:root {
  --navy:#003057;
  --blue:#0072ce;
  --teal:#147d78;
  --gold:#c68700;
  --green:#18794e;
  --red:#b42318;
  --ink:#1f2933;
  --muted:#5d6b77;
  --line:#d7e1e7;
  --bg:#f4f7f9;
  --card:#ffffff;
  --soft:#eaf3f8;
  --shadow:0 12px 30px rgba(0,48,87,.08);
}
*{box-sizing:border-box}
body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;background:var(--bg);color:var(--ink)}
button{font:inherit}
.skip-link{position:fixed;left:16px;top:12px;z-index:100;padding:10px 14px;border-radius:8px;background:var(--navy);color:#fff;transform:translateY(-160%)}
.skip-link:focus{transform:translateY(0)}
.app-shell{width:min(1180px,calc(100% - 28px));margin:14px auto 44px}
.site-nav{display:flex;align-items:center;justify-content:center;gap:8px;flex-wrap:wrap;margin-bottom:12px;padding:10px 14px;border:1px solid var(--line);border-radius:12px;background:var(--card);box-shadow:var(--shadow)}
.site-nav a{padding:7px 10px;border-radius:8px;color:var(--muted);font-size:.9rem;font-weight:800;text-decoration:none}
.site-nav a:hover,.site-nav a:focus-visible{color:var(--blue);background:var(--soft)}
.site-nav a[aria-current="page"]{color:#fff;background:var(--blue)}
.hero{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:15px 20px;border-radius:15px;background:linear-gradient(120deg,var(--navy),#0e567e);color:#fff;box-shadow:var(--shadow)}
.eyebrow{margin:0 0 3px;font-size:.76rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:#d8ebf6}
.hero h1{margin:0;font-size:clamp(1.55rem,3vw,2.2rem)}
.hero-copy{margin:5px 0 0;max-width:760px;color:#e9f4fa}
.hero-status{min-width:160px;padding:9px 12px;border:1px solid rgba(255,255,255,.28);border-radius:11px;background:rgba(255,255,255,.1);text-align:right}
.hero-status span,.hero-status strong{display:block}
.hero-status span{font-size:.78rem;color:#d9edf7}
.mission-nav{display:grid;grid-template-columns:repeat(3,1fr);gap:9px;margin:12px 0}
.mission-tab{display:flex;align-items:center;gap:8px;min-height:52px;padding:9px 12px;border:1px solid var(--line);border-radius:11px;background:#fff;color:var(--navy);font-weight:750;cursor:pointer;justify-content:center;text-align:center}
.mission-tab:hover,.mission-tab:focus-visible{border-color:var(--blue)}
.mission-tab.active{background:var(--blue);border-color:var(--blue);color:#fff}
.control:focus-visible,.dot:focus-visible,a:focus-visible{outline:3px solid var(--blue);outline-offset:3px}
.lesson-card{padding:17px;border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:var(--shadow)}
.lesson-heading-row{display:flex;align-items:center;justify-content:space-between;gap:14px;padding-bottom:11px;border-bottom:1px solid var(--line)}
.lesson-kicker,.step-label{margin:0 0 4px;font-size:.76rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase}
.lesson-kicker{color:var(--blue)}
.lesson-card h2{margin:0;color:var(--navy)}
.lesson-badge{padding:6px 10px;border-radius:999px;background:var(--soft);color:var(--navy);font-weight:750;font-size:.84rem}
.step-toolbar{display:flex;align-items:center;justify-content:space-between;gap:10px;margin:13px 0}
.step-toolbar.bottom{margin:15px 0 0}
.control{border:0;border-radius:9px;padding:9px 14px;font-weight:800;cursor:pointer}
.control:disabled{opacity:.38;cursor:not-allowed}
.control.primary{background:var(--blue);color:#fff}
.control.secondary{background:var(--soft);color:var(--navy)}
.control.ghost{background:#eef2f4;color:var(--muted)}
.step-dots{display:flex;justify-content:center;align-items:center;gap:6px;flex-wrap:wrap}
.dot{width:9px;height:9px;padding:0;border:0;border-radius:99px;background:#c6d2d9;cursor:pointer}
.dot.active{width:27px;background:var(--blue)}
.dot.done{background:var(--teal)}
.lesson-grid{display:grid;grid-template-columns:minmax(280px,.9fr) minmax(460px,1.55fr);gap:15px;min-height:530px}
.explanation-panel,.visual-panel{border:1px solid var(--line);border-radius:13px}
