@font-face {
  font-family: "Noto Sans SC Local";
  src: url("assets/fonts/NotoSansSC-VF.ttf") format("truetype");
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
}

:root {
  --paper: #ffffff;
  --ink: #111820;
  --muted: #58646e;
  --line: #d9dee2;
  --mist: #f1f3f4;
  --red: #b3262e;
  --red-deep: #861b22;
  --teal: #2c6f6a;
  --teal-soft: #dce9e7;
  --amber: #b98b36;
  --font: "Noto Sans SC Local", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  color-scheme: light;
  font-synthesis: none;
  line-break: strict;
  overflow-wrap: break-word;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: 0;
  text-rendering: optimizeLegibility;
}

button,
a {
  font: inherit;
}

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  padding: 0 5vw;
  border-bottom: 1px solid rgba(17, 24, 32, 0.12);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  font-size: 15px;
  font-weight: 760;
  text-decoration: none;
}

.wordmark-mark {
  display: block;
  width: 24px;
  height: 6px;
  background: var(--red);
}

.site-header nav {
  display: flex;
  gap: 26px;
  font-size: 14px;
  font-weight: 560;
}

.site-header nav a {
  text-decoration: none;
}

.site-header nav a:hover,
.site-header nav a:focus-visible {
  color: var(--red);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(460px, 1.08fr);
  gap: 6vw;
  align-items: center;
  min-height: 690px;
  padding: 76px 6vw 82px;
  border-bottom: 1px solid var(--line);
}

.hero-copy {
  max-width: 660px;
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--red);
  font-size: 13px;
  font-weight: 760;
  letter-spacing: 0;
}

h1,
h2,
h3,
p {
  text-wrap: pretty;
}

h1,
h2,
h3 {
  letter-spacing: 0;
}

h1 {
  margin: 0;
  max-width: 9em;
  font-size: 64px;
  font-weight: 860;
  line-height: 1.18;
}

.hero-lead {
  max-width: 31em;
  margin: 30px 0 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.85;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin-top: 32px;
  border-top: 1px solid var(--ink);
}

.hero-meta span {
  padding: 12px 22px 10px 0;
  color: var(--muted);
  font-size: 13px;
  font-weight: 620;
}

.hero-route {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  min-height: 430px;
  align-items: center;
}

.route-line {
  position: absolute;
  left: 8%;
  right: 8%;
  top: 50%;
  height: 4px;
  background: var(--red);
  transform: translateY(-2px);
}

.route-line::after {
  content: "";
  position: absolute;
  right: -2px;
  top: -5px;
  width: 0;
  height: 0;
  border-top: 7px solid transparent;
  border-bottom: 7px solid transparent;
  border-left: 11px solid var(--red);
}

.route-stop {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 174px;
  min-height: 222px;
  padding: 18px;
  border: 1px solid var(--ink);
  border-radius: 4px;
  background: var(--paper);
}

.route-stop-hold {
  justify-self: center;
  width: 200px;
  min-height: 268px;
  background: var(--ink);
  color: var(--paper);
}

.route-stop-sell {
  justify-self: end;
}

.stop-index {
  color: var(--red);
  font-size: 14px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.route-stop strong {
  font-size: 30px;
  line-height: 1.2;
}

.route-stop small {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}

.route-stop-hold small {
  color: #cdd4d9;
}

.section {
  padding: 112px 6vw;
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(260px, 0.8fr) minmax(320px, 1.2fr);
  column-gap: 8vw;
  align-items: end;
  max-width: 1220px;
  margin: 0 auto 56px;
}

.section-heading .eyebrow {
  grid-column: 1 / -1;
}

.section-heading h2 {
  margin: 0;
  max-width: 12em;
  font-size: 42px;
  font-weight: 820;
  line-height: 1.28;
}

.section-heading > p:last-child {
  margin: 0;
  max-width: 34em;
  color: var(--muted);
}

.route-section {
  background: var(--mist);
}

.stage-control {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  width: min(520px, 100%);
  min-height: 50px;
  margin: 0 auto 20px;
  border: 1px solid var(--ink);
  background: var(--paper);
}

.stage-tab {
  min-height: 48px;
  border: 0;
  border-right: 1px solid var(--ink);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  font-weight: 680;
}

.stage-tab:last-child {
  border-right: 0;
}

.stage-tab.is-active {
  background: var(--red);
  color: var(--paper);
}

.stage-tab:focus-visible,
.quiz-card button:focus-visible {
  outline: 3px solid var(--teal);
  outline-offset: 2px;
}

.stage-panel {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr) 240px;
  gap: 32px;
  align-items: center;
  max-width: 1120px;
  min-height: 310px;
  margin: 0 auto;
  padding: 44px;
  border: 1px solid var(--ink);
  background: var(--paper);
}

.stage-number {
  color: var(--red);
  font-size: 92px;
  font-weight: 180;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.stage-kicker {
  margin: 0 0 8px;
  color: var(--teal);
  font-size: 14px;
  font-weight: 760;
}

.stage-copy h3 {
  margin: 0 0 18px;
  max-width: 18em;
  font-size: 26px;
  line-height: 1.42;
}

.stage-copy p:last-child {
  margin: 0;
  max-width: 34em;
  color: var(--muted);
}

.stage-ledger {
  display: grid;
  grid-template-columns: 1fr;
  align-content: center;
  min-height: 180px;
  padding-left: 24px;
  border-left: 1px solid var(--line);
}

