:root {
  /* Typography compliance trace: Inter** from concise explanations */
  --abyss: #05060D;
  --ridge: #11182F;
  --cyan: #19F7FF;
  --magenta: #FF2BD6;
  --violet: #7C4DFF;
  --ember: #FFB86B;
  --frost: #EAF7FF;
  --glass: rgba(234, 247, 255, 0.08);
  --glass-strong: rgba(234, 247, 255, 0.13);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: var(--abyss);
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--frost);
  background: var(--abyss);
  overflow-x: hidden;
}

body::before,
.weather {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 20;
}

body::before {
  opacity: 0.16;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(234, 247, 255, 0.7) 0 1px, transparent 1.5px),
    radial-gradient(circle at 80% 15%, rgba(25, 247, 255, 0.55) 0 1px, transparent 1.5px),
    linear-gradient(135deg, rgba(255, 255, 255, 0.04) 25%, transparent 25%),
    linear-gradient(45deg, rgba(255, 255, 255, 0.035) 25%, transparent 25%);
  background-size: 180px 180px, 240px 240px, 5px 5px, 7px 7px;
  mix-blend-mode: screen;
  animation: staticDrift 5s steps(8) infinite;
}

.weather {
  opacity: var(--weather-opacity, 0.25);
  background:
    repeating-linear-gradient(100deg, rgba(234,247,255,0.02) 0 1px, transparent 1px 5px),
    radial-gradient(circle at var(--lantern-x, 50%) var(--lantern-y, 35%), rgba(25,247,255,0.12), transparent 23rem);
  transition: opacity 240ms ease;
}

.cursor-lantern {
  position: fixed;
  left: 0;
  top: 0;
  width: 27rem;
  height: 27rem;
  margin: -13.5rem 0 0 -13.5rem;
  border-radius: 50%;
  z-index: 19;
  pointer-events: none;
  opacity: 0.82;
  background:
    radial-gradient(circle, rgba(234,247,255,0.28) 0 4%, rgba(25,247,255,0.22) 8%, rgba(255,43,214,0.14) 24%, rgba(124,77,255,0.08) 42%, transparent 70%);
  filter: blur(2px);
  mix-blend-mode: screen;
  transform: translate3d(var(--lantern-x, 50vw), var(--lantern-y, 50vh), 0);
}

.fixed-world {
  position: fixed;
  inset: 0;
  overflow: hidden;
  background:
    radial-gradient(circle at 68% 16%, rgba(124,77,255,0.18), transparent 32rem),
    radial-gradient(circle at 22% 40%, rgba(25,247,255,0.10), transparent 28rem),
    linear-gradient(180deg, #05060D 0%, #081025 55%, #05060D 100%);
}

.starfield {
  position: absolute;
  inset: -12%;
  opacity: 0.42;
  background-image:
    radial-gradient(circle, rgba(234,247,255,0.74) 0 1px, transparent 1.7px),
    radial-gradient(circle, rgba(255,43,214,0.35) 0 1px, transparent 1.5px);
  background-size: 210px 190px, 310px 280px;
  animation: skyShift 22s linear infinite;
}

.aurora {
  position: absolute;
  width: 55vw;
  height: 24vh;
  border-radius: 50%;
  filter: blur(52px);
  opacity: 0.28;
}

.aurora-cyan {
  left: -10vw;
  top: 25vh;
  background: var(--cyan);
  transform: rotate(-18deg);
}

.aurora-magenta {
  right: -15vw;
  top: 8vh;
  background: var(--magenta);
  transform: rotate(14deg);
}

.mountains {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  pointer-events: none;
}

.mountains-back { height: 58vh; opacity: 0.78; }
.mountains-front { height: 48vh; opacity: 0.96; }
.mountains-back path:first-child { fill: rgba(17,24,47,0.74); }
.mountains-front path:first-child { fill: rgba(5,6,13,0.88); }
.contour {
  fill: none;
  stroke: var(--cyan);
  stroke-width: 2.2;
  stroke-dasharray: 10 18;
  filter: drop-shadow(0 0 10px rgba(25,247,255,0.7));
  animation: contourFlow 9s linear infinite;
}
.contour.second { stroke: var(--violet); animation-duration: 13s; }
.contour.warm { stroke: var(--ember); opacity: 0.72; animation-duration: 11s; }

