:root {
  --paper: #050505;
  --surface: #121212;
  --surface-2: #1a1a1a;
  --line: #262624;
  --dark: #000000;
  --white: #ffffff;
  --sans: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in: cubic-bezier(0.4, 0, 1, 1);

  /* Ink tiers — Figma color styles Ink/100..30, white @ opacity */
  --ink-100: rgba(255, 255, 255, 1);
  --ink-80: rgba(255, 255, 255, 0.8);
  --ink-65: rgba(255, 255, 255, 0.65);
  --ink-45: rgba(255, 255, 255, 0.45);
  --ink-30: rgba(255, 255, 255, 0.3);

  /* Type scale — Figma text styles, converted from the 2940px canvas at ratio 2940/1416 */
  --fs-h1: 38.5px;    /* H1 */
  --fs-h2: 28.9px;    /* H2 */
  --fs-t1: 23.1px;    /* T1 */
  --fs-h3: 18.3px;    /* H3 */
  --fs-body: 14.4px;  /* Body / Body Strong / Body Weak */
  --fs-eyebrow: 13.5px; /* Eyebrow */
  --fs-nav: 11.6px;   /* Nav Active / Nav Inactive */
  --fs-label: 10.6px; /* Index/Label / Meta Label */
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink-100);
  font-family: var(--sans);
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; }
a { color: inherit; }
button { font: inherit; }

.topbar {
  position: fixed;
  z-index: 30;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 56px;
  padding: 0 28px;
  border-bottom: 1px solid rgba(242, 242, 238, 0.1);
  background: rgba(5, 5, 5, 0.86);
  backdrop-filter: blur(16px);
}

.topbar a,
.topbar span {
  color: var(--ink-100);
  font: 400 var(--fs-nav)/1.5 var(--mono);
  letter-spacing: 0.02em;
  text-decoration: none;
}

.topbar__back:hover,
.topbar__title:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.page-shell {
  display: grid;
  grid-template-columns: 176px minmax(0, 1120px);
  gap: clamp(36px, 6vw, 96px);
  width: min(100% - 56px, 1416px);
  margin: 0 auto;
  padding-top: 56px;
}

.case-index {
  position: sticky;
  top: 96px;
  align-self: start;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 74px;
}

.case-index__title {
  margin: 0 0 12px;
  color: var(--ink-45);
  font: 400 var(--fs-label)/1 var(--mono);
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.case-index a {
  position: relative;
  color: var(--ink-45);
  font: 400 var(--fs-nav)/1.5 var(--mono);
  text-decoration: none;
  transition: color 180ms ease;
}

.case-index a::before {
  position: absolute;
  top: 0.65em;
  left: -18px;
  width: 8px;
  height: 1px;
  background: var(--ink-100);
  content: "";
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 180ms ease, transform 180ms ease;
}

.case-index a:hover,
.case-index a.is-active { color: var(--ink-100); }

.case-index a.is-active::before {
  opacity: 1;
  transform: none;
}

.case-main { min-width: 0; }

.hero {
  padding: clamp(72px, 9vw, 124px) 0 clamp(96px, 12vw, 156px);
}

.hero__heading { max-width: 800px; }

.eyebrow,
.caption {
  margin: 0;
  color: var(--ink-65);
  font: 400 var(--fs-eyebrow)/1.4 var(--mono);
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 18px 0;
  color: var(--ink-100);
  font-family: "Alibaba PuHuiTi 3.0", var(--sans);
  font-size: var(--fs-h1);
  font-weight: 600;
  letter-spacing: -0.045em;
  line-height: 1.03;
}

.hero__dek {
  max-width: 700px;
  margin: 0;
  color: var(--ink-80);
  font-size: var(--fs-h3);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.4;
}

.project-meta {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 24px;
  margin: clamp(52px, 7vw, 84px) 0 36px;
  padding: 20px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.project-meta div { min-width: 0; }

.project-meta dt {
  margin-bottom: 8px;
  color: var(--ink-30);
  font: 400 var(--fs-label)/1 var(--mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.project-meta dd {
  margin: 0;
  color: var(--ink-100);
  font-size: var(--fs-body);
  line-height: 1.5;
}

