:root{color-scheme:light;--ink:#213c35;--green:#176f58;--deep:#115640;--line:#d7e3dc;--paper:#fff;--muted:#5e7068;--wash:#f2f6f2;--gold:#bc8d36;--error:#a33e32;font-family:system-ui,-apple-system,"Segoe UI",sans-serif;font-size:17px;line-height:1.55;background:var(--wash);color:var(--ink)}
*{box-sizing:border-box}body{margin:0}button,input,select,textarea{font:inherit}button,a,input,select,textarea,summary{touch-action:manipulation}button{min-height:44px;border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--ink);padding:9px 15px;font-weight:600;cursor:pointer}button:hover{background:#edf5ef;border-color:#7ca591}button:disabled{cursor:default;opacity:.66}button.primary{background:var(--green);color:white;border-color:var(--green)}button.primary:hover{background:var(--deep)}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #bc8d36;outline-offset:3px}a{color:var(--green);text-underline-offset:3px}p{margin:0 0 14px}h1,h2,h3{line-height:1.25;text-wrap:balance}h1{font-size:clamp(1.8rem,3.4vw,2.75rem);letter-spacing:-.035em;margin:8px 0 18px}h2{font-size:1.4rem;margin:0 0 12px}h3{font-size:1.02rem;margin:0 0 10px}main{max-width:940px;margin:auto;padding:24px 24px 0}.site-header{max-width:1040px;margin:auto;padding:22px 24px;display:flex;align-items:center;justify-content:space-between;gap:15px}.brand{font-size:1.25rem;font-weight:800;text-decoration:none;letter-spacing:-.03em}.brand span{display:block;font-size:.72rem;letter-spacing:.035em;font-weight:500}.intro{padding:8px 0 28px;max-width:780px}.intro>p:last-child{max-width:660px;color:var(--muted)}.eyebrow{font-size:.73rem;letter-spacing:.085em;text-transform:uppercase;font-weight:750;color:var(--green);margin-bottom:6px}.muted{color:var(--muted)}.small{font-size:.84rem}.workspace{border:1px solid var(--line);border-radius:20px;background:var(--paper);padding:30px;box-shadow:0 10px 32px #173c2410}.task-top{display:flex;align-items:flex-start;gap:18px;justify-content:space-between}.chip{white-space:nowrap;border-radius:20px;background:var(--wash);padding:5px 10px;font-size:.75rem;color:var(--muted)}.formula{font-size:clamp(1.3rem,4vw,1.85rem);padding:20px 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0;gap:8px;flex-wrap:wrap}.step-track li{flex:1;min-width:82px;border-top:3px solid var(--line);padding-top:8px;font-size:.73rem;color:var(--muted)}.step-track li.current{border-color:var(--gold);color:var(--ink);font-weight:700}.step-track li.done{border-color:var(--green);color:var(--green)}.notebook-section{margin:0 0 26px}.notebook{list-style:none;padding:0;margin:0;border-left:2px solid #bbd3c4}.notebook li{padding:8px 12px;margin-left:8px;font-size:.88rem}.notebook li+li{border-top:1px dashed var(--line)}.notebook h4{margin:0 0 4px;font-size:.82rem;color:var(--green)}.notebook p:last-child{margin-bottom:0}.notebook math{font-size:1.04rem}.current-step{border-top:1px solid var(--line);padding-top:25px}.current-step h2{margin-bottom:14px}#stage-description{color:var(--muted);font-size:.95rem}#stage-fields{margin:18px 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p{font-size:.82rem;color:var(--muted);margin-bottom:10px}.topic-actions{display:flex;flex-wrap:wrap;gap:7px}.topic-actions button{font-size:.8rem}.topic-actions button[aria-current=true]{border-color:var(--green);background:#e3f1e8}.skip-link{position:absolute;left:12px;top:-100px;padding:10px;background:white;z-index:10}.skip-link:focus{top:10px}[hidden]{display:none!important}.loading-error{padding:20px;color:var(--error)}
@media(min-width:680px){.sign-table{grid-template-columns:repeat(2,minmax(0,1fr))}.answer-cells{grid-template-columns:repeat(3,minmax(0,1fr))}}
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@media(prefers-reduced-motion:no-preference){button{transition:background .14s,border-color .14s}}

#no-solutions{margin-top:12px}#no-solutions[aria-pressed=true]{border:2px solid var(--green);background:#dceee2}

/* A long formula scrolls inside its own row, including completed notebook
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.workspace,.task-top>div,.current-step,.notebook-section,.notebook li,
#preparation-content,#preparation-content>div,#stage-fields{min-width:0}
.notebook li>div,#preparation-content>div>div{
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}
.notebook p,#preparation-content p,#stage-description,.hint,#feedback,
.point-notes,.interval-label{overflow-wrap:anywhere}
.formula,.choice-content{max-width:100%;overscroll-behavior-x:contain}
.formula{justify-content:flex-start}
.mode-bar{grid-template-columns:repeat(3,minmax(0,1fr))}
.mode-bar button,button{min-width:0;max-width:100%;overflow-wrap:anywhere}
.site-header,.dialog-head,.sign-row{flex-wrap:wrap}
.site-header>*{min-width:0}
h1,h2,h3,.brand{overflow-wrap:anywhere;hyphens:auto}
.chip{white-space:normal;max-width:100%}
.actions>.primary{min-width:min(175px,100%)}
.sign-row select{min-width:min(90px,100%);max-width:100%}
.answer-cells{grid-template-columns:repeat(2,minmax(0,1fr))}
@media(min-width:680px){.answer-cells{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:560px){.actions>.primary{min-width:min(150px,100%)}}
@media(max-width:360px){
  .mode-bar{grid-template-columns:1fr}
  .mode-bar button{font-size:.84rem}
  .answer-cells{grid-template-columns:1fr}
}