:root {
  --ink: #1b1f24;
  --muted: #545c69;
  --line: #d4dae2;
  --bg: #f6f8fb;
  --card: #ffffff;
  --soft: #eef2f6;
  --navy: #13294b;
  --blue: #1f4e79;
  --sky: #9dbddb;
  --green: #2e7d5b;
  --green-t: #e6f2ec;
  --amber: #a8701a;
  --amber-t: #fbf0dc;
  --red: #9a3b2f;
  --red-t: #f6e4e1;
  --radius: 12px;
  --serif: "Source Serif 4", Georgia, serif;
  --sans: "Source Sans 3", "Segoe UI", system-ui, sans-serif;
  --bar: 58px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--sans); font-size: 18px; line-height: 1.5; }
h1, h2, h3 { font-family: var(--serif); color: var(--navy); line-height: 1.15; margin: 0 0 .4em; }
h1 { font-size: clamp(2.4rem, 6vw, 4.2rem); }
h2 { font-size: clamp(1.8rem, 3.6vw, 2.6rem); }
h3 { font-size: 1.25rem; }
p { margin: 0 0 1em; }
a { color: var(--blue); }
button { font: inherit; cursor: pointer; }
:focus-visible { outline: 3px solid #e0a43a; outline-offset: 2px; border-radius: 6px; }
.skiplink { position: absolute; left: -999px; top: 8px; background: #fff; padding: 8px 12px; z-index: 100; }
.skiplink:focus { left: 8px; }

/* top bar */
.topbar { position: fixed; inset: 0 0 auto 0; height: var(--bar); display: flex; align-items: center; gap: 16px; padding: 0 20px; background: rgba(255,255,255,.94); border-bottom: 1px solid var(--line); z-index: 50; backdrop-filter: blur(6px); }
.brand { font-family: var(--serif); font-weight: 700; color: var(--navy); white-space: nowrap; }
.chapters { flex: 1; overflow-x: auto; scrollbar-width: none; }
.chapters::-webkit-scrollbar { display: none; }
.chapters ol { list-style: none; display: flex; gap: 4px; margin: 0; padding: 0; }
.chapters a { display: block; padding: 6px 10px; border-radius: 999px; color: var(--muted); text-decoration: none; font-size: .85rem; white-space: nowrap; }
.chapters a:hover { background: var(--soft); color: var(--ink); }
.chapters a[aria-current="true"] { background: var(--navy); color: #fff; }
.chapters li.grp { align-self: center; font-size: .68rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--blue); padding: 0 4px 0 12px; white-space: nowrap; border-left: 1px solid var(--line); margin-left: 6px; }
.ctrl { display: flex; align-items: center; gap: 8px; font-size: .9rem; color: var(--muted); white-space: nowrap; }
.iconbtn { width: 36px; height: 36px; border-radius: 50%; border: 1px solid var(--line); background: #fff; color: var(--navy); font-size: 1.1rem; }
.iconbtn:hover { background: var(--soft); }
.progress { position: absolute; left: 0; right: 0; bottom: -1px; height: 3px; background: transparent; }
.progress span { display: block; height: 100%; width: 0; background: var(--blue); transition: width .3s; }

