:root{--navy:#102b3f;--navy2:#173e55;--cream:#f5f0e6;--paper:#fffdf8;--teal:#177c7a;--teal2:#0c5c5b;--copper:#b66b3d;--ink:#17232c;--muted:#596773;--line:#d8ddd9;--good:#166534;--bad:#991b1b;--shadow:0 18px 50px rgba(16,43,63,.10);--radius:18px;--max:1180px}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.62}a{color:var(--teal2);text-decoration-thickness:.08em;text-underline-offset:.16em}a:hover{color:var(--copper)}button,input,select,textarea{font:inherit}button{cursor:pointer}.shell{width:min(calc(100% - 36px),var(--max));margin-inline:auto}.narrow{max-width:850px}.skip-link{position:absolute;left:-999px;top:8px;background:#fff;padding:10px;z-index:100}.skip-link:focus{left:8px}.site-header{position:sticky;top:0;z-index:30;background:rgba(255,253,248,.94);backdrop-filter:blur(16px);border-bottom:1px solid rgba(16,43,63,.1)}.header-inner{min-height:78px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--navy)}.brand:hover{color:var(--navy)}.brand-mark{display:grid;place-items:center;width:46px;height:46px;border-radius:14px;background:var(--navy);color:var(--cream);font-weight:800;letter-spacing:.03em;box-shadow:inset 0 -5px 0 rgba(177,107,61,.3)}.brand strong,.brand small{display:block}.brand small{font-size:.75rem;color:var(--muted);font-weight:500}.main-nav{display:flex;align-items:center;gap:4px}.main-nav a{padding:9px 11px;border-radius:9px;text-decoration:none;color:var(--navy);font-size:.94rem;font-weight:650}.main-nav a:hover,.main-nav a[aria-current=page]{background:#e9f2ef;color:var(--teal2)}.nav-toggle{display:none;background:none;border:1px solid var(--line);border-radius:9px;padding:7px 10px}.hero{background:linear-gradient(135deg,var(--navy) 0%,#143b50 72%,#1c4c56 100%);color:white;padding:84px 0 76px;position:relative;overflow:hidden}.hero:after{content:"";position:absolute;width:430px;height:430px;border:1px solid rgba(245,240,230,.14);border-radius:50%;right:-130px;top:-210px;box-shadow:0 0 0 55px rgba(245,240,230,.035),0 0 0 110px rgba(245,240,230,.025)}.hero-grid{display:grid;grid-template-columns:1.45fr .75fr;gap:70px;align-items:center;position:relative;z-index:1}.hero h1,.page-hero h1{font-family:Georgia,"Times New Roman",serif;line-height:1.05;letter-spacing:-.035em;margin:.18em 0 .35em}.hero h1{font-size:clamp(2.6rem,5vw,5rem);max-width:820px}.lede{font-size:clamp(1.08rem,2vw,1.34rem);max-width:780px;color:inherit;opacity:.9}.eyebrow{margin:0 0 8px;text-transform:uppercase;letter-spacing:.14em;font-size:.77rem;font-weight:800;color:var(--copper)}.hero .eyebrow{color:#f0ae7e}.button-row{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}.button-row.compact{margin-top:14px}.button{display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:10px 18px;border:1px solid transparent;border-radius:11px;text-decoration:none;font-weight:750;transition:.18s transform,.18s background,.18s border-color}.button:hover{transform:translateY(-1px)}.button.primary{background:var(--teal);color:white}.button.primary:hover{background:var(--teal2);color:white}.button.secondary{background:transparent;border-color:#9fb2b8;color:var(--navy)}.hero .button.secondary{border-color:rgba(255,255,255,.42);color:white}.hero-panel{background:rgba(255,255,255,.09);border:1px solid rgba(255,255,255,.2);padding:28px;border-radius:var(--radius);backdrop-filter:blur(10px)}.hero-panel .label,.tag{display:inline-block;background:#e7f3ef;color:var(--teal2);border-radius:999px;padding:4px 9px;font-size:.75rem;font-weight:800;letter-spacing:.04em}.hero-panel h2{font-family:Georgia,serif;font-size:2rem;margin:.45em 0}.hero-panel a{color:#fff;font-weight:750}.page-hero{background:var(--cream);padding:58px 0;border-bottom:1px solid #e1d9ca}.page-hero h1{font-size:clamp(2.3rem,4.6vw,4.2rem);color:var(--navy);max-width:920px}.page-hero .lede{color:var(--muted)}.section{padding:70px 0}.section-tint{background:#eef4f1}.section-heading{display:flex;justify-content:space-between;gap:40px;align-items:end;margin-bottom:28px}.section-heading h2,.split-callout h2,.prose h2{font-family:Georgia,serif;color:var(--navy);font-size:clamp(1.8rem,3vw,2.7rem);line-height:1.15;margin:0}.section-heading>p{max-width:560px;color:var(--muted)}.card-grid{display:grid;gap:18px}.card-grid.four{grid-template-columns:repeat(4,1fr)}.card-grid.three{grid-template-columns:repeat(3,1fr)}.card{display:block;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:0 