:root{
  --bg:#ffffff;
  --surface:#ffffff;
  --surface-alt:#f6f0df;
  --text:#26313c;
  --muted:#66727e;
  --navy:#123b70;
  --blue:#2f6ca8;
  --green:#8fc36b;
  --green-dark:#527c36;
  --orange:#e5a13c;
  --border:#d9e0e6;
  --shadow:0 18px 50px rgba(25,42,60,.12);
  --radius:22px;
  --header-h:72px;
  --sidebar-w:290px;
}
[data-theme="dark"]{
  --bg:#101722;
  --surface:#17212e;
  --surface-alt:#1d2936;
  --text:#eef4f8;
  --muted:#aebbc6;
  --navy:#8dbef0;
  --blue:#72a9da;
  --green:#9ccd7b;
  --green-dark:#8ebd70;
  --orange:#f0b75c;
  --border:#2b3b4b;
  --shadow:0 18px 50px rgba(0,0,0,.28);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:88px}
body{margin:0;background:var(--bg);color:var(--text);font-family:Nunito,Arial,sans-serif;line-height:1.6}
a{color:inherit}
button,input{font:inherit}
.reading-progress{position:fixed;z-index:9999;top:0;left:0;height:4px;background:linear-gradient(90deg,var(--green),var(--orange));width:0}
.site-header{position:fixed;z-index:1000;top:0;left:0;right:0;height:var(--header-h);display:flex;align-items:center;justify-content:space-between;padding:0 22px;background:color-mix(in srgb,var(--surface) 92%,transparent);backdrop-filter:blur(14px);border-bottom:1px solid var(--border)}
.brand{display:flex;gap:10px;align-items:center;text-decoration:none}.brand-mark{font-size:2rem}.brand strong,.brand small{display:block}.brand strong{color:var(--navy);font-size:1.1rem}.brand small{color:var(--muted);font-size:.75rem}
.header-actions{display:flex;gap:8px}.icon-button,.menu-button{border:1px solid var(--border);background:var(--surface);color:var(--text);width:42px;height:42px;border-radius:12px;cursor:pointer}.menu-button{display:none}
.sidebar{position:fixed;z-index:900;top:var(--header-h);bottom:0;left:0;width:var(--sidebar-w);background:var(--surface);border-right:1px solid var(--border);overflow:auto;padding:18px}
.sidebar-nav{display:grid;gap:10px}.sidebar-home,.sidebar-nav summary,.sidebar-nav details a{display:block;padding:10px 12px;border-radius:10px;text-decoration:none}.sidebar-home,.sidebar-nav summary{font-weight:900;color:var(--navy)}.sidebar-nav summary{cursor:pointer}.sidebar-nav details a{margin-left:10px;color:var(--muted);font-size:.92rem}.sidebar-nav a:hover,.sidebar-nav a.active{background:var(--surface-alt);color:var(--navy)}
.content{margin-left:var(--sidebar-w);padding-top:var(--header-h)}
.hero{min-height:calc(100vh - var(--header-h));display:grid;grid-template-columns:1.1fr .9fr;align-items:center;gap:50px;padding:80px clamp(28px,6vw,90px);background:radial-gradient(circle at 85% 20%,rgba(143,195,107,.26),transparent 27%),linear-gradient(135deg,#0f315c,#184f84 65%,#163e69);color:#fff}
.eyebrow{display:inline-block;background:var(--orange);color:#1e2a35;padding:7px 14px;border-radius:999px;font-weight:900;font-size:.8rem}.hero h1{font-family:"Patrick Hand";font-size:clamp(4rem,8vw,7rem);line-height:.9;margin:22px 0}.hero-lead{font-size:1.35rem;max-width:700px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}.button{border:0;border-radius:14px;padding:14px 20px;font-weight:900;cursor:pointer;text-decoration:none}.button.primary{background:var(--green);color:#173019}.button.secondary{background:transparent;color:#fff;border:1px solid rgba(255,255,255,.5)}
.hero-visual{position:relative;display:grid;place-items:center}.hero-map{font-size:13rem;filter:drop-shadow(0 25px 25px rgba(0,0,0,.25))}.hero-pin{position:absolute;font-size:4rem;top:28%;left:53%;animation:bob 2.4s ease-in-out infinite}@keyframes bob{50%{transform:translateY(-10px)}}
.overview-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;padding:28px clamp(28px,6vw,90px);background:var(--surface-alt)}.overview-grid a{background:var(--surface);padding:22px;border-radius:18px;text-decoration:none;box-shadow:var(--shadow)}.overview-grid span{display:grid;place-items:center;width:38px;height:38px;background:var(--navy);color:#fff;border-radius:50%;font-weight:900}.overview-grid strong,.overview-grid small{display:block}.overview-grid strong{margin-top:14px;color:var(--navy)}.overview-grid small{color:var(--muted)}
.part-intro{display:grid;grid-template-columns:auto 1fr;gap:22px;align-items:center;padding:36px clamp(28px,6vw,90px);color:#fff}.part-intro span{border:2px solid currentColor;border-radius:16px;padding:10px 14px;font-weight:900}.part-intro h2{font-family:"Patrick Hand";font-size:2.8rem;line-height:1;margin:0}.part-intro p{margin:6px 0 0}.part-one{background:linear-gradient(100deg,#315f3b,#5e8d49)}.part-two{background:linear-gradient(100deg,#8d5c15,#d18b25)}.part-three{background:linear-gradient(100deg,#644b17,#aa7d27)}.part-four{background:linear-gradient(100deg,#365f35,#76964c)}