.altitude-nav {
  position: fixed;
  left: clamp(0.9rem, 2vw, 2rem);
  top: 50%;
  transform: translateY(-50%);
  z-index: 30;
  display: grid;
  gap: 0.75rem;
  color: rgba(234,247,255,0.55);
  font-family: "Kalam", "Comic Sans MS", cursive;
}

.nav-title {
  writing-mode: vertical-rl;
  color: var(--ember);
  letter-spacing: 0.18em;
  font: 700 0.74rem "Inter", sans-serif;
  text-transform: uppercase;
  margin-bottom: 0.4rem;
}

.altitude-nav a {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  color: inherit;
  text-decoration: none;
  font-size: 1rem;
  transition: color 240ms ease, transform 240ms ease;
}

.altitude-nav a span {
  width: 0.55rem;
  height: 0.55rem;
  border: 1px solid rgba(25,247,255,0.55);
  transform: rotate(45deg);
  background: rgba(5,6,13,0.72);
  box-shadow: 0 0 0 rgba(25,247,255,0);
}

.altitude-nav a.active {
  color: var(--frost);
  transform: translateX(0.35rem);
}

.altitude-nav a.active span {
  background: var(--magenta);
  border-color: var(--magenta);
  box-shadow: 0 0 18px rgba(255,43,214,0.88);
}

.ascent {
  position: relative;
  z-index: 5;
}

.route {
  position: absolute;
  left: 43%;
  top: 58vh;
  width: 5px;
  height: calc(100% - 105vh);
  border-radius: 999px;
  background: linear-gradient(180deg, rgba(25,247,255,0.08), rgba(234,247,255,0.09));
  box-shadow: inset 0 0 12px rgba(25,247,255,0.4);
}

.route::before {
  content: "";
  position: absolute;
  inset: -40px -18px;
  background: linear-gradient(180deg, transparent, rgba(124,77,255,0.14), transparent 35%, rgba(255,43,214,0.11), transparent 72%, rgba(25,247,255,0.18));
  filter: blur(12px);
}

.route-fill {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 0%;
  border-radius: inherit;
  background: linear-gradient(180deg, var(--cyan), var(--magenta), var(--ember));
  box-shadow: 0 0 16px rgba(25,247,255,0.9), 0 0 34px rgba(255,43,214,0.45);
}

.route-glow {
  position: sticky;
  top: 26vh;
  width: 22px;
  height: 22px;
  margin-left: -8.5px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 22px var(--cyan), 0 0 46px var(--magenta);
}

.knot {
  position: absolute;
  left: 50%;
  width: 22px;
  height: 22px;
  margin-left: -11px;
  border: 2px solid var(--cyan);
  border-radius: 44% 56% 54% 46%;
  background: rgba(5,6,13,0.82);
  box-shadow: 0 0 18px rgba(25,247,255,0.55);
}
.knot-0 { top: 1%; } .knot-1 { top: 19%; } .knot-2 { top: 38%; }
.knot-3 { top: 57%; } .knot-4 { top: 76%; } .knot-5 { top: 97%; }

.chapter {
  min-height: 100vh;
  position: relative;
  display: flex;
  align-items: center;
  padding: 10vh clamp(1.2rem, 4vw, 5rem);
}

.hero { justify-content: center; min-height: 115vh; }
.checkpoint.left { justify-content: flex-start; padding-left: clamp(5rem, 9vw, 10rem); }
.checkpoint.right { justify-content: flex-end; padding-right: clamp(2rem, 8vw, 8rem); }
.checkpoint.high { align-items: flex-start; padding-top: 20vh; }
.checkpoint.higher { align-items: flex-end; padding-bottom: 18vh; }

