .u1-figure{max-height:none}