.section{padding:82px clamp(28px,6vw,90px)}.section.alt{background:var(--surface-alt)}.section-heading{text-align:center;margin-bottom:34px}.section-heading span{display:inline-block;background:var(--green);color:#173019;padding:7px 15px;border-radius:999px;font-weight:900}.section-heading h2{font-family:"Patrick Hand";font-size:clamp(2.7rem,5vw,4.5rem);line-height:1;margin:14px 0;color:var(--navy)}.lead{max-width:880px;margin:0 auto 36px;text-align:center;font-size:1.18rem}
.site-footer{padding:48px;text-align:center;background:#0d2d51;color:#fff}.site-footer a{color:#c5e4aa}
.search-overlay{position:fixed;z-index:2000;inset:0;background:rgba(0,0,0,.6);padding:8vh 20px}.search-dialog{max-width:760px;margin:auto;background:var(--surface);border-radius:22px;box-shadow:var(--shadow);max-height:84vh;overflow:auto}.search-header{display:flex;gap:10px;padding:16px;border-bottom:1px solid var(--border)}.search-header input{flex:1;padding:13px;border:1px solid var(--border);border-radius:12px;background:var(--bg);color:var(--text)}.search-results{padding:12px}.search-results a{display:block;padding:13px;border-radius:12px;text-decoration:none}.search-results a:hover{background:var(--surface-alt)}.search-results strong,.search-results small{display:block}.search-results small{color:var(--muted)}
@media(max-width:1020px){.menu-button{display:block}.sidebar{transform:translateX(-100%);transition:.25s}.sidebar.open{transform:translateX(0)}.content{margin-left:0}.overview-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:720px){.hero{grid-template-columns:1fr;padding-top:55px}.hero-visual{display:none}.overview-grid{grid-template-columns:1fr}.part-intro{grid-template-columns:1fr}.part-intro h2{font-size:2.3rem}}
@media print{.site-header,.sidebar,.reading-progress,.search-overlay,.hero-actions{display:none!important}.content{margin:0;padding:0}.hero{min-height:auto;color:#000;background:#fff}.section,.part-intro{break-inside:avoid}.part-intro{color:#000;background:#fff!important;border-top:3px solid #000}}
.cards{display:grid;gap:18px}.cards.two{grid-template-columns:repeat(2,1fr)}.cards.three{grid-template-columns:repeat(3,1fr)}.cards.four{grid-template-columns:repeat(4,1fr)}
.cards article,.definition,.flow article,.worked-grid article,.observe-list article,.sector-grid article{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow)}
.cards h3,.flow h3,.worked-grid h3,.sector-grid h3{color:var(--navy);margin-top:0}.card-icon{font-size:2.5rem}
.mindmap{display:grid;grid-template-columns:1fr 220px 1fr;gap:18px;align-items:center}.mindmap article{background:var(--surface);border:2px solid var(--border);padding:22px;border-radius:20px}.mindmap-center{grid-column:2;grid-row:1/3;background:var(--green);color:#183119;border-radius:22px;padding:34px 14px;text-align:center;font-family:"Patrick Hand";font-size:2rem;font-weight:900}
.callout{margin-top:28px;padding:18px 22px;border:2px dashed var(--blue);border-radius:18px;background:var(--surface);text-align:center;font-weight:800}.callout.success{border-color:var(--green-dark)}
.comparison{display:grid;grid-template-columns:1fr auto 1fr;gap:20px;align-items:center}.comparison article{background:var(--surface);padding:28px;border-radius:22px;box-shadow:var(--shadow);border:2px solid var(--border)}.comparison-arrow{font-size:2.6rem;color:var(--green-dark)}
.timeline{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.timeline article{background:var(--surface);border-top:6px solid var(--green);padding:22px;border-radius:20px;box-shadow:var(--shadow)}.timeline b{font-size:1.4rem;color:var(--navy)}
.check-grid{max-width:850px;margin:auto;display:grid;gap:13px}.check-grid div{background:var(--surface);padding:16px;border-radius:14px;border:1px solid var(--border);font-weight:800}
.table-wrap{overflow:auto;background:var(--surface);border-radius:20px;box-shadow:var(--shadow)}table{border-collapse:collapse;width:100%}th,td{padding:16px;border-bottom:1px solid var(--border);text-align:left}th{background:var(--navy);color:#fff}
.glossary{display:grid;grid-template-columns:repeat(2,1fr);gap:15px}.glossary article{background:var(--surface);border-left:6px solid var(--orange);padding:20px;border-radius:16px;box-shadow:var(--shadow)}
