:root {
  --ink: #1e1e1e;
  --muted: #666a73;
  --red: #ff4d4f;
  --red-dark: #e73538;
  --pink: #fff1f1;
  --gray: #f4f5f7;
  --line: #dcdfe4;
  --white: #ffffff;
  --max: 1200px;
  --shadow: 0 18px 48px rgba(20, 20, 20, 0.11);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--white);
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
button, a { font: inherit; }
a { color: inherit; text-decoration: none; }
.skip-link { position: fixed; left: 12px; top: -80px; z-index: 99; padding: 10px 14px; color: #fff; background: var(--ink); }
.skip-link:focus { top: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: grid;
  grid-template-columns: 1fr auto auto;
  align-items: center;
  gap: 48px;
  width: min(calc(100% - 48px), 1400px);
  height: 78px;
  margin: 0 auto;
  border-bottom: 1px solid var(--line);
  background: rgba(255,255,255,.94);
  backdrop-filter: blur(14px);
}
.brand { font-size: 20px; font-weight: 800; letter-spacing: -0.04em; }
.brand strong { font-weight: 600; }
.nav { display: flex; gap: 34px; font-size: 15px; font-weight: 500; }
.nav a { position: relative; padding: 10px 0; }
.nav a::after { content: ""; position: absolute; left: 0; right: 100%; bottom: 4px; height: 2px; background: var(--red); transition: right .22s ease; }
.nav a:hover::after, .nav a:focus-visible::after { right: 0; }

.button {
  display: inline-flex;
  min-height: 52px;
  align-items: center;
  justify-content: center;
  padding: 0 26px;
  border: 1px solid var(--red);
  border-radius: 7px;
  color: #fff;
  background: var(--red);
  font-weight: 700;
  cursor: pointer;
  transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}
.button:hover { transform: translateY(-2px); background: var(--red-dark); box-shadow: 0 10px 25px rgba(255,77,79,.2); }
.button:focus-visible, .copy-button:focus-visible { outline: 3px solid rgba(255,77,79,.28); outline-offset: 3px; }
.button--small { min-height: 42px; padding: 0 18px; font-size: 14px; }
.button--outline { border-color: var(--ink); color: var(--ink); background: #fff; }
.button--outline:hover { color: #fff; background: var(--ink); box-shadow: 0 10px 25px rgba(30,30,30,.14); }

.section-shell { width: min(calc(100% - 48px), var(--max)); margin-inline: auto; }
.hero {
  display: grid;
  grid-template-columns: minmax(400px, .82fr) minmax(610px, 1.18fr);
  gap: clamp(30px, 5vw, 86px);
  align-items: center;
  width: min(calc(100% - 48px), 1400px);
  min-height: 800px;
  margin: 0 auto;
  padding: 58px 0 72px;
}
.hero__copy h1 { margin: 0; font-size: clamp(54px, 5.2vw, 86px); line-height: 1.12; letter-spacing: -0.075em; font-weight: 900; }
.hero__copy h1 span, .section-heading h2 span, .closing h2 span { color: var(--red); }
.hero__copy p { max-width: 580px; margin: 30px 0 34px; color: var(--muted); font-size: 20px; line-height: 1.85; }
.hero__actions { display: flex; flex-wrap: wrap; gap: 14px; }