/* slides */
main { scroll-snap-type: y proximity; }
.slide { min-height: 100vh; padding: calc(var(--bar) + 40px) 24px 56px; display: flex; align-items: center; scroll-snap-align: start; scroll-margin-top: 0; }
.slide.dark { background: var(--navy); color: #fff; }
.slide.dark h1 { color: #fff; }
.wrap { width: 100%; max-width: 1120px; margin: 0 auto; }
.kicker { text-transform: uppercase; letter-spacing: .12em; font-size: .8rem; font-weight: 700; color: var(--blue); margin-bottom: .6em; }
.dark .kicker { color: var(--sky); }
.slide.dark .wrap { position: relative; }
.hero-checks { list-style: none; margin: 0; padding: 0; position: absolute; right: 0; top: 50%; transform: translateY(-50%); width: 330px; display: flex; flex-direction: column; gap: 10px; }
.hero-checks li { display: flex; align-items: center; gap: 12px; background: rgba(255,255,255,.07); border: 1px solid rgba(157,189,219,.35); border-radius: 12px; padding: 12px 14px; color: #e6edf6; font-weight: 600; }
.hero-checks span { width: 30px; height: 30px; border-radius: 50%; background: #9dbddb; color: #13294b; display: grid; place-items: center; font-weight: 700; flex: none; }
.dark .lead, .dark h1, .dark .howto { max-width: 680px; }
.lead { font-size: clamp(1.15rem, 2vw, 1.45rem); max-width: 760px; color: #dfe7f1; }
.lead em { color: #fff; font-style: normal; border-bottom: 2px solid var(--sky); }
.sub { color: var(--muted); font-size: 1.05rem; max-width: 760px; }
.note { color: var(--muted); font-size: .95rem; margin-top: 1.4em; }
.note.small { font-size: .82rem; }
.mt { margin-top: 1.4em; }
.howto { display: flex; flex-wrap: wrap; gap: 10px 24px; margin: 28px 0; color: #c9d6e6; font-size: .95rem; }
kbd { display: inline-block; padding: 2px 8px; border: 1px solid #4b6488; border-radius: 6px; background: #1d3961; color: #fff; font-family: var(--sans); font-size: .85rem; }
.cta { background: var(--blue); color: #fff; border: 0; border-radius: 999px; padding: 14px 26px; font-weight: 700; font-size: 1rem; }
.dark .cta { background: #fff; color: var(--navy); }
.cta:hover { filter: brightness(1.08); }
.cta.small { padding: 11px 22px; }

/* toggles */
.toggle-row { display: inline-flex; gap: 4px; padding: 4px; background: var(--soft); border-radius: 999px; margin: 8px 0 22px; }
.toggle-row.wrapme { flex-wrap: wrap; border-radius: 18px; }
.seg { border: 0; background: transparent; padding: 9px 18px; border-radius: 999px; color: var(--muted); font-weight: 600; }
.seg.active { background: #fff; color: var(--navy); box-shadow: 0 1px 3px rgba(0,0,0,.12); }

/* model visual */
.scene { margin: 0; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 10px 14px 12px; }
.scene svg { display: block; width: 100%; height: auto; max-height: 52vh; }
.scene-legend { display: flex; flex-wrap: wrap; gap: 8px 22px; align-items: center; font-size: .9rem; color: var(--muted); padding: 4px 6px 0; }
.lg { display: inline-block; width: 12px; height: 12px; border-radius: 50%; margin-right: 6px; vertical-align: -1px; }
.lg.ok { background: var(--blue); } .lg.bad { background: var(--red); }
.scene-legend .score { margin-left: auto; font-weight: 700; color: var(--navy); }
.model-text { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 14px; }
.model-text .pt { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; font-size: .95rem; }
.model-text .pt b { display: block; color: var(--navy); margin-bottom: 2px; }
.model-text .pt.key { background: var(--navy); color: #e6edf6; border-color: var(--navy); }
.model-text .pt.key b { color: #fff; }
#modelSvg .fade { transition: opacity .5s; }
@media (max-width: 900px) { .model-text { grid-template-columns: 1fr; } }
.model-visual { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; display: flex; flex-direction: column; gap: 12px; }
.mrow { display: grid; grid-template-columns: 1.1fr 1.2fr 1fr; gap: 10px; align-items: center; }
.mrow .who { background: var(--soft); border-radius: 8px; padding: 10px 12px; font-weight: 600; font-size: .95rem; }
.mrow .who.bad { background: var(--red-t); color: var(--red); }
.mrow .bar { border-radius: 8px; padding: 10px 12px; font-size: .88rem; text-align: center; position: relative; }
.mrow .bar.wall { background: #ece4d8; color: #6b5a40; }
.mrow .bar.gate { background: #e3ecf5; color: var(--blue); font-weight: 600; }
.mrow .out { border-radius: 8px; padding: 10px 12px; font-weight: 700; font-size: .92rem; }
.mrow .out.ok { background: var(--green-t); color: var(--green); }
.mrow .out.no { background: var(--red-t); color: var(--red); }
.mrow .out.warn { background: var(--amber-t); color: var(--amber); }
.mhead { display: grid; grid-template-columns: 1.1fr 1.2fr 1fr; gap: 10px; font-size: .72rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.model-text h3 { margin-bottom: .3em; }
.model-text ul { padding-left: 1.1em; margin: 0; }
.model-text li { margin-bottom: .4em; }