.media { margin: 0; }
.media img { width: 100%; height: auto; }

.media figcaption {
  max-width: 720px;
  margin-top: 12px;
  color: var(--ink-45);
  font-size: 12px;
  line-height: 1.6;
}

.media--hero {
  overflow: hidden;
  display: grid;
  place-items: center;
  min-height: 420px;
  padding: clamp(24px, 4vw, 48px);
  background: var(--surface);
  border: 1px solid var(--line);
}

.media--hero img,
.media--hero video {
  max-width: min(100%, 810px);
  max-height: 576px;
  width: auto;
  height: auto;
  object-fit: contain;
}

.media--board,
.media--full {
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--line);
}

.section {
  padding: clamp(76px, 9vw, 112px) 0;
  border-top: 1px solid var(--line);
  scroll-margin-top: 72px;
}

.section-head {
  max-width: 820px;
  margin-bottom: clamp(44px, 5vw, 68px);
}

.section-head h2,
.chapter-title h2 {
  margin: 18px 0 0;
  color: var(--ink-100);
  font-size: var(--fs-h2);
  font-weight: 400;
  letter-spacing: -0.035em;
  line-height: 1.2;
}

.section-head--compact { margin-bottom: 56px; }

.section-head__intro,
.chapter-title__intro {
  max-width: 650px;
  margin: 26px 0 0;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.75;
}

.two-column-copy {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(40px, 7vw, 96px);
  max-width: 980px;
}

.two-column-copy h3,
.narrative-row h3 {
  margin: 0 0 14px;
  color: var(--ink-80);
  font-size: var(--fs-h3);
  font-weight: 400;
  letter-spacing: -0.015em;
  line-height: 1.4;
}

.two-column-copy p {
  margin: 0;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.8;
}

.chapter-title {
  position: relative;
  max-width: 900px;
  margin-bottom: clamp(56px, 7vw, 84px);
}

.chapter-title__type {
  position: absolute;
  top: 0;
  right: 0;
  margin: 0;
  color: var(--ink-45);
  font: 400 var(--fs-label)/1.4 var(--mono);
}

.narrative-row {
  display: grid;
  grid-template-columns: minmax(260px, 0.68fr) minmax(0, 1.32fr);
  gap: clamp(44px, 8vw, 104px);
  align-items: center;
  margin-bottom: clamp(64px, 8vw, 96px);
}

.narrative-row__copy p {
  margin: 0 0 18px;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.8;
}

.media-pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-top: 24px;
}

.narrative-row__copy p:last-child { margin-bottom: 0; }

/* Chapter note — plain text block, no heading weight beyond body copy */
.chapter-note {
  max-width: 700px;
  margin-bottom: clamp(32px, 4vw, 44px);
}

.chapter-note h3 {
  margin: 14px 0 12px;
  color: var(--ink-100);
  font-size: 20px;
  font-weight: 400;
  letter-spacing: -0.015em;
  line-height: 1.35;
}

.chapter-note p {
  margin: 0;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.8;
}

.chapter-note__followup {
  max-width: 700px;
  margin: clamp(28px, 4vw, 40px) 0 0;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.7;
}

.question-list.question-list--standalone {
  max-width: 700px;
  margin-top: 18px;
  margin-bottom: clamp(64px, 8vw, 96px);
}

/* Stat grid — highlighted numeric evidence, count up on reveal */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-bottom: clamp(64px, 8vw, 96px);
  background: var(--line);
  border: 1px solid var(--line);
}

.stat-grid article {
  padding: clamp(28px, 4vw, 40px);
  background: var(--surface);
}

.stat-grid__value {
  margin: 0 0 16px;
  color: var(--ink-100);
  font-size: var(--fs-h2);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1;
}

.stat-grid__label {
  max-width: 380px;
  margin: 0 0 14px;
  color: var(--ink-100);
  font-size: var(--fs-body);
  line-height: 1.6;
}

.stat-grid__source {
  margin: 0;
  color: var(--ink-45);
  font: 400 var(--fs-label)/1.4 var(--mono);
  letter-spacing: 0.04em;
}

/* Question list — supporting detail under a narrative-row, not a headline grid */
.question-list {
  display: grid;
  gap: 18px;
  margin: 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.question-list li {
  display: grid;
  grid-template-columns: 26px 1fr;
  gap: 12px;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.6;
}

