:root {
  /* Typography spec tokens: titles widen compress sections become labels jitter between condensed extended widths like variable-font oscilloscope. width/weight shifts acting live prototyping states rather than headings. */
  --asphalt: #08080A;
  --concrete: #B7B2A8;
  --cyan: #00F5FF;
  --magenta: #FF2BD6;
  --yellow: #F9FF00;
  --green: #39FF14;
  --orange: #FF6B00;
  --black: #08080A;
  --display: "Roboto Flex", "Roboto", sans-serif;
  --body: "Space Grotesk", "Inter", sans-serif;
  --mono: "JetBrains Mono", monospace;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  color: var(--concrete);
  background: var(--asphalt);
  font-family: var(--body);
}

.city-canvas,
.street-overlay,
.route-map,
.cursor-spark {
  position: fixed;
  pointer-events: none;
}

.city-canvas {
  inset: 0;
  z-index: 0;
  opacity: .92;
}

.street-overlay {
  inset: 0;
  z-index: 1;
  background:
    repeating-linear-gradient(90deg, transparent 0 70px, rgba(183,178,168,.08) 70px 73px, transparent 73px 136px),
    repeating-linear-gradient(0deg, transparent 0 82px, rgba(183,178,168,.07) 82px 85px, transparent 85px 151px),
    linear-gradient(135deg, transparent 0 47%, rgba(0,245,255,.08) 47% 48%, transparent 48% 100%);
  mix-blend-mode: screen;
}

.street-overlay::before,
.street-overlay::after {
  content: "";
  position: absolute;
  border: 4px solid var(--yellow);
  opacity: .55;
  transform: rotate(-2deg);
}

.street-overlay::before {
  width: 160px;
  height: 160px;
  left: 4vw;
  bottom: 9vh;
  border-radius: 50%;
  box-shadow: inset 0 0 0 18px var(--asphalt), inset 0 0 0 22px var(--yellow);
}

.street-overlay::after {
  right: 3vw;
  top: 18vh;
  width: 19vw;
  height: 38px;
  border-color: var(--orange);
  background: repeating-linear-gradient(90deg, var(--orange) 0 12px, transparent 12px 25px);
}

.cursor-spark {
  z-index: 30;
  width: 90px;
  height: 90px;
  border: 2px solid var(--cyan);
  border-radius: 50%;
  transform: translate(-50%, -50%) scale(.75);
  opacity: 0;
  box-shadow: 0 0 30px var(--cyan), inset 0 0 20px var(--magenta);
  transition: opacity .12s steps(2), transform .18s steps(3);
}

.route-map {
  inset: 0;
  width: 100vw;
  height: 420vh;
  z-index: 2;
  overflow: visible;
}

.route-map polyline {
  fill: none;
  stroke: var(--cyan);
  stroke-width: .85;
  stroke-linecap: square;
  stroke-linejoin: bevel;
  filter: drop-shadow(0 0 7px var(--cyan)) drop-shadow(9px 7px 0 var(--magenta));
  stroke-dasharray: 760;
  stroke-dashoffset: 760;
}

.route-map circle {
  fill: var(--yellow);
  stroke: var(--asphalt);
  stroke-width: .45;
  filter: drop-shadow(0 0 7px var(--yellow));
}

.field-manual {
  position: relative;
  z-index: 5;
}

.lesson {
  position: relative;
  min-height: 100vh;
  isolation: isolate;
  overflow: hidden;
  border-bottom: 8px solid var(--concrete);
}

.lesson::before {
  content: attr(data-step);
  position: absolute;
  right: 18px;
  bottom: 8px;
  color: var(--yellow);
  font: 700 clamp(72px, 17vw, 260px)/.78 var(--mono);
  opacity: .12;
  z-index: -1;
}

