:root {
  /* Design compliance tokens: IBM Plex Mono** probability values */
  --brown: #24150F;
  --amber: #D9822B;
  --cream: #F6E6B8;
  --coral: #F25F4C;
  --gold: #FFC857;
  --teal: #36C9A3;
  --plum: #5A2E49;
  --violet: #16142A;
  --pixel: 8px;
  --display: "Fraunces", Georgia, serif;
  --prose: "Libre Baskerville", Georgia, serif;
  --mono: "IBM Plex Mono", "Courier New", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--cream);
  background: var(--brown);
  font-family: var(--prose);
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -3;
  background:
    radial-gradient(circle at 20% 10%, rgba(255, 200, 87, .16), transparent 26%),
    radial-gradient(circle at 80% 35%, rgba(54, 201, 163, .10), transparent 25%),
    linear-gradient(135deg, var(--violet), var(--brown) 54%, #150c09);
}

.crt-overlay {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 30;
  background:
    repeating-linear-gradient(0deg, rgba(246, 230, 184, .045) 0 1px, transparent 1px 4px),
    repeating-linear-gradient(90deg, transparent 0 15px, rgba(217, 130, 43, .035) 15px 16px);
  mix-blend-mode: screen;
}

.boot-sequence {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: grid;
  place-items: center;
  background: var(--violet);
  animation: bootFade 3.2s steps(1, end) forwards;
}

.boot-card {
  width: min(680px, calc(100vw - 40px));
  padding: 32px;
  text-align: center;
  background: var(--brown);
  border: 4px solid var(--cream);
  box-shadow: 8px 8px 0 var(--coral), -8px -8px 0 var(--teal);
  animation: bootJitter .32s steps(2, end) infinite;
}

.boot-card strong {
  display: block;
  margin: 18px 0;
  font-family: var(--display);
  font-size: clamp(2.8rem, 8vw, 6.8rem);
  line-height: .9;
  color: var(--gold);
  text-shadow: 4px 0 0 var(--plum), 0 4px 0 var(--coral);
}

.boot-line, .boot-lock, .kicker, .hud-strip, .rail-readout, .field-note, .professor p, .tag, button {
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: .08em;
}

.hud-rail {
  position: fixed;
  left: 16px;
  top: 16px;
  bottom: 16px;
  z-index: 20;
  width: 82px;
  display: grid;
  grid-template-rows: 76px 1fr 160px 1fr 60px;
  gap: 12px;
  padding: 10px;
  background: rgba(22, 20, 42, .82);
  border: 2px solid var(--amber);
  box-shadow: 6px 6px 0 rgba(36, 21, 15, .8), inset 0 0 0 4px rgba(90, 46, 73, .5);
}

.rail-seal {
  display: grid;
  place-items: center;
  color: var(--brown);
  background: var(--gold);
  border: 2px solid var(--cream);
  font-family: var(--display);
  font-size: 2rem;
  box-shadow: 4px 4px 0 var(--coral);
}

.rail-readout {
  writing-mode: vertical-rl;
  display: flex;
  align-items: center;
  justify-content: space-around;
  color: var(--teal);
  font-size: .7rem;
}

.rail-readout strong { color: var(--gold); font-size: 1rem; }

.rail-meter { display: grid; gap: 8px; align-content: center; }
.rail-meter i { display: block; height: 18px; background: var(--plum); border: 1px solid var(--amber); animation: meterPulse 1.4s steps(3, end) infinite; }
.rail-meter i:nth-child(even) { animation-delay: .4s; }
.rail-beacon { background: var(--coral); border: 2px solid var(--gold); animation: beacon 1s steps(2, end) infinite; }

main { width: 100%; }

.level {
  position: relative;
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(104px, 12vw) 1fr minmax(340px, 44vw);
  grid-template-rows: 1fr auto 1fr;
  gap: 24px;
  padding: 48px 48px 48px max(130px, 12vw);
  overflow: hidden;
  border-bottom: 8px solid var(--brown);
  isolation: isolate;
}

.level::before, .level::after {
  content: "";
  position: absolute;
  z-index: -2;
}

.level::before {
  inset: 24px;
  background: rgba(22, 20, 42, .66);
  border: 2px solid var(--amber);
  box-shadow: inset 0 0 0 8px rgba(36, 21, 15, .58), 12px 12px 0 rgba(0,0,0,.22);
  clip-path: polygon(0 0, calc(100% - 32px) 0, 100% 32px, 100% 100%, 32px 100%, 0 calc(100% - 32px));
}