5px 18px rgba(16,43,63,.045);text-decoration:none;color:var(--ink);transition:.2s transform,.2s box-shadow,.2s border-color}.card:hover{transform:translateY(-3px);box-shadow:var(--shadow);border-color:#aebfba;color:var(--ink)}.card h2,.card h3{color:var(--navy);margin:.55em 0 .35em;line-height:1.2}.card p{color:var(--muted);margin-bottom:0}.card-link{display:block;margin-top:18px;color:var(--teal2);font-weight:750}.tool-icon{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:var(--navy);color:var(--cream);font-weight:800}.split-callout{display:flex;justify-content:space-between;align-items:center;gap:40px}.prose{font-size:1.04rem}.prose h2{margin-top:1.5em}.prose li{margin:.5em 0}.notice{padding:18px 20px;border-left:4px solid var(--copper);background:#fff7ef;border-radius:0 12px 12px 0;color:var(--ink)}.interactive{background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:clamp(20px,4vw,38px)}.generator-card.wide{max-width:1060px;margin:auto}.generator-toolbar{display:flex;justify-content:space-between;gap:18px;align-items:end;border-bottom:1px solid var(--line);padding-bottom:20px;margin-bottom:25px}.generator-toolbar label{display:grid;gap:6px;color:var(--muted);font-size:.9rem;font-weight:700}.generator-toolbar select{min-width:210px;padding:9px 12px;border:1px solid #acb6ba;border-radius:9px;background:#fff;color:var(--ink)}.question-box{background:#f2f6f4;border-radius:14px;padding:22px;margin:18px 0}.question-box h2{margin-top:0;color:var(--navy)}.data-table{width:100%;border-collapse:collapse;margin:18px 0;background:white}.data-table th,.data-table td{border:1px solid #cfd8d5;padding:10px;text-align:center}.data-table th{background:#e8f0ed;color:var(--navy)}.answer-form,.multi-answer{display:flex;gap:14px;align-items:end;flex-wrap:wrap;margin:22px 0}.answer-form label,.multi-answer label,.contact-form label{display:grid;gap:6px;font-weight:700;color:var(--navy)}.answer-form label{grid-template-columns:1fr auto;align-items:end}.answer-form label>span{padding-bottom:10px}.answer-form input,.multi-answer input,.contact-form input,.contact-form textarea{border:1px solid #9eaaae;border-radius:10px;padding:10px 12px;min-width:170px;background:#fff;color:var(--ink)}.answer-form label>input{grid-row:2;grid-column:1}.answer-form label>span{grid-row:2;grid-column:2}.multi-answer label{flex:1;min-width:180px}.feedback-panel,.solution-panel{margin-top:16px;border-radius:12px;padding:0;overflow:hidden}.feedback-panel:not(:empty),.solution-panel:not([hidden]){padding:16px 18px}.feedback-panel.good{background:#ecf8ef;color:var(--good);border:1px solid #b9dfc1}.feedback-panel.bad{background:#fff0f0;color:var(--bad);border:1px solid #efc1c1}.feedback-panel.neutral,.solution-panel{background:#f2f5f4;color:var(--ink);border:1px solid #d6dfdc}.solution-panel ol{margin-bottom:0}.text-button{border:0;background:none;color:var(--teal2);font-weight:750;padding:7px 3px;text-decoration:underline;text-underline-offset:3px}.option-stack{display:grid;gap:10px;margin-top:20px}.option-stack button{background:white;text-align:left;border:1px solid #aebbb8;border-radius:11px;padding:13px 15px}.option-stack button:hover{background:#eef6f3}.quiz-shell .quiz-progress{display:flex;justify-content:space-between;gap:20px;color:var(--muted);font-size:.9rem}.progress-track{height:8px;background:#e6ece9;border-radius:999px;overflow:hidden;margin:8px 0 24px}.progress-track span{display:block;height:100%;background:var(--teal);transition:width .25s}.statement-card{background:var(--navy);color:white;border-radius:16px;padding:28px;margin:18px 0}.statement-card h2{margin:0;font-family:Georgia,serif;font-size:clamp(1.35rem,3vw,2rem);line-height:1.36}.choice-row{display:grid;grid-template-columns:1fr 1fr;gap:14px}.choice-row button{border:2px solid #9eaeaa;background:#fff;border-radius:13px;padding:16px;font-weight:800;color:var(--navy)}.choice-row button:hover{border-color:var(--teal);background:#eef7f4}.quiz-controls{display:flex;justify-content:space-between;gap:15px;align-items:center;margin-top:20px}.score-pills{display:flex;gap:8px;flex-wrap:wrap}.score-pills span{background:#edf2f0;border-radius:999px;padding:5px 9px;font-size:.84rem}.audit-form fieldset{border:0;border-bottom:1px solid var(--line);padding:10px 0 22px;margin-bottom:18px}.audit-form legend{font-weight:800;color:var(--navy);margin-bottom:12px}.audit-form label{display:block;margin:8px 