/* problem cards */
.cards6 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.pcard { position: relative; min-height: 232px; perspective: 1000px; border: 0; padding: 0; background: none; text-align: left; }
.pcard .inner { position: absolute; inset: 0; transition: transform .5s; transform-style: preserve-3d; }
.pcard.flipped .inner { transform: rotateY(180deg); }
.pcard .face { position: absolute; inset: 0; backface-visibility: hidden; border-radius: var(--radius); padding: 18px 20px; display: flex; flex-direction: column; }
.pcard .front { background: #fff; border: 1px solid var(--line); }
.pcard .back { background: var(--navy); color: #e6edf6; transform: rotateY(180deg); font-size: .9rem; line-height: 1.42; gap: 8px; }
.pcard .back b { color: #fff; }
.pcard .pn { font-size: .78rem; font-weight: 700; letter-spacing: .1em; color: var(--red); }
.pcard .pt { font-family: var(--serif); font-size: 1.35rem; color: var(--navy); font-weight: 700; margin: 4px 0 8px; }
.pcard .pd { color: var(--muted); font-size: .95rem; }
.pcard .hint { margin-top: auto; font-size: .8rem; color: var(--blue); font-weight: 600; }
.pcard .back .hint { color: var(--sky); }

/* layers */
.layers { display: grid; grid-template-columns: 1fr 1.25fr; gap: 28px; align-items: start; }
.layer-stack { display: flex; flex-direction: column; gap: 8px; }
.layer-btn { display: flex; align-items: center; gap: 14px; text-align: left; border: 1px solid var(--line); background: #fff; border-radius: 10px; padding: 12px 16px; color: var(--ink); }
.layer-btn .ln { width: 30px; height: 30px; border-radius: 50%; background: var(--soft); display: grid; place-items: center; font-weight: 700; color: var(--navy); flex: none; }
.layer-btn .lt { font-weight: 600; }
.layer-btn .ls { font-size: .85rem; color: var(--muted); display: block; font-weight: 400; }
.layer-btn[aria-selected="true"] { background: var(--navy); color: #fff; border-color: var(--navy); }
.layer-btn[aria-selected="true"] .ln { background: var(--sky); }
.layer-btn[aria-selected="true"] .ls { color: var(--sky); }
.layer-info { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 24px 26px; }
.layer-info h3 { margin-bottom: .6em; }
.layer-info .ctrls { list-style: none; padding: 0; margin: 0 0 18px; }
.layer-info .ctrls li { display: grid; grid-template-columns: 1fr 1.2fr; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--soft); font-size: .95rem; }
.layer-info .ctrls b { color: var(--navy); }
.case { background: var(--red-t); border-radius: 10px; padding: 14px 16px; font-size: .95rem; }
.case .ct { font-weight: 700; color: var(--red); display: block; margin-bottom: 4px; }
.case .lesson { display: block; margin-top: 6px; font-weight: 600; }

/* stats */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.stat { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.stat .num { font-family: var(--serif); font-size: clamp(2.4rem, 5vw, 3.4rem); font-weight: 700; color: var(--blue); line-height: 1; margin-bottom: 10px; }
.stat .lbl { color: var(--muted); font-size: .95rem; }
.rules { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.rule { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.rule summary { cursor: pointer; font-weight: 700; color: var(--navy); font-size: 1.1rem; list-style: none; display: flex; flex-direction: column; gap: 4px; }
.rule summary::-webkit-details-marker { display: none; }
.rule summary::after { content: "Read what it requires"; font-size: .8rem; color: var(--blue); font-weight: 600; }
.rule[open] summary::after { content: "Close"; }
.rule p { margin: 10px 0 0; font-size: .95rem; }
.tag { font-size: .72rem; font-weight: 700; letter-spacing: .08em; color: var(--muted); text-transform: uppercase; }

