@layer reset, base, layout, components;
@layer reset{*{box-sizing:border-box}body,h1,h2,h3,p{margin:0}img,svg{max-width:100%}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}[hidden]{display:none!important}}
@layer base{
 :root{--ink:#20323b;--muted:#586b72;--paper:#fffcf5;--sand:#f2eadc;--line:#d8dfda;--teal:#176e72;--orange:#df7534;--purple:#7958a0;--radius:18px;color-scheme:light}
 body{background:var(--paper);color:var(--ink);font-family:system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;font-size:17px;line-height:1.6}
 h1,h2,h3{line-height:1.15;letter-spacing:-.025em}h1{font-size:clamp(2.25rem,6vw,4.3rem);font-weight:780}h2{font-size:clamp(1.65rem,4vw,2.3rem)}h3{font-size:1.22rem}p+p{margin-top:1rem}
 a{color:var(--teal);text-underline-offset:.2em}button{cursor:pointer}button:disabled{cursor:default;opacity:.42}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible,[data-cell]:focus-visible{outline:3px solid #d85b18;outline-offset:4px}
 input,select{padding:.75rem 1rem;border:1px solid #93a8aa;border-radius:10px;background:#fff;color:var(--ink)}label{font-weight:650}small{font-size:.86rem}strong{font-weight:750}ul,ol{padding-left:1.4rem}li+li{margin-top:.55rem}summary{cursor:pointer;font-weight:700}details[open]>summary{margin-bottom:1rem}
}
@layer layout{
 .shell{max-width:1140px;margin:0 auto;padding:0 32px}.site-header{border-bottom:1px solid var(--line)}.header-inner{display:flex;align-items:center;justify-content:space-between;gap:20px;min-height:80px}.brand{font-size:1.2rem;font-weight:800;letter-spacing:-.03em;text-decoration:none;color:var(--ink)}.brand-mark{display:inline-grid;place-items:center;width:35px;height:35px;border:2px solid var(--teal);border-radius:50%;font-size:20px;color:var(--teal);margin-right:9px}.header-inner nav{display:flex;gap:22px;font-size:.94rem}.header-inner nav a{color:var(--ink);text-decoration:none}.skip-link{position:absolute;top:-100px;background:white;padding:12px;z-index:50}.skip-link:focus{top:8px}
 main{padding:54px 0 72px}.hero{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:64px;align-items:center}.hero-copy{max-width:670px}.hero h1{margin:.5rem 0 1.2rem}.hero .lede{max-width:620px;color:var(--muted);font-size:1.15rem}.eyebrow{font-size:.79rem;letter-spacing:.15em;text-transform:uppercase;color:var(--teal);font-weight:800}.cover{width:260px;height:auto;border-radius:3px;box-shadow:18px 25px 0 #e4d5b9,0 20px 40px #20323b20;display:block;margin:0 auto;transform:rotate(3deg)}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin:24px 0}.byline{color:var(--muted);font-size:.92rem;margin-top:8px}.section{margin-top:58px}.section-heading{max-width:680px;margin-bottom:22px}.section-heading p{color:var(--muted);margin-top:12px}.feature-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.split{display:grid;grid-template-columns:1fr 1fr;gap:26px}.help-layout{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,.9fr);gap:36px;align-items:start}.help-board{position:sticky;top:24px}.board{background:#fffdf7;border:1px solid var(--line);border-radius:var(--radius);padding:15px;overflow:hidden}.board svg{display:block;width:100%;height:auto;font-family:system-ui,sans-serif}.legend{font-size:.85rem;color:var(--muted);padding:12px 0}.puzzle-heading{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-bottom:25px}.puzzle-heading h1{font-size:clamp(2rem,5vw,3.1rem)}.page-intro{max-width:780px;margin-bottom:30px}.page-intro h1{margin-bottom:16px}.page-intro p{color:var(--muted)}.narrow{max-width:770px;margin:0 auto}.small-cover{width:96px;float:right;margin:0 0 16px 24px;border-radius:3px;box-shadow:6px 7px 0 #e4d5b9}.footer-inner{display:flex;justify-content:space-between;align-items:start;gap:25px;flex-wrap:wrap}.site-footer{border-top:1px solid var(--line);background:#f3eee4;padding:28px 0;font-size:.9rem}.footer-links{display:flex;flex-wrap:wrap;gap:18px}.stats-panel{border-top:1px solid var(--line);padding:20px 0;margin-top:22px;max-width:800px;font-size:.85rem;color:var(--muted)}