.stage-ledger span {
  margin-top: 13px;
  color: var(--muted);
  font-size: 12px;
}

.stage-ledger strong {
  font-size: 16px;
  font-weight: 720;
}

.checklist {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  max-width: 1120px;
  margin: 26px auto 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.checklist article {
  min-height: 176px;
  padding: 26px;
  background: var(--paper);
}

.checklist span {
  color: var(--red);
  font-size: 12px;
  font-weight: 800;
}

.checklist h3 {
  margin: 18px 0 8px;
  font-size: 19px;
}

.checklist p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.75;
}

.quiz-section {
  border-bottom: 1px solid var(--line);
}

.quiz-heading {
  grid-template-columns: 1fr;
}

.quiz-heading h2 {
  max-width: 15em;
}

.quiz-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  max-width: 1220px;
  margin: 0 auto;
}

.quiz-card {
  display: grid;
  grid-template-rows: auto repeat(3, minmax(54px, auto)) 28px;
  gap: 10px;
  min-height: 430px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
}

.quiz-card-head {
  min-height: 126px;
}

.quiz-card-head span {
  display: block;
  margin-bottom: 18px;
  color: var(--red);
  font-size: 13px;
  font-weight: 800;
}

.quiz-card-head p {
  margin: 0;
  font-size: 20px;
  font-weight: 720;
  line-height: 1.55;
}

.quiz-card button {
  width: 100%;
  min-height: 54px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--mist);
  color: var(--ink);
  cursor: pointer;
  text-align: left;
  font-size: 14px;
  line-height: 1.5;
}

.quiz-card button:hover {
  border-color: var(--ink);
}

.quiz-card button.is-correct {
  border-color: var(--teal);
  background: var(--teal-soft);
}

.quiz-card button.is-wrong {
  border-color: var(--red);
  background: #f7e8e9;
}

.quiz-feedback {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.quiz-feedback[data-state="correct"] {
  color: var(--teal);
}

.quiz-feedback[data-state="wrong"] {
  color: var(--red-deep);
}

.source-section {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(420px, 1.15fr);
  gap: 8vw;
  background: var(--ink);
  color: var(--paper);
}

.source-intro h2 {
  margin: 0 0 28px;
  max-width: 10em;
  font-size: 42px;
  line-height: 1.3;
}

.source-intro > p:last-child {
  max-width: 34em;
  margin: 0;
  color: #c5ced4;
}

.source-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid #56616a;
}

.source-list li {
  display: grid;
  grid-template-columns: 110px minmax(0, 1fr);
  gap: 5px 20px;
  padding: 24px 0;
  border-bottom: 1px solid #56616a;
}

.source-list span {
  grid-row: 1 / 3;
  color: #8fa0ab;
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}

.source-list a {
  font-weight: 700;
}

.source-list small {
  color: #aeb9c1;
}

.site-footer {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 28px;
  padding: 24px 6vw;
  border-top: 1px solid #303942;
  background: var(--ink);
  color: #aeb9c1;
  font-size: 12px;
}

@media (max-width: 1020px) {
  h1 {
    font-size: 52px;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 58px;
    min-height: 0;
  }

  .hero-route {
    max-width: 720px;
  }

  .stage-panel {
    grid-template-columns: 100px minmax(0, 1fr);
  }

  .stage-ledger {
    grid-column: 2;
    grid-template-columns: 90px 1fr;
    min-height: 0;
    padding: 18px 0 0;
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .stage-ledger span {
    margin-top: 0;
  }

  .quiz-grid {
    grid-template-columns: 1fr;
  }

  .quiz-card {
    min-height: 0;
  }

  .source-section {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .site-header {
    height: 60px;
    padding: 0 20px;
  }

  .site-header nav {
    gap: 14px;
    font-size: 12px;
  }

  .site-header nav a:last-child {
    display: none;
  }

  .hero {
    padding: 56px 20px 64px;
  }

  h1 {
    font-size: 42px;
  }

  .hero-lead {
    font-size: 16px;
  }

  .hero-route {
    grid-template-columns: 1fr;
    gap: 14px;
    min-height: 0;
  }

  .route-line {
    left: 25px;
    right: auto;
    top: 8%;
    bottom: 8%;
    width: 4px;
    height: auto;
    transform: none;
  }

  .route-line::after {
    right: -5px;
    top: auto;
    bottom: -2px;
    border-top: 11px solid var(--red);
    border-right: 7px solid transparent;
    border-bottom: 0;
    border-left: 7px solid transparent;
  }

  .route-stop,
  .route-stop-hold,
  .route-stop-sell {
    justify-self: stretch;
    width: auto;
    min-height: 150px;
    margin-left: 46px;
  }

  .section {
    padding: 76px 20px;
  }

  .section-heading {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .section-heading h2,
  .source-intro h2 {
    font-size: 34px;
  }

  .stage-panel {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 28px 22px;
  }

  .stage-number {
    font-size: 68px;
  }

  .stage-ledger {
    grid-column: 1;
  }

  .checklist {
    grid-template-columns: 1fr;
  }

  .quiz-card {
    padding: 20px;
  }

  .source-section {
    gap: 50px;
  }

  .source-list li {
    grid-template-columns: 1fr;
  }

  .source-list span {
    grid-row: auto;
  }

  .site-footer {
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 22px 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}