0}.contact-form{display:grid;gap:16px}.contact-form textarea{resize:vertical}.honeypot{position:absolute!important;left:-9999px!important}.sim-controls{display:grid;grid-template-columns:1fr 1fr;gap:24px}.sim-controls label{display:grid;grid-template-columns:1fr auto;gap:8px;font-weight:700}.sim-controls input{grid-column:1/3;width:100%}canvas{display:block;max-width:100%;height:auto;background:#fff;border:1px solid var(--line);border-radius:12px;margin:24px 0}.site-footer{background:var(--navy);color:#d9e2e4;padding:52px 0 24px;margin-top:40px}.footer-grid{display:grid;grid-template-columns:2fr 1fr;gap:40px}.footer-grid p{max-width:620px;color:#bac8cc}.footer-grid nav{display:grid;align-content:start;gap:8px}.footer-grid a{color:#e9f1ef}.footer-small{border-top:1px solid rgba(255,255,255,.15);padding-top:20px;margin-top:30px;font-size:.85rem;color:#9fb1b5}@media(max-width:900px){.main-nav{display:none;position:absolute;top:70px;left:18px;right:18px;background:white;border:1px solid var(--line);border-radius:14px;padding:10px;box-shadow:var(--shadow);flex-direction:column;align-items:stretch}.main-nav.open{display:flex}.nav-toggle{display:block}.hero-grid{grid-template-columns:1fr;gap:35px}.card-grid.four,.card-grid.three{grid-template-columns:repeat(2,1fr)}.section-heading{align-items:start;flex-direction:column}.split-callout{align-items:start;flex-direction:column}}@media(max-width:620px){.shell{width:min(calc(100% - 24px),var(--max))}.brand small{display:none}.hero{padding:58px 0}.section{padding:48px 0}.card-grid.four,.card-grid.three{grid-template-columns:1fr}.choice-row{grid-template-columns:1fr}.generator-toolbar,.answer-form,.multi-answer{align-items:stretch;flex-direction:column}.answer-form label{width:100%}.answer-form input,.multi-answer input{width:100%;min-width:0}.sim-controls{grid-template-columns:1fr}.footer-grid{grid-template-columns:1fr}.page-hero{padding:42px 0}}


/* Temporary staging marker */
.staging-banner {
    position: relative;
    z-index: 1000;
    padding: 0.55rem 1rem;
    text-align: center;
    background: #fff3cd;
    color: #4b3b00;
    border-bottom: 1px solid #d9bd62;
    font-size: 0.92rem;
}

/* v0.2 content recovery and richer practice interfaces */
.legacy-intro-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(360px,.9fr);gap:48px;align-items:center}.legacy-figure{margin:0;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:10px;box-shadow:var(--shadow)}.legacy-figure img{display:block;width:100%;height:auto;border-radius:12px}.legacy-figure figcaption{padding:10px 8px 4px;color:var(--muted);font-size:.88rem}.bt-studio{padding:0;overflow:hidden}.app-tabs{display:flex;gap:0;border-bottom:1px solid var(--line);background:#f5f7f6}.app-tab{flex:1;border:0;border-right:1px solid var(--line);padding:17px 20px;background:transparent;color:var(--muted);font-weight:800}.app-tab:last-child{border-right:0}.app-tab:hover{background:#eef5f2;color:var(--navy)}.app-tab.active{background:#fff;color:var(--teal2);box-shadow:inset 0 -3px 0 var(--teal)}.app-panel{padding:clamp(22px,4vw,38px)}.bt-toolbar{align-items:end}.bt-toolbar label{flex:1}.bt-toolbar select{width:100%;min-width:170px}.toolbar-actions{display:flex;gap:10px;flex-wrap:wrap}.bt-question-meta{display:flex;gap:8px;flex-wrap:wrap;margin:0 0 10px}.bt-question-meta span{background:#e7f3ef;color:var(--teal2);border:1px solid #c8e0d9;border-radius:999px;padding:5px 10px;font-size:.78rem;font-weight:800}.bt-question-box{border:1px solid #d8e3df;background:linear-gradient(145deg,#f5f9f7,#edf4f1);box-shadow:inset 4px 0 0 var(--teal)}.bt-question-box header{display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap}.bt-question-box header h2{margin:.25rem 0;color:var(--navy)}.question-guidance{background:#fff8ef;border-left:3px solid var(--copper);padding:10px 13px;border-radius:0 8px 8px 0}.equation-strip{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}.equation-strip span{background:#fff;border:1px solid #c8d4d0;border-radius:9px;padding:8px 11px;font-family:"Source Code Pro",ui-monospace,monospace;font-size:.92rem}.bt-answer-form{margin-bottom:4px}.field-help{margin:0;color:var(--muted);font-size:.88rem}.bt-help-buttons{border-top:1px solid var(--line);padding-top:12px}.hint-label{margin:0;text-transform:uppercase;letter-spacing:.1em;font-size:.75rem;font-weight:800;color:var(--copper)}.worked-steps li{margin:.75rem 