.micro-label,
.section-label span,
.panel-number,
.lesson-tag span,
.diff-grid span {
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: -.03em;
  color: var(--yellow);
}

h1,
h2,
h3 {
  font-family: var(--display);
  margin: 0;
  text-transform: uppercase;
  color: var(--concrete);
  font-variation-settings: "wght" 850, "wdth" 125, "opsz" 144;
}

h1 {
  max-width: 72vw;
  color: var(--yellow);
  font-size: clamp(68px, 12.4vw, 190px);
  line-height: .73;
  letter-spacing: -.08em;
  text-shadow: 8px 8px 0 var(--magenta), -5px -5px 0 var(--cyan), 0 0 30px rgba(249,255,0,.26);
}

h2 {
  font-size: clamp(48px, 9vw, 146px);
  line-height: .81;
  letter-spacing: -.075em;
}

h3 {
  font-size: clamp(34px, 5vw, 78px);
  line-height: .82;
  letter-spacing: -.055em;
}

code {
  font-family: var(--mono);
  color: var(--green);
  background: var(--asphalt);
  border: 3px solid var(--green);
  padding: .45rem .65rem;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

.lesson--chalkline {
  padding: 12px 12px 18px;
}

.title-block {
  position: absolute;
  top: 14px;
  left: 12px;
  width: min(1120px, 92vw);
  padding: 18px 18px 24px;
  background: rgba(8,8,10,.86);
  border: 8px solid var(--concrete);
  box-shadow: 6px 6px 0 var(--orange), 14px 14px 0 var(--magenta);
}

.chalk-note {
  width: min(620px, 74vw);
  margin: 22px 0 0;
  color: var(--concrete);
  font-size: clamp(18px, 2vw, 28px);
  line-height: 1.05;
}

.top-right {
  position: absolute;
  top: 30px;
  right: 24px;
  display: grid;
  gap: 9px;
  transform: rotate(2deg);
  text-align: right;
  z-index: 2;
}

.top-right span {
  display: block;
  font: 700 clamp(13px, 1.4vw, 22px)/1 var(--mono);
  color: var(--cyan);
  background: var(--asphalt);
  border: 3px solid var(--cyan);
  padding: 8px 11px;
  box-shadow: -5px 5px 0 var(--magenta);
}

.lesson-tag {
  position: absolute;
  right: 7vw;
  bottom: 8vh;
  padding: 18px 20px;
  background: var(--yellow);
  color: var(--asphalt);
  border: 7px solid var(--asphalt);
  box-shadow: -8px 8px 0 var(--cyan), -17px 17px 0 var(--magenta);
  transform: rotate(-5deg);
}

.lesson-tag span,
.lesson-tag strong {
  display: block;
  color: var(--asphalt);
}

.lesson-tag strong {
  font: 850 clamp(33px, 6vw, 86px)/.82 var(--display);
  font-variation-settings: "wght" 850, "wdth" 65;
  text-transform: uppercase;
}

.manhole {
  position: absolute;
  left: 11vw;
  bottom: 9vh;
  display: grid;
  place-items: center;
  width: 148px;
  height: 148px;
  border: 8px double var(--concrete);
  border-radius: 50%;
  color: var(--green);
  font: 700 35px/1 var(--mono);
  background: radial-gradient(circle, var(--asphalt) 0 45%, var(--concrete) 46% 48%, var(--asphalt) 49%);
}

.sticker {
  position: absolute;
  left: 46vw;
  bottom: 28vh;
  font: 700 18px/1 var(--mono);
  padding: 12px 18px;
  transform: rotate(11deg);
  border: 4px solid var(--asphalt);
}

.sticker-yellow {
  color: var(--asphalt);
  background: var(--orange);
  box-shadow: 7px 7px 0 var(--yellow);
}

.lesson--compiler {
  padding: 11vh 2vw 9vh;
}

.section-label {
  margin-left: 2vw;
  width: min(780px, 90vw);
  background: var(--asphalt);
  border-left: 14px solid var(--orange);
  padding: 10px 22px 18px;
  box-shadow: 6px -6px 0 var(--cyan);
}

.compiler-panels {
  position: relative;
  min-height: 70vh;
}

.concrete-panel {
  position: absolute;
  width: min(465px, 82vw);
  background: var(--concrete);
  color: var(--asphalt);
  border: 8px solid var(--asphalt);
  padding: 18px;
  box-shadow: 9px 9px 0 var(--magenta), 15px 15px 0 var(--cyan);
}

