:root{--ink:#1a2735;--muted:#65717c;--blue:#0875bf;--blue-dark:#055e9b;--green:#328b47;--paper:#fffdf8;--line:#e4e8eb;--yellow:#ffd560}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.5 ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button,a{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{cursor:default}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible,.ruler:focus-visible{outline:3px solid #0e83cb;outline-offset:4px}a{color:var(--blue)}[hidden]{display:none!important}.sr-only,.skip:not(:focus){position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip-path:inset(50%);white-space:nowrap}.skip:focus{position:fixed;z-index:20;background:white;padding:12px}.masthead{max-width:1220px;margin:auto;padding:20px 30px 15px;display:flex;align-items:center;justify-content:space-between;position:relative}.masthead:after{content:"";position:absolute;bottom:0;left:30px;right:30px;height:3px;background:linear-gradient(90deg,#e72528 0 33.3%,#0684c9 33.3% 66.6%,#4dac3e 66.6%)}.masthead img{display:block;width:190px;height:auto;mix-blend-mode:multiply}.header-actions{display:flex;align-items:center;gap:24px}.dev-badge{font-size:12px;background:#f0f1e9;border:1px solid #e1e4d5;padding:5px 11px;border-radius:30px;color:#596349;white-space:nowrap}.dev-badge span{display:inline-block;width:6px;height:6px;background:#8a9c5b;border-radius:100%;margin-right:5px}.text-button{background:none;border:0;padding:5px 0;color:#4c6071;font-size:13px;font-weight:650;text-decoration:none}.text-button:hover{text-decoration:underline;color:var(--blue)}.header-actions .text-button span{display:inline-grid;place-items:center;width:21px;height:21px;border:1px solid #b9c6d0;border-radius:50%;margin-left:5px}main{max-width:1220px;margin:auto;padding:0 30px}.intro{display:flex;align-items:center;justify-content:space-between;padding:30px 0 23px;gap:20px}.eyebrow{font-size:10px;letter-spacing:2.2px;font-weight:800;color:var(--blue);margin:0 0 7px}h1{font-size:clamp(27px,3.2vw,41px);line-height:1.18;letter-spacing:-1.25px;margin:0;font-weight:800}h1 span{color:var(--blue)}.lead{color:var(--muted);font-size:14px;margin:11px 0 0}.tucik{display:flex;align-items:center;padding-right:28px;flex-shrink:0}.tucik img{width:94px;height:94px;object-fit:contain}.tucik p{font-size:13px;line-height:1.45;transform:rotate(-4deg);background:#fff3ca;padding:11px 16px 11px 11px;border-radius:4px 14px 14px 14px;margin:0 0 0 -5px}.tucik strong{font-size:14px}.game{background:#fff;border:1px solid #dee5e8;border-radius:19px;box-shadow:0 9px 30px #18354508;overflow:hidden}.game-toolbar{display:flex;justify-content:space-between;align-items:center;padding:16px 24px;gap:15px}.round-label,.game-tools{display:flex;align-items:center;gap:14px}.round-label strong{font-size:13px;white-space:nowrap}.round-label>span:last-child{color:var(--muted);font-size:12px;border-left:1px solid var(--line);padding-left:14px;white-space:nowrap}.round-dot{width:8px;height:8px;background:var(--green);border-radius:100%}.game-tools select{font-size:12px;background:white;border:1px solid #dfe5e8;border-radius:7px;padding:6px 25px 6px 9px;color:#455563;max-width:180px}.game-tools .text-button{font-size:12px;white-space:nowrap}.game-tools .text-button span{display:inline-block;padding:0 5px;background:#eff3f5;border-radius:4px;margin-left:3px}.progress-track{height:3px;background:#eef1f3}.progress-track>div{height:100%;width:0;background:var(--blue);transition:width .3s}.play-grid{display:grid;grid-template-columns:minmax(0,1.36fr) minmax(310px,.82fr)}.measure-panel{padding:22px 24px 15px;border-right:1px solid var(--line);min-width:0}.step-heading{display:flex;gap:9px;align-items:center}.step-heading>span{display:grid;place-items:center;width:23px;height:23px;flex-shrink:0;color:var(--blue);border-radius:50%;background:#eaf5fc;font-size:12px;font-weight:800}.step-heading h2{margin:0;font-size:17px;letter-spacing:-.25px}.step-heading .small{margin-left:auto;font-size:11px;font-weight:500}.book-heading{margin:17px 0 12px;height:49px;overflow:hidden}.book-heading>span{font-size:9px;letter-spacing:1.1px;font-weight:750;color:#768590;text-transform:uppercase}.book-heading