0}.method-steps{counter-reset:method;list-style:none;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.method-steps li{counter-increment:method;background:#f4f7f5;border:1px solid var(--line);border-radius:14px;padding:18px 18px 18px 60px;position:relative;margin:0}.method-steps li:before{content:counter(method);position:absolute;left:17px;top:17px;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;background:var(--navy);color:white;font-weight:850}.two-column-notes{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:28px 0}.practice-set-header{display:flex;justify-content:space-between;gap:30px;align-items:start}.practice-set-header h2{font-family:Georgia,serif;color:var(--navy);font-size:2rem;margin:.2em 0}.practice-questions{display:grid;gap:20px}.answer-key{margin-top:24px;border:1px solid var(--line);border-radius:14px;background:#f8faf9;padding:0 18px}.answer-key summary{cursor:pointer;padding:16px 0;font-weight:800;color:var(--teal2)}.answer-key section{padding:8px 0 18px;border-top:1px solid var(--line)}.print-only{display:none}.tutor-guide{max-width:1000px}.article-intro{margin-bottom:34px}.faq-list{list-style:none;padding:0;counter-reset:faq;display:grid;gap:18px}.faq-item{counter-increment:faq;background:#fff;border:1px solid var(--line);border-radius:16px;padding:24px 26px 24px 78px;position:relative;box-shadow:0 5px 18px rgba(16,43,63,.04)}.faq-item:before{content:counter(faq);position:absolute;left:24px;top:24px;width:38px;height:38px;display:grid;place-items:center;border-radius:12px;background:var(--navy);color:#fff;font-weight:850}.faq-item h2{font-size:clamp(1.25rem,2.1vw,1.65rem);margin:0 0 .55rem}.faq-item p{margin:0;color:#35444f}

/* More game-like quiz presentation without sacrificing accessibility */
.quiz-shell{position:relative}.quiz-start{text-align:center;padding:14px 0 6px}.quiz-start-icon{width:78px;height:78px;margin:0 auto 16px;display:grid;place-items:center;border-radius:24px;background:linear-gradient(145deg,var(--navy),var(--teal2));color:#fff;font-family:Georgia,serif;font-size:1.55rem;box-shadow:0 14px 30px rgba(16,43,63,.22)}.quiz-start h2{font-family:Georgia,serif;color:var(--navy);font-size:2rem;margin:.3rem 0}.quiz-status-row{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}.quiz-stat-group{display:flex;gap:8px;flex-wrap:wrap}.quiz-stat{background:#edf3f0;border:1px solid #d7e2de;border-radius:999px;padding:5px 10px;font-size:.82rem;color:var(--navy);font-weight:750}.statement-card{position:relative;overflow:hidden;min-height:180px;display:grid;place-items:center;text-align:center}.statement-card:after{content:"";position:absolute;width:180px;height:180px;border-radius:50%;right:-90px;top:-100px;border:1px solid rgba(255,255,255,.16);box-shadow:0 0 0 35px rgba(255,255,255,.035)}.statement-card h2{position:relative;z-index:1}.choice-row button{min-height:76px;display:flex;align-items:center;justify-content:center;gap:10px;font-size:1.1rem;transition:.18s transform,.18s background,.18s border-color}.choice-row button:hover{transform:translateY(-2px)}.choice-row button[data-answer="true"]:before{content:"T";display:grid;place-items:center;width:32px;height:32px;border-radius:10px;background:#e4f5e9;color:var(--good)}.choice-row button[data-answer="false"]:before{content:"F";display:grid;place-items:center;width:32px;height:32px;border-radius:10px;background:#fff0f0;color:var(--bad)}.choice-row button.selected-correct{border-color:#4ca36a;background:#effaf2}.choice-row button.selected-wrong{border-color:#cb6666;background:#fff1f1}.choice-row button:disabled{cursor:default;opacity:.78;transform:none}.feedback-panel.quiz-feedback:not(:empty){font-size:1.02rem}.feedback-explanation{display:block;margin-top:.35rem;color:inherit}.quiz-complete{text-align:center}.quiz-complete .result-ring{--score:0;width:126px;height:126px;border-radius:50%;margin:0 auto 20px;display:grid;place-items:center;background:conic-gradient(var(--teal) calc(var(--score)*1%),#e2e9e6 0);position:relative}.quiz-complete .result-ring:before{content:"";position:absolute;inset:12px;border-radius:50%;background:#fff}.quiz-complete .result-ring strong{position:relative;z-index:1;font-size:1.45rem;color:var(--navy)}

@media(max-width:900px){.legacy-intro-grid{grid-template-columns:1fr}.method-steps{grid-template-columns:1fr}.two-column-notes{grid-template-columns:1fr}}
