:root {
  --ink: #17202a;
  --muted: #5b6773;
  --paper: #f6f4ee;
  --cream: #fffaf0;
  --teal: #0f766e;
  --blue: #2b6cb0;
  --yellow: #f5b84b;
  --coral: #ed6a5a;
  --green: #2f9e70;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  overflow: hidden;
}

.deck {
  height: 100vh;
  overflow-y: auto;
  scroll-snap-type: y mandatory;
  scroll-behavior: smooth;
}

.slide {
  position: relative;
  display: grid;
  min-height: 100vh;
  height: 100vh;
  place-items: center;
  padding: clamp(28px, 5vw, 72px);
  overflow: hidden;
  scroll-snap-align: start;
  scroll-snap-stop: always;
}

.slide::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(255, 255, 255, 0.46) 1px, transparent 1px),
    linear-gradient(rgba(255, 255, 255, 0.4) 1px, transparent 1px);
  background-size: 54px 54px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.38), transparent 72%);
  pointer-events: none;
}

.slide-content {
  position: relative;
  z-index: 1;
  width: min(1140px, 100%);
  animation: rise 680ms ease both;
}

.hero {
  color: #ffffff;
  background:
    linear-gradient(120deg, rgba(23, 32, 42, 0.84), rgba(15, 118, 110, 0.7)),
    radial-gradient(circle at 80% 20%, rgba(245, 184, 75, 0.5), transparent 24%),
    linear-gradient(135deg, #17202a, #0f766e);
}

.problem {
  background: #fff4ea;
}

.solution {
  background: #eef8f6;
}

.feasibility {
  background: #fffaf0;
}

.feasibility h2 {
  font-size: clamp(2.1rem, 5vw, 4.45rem);
}

.target {
  background: #eef3ff;
}

.value {
  background: #f8f7ed;
}

.business {
  background: #f2f1f7;
}

.impact {
  color: #ffffff;
  background: linear-gradient(135deg, #17202a, #215b63 55%, #2f9e70);
}

.hero-layout,
.split {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(300px, 0.95fr);
  gap: clamp(30px, 6vw, 86px);
  align-items: center;
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--teal);
  font-size: clamp(0.82rem, 1.4vw, 1rem);
  font-weight: 850;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero .eyebrow,
.impact .eyebrow {
  color: var(--yellow);
}

h1,
h2 {
  margin: 0;
  font-weight: 870;
  line-height: 0.98;
  letter-spacing: 0;
}

h1 {
  max-width: 900px;
  font-size: clamp(3.25rem, 7.3vw, 6.6rem);
}

h2 {
  max-width: 990px;
  font-size: clamp(2.35rem, 5.7vw, 5.25rem);
}

h3 {
  margin: 14px 0 8px;
  font-size: clamp(1.12rem, 1.8vw, 1.45rem);
}

.lede {
  max-width: 720px;
  margin: 28px 0 0;
  font-size: clamp(1.15rem, 2.1vw, 1.75rem);
  line-height: 1.42;
}

.transit-visual {
  position: relative;
  min-height: min(44vw, 430px);
}

.peak-flow {
  min-height: min(46vw, 470px);
}

.platform-line {
  position: absolute;
  left: 4%;
  right: 0;
  top: 64%;
  height: 14px;
  background: linear-gradient(90deg, rgba(255, 255, 255, 0.42), #ffffff, rgba(245, 184, 75, 0.9));
  border-radius: 999px;
  box-shadow: 0 18px 0 rgba(255, 255, 255, 0.16);
}

.speed-line {
  position: absolute;
  left: -12%;
  height: 4px;
  width: 42%;
  border-radius: 999px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.7), transparent);
  animation: speed 1.9s linear infinite;
}

.speed-one {
  top: 26%;
}

.speed-two {
  top: 76%;
  animation-delay: 0.7s;
}

.entry-flow,
.exit-flow {
  position: absolute;
  display: flex;
  gap: 12px;
}

.entry-flow {
  left: 15%;
  top: 73%;
}

.exit-flow {
  right: 16%;
  top: 43%;
}

.entry-flow::before,
.exit-flow::before {
  content: "";
  position: absolute;
  top: 50%;
  width: 92px;
  height: 4px;
  border-radius: 999px;
  background: currentColor;
}

.entry-flow::after,
.exit-flow::after {
  content: "";
  position: absolute;
  top: calc(50% - 8px);
  width: 16px;
  height: 16px;
  border-top: 4px solid currentColor;
  border-right: 4px solid currentColor;
}

.entry-flow::before {
  left: 58px;
  color: #f5b84b;
}

.entry-flow::after {
  left: 132px;
  color: #f5b84b;
  transform: rotate(45deg);
}

.exit-flow::before {
  right: 58px;
  color: #ed6a5a;
}

.exit-flow::after {
  right: 132px;
  color: #ed6a5a;
  transform: rotate(225deg);
}