.question-list span {
  color: var(--ink-45);
  font: 400 var(--fs-label)/1.6 var(--mono);
}

/* Comparison toggle (draft/collapsed states) — reused card pattern */
.positioning-block { margin: 0 0 clamp(64px, 8vw, 96px); }

.phone-compare {
  display: grid;
  grid-template-columns: minmax(280px, 0.8fr) minmax(320px, 1.2fr);
  gap: clamp(42px, 8vw, 104px);
  align-items: center;
  min-height: 0;
  padding: clamp(36px, 6vw, 72px);
  background: var(--surface);
  border: 1px solid var(--line);
}

.phone-compare__copy {
  align-self: stretch;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.phone-compare__copy h3 {
  max-width: 380px;
  margin: 16px 0 0;
  color: var(--ink-80);
  font-size: var(--fs-t1);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.35;
}

.segmented-control {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  margin: 30px 0 26px;
  border-top: 1px solid #303030;
}

.segmented-control button {
  padding: 18px 0;
  border: 0;
  border-bottom: 1px solid #303030;
  background: transparent;
  color: var(--ink-30);
  font-size: var(--fs-body);
  text-align: left;
  cursor: pointer;
  transition: color 180ms ease;
}

.segmented-control button.is-active,
.segmented-control button:hover { color: var(--ink-100); }

.phone-compare__notes { min-height: 96px; }

.phone-compare__note {
  display: none;
  max-width: 400px;
  margin: 0;
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.7;
}

.phone-compare__note.is-active { display: block; }

.phone-compare__stage {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 320px;
}

.phone-compare__image {
  display: none;
  width: 100%;
  max-height: 560px;
  object-fit: contain;
  border-radius: 4px;
}

.phone-compare__image.is-active { display: block; }

p.narrative-row__quote {
  margin: 0;
  padding-left: 18px;
  border-left: 2px solid var(--line);
  color: var(--ink-80);
  font-size: var(--fs-t1);
  font-weight: 400;
  line-height: 1.35;
}


/* Single video result stage */
.solution-block--single {
  display: grid;
  place-items: center;
  margin-bottom: 0;
}

.solution-block__stage {
  display: grid;
  place-items: center;
  width: 100%;
  padding: clamp(32px, 5vw, 56px);
  background: var(--surface);
  border: 1px solid var(--line);
}

.result-video {
  max-width: min(100%, 810px);
  max-height: 576px;
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: 24px;
  background: #000;
}

/* Compressed contribution list — accordion drawer with a fixed-viewport preview window (ported from 点点3.0's other-explorer pattern) */
.contribution-list {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.contribution-list--interactive {
  display: grid;
  grid-template-columns: 1fr;
  overflow: hidden;
}

.contribution-list--interactive button {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 44px minmax(150px, 0.28fr) minmax(0, 1fr) 18px;
  align-items: center;
  gap: 20px;
  min-height: 92px;
  width: 100%;
  padding: 20px 18px;
  border: 0;
  border-bottom: 1px solid var(--line);
  background: transparent;
  color: var(--ink-100);
  text-align: left;
  cursor: pointer;
  scroll-margin-top: 72px;
  transition: background 180ms ease, color 180ms ease;
}

.contribution-list--interactive button > div { display: contents; }

.contribution-list span {
  color: var(--ink-45);
  font: 400 var(--fs-label)/1.4 var(--mono);
}

.contribution-list h3,
.contribution-list p { margin: 0; }

.contribution-list h3 {
  color: inherit;
  font-size: var(--fs-body);
  font-weight: 400;
}

.contribution-list h3 em {
  color: var(--ink-45);
  font-size: var(--fs-label);
  font-style: normal;
}

.contribution-list p {
  color: var(--ink-65);
  font-size: var(--fs-body);
  line-height: 1.6;
}

.contribution-list--interactive b {
  color: var(--ink-45);
  font: 300 22px/1 var(--sans);
  text-align: center;
}

.contribution-list--interactive button:hover b,
.contribution-list--interactive button.is-active b {
  color: var(--ink-100);
}

.contribution-list--interactive button.is-active {
  background: rgba(255, 255, 255, 0.08);
  border-bottom-color: #333333;
}