@media(max-width:620px){.app-tabs{flex-direction:column}.app-tab{border-right:0;border-bottom:1px solid var(--line)}.app-tab:last-child{border-bottom:0}.bt-toolbar,.toolbar-actions{width:100%}.toolbar-actions .button{flex:1}.faq-item{padding:20px 18px 20px 64px}.faq-item:before{left:16px;top:19px}.legacy-intro-grid{gap:26px}}

@media print{
  .site-header,.site-footer,.staging-banner,.page-hero,.legacy-intro-grid,.back-titration-guide,.app-tabs,#bt-single-panel,.generator-toolbar,#bt-print-set{display:none!important}
  body{background:#fff;color:#000;font-size:10.5pt}.section,.section-tint{padding:0;background:#fff}.shell{width:100%;max-width:none}.interactive{border:0;box-shadow:none;padding:0}.app-panel{padding:0}.print-only{display:block}.practice-set-header{border-bottom:2px solid #000;margin-bottom:16px}.practice-set .question-box{break-inside:avoid;background:#fff;border:1px solid #555;box-shadow:none;padding:14px;margin:0 0 14px}.practice-set .equation-strip span{border-color:#777}.answer-key{break-before:page;border:0;padding:0;background:#fff}.answer-key[open] summary{display:none}.answer-key:not([open]){display:none}.practice-set a{color:#000;text-decoration:none}
}
.hub-note{display:inline-block;max-width:820px;margin:10px 0 0;padding:9px 13px;border-radius:10px;background:rgba(255,255,255,.62);border:1px solid #ded6c8;color:#4d5d68;font-size:.94rem}
.study-intro .notice{align-self:center}
.colour-game-header{display:flex;justify-content:space-between;gap:24px;align-items:end;border-bottom:1px solid var(--line);padding-bottom:18px}.colour-game-header h2{margin:.15em 0;color:var(--navy);font-family:Georgia,serif}.colour-game-header label{display:grid;gap:5px;font-weight:750;color:var(--navy)}.colour-game-header select{padding:9px 12px;border:1px solid #aab6b3;border-radius:9px;background:#fff}.colour-stats{margin:16px 0}.colour-prompt{min-height:220px;display:grid;place-items:center;text-align:center;background:linear-gradient(145deg,var(--navy),#174b57);color:#fff;border-radius:18px;padding:30px;position:relative;overflow:hidden}.colour-prompt:after{content:"";position:absolute;width:210px;height:210px;border-radius:50%;right:-110px;top:-110px;border:1px solid rgba(255,255,255,.16);box-shadow:0 0 0 42px rgba(255,255,255,.035)}.colour-prompt>*{position:relative;z-index:1}.colour-prompt h2{font-family:Georgia,serif;font-size:clamp(2rem,5vw,3.4rem);margin:.15em 0}.colour-prompt p{margin:.2em 0;opacity:.9}.colour-context{text-transform:uppercase;letter-spacing:.1em;font-size:.75rem;font-weight:800}.large-swatch{display:block;width:70px;height:70px;border-radius:22px;background:var(--swatch);border:3px solid rgba(255,255,255,.75);box-shadow:0 10px 28px rgba(0,0,0,.22)}.colour-options{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:18px 0}.colour-options button{min-height:74px;text-align:left;display:flex;align-items:center;gap:13px;border:2px solid #aebbb8;background:#fff;border-radius:13px;padding:13px 15px;color:var(--navy);font-weight:800}.colour-options button:hover{border-color:var(--teal);background:#eef7f4;transform:translateY(-1px)}.colour-options button:disabled{cursor:default;transform:none;opacity:.85}.colour-options button.selected-correct{border-color:#4ca36a;background:#effaf2}.colour-options button.selected-wrong{border-color:#cb6666;background:#fff1f1}.colour-chip{flex:0 0 auto;width:38px;height:38px;border-radius:12px;background:var(--swatch);border:1px solid rgba(0,0,0,.18);box-shadow:inset 0 0 0 2px rgba(255,255,255,.22)}.formula-choice{font-family:Georgia,serif;font-size:1.2rem;min-width:115px}.colour-options small{font-weight:550;color:var(--muted)}
@media(max-width:620px){.colour-game-header{align-items:stretch;flex-direction:column}.colour-options{grid-template-columns:1fr}.colour-prompt{min-height:190px}}

/* v0.2 featured recovery card */
.featured-recovery { padding-top: 2rem; padding-bottom: 0; }
.featured-game-card {
    position: relative;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 220px;
    align-items: center;
    gap: 2rem;
    overflow: hidden;
    padding: clamp(1.6rem, 4vw, 3rem);
    border: 1px solid rgba(28, 121, 128, .25);
    border-radius: 26px;
    background: linear-gradient(135deg, #f8f3e8 0%, #edf7f5 62%, #e1eef1 100%);
    color: var(--ink, #153142);
    box-shadow: 0 18px 50px rgba(16, 43, 63, .10);
    text-decoration: none;
}
.featured-game-card h2 { margin: .2rem 0 .65rem; font-size: clamp(1.8rem, 4vw, 3rem); }
