:root {
  --cloud: #e8ecf0;
  --steel: #c8ced6;
  --charcoal: #3a3f47;
  --graphite: #5a6270;
  --pewter: #8b929c;
  --silver: #a8aeb8;
  --slate: #d5dae0;
  --ink: #2b2f36;
  --white: #ffffff;
}

* { box-sizing: border-box; }

html {
  scroll-snap-type: y proximity;
  background: var(--cloud);
}

body {
  margin: 0;
  font-family: "Nunito Sans", sans-serif;
  color: var(--charcoal);
  background: var(--cloud);
  overflow-x: hidden;
}

.stack { position: relative; z-index: 2; }

.panel {
  min-height: 100vh;
  position: relative;
  overflow: hidden;
  scroll-snap-align: start;
  display: grid;
  place-items: center;
}

h1, h2 {
  font-family: "Jost", sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin: 0;
  line-height: 0.95;
}

h1 {
  font-size: clamp(3rem, 8vw, 7rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--charcoal);
}

h2 {
  font-size: clamp(2rem, 5vw, 4rem);
  font-weight: 500;
  color: var(--charcoal);
}

p {
  font-size: clamp(1rem, 1.2vw, 1.15rem);
  line-height: 1.75;
  letter-spacing: 0.01em;
}

.section-label, .card-label {
  font-family: "Space Mono", monospace;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--pewter);
}

.field-overlay {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 1;
  opacity: 0.5;
}

.field-overlay path, .topology path, .morph-curve path {
  fill: none;
  stroke: var(--silver);
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
}

.thread {
  stroke-dasharray: 700;
  stroke-dashoffset: 700;
  transition: stroke-dashoffset 1s ease-out;
}

.thread.is-drawn { stroke-dashoffset: 0; }

.hero {
  background: radial-gradient(circle at center, #c8ced6 0%, #e8ecf0 70%);
}

.radial-field {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.radial-field line {
  stroke: var(--graphite);
  stroke-width: 0.5;
  opacity: 0.55;
  stroke-dasharray: 720;
  stroke-dashoffset: 720;
  transition: stroke-dashoffset 2s cubic-bezier(.2,.7,.1,1);
}

.radial-field.is-active line { stroke-dashoffset: 0; }

.hero-copy {
  position: relative;
  z-index: 4;
  text-align: center;
  transform: translateY(-34px);
}

.tagline {
  margin: 21px 0 0;
  font-family: "Jost", sans-serif;
  font-size: clamp(1rem, 2vw, 1.5rem);
  font-weight: 300;
  color: var(--graphite);
}

.singularity-point {
  position: absolute;
  left: calc(50% - 4px);
  top: calc(50% + 13px);
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ink);
  z-index: 5;
  box-shadow: 0 0 0 13px rgba(232,236,240,0.35), 0 0 55px rgba(43,47,54,0.25);
}

.solid {
  position: absolute;
  z-index: 2;
  filter: drop-shadow(20px 24px 22px rgba(42, 47, 54, 0.13));
}

.sphere {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, #ffffff 0%, #c8ced6 40%, #8b929c 100%);
  left: calc(50% - 100px);
  top: calc(50% - 100px + 13px);
  opacity: 0.9;
}

.cube {
  width: 150px;
  height: 150px;
  right: 8vw;
  top: 13vh;
  background: linear-gradient(135deg, #ffffff, #c8ced6 48%, #8b929c);
  transform: rotateX(58deg) rotateZ(45deg);
}

.cube span {
  position: absolute;
  inset: 14px;
  border: 1px solid rgba(255,255,255,0.45);
}

.cone {
  width: 0;
  height: 0;
  border-left: 78px solid transparent;
  border-right: 78px solid transparent;
  border-bottom: 188px solid var(--steel);
  right: 8vw;
  bottom: 8vh;
}

.cone::after {
  content: "";
  position: absolute;
  left: -56px;
  top: 58px;
  width: 112px;
  height: 112px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 20%, rgba(255,255,255,0.45), rgba(139,146,156,0.16) 70%);
}

.torus {
  width: 210px;
  height: 210px;
  right: 12vw;
  top: 18vh;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #ffffff, #c8ced6 45%, #8b929c 75%);
}

.torus::after {
  content: "";
  position: absolute;
  inset: 58px;
  border-radius: 50%;
  background: var(--cloud);
  box-shadow: inset 10px 12px 18px rgba(43,47,54,0.14);
}

.octahedron {
  width: 180px;
  height: 180px;
  left: 13vw;
  top: 13vh;
  background: linear-gradient(135deg, #ffffff 0 35%, #c8ced6 36% 62%, #8b929c 63%);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
  opacity: 0.75;
}

.bauhaus-block { position: absolute; z-index: 3; }
.block-one { width: 120px; height: 40px; background: var(--charcoal); left: 8vw; bottom: 13vh; }
.block-two { width: 40px; height: 160px; background: var(--pewter); right: 13vw; top: 8vh; }
.block-three { width: 80px; height: 80px; background: var(--steel); right: 21vw; bottom: 10vh; }