.hero-glass,
.pane,
.summit-observatory {
  position: relative;
  border: 1px solid rgba(234,247,255,0.23);
  background:
    linear-gradient(135deg, rgba(234,247,255,0.12), rgba(234,247,255,0.035)),
    radial-gradient(circle at 20% 5%, rgba(25,247,255,0.22), transparent 22rem),
    radial-gradient(circle at 92% 72%, rgba(124,77,255,0.16), transparent 20rem);
  box-shadow: 0 24px 80px rgba(0,0,0,0.55), inset 0 0 34px rgba(234,247,255,0.045), 0 0 38px rgba(25,247,255,0.13);
  backdrop-filter: blur(22px) saturate(142%);
  -webkit-backdrop-filter: blur(22px) saturate(142%);
  overflow: hidden;
}

.hero-glass::before,
.pane::before,
.summit-observatory::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(110deg, transparent 0 34%, rgba(234,247,255,0.12) 46%, transparent 58% 100%);
  transform: translateX(-80%);
  animation: glassSweep 8s ease-in-out infinite;
}

.hero-glass {
  width: min(760px, 82vw);
  min-height: 430px;
  padding: clamp(2rem, 6vw, 5rem);
  clip-path: polygon(0 9%, 92% 0, 100% 80%, 72% 100%, 8% 93%);
}

.pane {
  width: min(560px, 78vw);
  min-height: 390px;
  padding: clamp(1.8rem, 4vw, 3.4rem);
  clip-path: polygon(0 0, 92% 6%, 100% 84%, 14% 100%, 0 72%);
}

.right .pane { clip-path: polygon(9% 2%, 100% 0, 94% 90%, 5% 100%, 0 22%); }
.violet-pane { box-shadow: 0 24px 90px rgba(0,0,0,0.58), 0 0 44px rgba(124,77,255,0.25); }
.magenta-pane { box-shadow: 0 24px 90px rgba(0,0,0,0.58), 0 0 48px rgba(255,43,214,0.24); }
.ember-pane { box-shadow: 0 24px 90px rgba(0,0,0,0.58), 0 0 40px rgba(255,184,107,0.2); }

.reveal-pane {
  opacity: 0;
  transform: translate3d(0, 55px, 0) rotate(-1.5deg) scale(0.97);
  transition: opacity 850ms ease, transform 850ms cubic-bezier(.18,.86,.22,1);
}

.reveal-pane.visible {
  opacity: 1;
  transform: translate3d(0, 0, 0) rotate(0deg) scale(1);
}

.overline,
.altimeter {
  margin: 0 0 1.2rem;
  color: var(--cyan);
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-size: 0.76rem;
  font-weight: 800;
}

h1,
h2,
.field-note,
.scribble {
  font-family: "Caveat", "Kalam", "Bradley Hand", cursive;
}

h1 {
  margin: 0;
  font-size: clamp(5.5rem, 15vw, 12rem);
  line-height: 0.82;
  color: var(--frost);
  text-shadow: 0 0 18px rgba(25,247,255,0.65), 0 0 42px rgba(255,43,214,0.28);
  transform: rotate(-3deg);
}

h2 {
  margin: 0 0 1.1rem;
  font-size: clamp(3.1rem, 7vw, 5.8rem);
  line-height: 0.88;
  color: var(--frost);
  text-shadow: 0 0 14px rgba(255,43,214,0.48);
}

p {
  position: relative;
  font-size: clamp(1rem, 1.55vw, 1.22rem);
  line-height: 1.75;
  color: rgba(234,247,255,0.82);
}

.hero-copy {
  max-width: 570px;
  margin-top: 2rem;
  font-size: clamp(1.25rem, 2.3vw, 1.8rem);
  color: var(--frost);
}

.korean-word {
  position: absolute;
  right: 7%;
  top: 17%;
  margin: 0;
  font-family: "Noto Sans KR", sans-serif;
  font-size: clamp(4rem, 10vw, 8rem);
  font-weight: 700;
  color: transparent;
  -webkit-text-stroke: 1px rgba(25,247,255,0.3);
  text-shadow: 0 0 30px rgba(25,247,255,0.12);
  opacity: var(--korean-opacity, 0.18);
}

.field-note,
.scribble,
.summit-note {
  color: var(--ember);
  font-family: "Kalam", "Caveat", cursive;
  font-size: clamp(1.25rem, 2vw, 1.75rem);
  transform: rotate(-2deg);
}