h3{margin:1px 0 0;font-size:14px;line-height:1.4;font-weight:650}.desk{height:360px;border:1px solid #e0e8ea;background-color:#f1f6f5;background-image:linear-gradient(#c9d9d831 1px,transparent 1px),linear-gradient(90deg,#c9d9d831 1px,transparent 1px);background-size:20px 20px;border-radius:11px;position:relative;overflow:hidden;user-select:none}.desk-label{position:absolute;left:15px;bottom:11px;color:#8c9d9a;font-size:8px;letter-spacing:1.7px;font-weight:650}.book{position:absolute;top:26px;left:20%;box-shadow:3px 5px 0 #d4d8d6,8px 14px 19px #2d4e4a2b;isolation:isolate;transition:box-shadow .4s}.book:after{position:absolute;content:"";inset:0;box-shadow:inset 3px 0 5px #0a243a19;pointer-events:none}.book>img{display:block;width:100%;height:100%;object-fit:fill;background:#fff}.sleeve{position:absolute;inset:-3px;pointer-events:none;opacity:0;border:2px solid #8ab6cfaa;border-radius:2px;background:linear-gradient(120deg,#fff1 0 33%,#ffffff80 34%,#ffffff10 40%,transparent 65%,#ffffff80 87%,#ffffff10 92%);box-shadow:inset -15px 0 #d3e9f36b,inset 14px 0 #d3e9f36b;transition:opacity .5s}.book.wrapped .sleeve{opacity:1}.edge-guide{position:absolute;left:12%;right:9%;height:0;border-top:1px dashed #2b87b67a;opacity:0;pointer-events:none}.edge-guide.visible{opacity:1}.ruler{position:absolute;width:49px;touch-action:none;cursor:grab;z-index:3;filter:drop-shadow(3px 5px 2px #354c4220);border-radius:4px;user-select:none}.ruler.dragging{cursor:grabbing;filter:drop-shadow(5px 7px 3px #354c4230)}.ruler svg{display:block;width:49px;height:100%;overflow:visible}.ruler-grip{position:absolute;bottom:4px;right:4px;color:#8b6d1a;font-size:19px;line-height:1}.drag-note{position:absolute;right:12px;top:12px;text-align:right;color:#687e78;font-size:10px;line-height:1.45;pointer-events:none}.measure-bottom{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-top:14px}.measure-bottom p{font-size:10px;color:#7c8a92;line-height:1.4;margin:0;max-width:205px}.measure-bottom p span{font-size:15px;color:#78908b;margin-right:3px}.measure-bottom 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.15s,background .15s}.cover-choice strong{font-size:14px;display:block;color:#344b5c;letter-spacing:.4px}.cover-choice small{font-size:10px;display:block;color:#7c8b96;margin-top:2px}.cover-choice:after{content:"";position:absolute;right:9px;top:11px;width:11px;height:11px;border:1px solid #d0dbe2;border-radius:100%}.cover-choice:hover{border-color:#72afd5;background:#f8fcff}.cover-choice[aria-pressed=true]{border:2px solid var(--blue);padding:9px 10px;background:#eef8ff}.cover-choice[aria-pressed=true]:after{background:var(--blue);border-color:var(--blue);box-shadow:inset 0 0 0 2px #fff}.cover-choice.correct{border-color:var(--green);background:#eef8ef}.cover-choice.correct strong{color:#2e743c}.cover-choice.correct:after{background:var(--green);border-color:var(--green)}.more-button{border:0;background:transparent;display:flex;align-items:center;justify-content:space-between;width:100%;padding:10px 0;color:#6c7f8d;font-size:10px;text-align:left}.more-button span{font-size:15px}.more-choices{max-height:220px;overflow:auto;margin-bottom:12px;padding:2px}.primary-button,.secondary-button{border:0;border-radius:8px;padding:12px 16px;font-size:13px;font-weight:750;display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:44px;text-decoration:none;transition:background .15s}.primary-button{background:var(--blue);color:white;width:100%}.primary-button:hover{background:var(--blue-dark)}.primary-button>span{font-size:18px}.secondary-button{background:#edf3f7;color:#295674}.helper{color:#8a96a0;font-size:10px;text-align:center;margin:8px 0 10px}.hint-button{font-size:11px;display:block;margin:0 auto;color:#467593}.feedback{margin:0 0 12px;border-radius:9px;padding:12px;background:#fff6e4;border:1px solid #f1deb1;font-size:12px;line-height:1.5;color:#6e561d}.feedback strong{display:block;font-size:14px;margin-bottom:3px}.feedback p{margin:4px 0}.feedback.success{color:#2a6037;border-color:#cfe3d1;background:#eff8f0}.feedback.notice{background:#eff6fd;border-color:#cde1f1;color:#355e7a}.feedback .text-button{font-size:10px}.page-footer{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:21px 2px 25px;color:#879099;font-size:10px}.page-footer p{margin:0;line-height:1.65}.page-footer strong{font-weight:600;color:#65747c}.page-footer>div{display:flex;align-items:center;gap:24px}.page-footer a,.page-footer .text-button{font-size:10px;color:#617989}.loading{padding:80px 20px;text-align:center;color:var(--muted)}dialog{border:1px solid #dce5ec;border-radius:18px;box-shadow:0 25px 100px #112a4140;width:min(540px,calc(100% - 30px));max-height:85dvh;overflow:auto;padding:25px;color:var(--ink);font-size:14px}dialog::backdrop{background:#162d4b75;backdrop-filter:blur(3px)}.dialog-header{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:14px}.dialog-header h2{font-size:24px;line-height:1.2;letter-spacing:-.6px;margin:0}.close{flex-shrink:0;border:0;background:#eff3f6;width:32px;height:32px;font-size:23px;line-height:1;border-radius:50%;color:#667988}.help-list{padding-left:22px}.help-list li{padding-left:5px;margin-bottom:15px}.help-note{background:#f0f7fb;border-left:3px solid #67afd5;padding:13px 15px;font-size:12px}.muted{font-size:12px;color:var(--muted)}.library-dialog,.sources-dialog{width:min(850px,calc(100% - 30px))}.library-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.library-book{background:#f8fafb;border:1px solid #dfe6ea;border-radius:9px;padding:15px 10px;text-align:left}.library-book:hover{border-color:var(--blue);background:#f0f8fe}.library-book img{height:126px;width:100%;object-fit:contain;display:block;margin-bottom:10px}.library-book small{display:block;font-size:9px;color:#6f8494;letter-spacing:.4px}.library-book strong{display:block;font-size:11px;line-height:1.4;margin-top:3px}.sources-dialog details{border:1px solid var(--line);border-radius:8px;padding:13px;margin:12px 0}.sources-dialog summary{cursor:pointer;font-weight:700}.source-item{padding:13px 0;border-bottom:1px solid var(--line)}.source-item h3{margin:0 0 3px;font-size:14px}.source-item p{font-size:11px;margin:3px 0;color:var(--muted)}.source-item a{font-size:11px;margin-right:12px}.result{padding:35px;text-align:center}.result-icon{width:66px;height:66px;border-radius:50%;background:#e5f5e9;color:var(--green);display:grid;place-items:center;font-size:36px;margin:0 auto 18px}.result h2{font-size:30px;margin:0}#result-score{font-size:38px;font-weight:800;color:var(--blue);margin:10px 0}#result-text{color:var(--muted);font-size:14px}.result-actions{display:flex;justify-content:center;gap:12px;margin:22px 0}.result-actions .primary-button{width:auto}.review-item{max-width:580px;display:flex;align-items:center;gap:13px;padding:10px 0;border-bottom:1px solid var(--line);margin:auto;text-align:left;font-size:12px}.review-item img{width:28px;height:40px;object-fit:contain}.review-item>span:last-child{margin-left:auto;font-size:11px;color:#708393;white-space:nowrap}.review-item .mark{color:var(--green)}@media(min-width:1350px) and (min-height:1000px){.intro{padding-top:38px;padding-bottom:30px}.desk{height:410px}.measure-panel,.answer-panel{padding-top:25px;padding-bottom:24px}}@media(max-width:950px){.masthead{padding:16px 22px}.masthead:after{left:22px;right:22px}main{padding:0 22px}.tucik{padding-right:0}.tucik img{width:70px;height:70px}.tucik p{padding:8px;font-size:11px}.tucik strong{font-size:12px}.play-grid{grid-template-columns:minmax(0,1fr) 310px}.measure-panel{padding:18px}.answer-panel{padding:18px}.game-toolbar{padding:13px 18px}.game-tools{gap:9px}.round-label{gap:9px}.round-label>span:last-child{padding-left:9px}.desk{height:340px}.measure-bottom{flex-wrap:wrap}.measure-bottom p{max-width:150px}.measure-bottom label{margin-left:auto}.game-tools select{max-width:145px}}@media(max-width:740px){main{padding:0 15px}.masthead{padding:14px 15px}.masthead:after{left:15px;right:15px}.masthead img{width:150px}.header-actions{gap:15px}.dev-badge{font-size:9px;padding:4px 7px}.header-actions>.text-button{font-size:11px}.header-actions .text-button span{display:none}.intro{padding:23px 0 19px;align-items:center}.eyebrow{font-size:8px;letter-spacing:1.6px}h1{max-width:370px;font-size:29px;letter-spacing:-.8px}.lead{font-size:12px;max-width:300px;line-height:1.6}.tucik