.explanation-panel{padding:19px;background:#fbfcfd}
.step-label{color:var(--teal)}
.explanation-panel h3{margin:3px 0 9px;color:var(--navy);font-size:clamp(1.2rem,2vw,1.65rem)}
.explanation-panel>p:not(.step-label){font-size:1.01rem;line-height:1.64}
.concept-box{margin-top:17px;padding:12px 13px;border-left:5px solid var(--gold);border-radius:8px;background:#fff6dd}
.concept-box p{margin:4px 0 0;line-height:1.48}
.visual-panel{display:flex;align-items:center;justify-content:center;overflow:hidden;padding:18px;background:radial-gradient(circle at top,#fff,#eef5f8)}
.scene{width:100%;max-width:780px;text-align:center}
.row,.cols,.stack,.path,.network-row{display:flex;align-items:center;justify-content:center;gap:14px;flex-wrap:wrap}
.panel-card,.node,.component,.bank,.ledger-card,.decision-card,.contract-card{min-width:130px;padding:14px;border:1px solid var(--line);border-radius:12px;background:#fff;box-shadow:0 8px 18px rgba(0,48,87,.07)}
.panel-card strong,.node strong,.component strong,.bank strong,.ledger-card strong,.decision-card strong,.contract-card strong{display:block;color:var(--navy)}
.panel-card p,.node p,.component p,.bank p,.ledger-card p,.decision-card p,.contract-card p{margin:5px 0 0;font-size:.86rem;color:var(--muted)}
.icon{display:block;font-size:2.35rem;margin-bottom:5px}
.arrow{font-size:1.8rem;color:var(--blue);font-weight:900}
.banner{margin-top:15px;padding:11px 13px;border-radius:9px;font-weight:750}
.info{background:#e8f3fb;color:#164f74}
.ok{background:#eaf7ef;color:var(--green)}
.bad{background:#fff0ee;color:var(--red)}
.network-wrap{position:relative;width:100%;max-width:740px;margin:0 auto;padding:10px 0 0}
.network-svg{width:100%;height:300px;overflow:visible}
.network-label{font-size:13px;font-weight:700;fill:#123a52}
.net-node{fill:#fff;stroke:#6b8596;stroke-width:3}
.net-node.central{fill:#e8f3fb;stroke:#2f76b4}
.net-node.server{fill:#eef6ef;stroke:#3c8b63}
.net-node.peer{fill:#fff9eb;stroke:#c68700}
.net-node.fail{fill:#ffe4e1;stroke:#b42318;stroke-dasharray:6 4}
.net-line{stroke:#8fb0c3;stroke-width:3;stroke-linecap:round}
.net-line.active{stroke:var(--blue);stroke-dasharray:7 7;animation:dash 1.25s linear infinite}
.net-line.fail{stroke:#b42318;stroke-dasharray:4 4}
.badge-mini{display:inline-flex;align-items:center;gap:7px;padding:7px 10px;border-radius:999px;background:#fff;font-weight:800;border:1px solid var(--line)}
.server-grid{display:grid;grid-template-columns:repeat(3,minmax(130px,1fr));gap:12px}
.server-grid .component.offline{border:2px solid var(--red);background:#fff0ee}
.flow-grid{display:grid;grid-template-columns:repeat(5,minmax(110px,1fr));gap:12px;align-items:center}
.flow-grid .arrow-col{font-size:1.8rem;color:var(--blue);font-weight:900}
.fee-strip{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin-top:10px}
.fee-pill{padding:8px 11px;border-radius:999px;background:#fff6dd;color:#795600;font-weight:800}
.shared-ledger{padding:16px;border:1px solid var(--line);border-radius:13px;background:#fff;box-shadow:0 8px 18px rgba(0,48,87,.07)}
.ledger-strip{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:10px}
.ledger-block{padding:10px 14px;border-radius:10px;background:#eef6ef;border:1px solid #a2d3b7;font-weight:800;color:#205f3f}
.decision-flow{display:grid;gap:10px;max-width:610px;margin:0 auto}
.decision-step{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:12px 14px;border:1px solid var(--line);border-radius:12px;background:#fff}
.decision-step .answer{padding:6px 10px;border-radius:999px;font-weight:800}
.answer.yes{background:#eaf7ef;color:#205f3f}
.answer.no{background:#fff0ee;color:#8e1e18}
.layer-stack{display:grid;gap:10px;max-width:520px;margin:0 auto}
.layer{padding:14px;border-radius:12px;color:#fff;font-weight:800;box-shadow:0 8px 18px rgba(0,48,87,.1)}