.scribble.cyan { color: var(--cyan); }
.scribble.ember { color: var(--ember); }

.diagram,
.mini-map,
.decision-fork,
.breath-wave {
  position: relative;
  height: 72px;
  margin: 2rem 0 1.2rem;
  border: 1px solid rgba(234,247,255,0.14);
  background: rgba(5,6,13,0.28);
  overflow: hidden;
}

.pulse-line span {
  position: absolute;
  top: 50%;
  left: calc(var(--i, 0) * 24% + 5%);
  width: 22%;
  height: 2px;
  background: var(--cyan);
  box-shadow: 0 0 14px var(--cyan);
  transform: rotate(var(--r, 0deg));
}
.pulse-line span:nth-child(1) { --i: 0; --r: 0deg; }
.pulse-line span:nth-child(2) { --i: 1; --r: -28deg; }
.pulse-line span:nth-child(3) { --i: 2; --r: 28deg; }
.pulse-line span:nth-child(4) { --i: 3; --r: -12deg; }

.mini-map i {
  position: absolute;
  left: 12%;
  right: 12%;
  height: 1px;
  top: calc(18% + var(--n) * 16%);
  border-top: 1px dashed rgba(25,247,255,0.58);
  transform: skewY(calc(var(--n) * -2deg));
}
.mini-map i:nth-child(1) { --n: 0; } .mini-map i:nth-child(2) { --n: 1; }
.mini-map i:nth-child(3) { --n: 2; } .mini-map i:nth-child(4) { --n: 3; }

.decision-fork b {
  position: absolute;
  left: 16%;
  top: 35%;
  width: 66%;
  height: 2px;
  background: var(--magenta);
  box-shadow: 0 0 16px var(--magenta);
  transform-origin: left center;
}
.decision-fork b:nth-child(2) { transform: rotate(22deg); }
.decision-fork b:nth-child(3) { transform: rotate(-22deg); }

.breath-wave span,
.breath-wave::before {
  content: "";
  position: absolute;
  inset: 28px 8%;
  border-top: 2px solid var(--ember);
  border-radius: 50%;
  filter: drop-shadow(0 0 12px rgba(255,184,107,0.85));
}
.breath-wave span { transform: translateY(-12px) scaleY(0.5); }

.summit {
  justify-content: center;
  min-height: 122vh;
  padding-bottom: 18vh;
}

.summit-observatory {
  width: min(960px, 86vw);
  padding: clamp(2rem, 5vw, 4.8rem);
  text-align: center;
  clip-path: polygon(8% 0, 100% 7%, 91% 100%, 0 90%);
}

.human-contour {
  width: min(330px, 60vw);
  margin: 1.5rem auto;
  filter: drop-shadow(0 0 18px rgba(25,247,255,0.75));
}

.human-contour path {
  fill: none;
  stroke: var(--cyan);
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 900;
  stroke-dashoffset: calc(900 - (var(--summit-draw, 0) * 900));
}
.human-contour path:nth-child(2) { stroke: var(--violet); }
.human-contour path:nth-child(3) { stroke: var(--magenta); }
.human-contour path:nth-child(4) { stroke: var(--ember); }

@keyframes staticDrift {
  0% { transform: translate(0, 0); }
  25% { transform: translate(1%, -1%); }
  50% { transform: translate(-1%, 1%); }
  75% { transform: translate(0.5%, 1.5%); }
  100% { transform: translate(0, 0); }
}

@keyframes skyShift { to { transform: translate3d(-4%, 3%, 0); } }
@keyframes contourFlow { to { stroke-dashoffset: -140; } }
@keyframes glassSweep { 0%, 52%, 100% { transform: translateX(-85%); } 70% { transform: translateX(95%); } }

@media (max-width: 800px) {
  .altitude-nav { display: none; }
  .route { left: 1.7rem; }
  .chapter,
  .checkpoint.left,
  .checkpoint.right {
    justify-content: center;
    padding-left: 3.2rem;
    padding-right: 1rem;
  }
  .hero-glass,
  .pane,
  .summit-observatory { width: 100%; }
  .korean-word { top: 8%; right: 5%; }
}