.entry-flow span,
.exit-flow span {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: #ffffff;
  box-shadow: 0 0 0 6px rgba(255, 255, 255, 0.16);
}

.entry-flow span {
  animation: enterTrain 1.7s ease-in-out infinite;
}

.exit-flow span {
  animation: exitTrain 1.7s ease-in-out infinite;
}

.entry-flow span:nth-child(2),
.exit-flow span:nth-child(2) {
  animation-delay: 0.18s;
}

.entry-flow span:nth-child(3),
.exit-flow span:nth-child(3) {
  animation-delay: 0.36s;
}

.train {
  position: absolute;
  left: 2%;
  top: 30%;
  width: min(76vw, 560px);
  height: 156px;
  padding: 30px 28px 30px 76px;
  border-radius: 76px 24px 24px 76px;
  background:
    linear-gradient(90deg, rgba(237, 106, 90, 0.95) 0 13%, transparent 13%),
    linear-gradient(180deg, transparent 0 64%, rgba(15, 118, 110, 0.16) 64% 70%, transparent 70%),
    linear-gradient(135deg, #ffffff, #d9f3ef);
  box-shadow: 0 38px 80px rgba(0, 0, 0, 0.28);
  animation: trainMove 4.8s ease-in-out infinite;
}

.window,
.door {
  display: inline-block;
  height: 48px;
  margin-right: 12px;
  border-radius: 12px;
  background: #9dd9ee;
}

.window {
  width: 72px;
}

.door {
  width: 48px;
  background: #6fc2dc;
}

.exit-door {
  outline: 4px solid rgba(237, 106, 90, 0.65);
}

.front-light {
  position: absolute;
  left: 20px;
  top: 62px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--yellow);
  box-shadow: 0 0 22px rgba(245, 184, 75, 0.9);
}

.track {
  position: absolute;
  left: 7%;
  right: 7%;
  bottom: -26px;
  height: 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  box-shadow: 0 16px 0 rgba(255, 255, 255, 0.32);
}

.cards,
.feature-grid,
.proposal-grid,
.persona-board,
.value-row,
.model-list,
.impact-grid {
  display: grid;
  gap: 18px;
}

.cards {
  margin: 0;
  padding: 0;
  list-style: none;
}

.cards li,
.feature-grid article,
.proposal-grid article,
.persona-board article,
.value-row div,
.model-list article,
.impact-grid article {
  min-height: 142px;
  padding: 22px;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(23, 32, 42, 0.09);
  box-shadow: 0 20px 45px rgba(23, 32, 42, 0.08);
}

.cards strong,
.value-row strong,
.model-list b,
.impact-grid span {
  display: block;
  margin-bottom: 9px;
  color: var(--teal);
  font-size: clamp(1.18rem, 1.9vw, 1.55rem);
}

.cards span,
.feature-grid p,
.proposal-grid p,
.persona-board p,
.value-row p,
.model-list span,
.impact-grid p {
  color: var(--muted);
  font-size: clamp(0.98rem, 1.45vw, 1.18rem);
  line-height: 1.45;
}

.feature-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: clamp(28px, 5vw, 54px);
}

.feature-grid article span {
  display: inline-grid;
  width: 42px;
  height: 42px;
  place-items: center;
  color: #ffffff;
  background: var(--blue);
  border-radius: 50%;
  font-weight: 850;
}

.proposal-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: clamp(24px, 4vw, 42px);
}

.single-proposal {
  grid-template-columns: minmax(0, 0.82fr);
}

.proposal-grid article {
  min-height: 360px;
}

.single-proposal article {
  min-height: 280px;
}

.proposal-grid h3 {
  color: var(--teal);
}

.door-illustration,
.seat-illustration {
  position: relative;
  height: 128px;
  margin-bottom: 20px;
  overflow: hidden;
  background: linear-gradient(135deg, rgba(15, 118, 110, 0.1), rgba(43, 108, 176, 0.08));
}

.mini-platform {
  position: absolute;
  left: 7%;
  right: 7%;
  bottom: 24px;
  height: 10px;
  border-radius: 999px;
  background: rgba(23, 32, 42, 0.2);
}

.mini-car {
  position: absolute;
  left: 12%;
  right: 12%;
  top: 36px;
  height: 70px;
  display: flex;
  align-items: center;
  justify-content: space-around;
  padding: 10px;
  border-radius: 34px 14px 14px 34px;
  background:
    linear-gradient(90deg, rgba(237, 106, 90, 0.9) 0 12%, transparent 12%),
    #eefdfa;
  box-shadow: 0 18px 35px rgba(23, 32, 42, 0.14);
}

.mini-door,
.mini-window {
  display: grid;
  min-width: 64px;
  height: 40px;
  place-items: center;
  border-radius: 10px;
  font-size: 0.78rem;
  font-weight: 850;
}