}
@layer components{
 .button{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:11px 20px;border:1px solid var(--teal);border-radius:10px;background:var(--teal);color:#fff;font-weight:700;text-decoration:none;font-size:.97rem;line-height:1.35;gap:9px}.button.secondary{background:transparent;color:var(--teal)}.button.quiet{border-color:var(--line);background:#fff;color:var(--ink)}.button.small{min-height:42px;padding:8px 13px;font-size:.86rem}.text-button{background:none;border:0;padding:5px 0;text-decoration:underline;text-underline-offset:.2em;color:var(--teal)}.actions{display:flex;flex-wrap:wrap;gap:10px}.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px}.card p{color:var(--muted);margin-top:12px}.card .button{margin-top:18px}.card-number{color:var(--orange);font-size:2.2rem;font-weight:800;line-height:1;margin-bottom:20px}.finder{background:#e6efeb;border:1px solid #c6d7cf;border-radius:var(--radius);padding:30px;margin-top:30px}.finder h2{font-size:1.6rem}.finder form{display:flex;flex-wrap:wrap;align-items:end;gap:12px;margin-top:18px}.finder form label{display:block;margin-bottom:6px}.finder input{width:170px}.input-error,.error{color:#9d321c;font-weight:650;margin-top:12px}.notice{background:#f7efdb;border-left:4px solid var(--orange);padding:15px 18px;border-radius:0 12px 12px 0;margin:18px 0}.notice.trial{background:#f0eaf7;border-color:var(--purple)}.muted{color:var(--muted)}.kicker{color:var(--teal);font-weight:800;font-size:.82rem;letter-spacing:.07em;text-transform:uppercase}.progress-line{display:flex;justify-content:space-between;gap:12px;font-size:.88rem;color:var(--muted);margin:16px 0 9px}.progress-track{height:6px;border-radius:6px;background:var(--sand);overflow:hidden}.progress-track span{display:block;height:100%;background:var(--teal);width:0}.guide-card{padding:26px;border:1px solid var(--line);border-radius:var(--radius);background:#fff}.guide-card h2{font-size:1.4rem;margin-bottom:16px}.guide-card .actions{margin:18px 0}.explanation{font-size:1.03rem}.detail-copy{font-size:.9rem;color:var(--muted);margin-top:18px}.detail-copy li{margin-top:8px}.after-help{padding-top:22px;margin-top:24px;border-top:1px solid var(--line)}.after-help .actions{margin-top:13px}.answer{margin-top:22px}.answer h3{margin-bottom:14px}.answer img{width:100%;height:auto;display:block}.save-choice{display:flex;align-items:center;gap:9px;font-size:.85rem;font-weight:500;margin-top:20px}.save-choice input{width:18px;height:18px}.status-text{font-size:.86rem;color:var(--muted);margin-top:12px;min-height:1.4em}.puzzle-links{display:grid;grid-template-columns:repeat(auto-fill,minmax(58px,1fr));gap:9px;margin-top:20px}.puzzle-links a{text-align:center;padding:9px;border:1px solid var(--line);border-radius:8px;background:#fff;text-decoration:none;font-size:.9rem}.filters{display:flex;gap:10px;flex-wrap:wrap;margin:18px 0}.browse-group{margin-top:32px}.breadcrumbs{font-size:.85rem;color:var(--muted);margin-bottom:18px}.breadcrumbs a{color:var(--muted)}.book-scope{border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:22px}.downloads-list{display:grid;gap:15px}.downloads-list .card{display:flex;justify-content:space-between;align-items:center;gap:24px}.privacy-copy h2{font-size:1.45rem;margin:30px 0 14px}.privacy-copy p{margin:12px 0}.game-tools{display:flex;flex-wrap:wrap;align-items:center;gap:10px;margin-bottom:18px}.game-tools select{max-width:100%}#gameMessage{margin-top:18px;min-height:2.4em}.game-grid [data-cell]{cursor:pointer}.game-grid [data-cell][aria-disabled=true]{cursor:default}.game-grid [data-cell]:focus{stroke:#d85b18;stroke-width:3;outline:none}dialog{border:0;border-radius:20px;padding:25px;width:min(92vw,820px);max-height:90vh;color:var(--ink);box-shadow:0 20px 100px #20323b40}dialog::backdrop{background:#20323b80}.dialog-head{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:18px}.dialog-head h2{font-size:1.6rem}dialog .board{max-width:500px;margin:0 auto 15px}.dialog-explanation{margin:15px 0}#trialStatus{color:var(--purple);font-size:.86rem}.qr-sample{width:170px;height:170px;border:1px solid var(--line)}.resource-link{display:block;font-weight:650;margin-top:10px}.print-notes{border-top:1px solid #abb9b9;height:35mm;background:repeating-linear-gradient(transparent,transparent 9mm,#d6dcda 9mm,#d6dcda 9.2mm)}
}
.small-cover{height:auto}
@media(max-width:760px){.shell{padding:0 20px}.header-inner{min-height:66px}.header-inner nav{gap:13px;font-size:.84rem}.brand{font-size:1rem}.brand-mark{width:28px;height:28px;font-size:17px;margin-right:6px}main{padding:30px 0 45px}.hero{grid-template-columns:1fr;gap:30px}.hero h1{font-size:2.55rem}.hero .cover{width:160px;box-shadow:10px 12px 0 #e4d5b9;transform:rotate(2deg)}.hero-art{order:-1}.hero-actions{margin:18px 0}.feature-grid,.split,.help-layout{grid-template-columns:1fr}.feature-grid{gap:14px}.card{padding:22px}.section{margin-top:38px}.help-layout{gap:20px}.help-board{position:static}.board{padding:4px}.legend{font-size:.79rem}.finder{padding:23px}.finder input{width:150px}.puzzle-heading{align-items:start;gap:14px}.puzzle-heading .actions{max-width:125px;justify-content:end}.puzzle-heading h1{font-size:2.1rem}.guide-card{padding:22px}.downloads-list .card{display:block}.downloads-list .button{margin-top:15px}.small-cover{width:76px;margin-left:16px}.footer-inner{display:block}.footer-links{margin-top:15px}dialog{padding:18px}.stats-panel .actions{margin-top:10px}}
@media(prefers-reduced-motion:no-preference){a,button{transition:background .14s,color .14s,box-shadow .14s}.button:hover{box-shadow:0 4px 12px #20323b20}.progress-track span{transition:width .2s}}
@media print{.site-header,.site-footer,.no-print,.breadcrumbs,.print-tools{display:none!important}body{background:#fff;color:#111;font-size:11pt}.shell{padding:0;max-width:none}main{padding:0}.print-page{max-width:175mm;margin:0 auto}.print-page h1{font-size:17pt;margin:0 0 3mm}.print-page .board{border:0;padding:0;border-radius:0;width:165mm;max-width:100%;margin:3mm auto}.print-page .board svg{width:100%;max-height:170mm}.print-page .print-notes{margin-top:6mm}.print-page p{font-size:10pt}.print-caption{margin-top:4mm}@page{size:auto;margin:15mm}}

/* Additional value, led by the original extra collection. */
.brand{display:inline-flex;align-items:center;gap:9px}.track-mark{flex:none;color:var(--teal)}
.site-footer{margin-top:0;padding:24px 0;border-top:1px solid var(--line)}.footer-links{margin:0;gap:22px;font-size:.83rem}