.featured-game-card p:not(.eyebrow) { max-width: 58rem; margin-bottom: 1.25rem; }
.featured-game-card .button { display: inline-flex; }
.colour-orbit { position: relative; width: 190px; height: 190px; margin-inline: auto; }
.colour-orbit::before {
    content: '';
    position: absolute;
    inset: 31px;
    border: 2px dashed rgba(16,43,63,.22);
    border-radius: 50%;
}
.colour-orbit span { position: absolute; width: 64px; height: 64px; border-radius: 50%; box-shadow: inset 0 0 0 8px rgba(255,255,255,.45), 0 10px 24px rgba(16,43,63,.16); }
.colour-orbit span:nth-child(1) { background:#174b9a; left:63px; top:0; }
.colour-orbit span:nth-child(2) { background:#d66a22; right:0; top:55px; }
.colour-orbit span:nth-child(3) { background:#6d2f8c; right:27px; bottom:0; }
.colour-orbit span:nth-child(4) { background:#416b45; left:13px; bottom:18px; }
.colour-orbit span:nth-child(5) { background:#e2c51b; left:0; top:43px; }
@media (max-width: 720px) {
    .featured-game-card { grid-template-columns: 1fr; }
    .colour-orbit { width: 150px; height: 150px; order: -1; }
    .colour-orbit span { width: 50px; height: 50px; }
    .colour-orbit span:nth-child(1) { left:50px; }
}

/* v0.3 matching engine */
.matching-shell{max-width:1180px;margin:auto}.matching-start{text-align:center;padding:18px 0}.matching-start-mark{width:76px;height:76px;margin:0 auto 16px;border-radius:24px;display:grid;place-items:center;background:linear-gradient(145deg,var(--navy),var(--teal2));color:#fff;font-size:2rem;font-weight:850;box-shadow:0 14px 30px rgba(16,43,63,.2)}.matching-start h2,.matching-finish h2,.matching-column h2,.kc-studio h2{font-family:Georgia,serif;color:var(--navy)}.matching-start p{max-width:760px;margin:0 auto 22px;color:var(--muted)}.matching-start-controls{display:flex;justify-content:center;align-items:end;gap:14px;flex-wrap:wrap}.matching-start-controls label{display:grid;gap:6px;text-align:left;color:var(--navy);font-weight:750}.matching-start-controls select{min-width:180px;padding:10px 12px;border:1px solid #aebbb8;border-radius:10px;background:#fff}.matching-status-row{display:flex;justify-content:space-between;gap:16px;align-items:center;flex-wrap:wrap}.matching-message{margin:18px 0;padding:12px 15px;border-radius:11px;background:#eef3f1;border:1px solid #d6dfdc;color:var(--navy);font-weight:700;text-align:center}.matching-message.good{background:#edf8f0;border-color:#b8ddc1;color:var(--good)}.matching-message.bad{background:#fff0f0;border-color:#efc3c3;color:var(--bad)}.matching-message.warning{background:#fff8e7;border-color:#ead39a;color:#7a5608}.matching-board{display:grid;grid-template-columns:1fr 1.35fr;gap:18px;align-items:start}.matching-column{border:1px solid var(--line);border-radius:16px;padding:18px;background:#f8faf9}.matching-column h2{margin:.1em 0 .7em;text-align:center;font-size:1.45rem}.matching-list{display:grid;gap:9px}.matching-card{width:100%;border:1px solid #b7c2bf;border-radius:11px;background:#fff;padding:12px 14px;text-align:left;color:var(--ink);font-weight:650;line-height:1.42;transition:.16s transform,.16s border-color,.16s background;display:flex;justify-content:space-between;align-items:center;gap:10px}.matching-card:hover{transform:translateY(-1px);border-color:var(--teal);background:#eef7f4}.matching-card.selected{border:2px solid var(--teal);background:#dff1ec;box-shadow:0 0 0 3px rgba(23,124,122,.12)}.matching-card.matched{background:#edf8f0;border-color:#9bc9a7;color:#31543a;opacity:.62}.matching-count{flex:0 0 auto;padding:3px 7px;border-radius:999px;background:#e8eeec;color:var(--muted);font-size:.72rem}.matching-finish{text-align:center;padding:30px 0 10px}.matching-finish .result-ring{--score:0;width:126px;height:126px;border-radius:50%;margin:0 auto 20px;display:grid;place-items:center;background:conic-gradient(var(--teal) calc(var(--score)*1%),#e2e9e6 0);position:relative}.matching-finish .result-ring:before{content:"";position:absolute;inset:12px;border-radius:50%;background:#fff}.matching-finish .result-ring strong{position:relative;z-index:1;font-size:1.45rem;color:var(--navy)}.shake{animation:matchingShake .4s cubic-bezier(.36,.07,.19,.97) both}@keyframes matchingShake{10%,90%{transform:translateX(-1px)}20%,80%{transform:translateX(2px)}30%,50%,70%{transform:translateX(-4px)}40%,60%{transform:translateX(4px)}}

/* v0.3 isotope generator */