.layer.storage{background:linear-gradient(90deg,#3a86c6,#68aee3)}
.layer.communication{background:linear-gradient(90deg,#0f8a8a,#38b8b8)}
.layer.computation{background:linear-gradient(90deg,#845ec2,#a97fe0)}
.escrow-stage{display:grid;grid-template-columns:1fr auto 1fr;gap:14px;align-items:center}
.actor{padding:14px;border:1px solid var(--line);border-radius:12px;background:#fff;box-shadow:0 8px 18px rgba(0,48,87,.07)}
.actor strong{display:block;color:var(--navy)}
.actor p{margin:5px 0 0;font-size:.86rem;color:var(--muted)}
.contract-box{position:relative;padding:16px 14px 18px;border:3px solid #7d92a4;border-radius:16px;background:linear-gradient(180deg,#fefefe,#f3f7fa);box-shadow:0 12px 20px rgba(0,48,87,.08)}
.contract-box h4{margin:0 0 8px;color:var(--navy)}
.rule{padding:9px 10px;border-radius:10px;background:#fff;border:1px solid var(--line);margin-top:8px;text-align:left;font-size:.9rem}
.token{display:inline-flex;align-items:center;justify-content:center;width:58px;height:58px;border-radius:50%;font-size:1.8rem;background:#fff6dd;border:2px solid #e4c264;box-shadow:0 10px 18px rgba(198,135,0,.18)}
.package{display:inline-flex;align-items:center;justify-content:center;width:58px;height:58px;border-radius:14px;font-size:1.8rem;background:#e8f3fb;border:2px solid #84b8df}
.oracle{padding:10px 12px;border-radius:11px;background:#fff;border:1px dashed #6b8596;font-weight:800}
.arch{display:grid;grid-template-columns:1fr;gap:10px;max-width:430px;margin:0 auto}
.arch .component{padding:14px 16px}
.arch .link-arrow{font-size:1.7rem;color:var(--blue)}
.pop{animation:pop .55s ease}.slide{animation:slide .85s ease}.pulse{animation:pulse .85s ease}.shake{animation:shake .55s ease}.fade{animation:fade .75s ease}.float{animation:float 2.1s ease-in-out infinite}
@keyframes dash{to{stroke-dashoffset:-28}}
@keyframes pulse{50%{transform:scale(1.08)}}
@keyframes slide{from{transform:translateX(-70px);opacity:.2}to{transform:none;opacity:1}}
@keyframes pop{from{transform:scale(.75);opacity:.1}to{transform:scale(1);opacity:1}}
@keyframes shake{25%{transform:translateX(-7px)}50%{transform:translateX(7px)}75%{transform:translateX(-4px)}}
@keyframes fade{from{opacity:.1}to{opacity:1}}
@keyframes float{50%{transform:translateY(-7px)}}
.learning-summary{margin-top:16px;padding:17px;border:1px solid var(--line);border-radius:15px;background:#fff}
.learning-summary h2{margin:0 0 12px;color:var(--navy)}
.summary-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}
.summary-grid div{padding:12px;border-radius:10px;background:#f6f9fa}
.summary-grid span{font-size:1.65rem}
.summary-grid strong{display:block;color:var(--navy)}
.summary-grid p{margin:4px 0 0;font-size:.86rem;color:var(--muted)}
.resource-credit{margin-top:16px;padding:17px;border:1px solid var(--line);border-radius:15px;background:var(--card);box-shadow:var(--shadow);color:var(--muted);line-height:1.6}
.resource-credit p{margin:4px 0}.resource-credit a{color:var(--blue)}.resource-credit details{margin-top:8px}.resource-credit summary{color:var(--navy);cursor:pointer;font-weight:800}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}}
@media(max-width:980px){.mission-nav{grid-template-columns:1fr}.lesson-grid{grid-template-columns:1fr;min-height:0}.visual-panel{min-height:440px}.summary-grid{grid-template-columns:1fr 1fr}.flow-grid{grid-template-columns:1fr}.flow-grid .arrow-col{transform:rotate(90deg)}.escrow-stage{grid-template-columns:1fr;}.server-grid{grid-template-columns:1fr}.hero{align-items:flex-start}}
@media(max-width:560px){.app-shell{width:min(100% - 16px,1180px)}.hero{display:block}.hero-status{margin-top:10px;text-align:left}.lesson-heading-row{align-items:flex-start;flex-direction:column}.step-toolbar{flex-wrap:wrap}.step-dots{order:3;width:100%}.visual-panel{padding:12px}.summary-grid{grid-template-columns:1fr}.network-svg{height:260px}}