.value-hero{display:grid;grid-template-columns:1fr 1fr;gap:64px;align-items:center;padding:12px 0 34px}.value-copy h1{font-size:clamp(3rem,6.2vw,5.1rem);line-height:1.02;margin:16px 0 22px;letter-spacing:-.05em}.value-lede{font-size:1.12rem;color:var(--muted);max-width:390px;margin-bottom:28px}.value-small{font-size:.89rem;color:var(--muted);margin-top:17px}.featured-preview{display:block;text-decoration:none;color:var(--ink);background:#f3eadc;border:1px solid #e0d0b6;border-radius:24px;padding:20px 22px 14px;box-shadow:7px 9px 0 #e9d8b5}.featured-preview img{display:block;width:100%;height:auto;background:var(--paper);border-radius:10px;margin:14px 0 8px}.preview-label{display:flex;justify-content:space-between;gap:10px;font-size:.85rem}.preview-label span:first-child{font-weight:750;color:var(--teal)}.preview-caption{display:block;font-size:.81rem;color:var(--muted)}
.value-options{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-top:20px;border-top:1px solid var(--line);padding-top:25px}.value-option{position:relative;padding:8px 32px 12px 0;text-decoration:none;color:var(--ink)}.value-option span{display:block;font-size:1.1rem;font-weight:750}.value-option small{display:block;color:var(--muted);margin-top:6px;max-width:330px}.value-option b{position:absolute;right:8px;top:12px;color:var(--teal);font-size:22px}.book-link{display:flex;align-items:center;gap:14px;margin-top:24px;font-size:.88rem;color:var(--muted)}.book-link img{flex:none;border-radius:2px}.book-link a{font-weight:700}.compact-intro{margin-bottom:28px;max-width:700px}.compact-intro h1{font-size:clamp(2.3rem,5vw,3.8rem);margin:10px 0 15px}.compact-intro p{color:var(--muted)}.quiet-actions{display:flex;flex-wrap:wrap;gap:22px;margin:26px 0;font-size:.9rem}.text-link{font-size:.88rem}.small{font-size:.86rem}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}
.bonus-filters{display:flex;gap:9px;margin-bottom:24px}.bonus-filters button{background:transparent;border:1px solid var(--line);padding:7px 20px;border-radius:22px;color:var(--ink);font-size:.9rem}.bonus-filters button[aria-pressed=true]{background:var(--teal);color:#fff;border-color:var(--teal)}.bonus-catalogue{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}.bonus-card{position:relative;background:#fff;border:1px solid var(--line);border-radius:16px;padding:17px;text-decoration:none;color:var(--ink)}.card-top{display:flex;justify-content:space-between;color:var(--muted);font-size:.8rem}.bonus-card img{width:100%;height:auto;margin:10px 0}.bonus-card h2{font-size:1.17rem}.bonus-card p{font-size:.88rem;color:var(--muted);margin-top:5px}.card-play{display:block;margin-top:16px;color:var(--teal);font-size:.88rem;font-weight:700}.solved-tag{display:inline-block;margin-top:8px;font-size:.75rem;color:var(--teal);font-weight:700}
.bonus-play{max-width:990px;margin:auto}.bonus-title{display:flex;align-items:center;justify-content:space-between;gap:22px}.bonus-title h1{font-size:clamp(2rem,5vw,3rem);margin-top:6px}.bonus-goal{margin:15px 0 24px;color:var(--muted)}.player-layout{display:grid;grid-template-columns:minmax(0,1.45fr) minmax(270px,1fr);gap:30px}.player-layout .board{padding:9px}.tool-instruction{font-size:.9rem;color:var(--muted);margin-bottom:13px}.piece-palette{display:grid;grid-template-columns:repeat(4,1fr);gap:7px}.piece-palette button{min-height:62px;border:1px solid var(--line);border-radius:11px;background:#fff;color:var(--teal);display:grid;place-items:center;padding:5px;font-size:.7rem}.piece-palette button svg{width:36px;height:36px;fill:none;stroke:currentColor;stroke-width:4;stroke-linecap:round}.piece-palette button[aria-pressed=true]{background:#e2efea;border:2px solid var(--teal);padding:4px}.piece-palette button span:empty{display:none}.piece-palette