.isotope{font-family:Georgia,"Times New Roman",serif;font-weight:750;white-space:nowrap}.hard-isotope-question .tag{margin-bottom:8px}.math-line{display:inline-block;margin-top:6px;padding:7px 9px;border-radius:8px;background:#e8efed;font-family:Georgia,"Times New Roman",serif;overflow-wrap:anywhere}

/* v0.3 Kc studio */
.kc-studio{max-width:1180px;margin:auto}.app-tabs{display:flex;border:1px solid var(--line);border-radius:13px 13px 0 0;overflow:hidden;background:#eef3f1}.app-tab{flex:1;border:0;border-right:1px solid var(--line);padding:13px 16px;background:transparent;color:var(--navy);font-weight:800}.app-tab:last-child{border-right:0}.app-tab.active{background:var(--navy);color:#fff}.app-panel{padding:26px 4px 4px}.kc-sim-heading{display:flex;justify-content:space-between;gap:24px;align-items:start;margin-bottom:18px}.kc-sim-heading h2{margin:.1em 0 .3em;font-size:clamp(1.55rem,3vw,2.35rem)}.kc-sim-heading p{margin:0;max-width:820px;color:var(--muted)}.tag.active-catalyst{background:#dff3e7;color:#135b31}.kc-control-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:9px;margin:18px 0}.kc-control-grid button{min-height:46px;border:1px solid #aab8b5;border-radius:10px;background:#fff;color:var(--navy);font-weight:750;padding:8px 10px}.kc-control-grid button:hover{background:#eef7f4;border-color:var(--teal)}.kc-control-grid button.active{background:#dfeaf8;border-color:#7e9fc4}.kc-control-grid button.reset{background:#fff2e9;border-color:#d8a17f;color:#7b3f1e}.kc-control-grid button:disabled{opacity:.5;cursor:not-allowed}.kc-sim-grid{display:grid;grid-template-columns:1.15fr .85fr;gap:18px}.kc-visual-panel,.kc-data-panel{border:1px solid var(--line);border-radius:16px;background:#f8faf9;padding:20px}.kc-visual-panel h3,.kc-data-panel h3{margin:.1em 0 1em;color:var(--navy);text-align:center}.kc-bars{height:250px;display:flex;align-items:end;justify-content:space-around;gap:22px;padding:30px 12px 0;border-bottom:2px solid #aab8b5}.kc-bar-wrap{height:100%;flex:1;display:flex;flex-direction:column;justify-content:end;align-items:center;gap:8px}.kc-bar{width:min(82px,72%);min-height:8px;border-radius:11px 11px 0 0;position:relative;transition:height .12s linear;box-shadow:inset 0 0 0 1px rgba(255,255,255,.25)}.kc-bar span{position:absolute;top:-28px;left:50%;transform:translateX(-50%);font-size:.82rem;font-weight:800;color:var(--navy);background:#fff;padding:2px 5px;border-radius:5px;white-space:nowrap}.kc-bar.n2{background:#3f73a8}.kc-bar.h2{background:#4f8b5d}.kc-bar.nh3{background:#bd6a3f}.kc-rate-display{display:flex;justify-content:center;align-items:center;gap:8px;margin:24px 0 12px;color:var(--muted);font-weight:750}.rate-arrow{font-size:1.8rem;display:inline-block}.kc-rate-display[data-direction="forward"] .forward{color:var(--good);animation:rateForward .65s alternate infinite}.kc-rate-display[data-direction="forward"] .reverse{opacity:.35}.kc-rate-display[data-direction="reverse"] .reverse{color:var(--bad);animation:rateReverse .65s alternate infinite}.kc-rate-display[data-direction="reverse"] .forward{opacity:.35}.kc-rate-display[data-direction="equilibrium"] .forward,.kc-rate-display[data-direction="equilibrium"] .reverse{color:var(--teal);animation:ratePulse 1.3s alternate infinite}@keyframes rateForward{to{transform:translateX(5px)}}@keyframes rateReverse{to{transform:translateX(-5px)}}@keyframes ratePulse{to{opacity:.45}}.kc-data-list{display:grid;gap:8px;margin:0}.kc-data-list div{display:flex;justify-content:space-between;gap:18px;padding:9px 0;border-bottom:1px solid #dce3e0}.kc-data-list dt{color:var(--muted)}.kc-data-list dd{margin:0;font-weight:800;color:var(--navy)}.kc-calculation{margin-top:18px;background:#eaf1ef;border:1px solid #d1ddda;border-radius:12px;padding:14px;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;line-height:1.7;overflow-wrap:anywhere}.kc-explanation{margin-top:18px}.kc-explanation h3{margin-top:0;color:var(--navy)}

@media(max-width:900px){.matching-board{grid-template-columns:1fr}.kc-control-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.kc-sim-grid{grid-template-columns:1fr}}
@media(max-width:620px){.matching-start-controls{align-items:stretch;flex-direction:column}.matching-start-controls select{width:100%}.matching-status-row{align-items:stretch;flex-direction:column}.matching-card{font-size:.93rem}.kc-sim-heading{flex-direction:column}.kc-control-grid{grid-template-columns:1fr 1fr}.kc-bars{height:220px;gap:8px}.kc-bar{width:64px}.app-panel{padding-top:20px}}