/* simulator */
.sim { display: grid; grid-template-columns: 1fr 1.35fr; gap: 28px; }
fieldset { border: 0; padding: 0; margin: 0 0 16px; }
legend { font-weight: 700; color: var(--navy); margin-bottom: 8px; }
.scenarios { display: flex; flex-direction: column; gap: 8px; }
.scen { display: flex; gap: 10px; align-items: flex-start; background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 11px 14px; cursor: pointer; font-size: .95rem; }
.scen input { margin-top: 5px; accent-color: var(--blue); }
.scen:has(input:checked) { border-color: var(--blue); box-shadow: 0 0 0 2px rgba(31,78,121,.15); }
.switch-row { display: flex; align-items: center; gap: 12px; margin: 14px 0 18px; font-weight: 600; }
.switch { width: 54px; height: 30px; border-radius: 999px; border: 0; background: #b9c1cc; position: relative; padding: 0; }
.switch span { position: absolute; top: 3px; left: 3px; width: 24px; height: 24px; border-radius: 50%; background: #fff; transition: left .2s; }
.switch.on { background: var(--green); }
.switch.on span { left: 27px; }
.gates { list-style: none; padding: 0; margin: 0 0 14px; display: flex; flex-direction: column; gap: 8px; }
.gate { display: grid; grid-template-columns: 34px 150px 1fr; gap: 12px; align-items: center; background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; transition: background .3s, border-color .3s; }
.gate .gn { width: 30px; height: 30px; border-radius: 50%; background: var(--soft); display: grid; place-items: center; font-weight: 700; color: var(--navy); }
.gate .gt { font-weight: 700; color: var(--navy); }
.gate .gr { font-size: .9rem; color: var(--muted); }
.gate.pass { background: var(--green-t); border-color: #a9d1bd; }
.gate.pass .gn { background: var(--green); color: #fff; }
.gate.fail { background: var(--red-t); border-color: #e2b4ad; }
.gate.fail .gn { background: var(--red); color: #fff; }
.gate.never { opacity: .45; }
.verdict { border-radius: 10px; padding: 14px 16px; background: var(--soft); font-weight: 600; }
.verdict.good { background: var(--green-t); color: #1f5a40; }
.verdict.bad { background: var(--red-t); color: var(--red); }

/* architecture */
.arch { display: grid; grid-template-columns: 1.55fr 1fr; gap: 24px; align-items: start; }
.arch-diagram { display: flex; flex-direction: column; gap: 12px; }
.arch-cols { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; }
.arch-col { display: flex; flex-direction: column; gap: 8px; }
.arch-col.mid { justify-content: stretch; }
.colhead { font-size: .75rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.ab { border: 1px solid var(--line); background: #fff; border-radius: 10px; padding: 12px 14px; text-align: left; color: var(--ink); font-weight: 600; font-size: .95rem; }
.ab:hover { border-color: var(--blue); }
.ab.active { outline: 3px solid var(--blue); outline-offset: 1px; }
.ab.guard { background: #e3ecf5; border-color: #b5c9de; }
.ab.idp { background: var(--navy); color: #fff; flex: 1; font-size: 1.1rem; }
.ab.idp small { font-weight: 400; color: var(--sky); font-size: .85rem; }
.ab.zone { background: var(--green-t); border-color: #a9d1bd; }
.ab.plat { background: var(--soft); }
.ab.cust { border-style: dashed; border-color: var(--red); }
.ab.res { background: var(--soft); }
.arch-info { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; min-height: 260px; }
.arch-info .why { margin-top: 10px; padding-top: 10px; border-top: 1px solid var(--soft); color: var(--muted); font-size: .95rem; }

/* decisions */
.decisions { display: flex; flex-direction: column; gap: 8px; }
.dec { background: #fff; border: 1px solid var(--line); border-radius: 10px; }
.dec summary { list-style: none; cursor: pointer; display: grid; grid-template-columns: 48px 1fr auto; gap: 14px; align-items: center; padding: 12px 16px; }
.dec summary::-webkit-details-marker { display: none; }
.dec .dn { background: var(--blue); color: #fff; font-weight: 700; border-radius: 8px; text-align: center; padding: 4px 0; font-size: .9rem; }
.dec .dt { font-weight: 700; color: var(--navy); }
.dec .dp { font-size: .8rem; color: var(--muted); font-weight: 600; }
.dec .body { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; padding: 0 16px 16px 78px; }
.dec .ch, .dec .rj { border-radius: 8px; padding: 12px 14px; font-size: .95rem; }
.dec .ch { background: var(--green-t); }
.dec .rj { background: var(--red-t); }
.dec .ch b { color: var(--green); } .dec .rj b { color: var(--red); }

