/* Organic Structures Suite v0.1.0 · isolated from existing Chemistry Help CSS. */
.os-shell{--os-ink:#183449;--os-accent:#13677b;--os-border:#cbdce2;--os-muted:#536979;--os-background:#f1f7f8;--os-success:#16603e;--os-wrong:#922d23;max-width:1150px;margin:0 auto;padding:28px 22px 45px;color:var(--os-ink);font:16px/1.5 Arial,Helvetica,sans-serif;box-sizing:border-box}
.os-shell *{box-sizing:border-box}.os-shell [hidden]{display:none!important}
.os-shell h1,.os-shell h2{color:var(--os-ink)}.os-shell h1{font:700 clamp(28px,3.2vw,40px)/1.12 Georgia,serif;margin:4px 0 12px}.os-shell h2{font:700 clamp(20px,2.5vw,27px)/1.25 Georgia,serif}
.os-heading{display:flex;gap:18px;justify-content:space-between;align-items:center;margin-bottom:22px}.os-heading p{margin:0;max-width:650px;color:var(--os-muted)}.os-heading .os-kicker{font:600 12px/1.3 Arial,sans-serif;text-transform:uppercase;letter-spacing:.09em;color:var(--os-accent)}
.os-shell button,.os-shell select{font:inherit;letter-spacing:normal;text-transform:none}.os-button{min-height:42px;border:1px solid var(--os-border);border-radius:7px;padding:10px 16px;font-weight:600;cursor:pointer}.os-button:disabled{opacity:.55;cursor:not-allowed}.os-primary{background:var(--os-accent);color:white;border-color:var(--os-accent)}.os-secondary{background:white;color:var(--os-accent)}.os-text{background:transparent;border:0;color:var(--os-accent);padding:6px 8px;min-height:34px}.os-shell button:hover:not(:disabled){filter:brightness(.96)}.os-shell :focus-visible{outline:3px solid #229abb;outline-offset:3px}
.os-modes{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:9px;margin:0 0 20px}.os-mode{border:1px solid var(--os-border);border-radius:9px;background:white;padding:13px 11px;cursor:pointer;text-align:left;min-height:113px;color:var(--os-ink)}.os-mode strong{font-size:15px;line-height:1.25;display:block}.os-mode span{font-size:12px;line-height:1.4;display:block;margin-top:6px;color:var(--os-muted)}.os-mode[aria-pressed=true]{background:#e8f4f6;border-color:var(--os-accent);box-shadow:inset 0 0 0 1px var(--os-accent)}
.os-settings{border-block:1px solid var(--os-border);display:flex;flex-wrap:wrap;gap:14px;padding:15px 0;align-items:end}.os-settings label{display:grid;gap:5px;color:var(--os-muted);font-size:13px;flex:1 1 126px}.os-settings select{background:white;border:1px solid #91a9b5;color:var(--os-ink);min-height:42px;border-radius:6px;padding:8px;width:100%}.os-settings button{flex:0 0 auto}.os-scope{font-size:13px;color:var(--os-muted);margin:10px 0}.os-progress{display:flex;flex-wrap:wrap;align-items:center;gap:22px;padding:11px 0;margin-top:6px;border-bottom:1px solid var(--os-border);font-size:14px}.os-progress strong{color:var(--os-accent);font-size:21px}.os-progress button{margin-left:auto}
.os-question{min-height:480px;text-align:center;padding:9px 0 18px}.os-question h2{margin:14px 0 12px;font:600 clamp(18px,2.2vw,25px)/1.35 Arial,Helvetica,sans-serif}.os-main-drawing{width:min(100%,780px);height:clamp(220px,33vh,360px);margin:0 auto 18px;display:flex;align-items:center;justify-content:center;overflow:hidden;background:#fff;border:1px solid #e3eaed;border-radius:9px}.os-main-drawing svg{height:100%;width:100%;max-width:100%;max-height:100%;object-fit:contain;pointer-events:none}.os-main-drawing .cs-error{color:var(--os-wrong)}.os-formula-hint{margin:0 0 12px;font-size:14px;color:var(--os-muted)}
.os-options{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;width:min(100%,860px);margin:0 auto}.os-answer{display:flex;gap:10px;align-items:center;justify-content:flex-start;text-align:left;background:#fff;border:2px solid var(--os-border);border-radius:8px;color:var(--os-ink);min-height:63px;width:100%;padding:12px 16px;cursor:pointer;position:relative;overflow:hidden}.os-answer[aria-pressed=true]{background:#e3f1f5;border-color:var(--os-accent)}.os-answer.is-correct{border-color:var(--os-success);background:#eaf7ef}.os-answer.is-wrong{border-color:var(--os-wrong);background:#fff0ee}.os-answer.is-missed{border-color:var(--os-success);border-style:dashed}.os-answer:disabled{cursor:default;opacity:1}.os-answer-letter{width:28px;height:28px;display:grid;place-items:center;flex:0 0 28px;border:1px solid var(--os-border);border-radius:6px;color:var(--os-accent);font-weight:600}.os-answer-name{font-size:17px;font-weight:500;overflow-wrap:anywhere}.os-answer.is-none{grid-column:1 / -1;min-height:48px;background:var(--os-background)}.os-answer.is-none[aria-pressed=true]{background:#dbeff2}.os-answer.is-none.is-correct{background:#eaf7ef}.os-answer.is-none.is-wrong{background:#fff0ee}