.argument { background: var(--cloud); }
.vertical-bar { position: absolute; width: 16px; height: 60vh; top: 20vh; z-index: 2; }
.bar-left { left: 38.2vw; background: var(--charcoal); transform: translateX(-360px); }
.bar-right { left: 61.8vw; background: var(--pewter); transform: translateX(344px); }
.morph-curve { position: absolute; inset: 20vh 5vw auto; width: 90vw; height: 55vh; z-index: 0; opacity: 0.3; }
.text-column { position: relative; z-index: 3; max-width: 640px; padding: 0 2rem; transform: translate(8px, -13px); }
.text-column p { color: var(--charcoal); }

.search {
  background: linear-gradient(180deg, #e8ecf0 0%, #d5dae0 100%);
  align-content: center;
  gap: 55px;
  padding: 89px 5vw;
}

.section-heading { width: min(960px, 90vw); justify-self: center; transform: translateX(-21px); }
.section-heading h2 { max-width: 780px; }
.cards { width: min(1100px, 92vw); display: flex; justify-content: space-around; gap: 34px; }

.search-card {
  width: 200px;
  min-height: 280px;
  position: relative;
  padding: 10px 13px 21px;
  text-align: center;
  background: linear-gradient(145deg, #e8ecf0, #c8ced6);
  border: 1px solid var(--slate);
  box-shadow: 4px 4px 12px rgba(42, 47, 54, 0.08);
  transform: perspective(700px) rotateX(7deg) rotateY(-5deg);
  transition: transform 450ms ease, box-shadow 450ms ease;
}

.search-card:hover { transform: perspective(700px) rotateX(0deg) rotateY(0deg) translateY(-8px); box-shadow: 13px 21px 34px rgba(42,47,54,0.12); }
.search-card::after { content: ""; position: absolute; left: 50%; top: 89px; width: 120px; height: 120px; margin: -60px; border-radius: 50%; border: 1px solid var(--silver); opacity: 0; transform: scale(0); pointer-events: none; }
.search-card.ripple-on::after { animation: cardRipple 1.5s ease-out; }
.inscribed-circle { width: 180px; height: 180px; border-radius: 50%; margin: 0 auto 13px; border: 1px solid var(--pewter); background: radial-gradient(circle at 35% 25%, #ffffff, #c8ced6 48%, #8b929c); box-shadow: inset -10px -14px 18px rgba(43,47,54,0.09); }
.search-card p:not(.card-label) { margin: 0; font-size: 0.92rem; color: var(--graphite); line-height: 1.45; }

.theory {
  background-color: var(--cloud);
  background-image: repeating-radial-gradient(circle at center, #d5dae0 0 1px, transparent 1px 40px);
}
.topology { position: absolute; inset: 0; width: 100%; height: 100%; opacity: 0.72; }
.topology path { stroke-dasharray: 900; stroke-dashoffset: 900; animation: drawTopology 8s ease-in-out infinite; }
.topology path:nth-child(2) { animation-delay: 1s; }
.topology path:nth-child(3) { animation-delay: 2s; }
.topology path:nth-child(4) { animation-delay: 3s; }
.rotated-block { position: absolute; bottom: 15vh; left: 10vw; max-width: 480px; padding: 34px; background: rgba(232,236,240,0.84); border-left: 16px solid var(--charcoal); transform: rotate(-3deg); z-index: 3; box-shadow: 21px 21px 55px rgba(42,47,54,0.08); }

.one { background: var(--cloud); }
.one-stage { position: relative; width: min(70vw, 620px); height: 90vh; display: grid; place-items: center; transform: translateX(13px); }
.numeral { font-family: "Jost", sans-serif; font-size: clamp(40vh, 60vh, 80vh); font-weight: 700; line-height: 0.8; color: var(--ink); position: relative; z-index: 3; }
.vertical-word { position: absolute; left: calc(50% - 120px); top: 23vh; writing-mode: vertical-rl; font-family: "Jost", sans-serif; font-weight: 300; font-size: 1.2rem; letter-spacing: 0.15em; color: var(--pewter); z-index: 4; text-transform: uppercase; }
.ripple { position: absolute; left: 50%; top: 50%; width: 200px; height: 200px; margin: -100px; border: 1px solid var(--slate); border-radius: 50%; opacity: 0; transform: scale(0.1); animation: oneRipple 4s ease-out infinite; will-change: transform, opacity; }
.ripple-b { animation-delay: 1.3s; }
.ripple-c { animation-delay: 2.6s; }

@keyframes cardRipple { 0% { opacity: 0.8; transform: scale(0); } 100% { opacity: 0; transform: scale(2.5); } }
@keyframes oneRipple { 0% { opacity: 0.5; transform: scale(0.1); } 70%, 100% { opacity: 0; transform: scale(2.8); } }
@keyframes drawTopology { 0% { stroke-dashoffset: 900; opacity: 0; } 25% { opacity: 0.8; } 55% { stroke-dashoffset: 0; opacity: 0.8; } 100% { stroke-dashoffset: -900; opacity: 0; } }

@media (max-width: 820px) {
  .cards { flex-direction: column; align-items: center; }
  .search { min-height: auto; }
  .bar-left { left: 8vw; transform: none; }
  .bar-right { left: auto; right: 8vw; transform: none; }
  .cube, .cone, .torus, .octahedron { opacity: 0.35; }
  .rotated-block { left: 8vw; right: 8vw; max-width: none; }
}