/* resilience lab */
.lab { display: grid; grid-template-columns: 1fr 1fr; gap: 20px 28px; }
.chain { grid-column: 1 / -1; display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.link { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; text-align: center; transition: opacity .3s, background .3s; }
.link b { display: block; color: var(--navy); }
.link span { font-size: .85rem; color: var(--muted); }
.link.off { opacity: .35; text-decoration: line-through; }
.link.dbl { background: var(--green-t); border-color: #a9d1bd; }
.times { color: var(--muted); font-weight: 700; }
.lab-controls { display: flex; flex-direction: column; gap: 10px; }
.chk { display: flex; gap: 10px; align-items: flex-start; background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; cursor: pointer; }
.chk input { margin-top: 6px; width: 18px; height: 18px; accent-color: var(--green); }
.chk small { display: block; color: var(--muted); }
.lab-out { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-content: start; }
.lab-out > div { background: var(--navy); color: #fff; border-radius: var(--radius); padding: 20px; }
.lab-out .big { font-family: var(--serif); font-size: clamp(2rem, 4vw, 2.8rem); font-weight: 700; }
.lab-out .lbl { color: var(--sky); font-size: .9rem; }
.lab .note { grid-column: 1 / -1; margin-top: 0; }

/* adapt */
.lenses { display: flex; flex-direction: column; gap: 10px; }
.lens { display: grid; grid-template-columns: 170px 1fr 1.25fr; gap: 10px; align-items: stretch; }
.lens .lk { background: var(--navy); color: #fff; border-radius: 10px; padding: 12px 14px; font-weight: 700; display: flex; align-items: center; }
.lens .lf { background: var(--soft); border-radius: 10px; padding: 12px 14px; font-size: .95rem; }
.lens .la { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; font-size: .95rem; }
.pill { display: inline-block; font-size: .72rem; font-weight: 700; letter-spacing: .08em; padding: 2px 10px; border-radius: 999px; margin-bottom: 4px; }
.pill.STRENGTHEN { background: var(--green-t); color: var(--green); }
.pill.TRANSLATE { background: var(--amber-t); color: var(--amber); }
.pill.ADD { background: var(--red-t); color: var(--red); }
.firm-note { color: var(--muted); font-size: .9rem; margin-top: 12px; }

/* incident */
.timeline { list-style: none; padding: 0; margin: 22px 0; display: grid; grid-template-columns: repeat(6, 1fr); gap: 10px; position: relative; }
.timeline li { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 14px; opacity: .35; transform: translateY(6px); transition: all .4s; }
.timeline li.on { opacity: 1; transform: none; border-color: var(--blue); }
.timeline li.on.urgent { border-color: var(--red); background: var(--red-t); }
.timeline .tt { font-weight: 700; color: var(--navy); display: block; }
.timeline .tw { font-family: var(--serif); font-size: 1.3rem; color: var(--blue); font-weight: 700; display: block; margin: 2px 0 4px; }
.timeline .urgent .tw { color: var(--red); }
.timeline .td { font-size: .85rem; color: var(--muted); }
.metrics { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.metrics div { background: var(--green-t); border-radius: 10px; padding: 14px 16px; }
.metrics b { font-family: var(--serif); font-size: 1.8rem; color: var(--green); display: block; }
.metrics span { font-size: .9rem; }

/* trade-offs */
.tradeoffs { display: flex; flex-direction: column; gap: 8px; }
.to { display: grid; grid-template-columns: 1fr 34px 1.1fr; gap: 10px; align-items: center; }
.to .tp { background: var(--soft); border-radius: 10px; padding: 12px 16px; }
.to .tp b { color: var(--navy); display: block; }
.to .tp span { font-size: .9rem; color: var(--muted); }
.to .arrow { text-align: center; color: var(--muted); font-size: 1.3rem; }
.to .tm { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 12px 16px; font-size: .95rem; }
.residual { margin-top: 18px; background: var(--navy); color: #e6edf6; border-radius: var(--radius); padding: 16px 20px; }
.residual strong { color: var(--sky); }