.level::after {
  width: 220px;
  height: 220px;
  right: 8%;
  top: 12%;
  background: repeating-linear-gradient(45deg, rgba(255, 200, 87, .16) 0 8px, transparent 8px 16px);
  opacity: .5;
}

.chamber-grid {
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(rgba(217, 130, 43, .16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(217, 130, 43, .16) 1px, transparent 1px);
  background-size: 32px 32px;
  mask-image: radial-gradient(circle at 55% 50%, black, transparent 75%);
}

.lesson-card {
  grid-column: 2 / 3;
  grid-row: 2 / 3;
  align-self: center;
  max-width: 690px;
  padding: 30px;
  background: var(--cream);
  color: var(--brown);
  border: 3px solid var(--brown);
  box-shadow: 8px 8px 0 var(--plum), 14px 14px 0 rgba(242, 95, 76, .58);
}

.title-card { transform: translateY(-10px); }

.kicker {
  display: inline-block;
  margin-bottom: 14px;
  padding: 6px 8px;
  color: var(--brown);
  background: var(--gold);
  border: 2px solid var(--brown);
  font-size: .72rem;
}

h1, h2 {
  margin: 0;
  font-family: var(--display);
  font-weight: 900;
  line-height: .9;
  color: var(--violet);
  text-shadow: 3px 3px 0 rgba(217, 130, 43, .55);
}

h1 { font-size: clamp(4rem, 12vw, 10rem); letter-spacing: -.06em; }
h2 { font-size: clamp(2.6rem, 6vw, 6rem); }

p { font-size: clamp(1rem, 1.28vw, 1.2rem); line-height: 1.75; }

.artifact {
  grid-column: 3 / 4;
  grid-row: 1 / 4;
  align-self: center;
  justify-self: center;
  position: relative;
  width: min(520px, 100%);
  height: min(520px, 70vh);
}

.hud-strip {
  position: absolute;
  left: max(130px, 12vw);
  right: 48px;
  bottom: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  padding: 10px;
  color: var(--teal);
  background: rgba(36, 21, 15, .86);
  border: 2px solid var(--amber);
  box-shadow: 4px 4px 0 var(--plum);
  font-size: .78rem;
}

.hud-strip b, .hud-strip span { padding: 6px 8px; border: 1px solid rgba(54, 201, 163, .6); background: rgba(22, 20, 42, .72); }
.hud-strip b { color: var(--gold); }

.field-note, .professor {
  position: absolute;
  max-width: 360px;
  padding: 16px;
  right: 7vw;
  bottom: 104px;
  color: var(--cream);
  background: var(--plum);
  border: 2px solid var(--gold);
  box-shadow: 6px 6px 0 var(--brown);
  font-size: .8rem;
}

.plum { background: var(--violet); }

.dice-orbit .die {
  position: absolute;
  width: 128px;
  height: 128px;
  left: 28%;
  top: 28%;
  background: var(--gold);
  border: 4px solid var(--brown);
  box-shadow: 16px 16px 0 var(--plum), inset -12px -12px 0 var(--amber);
  transform: rotate(45deg) skew(-8deg, -8deg);
  animation: floatTile 2.8s steps(5, end) infinite;
}

.die-b { left: 54% !important; top: 46% !important; background: var(--teal) !important; animation-delay: .6s !important; }
.die span { position: absolute; width: 18px; height: 18px; background: var(--violet); box-shadow: 0 0 0 4px var(--cream); }
.die span:nth-child(1) { left: 22px; top: 22px; }
.die span:nth-child(2) { right: 22px; top: 22px; }
.die span:nth-child(3) { left: 55px; top: 55px; background: var(--coral); animation: beacon .8s steps(2,end) infinite; }
.die span:nth-child(4) { left: 22px; bottom: 22px; }
.die span:nth-child(5) { right: 22px; bottom: 22px; }
.pip-star { position: absolute; width: 14px; height: 14px; background: var(--gold); box-shadow: 0 0 20px var(--gold); animation: twinkle 1.2s steps(2,end) infinite; }
.s1 { left: 12%; top: 18%; } .s2 { right: 18%; top: 22%; animation-delay: .3s; } .s3 { left: 24%; bottom: 14%; animation-delay: .7s; }