.os-options.is-isomers{grid-template-columns:repeat(2,minmax(0,1fr));max-width:1020px}.os-options.is-isomers .os-answer{display:flex;flex-direction:column;justify-content:flex-start;text-align:center;min-height:200px;padding:10px}.os-options.is-isomers .os-answer:not(.is-none) .os-answer-letter{align-self:flex-start}.os-options.is-isomers .os-answer.is-none{min-height:54px;flex-direction:row;justify-content:center}.os-mini-drawing{width:100%;height:150px;display:flex;align-items:center;justify-content:center;overflow:hidden}.os-mini-drawing svg{max-width:100%;max-height:100%;width:100%;height:100%;pointer-events:none}.os-condensed{font-size:clamp(17px,2vw,24px);font-weight:600;letter-spacing:.015em;line-height:1.35;word-break:break-word;margin:auto 0}.os-answer .os-loading{color:var(--os-muted);font-weight:400;font-size:13px}
.os-actions{display:flex;align-items:center;justify-content:center;gap:12px;margin:19px 0 0}.os-actions button{min-width:160px}.os-feedback{max-width:820px;margin:14px auto 2px;padding:16px 18px;border:1px solid var(--os-border);border-radius:9px;background:#f4f8f9;text-align:left}.os-feedback.is-right{border-color:#8ebfa7;background:#f1faf4}.os-feedback.is-wrong{border-color:#e3b3ad;background:#fff7f5}.os-feedback strong{display:block;font-size:18px}.os-feedback p{margin:6px 0 0}.os-feedback .os-answer-key{font-weight:600}.os-summary{padding:40px 20px;text-align:center}.os-big-score{font:700 clamp(40px,6vw,68px)/1.2 Arial;color:var(--os-accent)}.os-followups{border-top:1px solid var(--os-border);margin-top:20px;padding-top:20px}.os-followups h2{font-size:20px;margin:0 0 9px}.os-followups>div{display:flex;gap:12px;flex-wrap:wrap}.os-followups a{color:var(--os-accent);font-weight:600;text-decoration:underline;text-underline-offset:3px}.os-followups p{color:var(--os-muted);font-size:13px;margin:13px 0 0}
body.os-projector .site-header,body.os-projector .site-footer,body.os-projector>header,body.os-projector>footer,body.os-projector .tutee-preview-bar{display:none!important}body.os-projector{background:white!important}body.os-projector main{max-width:none!important;width:100%!important;padding:0!important;margin:0!important}.os-shell.is-projector{max-width:1700px;min-height:100vh;padding:20px 3vw;background:white}.os-shell.is-projector .os-modes,.os-shell.is-projector .os-settings,.os-shell.is-projector .os-followups,.os-shell.is-projector .os-scope{display:none!important}.os-shell.is-projector .os-main-drawing{height:clamp(220px,39vh,520px);max-width:1100px}.os-shell.is-projector .os-question h2{font-size:clamp(24px,2.6vw,39px)}.os-shell.is-projector .os-answer-name{font-size:clamp(19px,2vw,29px)}.os-shell.is-projector .os-options.is-isomers .os-answer{min-height:230px}.os-shell.is-projector .os-mini-drawing{height:185px}.os-shell.is-projector .os-heading p:not(.os-kicker){display:none}.os-shell.is-projector .os-question{padding-bottom:5px}
@media(max-width:950px){.os-modes{grid-template-columns:repeat(3,minmax(0,1fr))}.os-mode{min-height:87px}}
@media(max-width:630px){.os-shell{padding:17px 13px 26px}.os-heading{align-items:flex-start;gap:10px}.os-heading h1{font-size:27px}.os-heading p:not(.os-kicker){font-size:13px}.os-heading .os-button{padding:8px;font-size:12px;flex-shrink:0}.os-modes{grid-template-columns:repeat(2,minmax(0,1fr));gap:7px}.os-mode{min-height:79px;padding:10px}.os-mode strong{font-size:13px}.os-mode span{font-size:11px;margin-top:3px}.os-settings{gap:8px}.os-settings label{flex-basis:44%}.os-settings button{width:100%}.os-progress{gap:12px}.os-question h2{font-size:18px}.os-main-drawing{height:230px;margin-bottom:12px}.os-options{gap:7px}.os-answer{padding:8px 9px;min-height:58px}.os-answer-name{font-size:14px}.os-answer-letter{width:22px;height:22px;flex-basis:22px}.os-options.is-isomers .os-answer{min-height:156px}.os-mini-drawing{height:105px}.os-condensed{font-size:16px}.os-shell.is-projector{padding:12px}.os-shell.is-projector .os-main-drawing{height:32vh}.os-shell.is-projector .os-mini-drawing{height:110px}}
@media(prefers-reduced-motion:reduce){.os-shell *{scroll-behavior:auto!important;transition:none!important;animation:none!important}}