.workbench { position: relative; min-height: 620px; border-radius: 10px; background: #fff; overflow: hidden; }
.workbench::before { content: ""; position: absolute; inset: 12% 0 10%; background: linear-gradient(90deg, transparent, #fafafa 25%, #fff 85%); border-top: 1px solid #eee; border-bottom: 1px solid #eee; }
.workbench__label, .master-label, .variants-label { position: absolute; z-index: 4; color: var(--red); font-size: 13px; font-weight: 700; letter-spacing: .03em; }
.label-source { top: 80px; left: 2%; }
.source-shot { position: absolute; top: 110px; left: 0; z-index: 2; width: 23%; margin: 0; padding: 7px; border: 1px solid #bbb; background: #fff; box-shadow: 0 12px 24px rgba(0,0,0,.09); transform: rotate(-2deg); }
.source-shot img { aspect-ratio: 3/4; object-fit: cover; }
.reason-note { position: absolute; top: 338px; left: 12%; z-index: 5; display: grid; width: 170px; padding: 18px 20px; background: #fff2a8; box-shadow: 0 10px 18px rgba(0,0,0,.15); transform: rotate(2deg); }
.reason-note strong { margin-bottom: 8px; color: var(--red); font-size: 13px; }
.reason-note span { font-size: 14px; font-weight: 600; }
.master-label { top: 30px; left: 39%; }
.master-shot { position: absolute; top: 62px; left: 37%; z-index: 3; width: 27%; margin: 0; padding: 8px; border: 1px solid #777; background: #fff; box-shadow: var(--shadow); }
.master-shot img { aspect-ratio: 3/4; object-fit: cover; }
.master-shot::before, .master-shot::after { content: ""; position: absolute; width: 18px; height: 18px; border-color: var(--ink); }
.master-shot::before { top: -7px; left: -7px; border-top: 1px solid; border-left: 1px solid; }
.master-shot::after { right: -7px; bottom: -7px; border-right: 1px solid; border-bottom: 1px solid; }
.variants-label { top: 138px; right: 19%; }
.variant-strip { position: absolute; top: 172px; right: 0; z-index: 3; display: flex; align-items: end; width: 38%; gap: 7px; }
.variant-strip figure { flex: 1; margin: 0; }
.variant-strip img { aspect-ratio: 3/4; object-fit: cover; border: 1px solid #bbb; box-shadow: 0 10px 20px rgba(0,0,0,.08); }
.variant-strip figcaption { margin-top: 6px; color: var(--red); text-align: center; font-size: 12px; font-weight: 700; }
.route { position: absolute; z-index: 1; overflow: visible; fill: none; stroke: var(--red); stroke-width: 2; }
.route--one { top: 154px; left: 20%; width: 22%; }
.route--two { top: 338px; left: 57%; width: 17%; transform: rotate(-7deg); }
.annotation { position: absolute; z-index: 6; color: var(--red); font-family: "STKaiti", "KaiTi", serif; font-size: 17px; transform: rotate(-5deg); }
.annotation--top { top: 4px; right: 7%; }
.annotation--bottom { right: 2%; bottom: 35px; padding-bottom: 2px; border-bottom: 2px solid var(--red); }

.statement { padding: 72px 0 100px; border-top: 1px solid var(--line); }
.statement h2 { margin: 0 0 12px; font-size: clamp(40px, 5vw, 68px); line-height: 1.15; letter-spacing: -0.06em; }
.statement p { margin: 0; color: var(--muted); font-size: 18px; }
.section-heading { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(260px, .6fr); gap: 64px; align-items: end; margin-bottom: 64px; }
.section-heading h2 { margin: 0; font-size: clamp(42px, 5vw, 68px); line-height: 1.14; letter-spacing: -0.06em; }
.section-heading p { margin: 0; color: var(--muted); font-size: 17px; }
.section-heading--wide { display: block; }
.section-heading--wide p { margin-top: 20px; }

.capabilities { padding: 120px 0 148px; }
.capability-layout { display: grid; grid-template-columns: minmax(390px, .72fr) minmax(0, 1.28fr); gap: 84px; align-items: center; }
.capability-list { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.capability-list li { display: grid; grid-template-columns: 70px 1fr; align-items: center; min-height: 72px; border-bottom: 1px solid var(--line); }
.capability-list span { color: var(--red); font-size: 24px; font-weight: 800; }
.capability-list strong { font-size: 18px; }
.process-board { position: relative; padding: 42px; border: 1px solid var(--line); background: #fff; box-shadow: var(--shadow); }
.board-row { display: flex; align-items: center; justify-content: center; gap: 18px; }
.board-row figure { width: 145px; margin: 0; }
.board-row figure img { aspect-ratio: 3/4; object-fit: cover; border: 1px solid #ccc; }
.board-row figcaption { margin-top: 6px; font-size: 12px; font-weight: 700; text-align: center; }
.board-master { width: 125px !important; }
.board-arrow { color: var(--red); font-size: 28px; }
.board-note, .data-paper { padding: 16px; border: 1px solid #ccc; background: var(--gray); }
.board-note strong, .data-paper strong { display: block; margin-bottom: 8px; }
.board-note p { margin: 0; font-size: 14px; }
.board-line { width: 65%; height: 54px; margin: 14px auto; border-right: 2px solid var(--red); border-bottom: 2px solid var(--red); border-bottom-right-radius: 30px; }
.board-row--bottom { justify-content: flex-end; }
.mini-variants { display: flex; gap: 7px; }
.mini-variants img { width: 74px; aspect-ratio: 3/4; object-fit: cover; border: 1px solid #bbb; }
.data-paper { display: grid; gap: 6px; font-size: 12px; background: #fffdf4; transform: rotate(1deg); box-shadow: 0 8px 18px rgba(0,0,0,.08); }