.mini-door.entry {
  color: #17202a;
  background: var(--yellow);
}

.mini-door.exit {
  color: #ffffff;
  background: var(--coral);
}

.mini-window {
  background: #9dd9ee;
}

.entry-arrow,
.exit-arrow {
  position: absolute;
  bottom: 38px;
  font-size: 2.2rem;
  font-weight: 900;
}

.entry-arrow {
  left: 16%;
  color: var(--yellow);
}

.exit-arrow {
  right: 18%;
  color: var(--coral);
}

.seat-illustration {
  display: flex;
  align-items: end;
  justify-content: center;
  gap: 30px;
  padding-bottom: 22px;
}

.seat-shell {
  position: relative;
  width: 110px;
  height: 106px;
}

.second-seat {
  transform: translateY(10px);
}

.headrest,
.seat-back,
.seat-base {
  position: absolute;
  display: block;
  background: linear-gradient(135deg, #9dd9ee, #6fc2dc);
  box-shadow: 0 14px 28px rgba(23, 32, 42, 0.14);
}

.headrest {
  left: 28px;
  top: 0;
  width: 54px;
  height: 36px;
  border-radius: 18px 18px 10px 10px;
  background: linear-gradient(135deg, var(--yellow), #ffd980);
}

.seat-back {
  left: 18px;
  top: 30px;
  width: 74px;
  height: 68px;
  border-radius: 22px 22px 12px 12px;
}

.seat-base {
  left: 10px;
  bottom: 0;
  width: 90px;
  height: 32px;
  border-radius: 10px 10px 22px 22px;
  background: linear-gradient(135deg, #d9f3ef, #9dd9ee);
}

.persona-board {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.persona-board article {
  min-height: 220px;
}

.value-row {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: clamp(30px, 5vw, 58px);
}

.value-row div {
  min-height: 240px;
  border-top: 9px solid var(--yellow);
}

.model-list article {
  display: grid;
  grid-template-columns: minmax(140px, 0.45fr) 1fr;
  gap: 20px;
  align-items: start;
}

.impact-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-top: clamp(30px, 5vw, 54px);
}

.impact-grid article {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.16);
  box-shadow: none;
}

.impact-grid span {
  color: var(--yellow);
}

.impact-grid p {
  color: rgba(255, 255, 255, 0.84);
}

.closing-question {
  display: inline-block;
  margin: 34px 0 0;
  padding: 18px 22px;
  color: var(--ink);
  background: var(--yellow);
  font-size: clamp(1.05rem, 2vw, 1.36rem);
  font-weight: 850;
}

.dots {
  position: fixed;
  z-index: 5;
  right: 24px;
  top: 50%;
  display: grid;
  gap: 12px;
  transform: translateY(-50%);
}

.dots button {
  width: 13px;
  height: 13px;
  padding: 0;
  border: 2px solid rgba(23, 32, 42, 0.5);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.7);
  cursor: pointer;
}

.dots button[aria-current="true"] {
  background: var(--coral);
  border-color: var(--coral);
  transform: scale(1.3);
}

.progress {
  position: fixed;
  z-index: 5;
  left: 0;
  bottom: 0;
  height: 6px;
  width: 0;
  background: linear-gradient(90deg, var(--teal), var(--yellow), var(--coral));
  transition: width 220ms ease;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes trainMove {
  0%,
  100% {
    transform: translateX(-10px);
  }
  50% {
    transform: translateX(22px);
  }
}

@keyframes speed {
  from {
    opacity: 0;
    transform: translateX(0);
  }
  35% {
    opacity: 1;
  }
  to {
    opacity: 0;
    transform: translateX(150%);
  }
}

@keyframes enterTrain {
  0%,
  100% {
    transform: translateX(0);
  }
  50% {
    transform: translateX(42px);
  }
}

@keyframes exitTrain {
  0%,
  100% {
    transform: translateX(0);
  }
  50% {
    transform: translateX(-42px);
  }
}

@media (max-width: 900px) {
  body {
    overflow: auto;
  }

  .slide {
    padding: 28px;
  }

  .hero-layout,
  .split,
  .feature-grid,
  .proposal-grid,
  .persona-board,
  .value-row,
  .impact-grid {
    grid-template-columns: 1fr;
  }

  .transit-visual {
    min-height: 250px;
  }

  .train {
    left: 8%;
    width: min(82vw, 420px);
    height: 130px;
    padding: 24px 18px 24px 38px;
  }

  .window {
    width: 50px;
    height: 42px;
  }

  .door {
    width: 38px;
    height: 42px;
  }

  .model-list article {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .cards li,
  .feature-grid article,
  .proposal-grid article,
  .persona-board article,
  .value-row div,
  .model-list article,
  .impact-grid article {
    min-height: auto;
    padding: 18px;
  }

  .dots {
    right: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    scroll-behavior: auto !important;
    transition-duration: 1ms !important;
  }
}