.coin-platforms { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 24px; }
.iso-platform { position: relative; height: 220px; background: var(--plum); border: 3px solid var(--amber); box-shadow: 12px 12px 0 var(--brown); transform: skewY(-10deg); }
.iso-platform small { position: absolute; left: 16px; bottom: 12px; font: 700 1rem var(--mono); color: var(--teal); }
.coin { position: absolute; left: 50%; top: 42%; width: 108px; height: 108px; margin: -54px; display: grid; place-items: center; border-radius: 0; background: var(--gold); color: var(--brown); border: 5px solid var(--cream); box-shadow: 8px 8px 0 var(--coral); font: 900 3rem var(--display); transform: skewY(10deg); animation: coinFlip 1.6s steps(4,end) infinite; }
.coin-b { background: var(--teal); animation-delay: .8s; }
.trail { position: absolute; width: 28px; height: 12px; background: var(--coral); animation: trailDrift 1.4s steps(3,end) infinite; }
.t1 { left: 20%; top: 25%; } .t2 { left: 48%; top: 18%; animation-delay: .3s; } .t3 { left: 70%; top: 68%; animation-delay: .6s; }
.professor { left: max(130px, 12vw); right: auto; display: flex; gap: 12px; align-items: center; }
.professor span { width: 44px; height: 56px; background: var(--teal); border: 3px solid var(--brown); box-shadow: inset 12px 0 0 var(--gold), 5px 5px 0 var(--coral); }
.professor p { margin: 0; font-size: .72rem; line-height: 1.45; }

.branch-map .stair { position: absolute; width: 96px; height: 48px; background: var(--amber); border: 3px solid var(--brown); box-shadow: 10px 10px 0 var(--plum); transform: skewY(-18deg); }
.root { left: 40%; top: 58%; } .a { left: 22%; top: 42%; } .b { left: 58%; top: 39%; } .c { left: 10%; top: 24%; } .d { left: 72%; top: 20%; }
.walker { position: absolute; width: 24px; height: 32px; background: var(--coral); left: 45%; top: 54%; box-shadow: 0 -12px 0 var(--gold), 6px 6px 0 var(--brown); animation: walkPath 4s steps(5,end) infinite; }
.tag { position: absolute; color: var(--brown); background: var(--cream); border: 2px solid var(--teal); padding: 5px; font-size: .8rem; }
.tag-a { left: 27%; top: 36%; } .tag-b { left: 60%; top: 33%; } .tag-c { left: 74%; top: 14%; }

.bayes-console { display: grid; grid-template-columns: 1.1fr .9fr; gap: 24px; align-items: center; }
.scope { position: relative; height: 320px; background: var(--violet); border: 4px solid var(--teal); box-shadow: 10px 10px 0 var(--plum), inset 0 0 0 12px var(--brown); overflow: hidden; }
.scope::before { content: ""; position: absolute; inset: 32px; border: 2px solid var(--amber); border-radius: 50%; box-shadow: 0 0 0 20px rgba(54, 201, 163, .08); }
.cross::before, .cross::after { content: ""; position: absolute; background: var(--teal); opacity: .7; }
.cross::before { left: 50%; top: 20px; bottom: 20px; width: 2px; } .cross::after { top: 50%; left: 20px; right: 20px; height: 2px; }
.stars { position: absolute; inset: 20px; background: radial-gradient(circle at 20% 24%, var(--gold) 0 3px, transparent 4px), radial-gradient(circle at 62% 45%, var(--coral) 0 4px, transparent 5px), radial-gradient(circle at 74% 26%, var(--cream) 0 3px, transparent 4px), radial-gradient(circle at 40% 70%, var(--teal) 0 4px, transparent 5px); animation: signalFocus 2s steps(4,end) infinite; }
.bands { display: grid; gap: 10px; font: 700 .75rem var(--mono); text-transform: uppercase; color: var(--cream); }
.bands i { height: 28px; display: block; background: linear-gradient(90deg, var(--coral) 25%, var(--amber) 25% 55%, var(--teal) 55%); border: 2px solid var(--brown); box-shadow: 4px 4px 0 var(--plum); animation: bandShift 2.2s steps(5,end) infinite; }

.noise-garden { background: rgba(22,20,42,.72); border: 4px solid var(--amber); box-shadow: 12px 12px 0 var(--plum), inset 0 0 0 8px rgba(36,21,15,.7); }
.particle { position: absolute; width: 8px; height: 8px; background: var(--gold); box-shadow: 0 0 0 2px rgba(246,230,184,.3); animation: particleDrift 3s steps(6,end) infinite; }
.particle.teal { background: var(--teal); } .particle.coral { background: var(--coral); }
.particle.clustered { animation-name: clusterPulse; }