img{width:75px;height:88px}.tucik p{display:none}.game-toolbar{padding:12px 15px;flex-wrap:wrap;gap:10px}.round-label{justify-content:space-between;width:100%}.round-label strong{margin-right:auto}.game-tools{width:100%;justify-content:space-between}.game-tools select{max-width:47%;font-size:11px}.game-tools .text-button{margin-left:auto}.play-grid{grid-template-columns:1fr}.measure-panel{border-right:0;border-bottom:1px solid var(--line);padding:17px 15px 15px}.book-heading{margin:12px 0 10px;height:auto;min-height:41px}.book-heading h3{font-size:13px}.desk{height:350px}.book{left:22%}.measure-bottom{flex-wrap:nowrap}.measure-bottom p{max-width:160px;font-size:9px}.measure-bottom label{font-size:11px;gap:7px}.number-wrap{padding:4px 7px 4px 2px}.number-wrap input{font-size:16px;width:48px}.answer-panel{padding:17px 15px 18px}.answer-intro{margin:8px 0 14px}.choices{grid-template-columns:repeat(3,minmax(0,1fr));gap:7px}.cover-choice{padding:10px;min-height:63px}.cover-choice strong{font-size:13px}.cover-choice small{font-size:9px}.cover-choice:after{right:6px;top:9px;width:9px;height:9px}.cover-choice[aria-pressed=true]{padding:9px}.answer-panel .primary-button{margin-top:5px}.more-button{padding:9px 0}.page-footer{align-items:flex-start;font-size:9px;padding:18px 0 23px}.page-footer>div{flex-direction:column;align-items:flex-end;gap:4px}.page-footer a,.page-footer .text-button{font-size:9px}.page-footer p{max-width:185px}.library-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.library-book img{height:140px}.result{padding:30px 18px}.result h2{font-size:26px}.result-actions{flex-direction:column;align-items:stretch}.result-actions .primary-button{width:100%}.review-item{font-size:10px;gap:8px}.review-item>span:last-child{font-size:9px}}@media(max-width:380px){h1{font-size:26px}.intro{gap:2px}.tucik img{width:62px}.choices{grid-template-columns:repeat(2,minmax(0,1fr))}.desk{height:330px}.measure-bottom p{max-width:126px}.game-tools{gap:6px}.game-tools select{max-width:44%}.game-tools .text-button{font-size:10px}.dev-badge span{display:none}.header-actions{gap:10px}.header-actions .text-button{font-size:10px}.masthead img{width:139px}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{transition:none!important;scroll-behavior:auto!important}}

.game-note{margin:16px 0 0;padding:12px 16px;border:1px solid #e6dfc7;border-radius:10px;background:#fff9e9;color:#6d613e;font-size:12px;line-height:1.6}.game-note p{margin:0}.game-note strong{color:#5b5030}
@media(max-width:740px){.game-note{font-size:11px;padding:11px 13px}}

.cover-choice.fixed-cover strong{font-size:12px;letter-spacing:0}

/* Two ways to wrap a book and an immediate answer. */
.cover-route{border:0;padding:0;margin:0;min-width:0}.cover-route legend{padding:0;margin-bottom:8px;font-size:12px;font-weight:750;color:#344b5c}.cover-route legend span{display:block;font-size:10px;font-weight:400;color:#71828f;margin-top:2px}.fixed-route{margin:3px 0 15px;padding-top:12px;border-top:1px solid var(--line)}.answer-panel .choices{grid-template-columns:repeat(2,minmax(0,1fr))}.cover-choice:disabled{cursor:default;opacity:1}.cover-choice.incorrect{border:2px solid #b64539;background:#fff1ef}.cover-choice.incorrect strong{color:#9b352c}.choice-result{display:block;font-size:10px;font-weight:750;margin-top:5px;color:#2e743c}.incorrect .choice-result{color:#9b352c}.solution-options{margin-top:10px;padding-top:8px;border-top:1px solid #bfd8c3}.solution-options p{margin:5px 0}.solution-options strong{font-size:11px;margin:0}.success-next{background:var(--green)}.success-next:hover{background:#286b38}#answer-result{scroll-margin-block:20px}.answer-intro{line-height:1.5}.fixed-cover small{font-size:9px}.fixed-route .choices{gap:7px}.fixed-route .cover-choice{min-height:58px}@media(max-width:740px){.cover-route legend{font-size:13px}.cover-route legend span{font-size:11px}.answer-panel .choices{grid-template-columns:repeat(2,minmax(0,1fr))}.feedback{font-size:13px}.feedback strong{font-size:16px}.solution-options strong{font-size:12px}.choice-result{font-size:11px}}