button>span:first-child:not(:empty){font-size:25px}.player-actions{display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin-top:16px}.player-message{font-size:.91rem;min-height:1.5em;margin-top:16px;color:var(--muted)}.hint-area{padding:16px 0;border-bottom:1px solid var(--line)}#bonusHintBox{margin:12px 0 4px;font-size:.93rem}#bonusExplain{margin-top:10px}.player-more{font-size:.86rem;margin-top:18px;color:var(--muted)}.player-more summary{font-weight:550}.win-panel{padding:20px;border-radius:13px;background:#e3eee7;margin-top:18px}.win-panel p{font-size:.9rem;margin:7px 0 16px}.bonus-answer{max-width:610px;margin:32px auto}.bonus-answer h2{font-size:1.5rem}.download-choice{padding:25px;border:1px solid var(--line);border-radius:16px;background:#fff}.download-choice h2{font-size:1.5rem}.download-choice p{font-size:.95rem;margin:12px 0 20px}.separate-answer{padding-top:20px;margin-top:22px;border-top:1px solid var(--line);font-size:.9rem}
.learn-page{max-width:1040px;margin:auto}.lesson-tabs{display:flex;gap:8px;list-style:none;padding:0;counter-reset:lesson;margin-bottom:24px}.lesson-tabs li+li{margin-top:0}.lesson-tabs button{padding:9px 14px;background:transparent;border:1px solid var(--line);border-radius:10px;color:var(--muted);font-size:.88rem}.lesson-tabs [aria-current=step]{background:var(--teal);color:white}.lesson-layout{display:grid;grid-template-columns:1.3fr 1fr;gap:30px}.lesson-question h2{font-size:1.7rem;margin:8px 0 18px}.lesson-question p{font-size:.95rem;margin:12px 0}.lesson-options{display:flex;flex-wrap:wrap;gap:9px;margin:20px 0}.lesson-option{display:flex;align-items:center;gap:8px;padding:10px 14px;border:1px solid var(--line);background:#fff;border-radius:10px;font-size:.88rem;color:var(--teal)}.lesson-option svg{width:27px;height:27px;fill:none;stroke:currentColor;stroke-width:4;stroke-linecap:round}.lesson-option.correct{background:#e2efea;border-color:var(--teal)}.lesson-next{margin-top:20px}.lesson-reason{padding:16px;background:#f3eadc;border-radius:10px}.simple-rules{margin-top:28px;font-size:.9rem;color:var(--muted)}
@media(max-width:760px){.value-hero{grid-template-columns:1fr;gap:30px;padding:0}.value-copy h1{font-size:3.1rem;margin:13px 0 15px}.value-copy h1 br{display:none}.value-copy .value-lede{font-size:1rem;margin-bottom:19px}.featured-preview{padding:14px 15px 12px;box-shadow:4px 5px 0 #e9d8b5}.value-options{grid-template-columns:1fr;gap:6px;margin-top:29px;padding-top:17px}.value-option small{font-size:.85rem}.book-link{font-size:.84rem;margin-top:16px}.bonus-catalogue{grid-template-columns:repeat(2,minmax(0,1fr));gap:13px}.bonus-card{padding:12px}.bonus-card p{font-size:.79rem}.card-top{font-size:.71rem;gap:5px}.compact-intro h1{font-size:2.45rem}.player-layout,.lesson-layout{grid-template-columns:1fr;gap:19px}.player-layout .board{padding:3px}.player-panel .piece-palette{max-width:440px;margin:auto}.piece-palette button{min-height:57px}.player-actions{justify-content:center}.tool-instruction{text-align:center}.player-more{margin-top:13px}.player-message{min-height:1.2em}.bonus-title h1{font-size:2rem}.bonus-goal{font-size:.9rem;margin:12px 0 19px}.lesson-tabs{gap:6px;flex-wrap:wrap}.lesson-tabs button{font-size:.77rem;padding:8px}.lesson-question h2{font-size:1.5rem}.header-inner nav{gap:12px;font-size:.81rem}.brand{font-size:1rem;gap:6px}.track-mark{width:23px;height:23px}.quiet-actions{gap:17px}.site-footer{padding:18px 0}}

@media(max-width:360px){.header-inner{gap:10px}.brand{white-space:nowrap;font-size:.92rem;gap:5px}.track-mark{width:19px;height:19px}.header-inner nav{gap:12px;font-size:.75rem}.header-inner nav a{white-space:nowrap;display:inline-flex;align-items:center;min-height:44px}}