/* quiz */
.quiz { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.q { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.q p { font-weight: 700; color: var(--navy); margin-bottom: 10px; }
.q .opts { display: flex; flex-direction: column; gap: 6px; }
.q button { text-align: left; border: 1px solid var(--line); background: var(--bg); border-radius: 8px; padding: 8px 12px; font-size: .92rem; color: var(--ink); }
.q button:hover:not(:disabled) { border-color: var(--blue); }
.q button.right { background: var(--green-t); border-color: var(--green); }
.q button.wrong { background: var(--red-t); border-color: var(--red); }
.q button:disabled { cursor: default; }
.q .fb { font-size: .88rem; color: var(--muted); margin-top: 8px; }
.quiz-score { margin-top: 14px; font-weight: 700; color: var(--navy); }

.sources { columns: 2; column-gap: 32px; padding-left: 1.1em; font-size: .95rem; }
.sources li { margin-bottom: 8px; break-inside: avoid; }

@media (max-width: 900px) {
  .hero-checks { position: static; transform: none; width: auto; margin-top: 28px; }
  body { font-size: 17px; }
  .brand { display: none; }
  .slide { min-height: auto; padding-top: calc(var(--bar) + 28px); }
  main { scroll-snap-type: none; }
  .model-grid, .sim, .arch, .layers, .lab, .quiz { grid-template-columns: 1fr; }
  .cards6, .stats, .rules { grid-template-columns: 1fr 1fr; }
  .timeline { grid-template-columns: 1fr 1fr 1fr; }
  .metrics { grid-template-columns: 1fr 1fr; }
  .lens { grid-template-columns: 1fr; }
  .dec .body { grid-template-columns: 1fr; padding-left: 16px; }
  .sources { columns: 1; }
}
@media (max-width: 560px) {
  .cards6, .stats, .rules, .arch-cols { grid-template-columns: 1fr; }
  .timeline { grid-template-columns: 1fr 1fr; }
  .gate { grid-template-columns: 30px 1fr; }
  .gate .gr { grid-column: 2; }
  .to { grid-template-columns: 1fr; }
  .to .arrow { display: none; }
  .ctrl #counter { display: none; }
  .lab-out { grid-template-columns: 1fr; }
}

/* intro levels */
.levels { list-style: none; padding: 0; margin: 26px 0 8px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; counter-reset: lv; max-width: 900px; }
.levels li { counter-increment: lv; background: rgba(255,255,255,.07); border: 1px solid rgba(157,189,219,.35); border-radius: 12px; padding: 14px 16px; display: flex; flex-direction: column; gap: 4px; }
.levels li::before { content: counter(lv); width: 26px; height: 26px; border-radius: 50%; background: var(--sky); color: var(--navy); display: grid; place-items: center; font-weight: 700; font-size: .85rem; margin-bottom: 4px; }
.levels b { color: #fff; } .levels span { color: #c9d6e6; font-size: .9rem; }

.two { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; align-items: start; }
.muted { color: var(--muted); }

/* shared responsibility stack */
.stack { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 6px; }
.stack li { display: flex; justify-content: space-between; align-items: center; padding: 13px 16px; border-radius: 10px; font-weight: 600; transition: background .35s, color .35s; }
.stack li.cust { background: var(--navy); color: #fff; }
.stack li.prov { background: var(--soft); color: var(--muted); }
.stack li em { font-style: normal; font-size: .8rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.stack li.always { box-shadow: 0 0 0 3px var(--sky) inset; }
.explain { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 22px; }
.explain .rule-line { margin-top: 12px; padding: 12px 14px; background: var(--soft); border-radius: 8px; font-weight: 600; color: var(--navy); }

/* authn / authz */
.defs { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 18px; }
.def { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; }
.def b { display: block; color: var(--navy); font-size: 1.1rem; }
.def span { color: var(--muted); }
.sorter { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.sort-item { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; display: flex; flex-direction: column; gap: 8px; }
.sort-item .lbl { font-weight: 700; color: var(--ink); }
.sort-item .btns { display: flex; gap: 6px; }
.sort-item button { flex: 1; border: 1px solid var(--line); background: var(--bg); border-radius: 8px; padding: 6px 8px; font-size: .85rem; color: var(--ink); }
.sort-item.right { border-color: var(--green); background: var(--green-t); }
.sort-item.wrong { border-color: var(--red); background: var(--red-t); }
.sort-item .why { font-size: .85rem; color: var(--muted); }
.result-line { margin-top: 12px; font-weight: 700; color: var(--navy); }