/* Drawer: opens directly under whichever row was clicked */
.contribution-list--interactive .other-preview {
  width: 100%;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transform: translateY(-10px);
  border-bottom: 0 solid var(--line);
  transition: max-height 520ms var(--ease), opacity 240ms ease, transform 420ms var(--ease), border-width 0s linear 520ms;
}

.contribution-list--interactive .other-preview.is-open {
  max-height: 900px;
  opacity: 1;
  transform: none;
  border-bottom-width: 1px;
  transition: max-height 620ms var(--ease), opacity 300ms 90ms ease, transform 520ms var(--ease), border-width 0s;
}

.other-preview {
  background: var(--dark);
  color: var(--ink-100);
}

.other-preview__topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 15px 18px;
  border-bottom: 1px solid #333333;
  cursor: pointer;
}

.other-preview__topline p,
.other-preview__topline span {
  margin: 0;
  color: var(--ink-65);
  font: 400 var(--fs-label)/1.4 var(--mono);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.other-preview__topline p { color: var(--ink-65); }
.other-preview__topline:focus-visible { outline: 1px solid var(--ink-100); outline-offset: -3px; }

.other-preview__viewport {
  position: relative;
  overflow: hidden;
  max-width: 90%;
  height: 576px;
  margin: 0 auto;
  background: #000;
}

.other-preview__panel {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 420ms var(--ease), visibility 0s linear 420ms;
}

.other-preview__panel.is-active {
  opacity: 1;
  visibility: visible;
  transition-delay: 0s;
}

.other-preview__panel img,
.other-preview__panel video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  opacity: 0;
  transform: scale(1.012);
  transition: opacity 500ms var(--ease), transform 900ms var(--ease);
}

.other-preview__panel img.is-active,
.other-preview__panel video.is-active {
  opacity: 1;
  transform: none;
}

.other-preview__empty {
  position: relative;
  margin: 0;
  color: var(--ink-45);
  font-size: var(--fs-body);
}

@media (max-width: 900px) {
  .contribution-list--interactive button { grid-template-columns: 34px minmax(120px, 0.4fr) minmax(0, 1fr) 16px; gap: 12px; }
}

@media (max-width: 560px) {
  .contribution-list--interactive button {
    grid-template-columns: 28px 1fr 16px;
    align-items: start;
    min-height: 0;
  }
  .contribution-list--interactive button > div { display: block; }
  .contribution-list h3 { margin: -3px 0 7px; }
  .contribution-list--interactive .other-preview.is-open { max-height: 620px; }
  .other-preview__viewport { height: 360px; }
}

@media (prefers-reduced-motion: reduce) {
  .contribution-list--interactive .other-preview,
  .contribution-list--interactive .other-preview.is-open { transition: none; }
}

.case-end-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  margin-top: clamp(72px, 9vw, 112px);
  padding: 24px 0;
  border-top: 1px solid var(--ink-100);
}

.case-end-nav span,
.case-end-nav a {
  color: var(--ink-45);
  font: 400 var(--fs-label)/1.5 var(--mono);
  text-decoration: none;
}

.case-end-nav a { color: var(--ink-45); }

.case-end-nav a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 700ms var(--ease), transform 700ms var(--ease);
}

[data-reveal][data-revealed] {
  opacity: 1;
  transform: none;
}

@media (max-width: 1040px) {
  .page-shell {
    display: block;
    width: min(100% - 40px, 920px);
  }

  .case-index { display: none; }

  .narrative-row,
  .phone-compare,
  .media-pair { grid-template-columns: 1fr; }

  .narrative-row { gap: 40px; }
}

@media (max-width: 720px) {
  .topbar { min-height: 52px; padding: 0 18px; }
  .topbar__title { display: none; }

  .page-shell { width: min(100% - 32px, 620px); padding-top: 52px; }

  .hero { padding-top: 56px; }
  .hero h1 { font-size: 32px; }
  .hero__dek { font-size: 16px; }

  .project-meta { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: 22px; }

  .media--hero { min-height: 280px; padding: 20px 14px; }

  .two-column-copy,
  .stat-grid { grid-template-columns: 1fr; }

  .question-list li { grid-template-columns: 22px 1fr; }

  .two-column-copy { gap: 40px; }

  .phone-compare { padding: 32px 24px 42px; }
  .phone-compare__stage { min-height: 280px; }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  [data-reveal] { opacity: 1; transform: none; }
}