.concrete-panel h3 {
  color: var(--asphalt);
}

.concrete-panel p {
  margin: 15px 0 20px;
  font-size: clamp(17px, 1.8vw, 24px);
  line-height: 1.02;
  font-weight: 600;
}

.panel-number {
  display: inline-block;
  margin-bottom: 12px;
  padding: 5px 8px;
  color: var(--asphalt);
  background: var(--yellow);
  border: 3px solid var(--asphalt);
}

.panel-a { top: 5vh; left: 5vw; transform: rotate(-2deg); }
.panel-b { top: 4vh; right: 8vw; transform: rotate(1.5deg); }
.panel-c { top: 42vh; left: 18vw; transform: rotate(2.5deg); }
.panel-d { top: 49vh; right: 3vw; transform: rotate(-2.5deg); }

.crosswalk {
  position: absolute;
  background: repeating-linear-gradient(90deg, var(--concrete) 0 20px, transparent 20px 38px);
  opacity: .7;
}

.crosswalk-left {
  left: -5vw;
  bottom: 20vh;
  width: 35vw;
  height: 55px;
  transform: rotate(-37deg);
}

.lesson--mutation {
  padding: 7vh 4vw 7vh;
}

.map-header {
  position: relative;
  z-index: 2;
  margin-left: auto;
  width: min(860px, 87vw);
  text-align: right;
  padding: 16px;
  background: var(--asphalt);
  border: 6px solid var(--cyan);
  box-shadow: -10px 10px 0 var(--magenta);
}

.map-header h2 {
  color: var(--cyan);
  text-shadow: -5px 5px 0 var(--magenta);
}

.mutation-board {
  position: absolute;
  left: 3vw;
  bottom: 6vh;
  width: 86vw;
  height: 61vh;
  border: 9px solid var(--concrete);
  background:
    linear-gradient(90deg, rgba(0,245,255,.28) 0 3px, transparent 3px 100%),
    linear-gradient(0deg, rgba(249,255,0,.19) 0 3px, transparent 3px 100%),
    repeating-linear-gradient(90deg, transparent 0 88px, rgba(183,178,168,.18) 88px 95px),
    repeating-linear-gradient(0deg, transparent 0 65px, rgba(183,178,168,.15) 65px 72px),
    var(--asphalt);
  background-size: 143px 100%, 100% 117px, auto, auto, auto;
  box-shadow: 12px 12px 0 var(--orange), 24px 24px 0 var(--yellow);
  overflow: hidden;
}

.node-network {
  position: absolute;
  inset: 0;
}

.node-network::before,
.node-network::after {
  content: "";
  position: absolute;
  inset: 16% 10% 20% 9%;
  border-top: 5px solid var(--green);
  border-right: 5px solid var(--green);
  transform: skewY(-12deg);
  filter: drop-shadow(0 0 12px var(--green));
}

.node-network::after {
  inset: 35% 22% 12% 28%;
  border-color: var(--magenta);
  transform: skewY(18deg);
}

.node-network span {
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--green);
  border: 5px solid var(--asphalt);
  box-shadow: 0 0 0 4px var(--green), 0 0 24px 10px rgba(57,255,20,.4);
  animation: pulse-node 1.2s steps(2) infinite;
}

.map-copy {
  position: absolute;
  right: 24px;
  bottom: 24px;
  width: min(515px, 72vw);
  padding: 16px;
  color: var(--asphalt);
  background: var(--yellow);
  border: 6px solid var(--asphalt);
  box-shadow: -7px 7px 0 var(--magenta);
}

.map-copy p {
  margin: 15px 0 0;
  font-size: clamp(20px, 2.4vw, 34px);
  line-height: .98;
  font-weight: 700;
}

.compile-stamp {
  position: absolute;
  left: 7vw;
  top: 22vh;
  display: grid;
  place-items: center;
  width: 170px;
  height: 170px;
  border: 8px solid var(--green);
  border-radius: 50%;
  color: var(--green);
  font: 700 24px/.85 var(--mono);
  text-align: center;
  transform: rotate(-17deg);
  box-shadow: 0 0 35px rgba(57,255,20,.5);
}