.flow{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.flow b,.worked-grid>article>b{display:grid;place-items:center;width:38px;height:38px;background:var(--green-dark);color:#fff;border-radius:50%}
blockquote{max-width:760px;margin:34px auto;background:var(--surface);border-left:8px solid var(--orange);padding:26px;border-radius:8px 22px 22px 8px;font-family:Georgia,serif;font-size:1.6rem;color:var(--navy);font-style:italic;box-shadow:var(--shadow)}
.split{display:grid;grid-template-columns:1fr 1fr;gap:18px}.formula-strip{max-width:760px;margin:30px auto;display:grid;grid-template-columns:auto 1fr;gap:10px;background:var(--surface);padding:22px;border-radius:18px;border:2px dashed var(--green-dark)}.formula-strip strong{color:var(--navy)}
.equation{display:grid;grid-template-columns:1fr auto 1.5fr auto 1fr;gap:12px;align-items:center;margin:30px 0}.equation span{background:var(--surface);padding:20px;border:1px solid var(--border);border-radius:16px;text-align:center;font-weight:900}.equation b{font-size:2rem}
.example-data{display:grid;grid-template-columns:repeat(5,1fr);gap:12px;margin-bottom:24px}.example-data span{background:var(--surface);padding:14px;border-radius:14px;border:1px solid var(--border)}
.worked-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.worked-grid strong{color:var(--green-dark);font-size:1.3rem}
.calculator{background:var(--surface);padding:28px;border-radius:24px;box-shadow:var(--shadow)}.form-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.form-grid label{font-weight:800}.form-grid input{width:100%;margin-top:6px;padding:12px;border:1px solid var(--border);border-radius:10px;background:var(--bg);color:var(--text)}.result-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:20px}.result-grid div{background:var(--surface-alt);padding:18px;border-radius:14px}.result-grid small,.result-grid strong{display:block}.result-grid strong{font-size:1.35rem;color:var(--navy)}.grand-total{display:flex;justify-content:space-between;align-items:center;margin-top:18px;padding:18px;background:var(--navy);color:#fff;border-radius:14px}.grand-total strong{font-size:1.6rem}
.category-heading{display:grid;grid-template-columns:auto 1fr auto;gap:16px;align-items:center;margin-bottom:24px}.category-heading span{background:var(--navy);color:#fff;padding:8px 13px;border-radius:999px;font-weight:900}.category-heading h2{font-family:"Patrick Hand";font-size:3.2rem;color:var(--navy);margin:0}.category-heading div{font-size:3rem}
.sector-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.interactive-checklist{display:grid;gap:12px;max-width:900px;margin:auto}.interactive-checklist.two-columns{grid-template-columns:repeat(2,1fr);max-width:none}.interactive-checklist label{background:var(--surface);border:1px solid var(--border);padding:15px;border-radius:14px;box-shadow:0 6px 16px rgba(0,0,0,.05)}.interactive-checklist input{width:20px;height:20px;accent-color:var(--green-dark);vertical-align:middle;margin-right:8px}
.observe-list{display:grid;gap:14px;max-width:900px;margin:auto}.observe-list article{display:flex;gap:14px}.observe-list article>b{flex:0 0 38px;height:38px;display:grid;place-items:center;background:var(--green-dark);color:#fff;border-radius:50%}.observe-list h3{margin:0;color:var(--navy)}
.layer-flow{display:flex;align-items:center;justify-content:center;gap:10px;flex-wrap:wrap;padding:24px;background:var(--surface);border:2px dashed var(--blue);border-radius:20px}.layer-flow span{background:var(--surface-alt);padding:10px 14px;border-radius:999px;font-weight:900}
@media(max-width:980px){.cards.four,.timeline,.sector-grid,.worked-grid{grid-template-columns:repeat(2,1fr)}.cards.three,.flow,.form-grid,.result-grid{grid-template-columns:repeat(2,1fr)}.mindmap{grid-template-columns:1fr}.mindmap-center{grid-column:auto;grid-row:auto}.example-data{grid-template-columns:repeat(2,1fr)}.equation{grid-template-columns:1fr}.equation b{text-align:center;transform:rotate(90deg)}}
@media(max-width:640px){.cards.two,.cards.three,.cards.four,.timeline,.sector-grid,.worked-grid,.flow,.split,.form-grid,.result-grid,.example-data,.glossary,.interactive-checklist.two-columns{grid-template-columns:1fr}.comparison{grid-template-columns:1fr}.comparison-arrow{text-align:center;transform:rotate(90deg)}.category-heading{grid-template-columns:1fr auto}.category-heading span{grid-column:1/-1;width:max-content}.category-heading h2{font-size:2.5rem}}