/* v0.4 rate equation laboratory and board overview */
.rate-lab{max-width:1120px}.rate-app-heading{display:flex;justify-content:space-between;gap:28px;align-items:flex-start;margin-bottom:24px}.rate-app-heading h2{font-family:Georgia,"Times New Roman",serif;color:var(--navy);font-size:clamp(1.8rem,3.2vw,2.7rem);line-height:1.15;margin:.15em 0 .35em}.rate-app-heading p:not(.eyebrow){margin:0;max-width:760px;color:var(--muted)}.rate-toolbar{display:grid;grid-template-columns:1fr 1.45fr 1fr auto;align-items:end}.rate-toolbar label{min-width:0}.rate-toolbar select{width:100%;min-width:0}.checkbox-control{display:flex!important;align-items:center;gap:9px;min-height:46px;padding:9px 12px;border:1px solid #c7d1ce;border-radius:10px;background:#f8faf9;color:var(--navy)!important}.checkbox-control input{width:18px;height:18px;margin:0}.muted-control{opacity:.52}.rate-question-box{box-shadow:inset 4px 0 0 var(--teal)}.rate-data-table small{font-size:.72rem;font-weight:600;color:var(--muted)}.table-scroll{overflow-x:auto}.rate-answer-form fieldset{border:1px solid var(--line);border-radius:15px;padding:20px;margin:22px 0 0;background:#fbfcfb}.rate-answer-form legend{padding:0 8px;font-family:Georgia,"Times New Roman",serif;color:var(--navy);font-size:1.35rem;font-weight:800}.rate-input-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.rate-k-grid{grid-template-columns:1fr 1fr;margin-top:14px;padding-top:14px;border-top:1px solid var(--line)}.single-unit-grid{grid-template-columns:minmax(250px,420px);margin-top:14px}.rate-input-grid label{display:grid;gap:6px;color:var(--navy);font-weight:750}.rate-input-grid input,.rate-input-grid select{width:100%;min-width:0;padding:11px 12px;border:1px solid #9eaaae;border-radius:10px;background:#fff;color:var(--ink)}.answer-correct{border-color:#26914e!important;background:#edf9f0!important;box-shadow:0 0 0 3px rgba(38,145,78,.12)}.answer-incorrect{border-color:#c34b4b!important;background:#fff2f2!important;box-shadow:0 0 0 3px rgba(195,75,75,.11)}.clue-stack{display:grid;gap:10px;margin-top:18px}.clue-card{margin:0;padding:13px 15px;border-radius:11px;border-left:4px solid var(--copper);background:#fff8ef}.rate-solution-step{padding:4px 0 18px;border-bottom:1px solid var(--line)}.rate-solution-step:last-child{border-bottom:0}.rate-solution-step h3{color:var(--navy);margin:.7em 0 .35em}.rate-solution-step ol{margin-top:.4em}.equation-result{display:inline-block;padding:10px 14px;border:1px solid #bed4ce;border-radius:10px;background:#eaf3f0;color:var(--navy);font-family:Georgia,"Times New Roman",serif;font-size:1.2rem;font-weight:800}.board-scope-note{margin:0 0 18px;padding:14px 16px;border-radius:12px}.board-scope-note.aqa-note{background:#eef3f8;border:1px solid #cbd9e7;color:#234c70}.board-scope-note.ocr-note{background:#eef7f2;border:1px solid #c8dfd1;color:#205c3b}.detective-case-file{box-shadow:inset 4px 0 0 var(--copper)}.evidence-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:18px}.evidence-card{display:grid;grid-template-columns:38px 1fr;gap:12px;align-items:start;padding:15px;border:1px solid #d4ddda;border-radius:13px;background:#fff}.evidence-card.ocr-evidence{border-color:#a9cfba;background:#f0f8f3}.evidence-number{display:grid;place-items:center;width:34px;height:34px;border-radius:10px;background:var(--navy);color:white;font-weight:850}.evidence-card.ocr-evidence .evidence-number{background:#2f744d}.evidence-card p{margin:0}.evidence-type{text-transform:uppercase;letter-spacing:.08em;font-size:.72rem;font-weight:850;color:var(--copper);margin-bottom:4px!important}.ocr-evidence .evidence-type{color:#2f744d}.board-route-card{min-height:240px}.board-route-card .tag{margin-bottom:4px}
@media(max-width:900px){.rate-toolbar{grid-template-columns:1fr 1fr}.rate-toolbar .button{width:100%}.rate-input-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.evidence-grid{grid-template-columns:1fr}}
@media(max-width:620px){.rate-app-heading{flex-direction:column}.rate-toolbar{display:flex;flex-direction:column;align-items:stretch}.rate-toolbar label,.rate-toolbar .button{width:100%}.rate-input-grid,.rate-k-grid,.single-unit-grid{grid-template-columns:1fr}.rate-answer-form fieldset{padding:16px}.evidence-card{grid-template-columns:32px 1fr}.evidence-number{width:30px;height:30px}}