.lesson--diff {
  min-height: 100vh;
  padding: 12vh 3vw 7vh;
}

.rooftop-lines {
  position: absolute;
  inset: auto 0 0;
  height: 25vh;
  background:
    linear-gradient(90deg, transparent 8%, var(--concrete) 8% 9%, transparent 9% 31%, var(--concrete) 31% 32%, transparent 32% 75%, var(--concrete) 75% 76%, transparent 76%),
    linear-gradient(0deg, var(--concrete) 0 9px, transparent 9px 100%);
}

.billboard {
  width: min(1180px, 92vw);
  min-height: 62vh;
  margin-left: auto;
  background: var(--concrete);
  color: var(--asphalt);
  border: 10px solid var(--asphalt);
  padding: clamp(18px, 3vw, 45px);
  box-shadow: -12px 12px 0 var(--cyan), -24px 24px 0 var(--magenta), 9px -9px 0 var(--orange);
  transform: rotate(.75deg);
}

.billboard h2 {
  color: var(--asphalt);
  max-width: 960px;
}

.diff-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin-top: 34px;
}

.before,
.after {
  min-height: 210px;
  padding: 18px;
  border: 6px solid var(--asphalt);
  background: var(--asphalt);
  color: var(--concrete);
}

.before {
  box-shadow: inset 0 0 0 6px var(--orange);
}

.after {
  box-shadow: inset 0 0 0 6px var(--green);
}

.diff-grid p {
  margin: 12px 0;
  font-size: clamp(19px, 2.3vw, 31px);
  line-height: .98;
  font-weight: 700;
}

del {
  color: var(--orange);
  text-decoration-color: var(--magenta);
  text-decoration-thickness: 5px;
}

.final-code {
  position: absolute;
  left: 4vw;
  bottom: 9vh;
  display: grid;
  gap: 10px;
  transform: rotate(-4deg);
}

.final-code strong {
  display: block;
  padding: 12px;
  color: var(--asphalt);
  background: var(--green);
  border: 5px solid var(--asphalt);
  font: 850 clamp(30px, 4vw, 60px)/.85 var(--display);
  font-variation-settings: "wght" 850, "wdth" 125;
  text-transform: uppercase;
}

.slam {
  opacity: 0;
  transform: translate(var(--slam-x, -18px), var(--slam-y, 20px)) rotate(var(--slam-r, 0deg));
  transition: opacity .08s steps(1), transform .24s steps(4), box-shadow .24s steps(3), font-variation-settings .24s steps(3);
}

.slam.is-visible {
  opacity: 1;
  transform: translate(0, 0) rotate(var(--settle-r, 0deg));
}

.lesson.is-active h1,
.lesson.is-active h2 {
  font-variation-settings: "wght" 940, "wdth" 145, "opsz" 144;
}

.lesson:not(.is-active) h1,
.lesson:not(.is-active) h2 {
  font-variation-settings: "wght" 780, "wdth" 92, "opsz" 72;
}

@keyframes pulse-node {
  0%, 100% { transform: scale(.85); filter: brightness(1); }
  50% { transform: scale(1.22); filter: brightness(1.7); }
}

@media (max-width: 900px) {
  .top-right { top: auto; bottom: 30vh; right: 14px; }
  .title-block { width: calc(100vw - 24px); }
  h1 { max-width: 90vw; }
  .compiler-panels { min-height: 150vh; }
  .concrete-panel { position: relative; left: auto; right: auto; top: auto; margin: 22px 0 0 6vw; }
  .panel-b, .panel-d { margin-left: 13vw; }
  .lesson--compiler { min-height: 180vh; }
  .mutation-board { position: relative; inset: auto; width: 94vw; height: 67vh; margin-top: 10vh; }
  .diff-grid { grid-template-columns: 1fr; }
  .final-code { position: relative; left: auto; bottom: auto; margin-top: 30px; }
}