/* MFA factors */
.factors { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-bottom: 16px; }
.fcat { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; }
.fcat h3 { font-size: 1.05rem; margin-bottom: 10px; }
.fcat .chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { border: 1px solid var(--line); background: var(--bg); border-radius: 999px; padding: 7px 14px; font-weight: 600; color: var(--ink); font-size: .92rem; }
.chip[aria-pressed="true"] { background: var(--blue); color: #fff; border-color: var(--blue); }

/* least privilege tiles */
.tiles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-bottom: 14px; }
.tile { border-radius: 10px; padding: 14px 16px; border: 1px solid var(--line); background: #fff; transition: all .35s; }
.tile b { display: block; } .tile span { font-size: .85rem; color: var(--muted); }
.tile.on { background: var(--green-t); border-color: #a9d1bd; }
.tile.on.risk { background: var(--red-t); border-color: #e2b4ad; }
.tile.off { opacity: .45; background: var(--soft); }
.tile .st { font-size: .75rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; margin-top: 6px; display: block; }
.tile.on .st { color: var(--green); } .tile.on.risk .st { color: var(--red); } .tile.off .st { color: var(--muted); }

/* data states */
.state-card { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 18px; }
.state-card > div { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; }
.state-card b { display: block; color: var(--navy); margin-bottom: 4px; }
.mini-case { background: var(--navy); color: #e6edf6; border-radius: var(--radius); padding: 18px 20px; }
.mini-case b { color: #fff; }
.mini-case .ans { display: flex; gap: 10px; }
.mini-case .ans button { border: 1px solid #4b6488; background: #1d3961; color: #fff; border-radius: 999px; padding: 8px 22px; font-weight: 700; }
.mini-case .ans button.right { background: var(--green); border-color: var(--green); }
.mini-case .ans button.wrong { background: var(--red); border-color: var(--red); }
.mini-case .fb { margin: 10px 0 0; color: #dfe7f1; }

/* policy */
.form { display: flex; flex-direction: column; gap: 10px; align-items: stretch; }
.form .cta { align-self: flex-start; margin-top: 6px; }
.policy-out { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; min-height: 240px; }
.policy-out .res { font-family: var(--serif); font-size: 1.6rem; font-weight: 700; margin-bottom: 10px; }
.policy-out .res.ok { color: var(--green); } .policy-out .res.no { color: var(--red); }
.policy-out ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 6px; }
.policy-out li { padding: 8px 12px; border-radius: 8px; font-size: .95rem; }
.policy-out li.ok { background: var(--green-t); } .policy-out li.no { background: var(--red-t); color: var(--red); font-weight: 600; }

/* replication vs backup */
.rb { margin-top: 22px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.rb-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 10px; margin-bottom: 12px; }
.rb-head h3 { margin: 0; }
.rb-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.rb-box { border-radius: 10px; padding: 12px 14px; background: var(--green-t); border: 1px solid #a9d1bd; transition: all .4s; }
.rb-box b { display: block; color: var(--navy); } .rb-box span { font-size: .88rem; color: var(--muted); }
.rb-box.hit { background: var(--red-t); border-color: var(--red); }
.rb-box.hit b { color: var(--red); }
.rb-box.safe { box-shadow: 0 0 0 3px var(--green) inset; }
.rb .fb { margin: 12px 0 0; font-weight: 600; color: var(--navy); }
.lens.clickable { cursor: default; }

@media (max-width: 900px) {
  .levels, .two, .defs, .state-card, .rb-grid { grid-template-columns: 1fr 1fr; }
  .two { grid-template-columns: 1fr; }
  .sorter, .factors, .tiles { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 560px) {
  .levels, .defs, .state-card, .rb-grid, .sorter, .factors, .tiles { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}

/* site sections switch */
.modes { display: inline-flex; gap: 2px; padding: 3px; background: var(--soft); border-radius: 999px; flex: none; }
.modes a { padding: 5px 14px; border-radius: 999px; text-decoration: none; color: var(--muted); font-weight: 600; font-size: .88rem; }
.modes a[aria-current="page"] { background: var(--navy); color: #fff; }
.small-lead { font-size: 1rem !important; margin-top: 18px; }
.small-lead a { color: #fff; }
@media (max-width: 560px) { .brand { display: none; } }