.orbital-map { display: grid; place-items: center; }
.orbit { position: absolute; border: 3px dashed var(--teal); transform: rotate(45deg) skew(-10deg); animation: orbitGlow 2s steps(4,end) infinite; }
.o1 { width: 190px; height: 190px; } .o2 { width: 310px; height: 310px; border-color: var(--amber); animation-delay: .4s; } .o3 { width: 430px; height: 430px; border-color: var(--coral); animation-delay: .8s; }
.observatory-core { width: 116px; height: 116px; display: grid; place-items: center; color: var(--brown); background: var(--gold); border: 4px solid var(--cream); box-shadow: 10px 10px 0 var(--plum); font: 900 4rem var(--display); z-index: 2; }
.capsule { position: absolute; width: 42px; height: 70px; background: var(--teal); border: 3px solid var(--brown); box-shadow: 6px 6px 0 var(--coral); animation: floatTile 2.3s steps(4,end) infinite; }
.c1 { left: 20%; top: 28%; } .c2 { right: 20%; top: 44%; animation-delay: .5s; background: var(--amber); } .c3 { left: 48%; bottom: 14%; animation-delay: 1s; background: var(--cream); }
.experiment-button { margin-top: 12px; padding: 14px 16px; color: var(--cream); background: var(--coral); border: 3px solid var(--brown); box-shadow: 5px 5px 0 var(--gold); cursor: pointer; }
.experiment-button.pulse { animation: buttonPulse .7s steps(3,end) 2; }

.coin-level::before { background: rgba(90, 46, 73, .58); }
.branch-level::before { background: rgba(36, 21, 15, .74); }
.bayes-level::before { background: rgba(22, 20, 42, .78); }
.noise-level::before { background: rgba(90, 46, 73, .48); }
.final-level::before { background: rgba(22, 20, 42, .82); }

@keyframes bootFade { 0%, 84% { opacity: 1; visibility: visible; } 100% { opacity: 0; visibility: hidden; } }
@keyframes bootJitter { 0%, 100% { transform: translate(0); } 50% { transform: translate(4px, -2px); } }
@keyframes meterPulse { 0%,100% { background: var(--plum); } 50% { background: var(--teal); } }
@keyframes beacon { 0%,100% { opacity: 1; box-shadow: 0 0 0 0 rgba(242,95,76,.5); } 50% { opacity: .55; box-shadow: 0 0 0 8px rgba(242,95,76,.22); } }
@keyframes floatTile { 0%,100% { translate: 0 0; } 50% { translate: 0 -16px; } }
@keyframes twinkle { 0%,100% { opacity: .35; } 50% { opacity: 1; } }
@keyframes coinFlip { 0% { transform: skewY(10deg) scaleX(1); } 50% { transform: skewY(10deg) scaleX(.18); } 100% { transform: skewY(10deg) scaleX(1); } }
@keyframes trailDrift { 0% { opacity: 0; translate: 0 0; } 50% { opacity: 1; } 100% { opacity: 0; translate: -30px 20px; } }
@keyframes walkPath { 0% { left: 45%; top: 54%; } 25% { left: 27%; top: 38%; } 50% { left: 12%; top: 20%; } 75% { left: 62%; top: 34%; } 100% { left: 76%; top: 16%; } }
@keyframes signalFocus { 0%,100% { filter: blur(0); transform: scale(1); } 50% { filter: blur(2px); transform: scale(1.08); } }
@keyframes bandShift { 0%,100% { background-position: 0; } 50% { background-position: 60px; } }
@keyframes particleDrift { 0%,100% { translate: 0 0; } 50% { translate: 18px -22px; } }
@keyframes clusterPulse { 0%,100% { transform: scale(1); } 50% { transform: scale(1.8); } }
@keyframes orbitGlow { 0%,100% { opacity: .45; } 50% { opacity: 1; } }
@keyframes buttonPulse { 0%,100% { transform: translate(0); } 50% { transform: translate(-3px, -3px); box-shadow: 9px 9px 0 var(--teal); } }

@media (max-width: 920px) {
  .hud-rail { left: 8px; width: 58px; }
  .level { grid-template-columns: 64px 1fr; grid-template-rows: auto auto 1fr; padding: 96px 18px 84px 82px; }
  .lesson-card { grid-column: 2; grid-row: 1; }
  .artifact { grid-column: 2; grid-row: 2 / 4; width: 100%; height: 420px; }
  .hud-strip { left: 82px; right: 18px; bottom: 18px; }
  .field-note, .professor { right: 18px; bottom: 92px; left: 82px; }
}

@media (max-width: 640px) {
  h1 { font-size: 3.2rem; }
  h2 { font-size: 2.3rem; }
  .coin-platforms, .bayes-console { grid-template-columns: 1fr; }
  .artifact { height: 360px; }
  .lesson-card { padding: 20px; }
}