.workflow { padding: 136px 0; }
.timeline { position: relative; }
.timeline::before { content: ""; position: absolute; top: 34px; bottom: 34px; left: 50%; width: 2px; background: var(--red); transform: translateX(-50%); }
.step { position: relative; display: grid; grid-template-columns: 1fr 82px 1fr; align-items: center; min-height: 310px; padding: 42px 0; border-bottom: 1px dashed var(--line); }
.step__number { grid-column: 2; display: grid; place-items: center; z-index: 2; width: 54px; height: 54px; justify-self: center; border: 2px solid var(--red); border-radius: 50%; color: var(--red); background: #fff; font-size: 18px; font-weight: 800; }
.step__copy { grid-column: 1; grid-row: 1; padding-right: 70px; }
.step__visual { grid-column: 3; grid-row: 1; margin-left: 70px; }
.step--reverse .step__copy { grid-column: 3; padding: 0 0 0 70px; }
.step--reverse .step__visual { grid-column: 1; margin: 0 70px 0 0; }
.step__copy h3 { margin: 0 0 12px; font-size: 30px; letter-spacing: -0.04em; }
.step__copy p { margin: 0; color: var(--muted); font-size: 16px; }
.material-stack { position: relative; display: flex; align-items: center; gap: 20px; }
.material-stack img { width: 150px; aspect-ratio: 3/4; object-fit: cover; padding: 6px; border: 1px solid #bbb; background: #fff; box-shadow: 0 12px 24px rgba(0,0,0,.08); transform: rotate(-2deg); }
.paper-note { padding: 26px; background: #fff2a8; box-shadow: 0 10px 20px rgba(0,0,0,.1); font-weight: 700; transform: rotate(2deg); }
.reason-sheet { display: grid; grid-template-columns: auto 1fr; gap: 10px 18px; padding: 28px; border: 1px solid var(--line); }
.reason-sheet span { color: var(--red); font-size: 13px; font-weight: 700; }
.path-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.path-list span { padding: 16px; border: 1px solid var(--line); background: #fff; text-align: center; font-weight: 600; }
.path-list .active { border-color: var(--red); color: var(--red); background: var(--pink); }
.ratios { display: flex; align-items: end; justify-content: center; gap: 16px; }
.ratios img { width: 150px; aspect-ratio: 3/4; object-fit: cover; box-shadow: var(--shadow); }
.ratio { display: grid; place-items: center; border: 1px solid var(--red); color: var(--red); font-weight: 800; }
.ratio--three { width: 75px; aspect-ratio: 3/4; }
.ratio--nine { width: 58px; aspect-ratio: 9/16; }
.edit-row { position: relative; display: flex; align-items: center; justify-content: center; gap: 16px; }
.edit-row img { width: 125px; aspect-ratio: 3/4; object-fit: cover; border: 1px solid #bbb; }
.edit-row > span { color: var(--red); font-size: 28px; }
.edit-row em { position: absolute; top: -28px; right: 12%; color: var(--red); font-family: "STKaiti", "KaiTi", serif; }
.final-strip { display: flex; justify-content: center; gap: 10px; }
.final-strip img { width: 105px; aspect-ratio: 3/4; object-fit: cover; border: 1px solid #bbb; }
.principle { display: grid; grid-template-columns: 1fr 1.5fr; gap: 40px; align-items: center; margin-top: 68px; padding: 28px 34px; border: 1px solid var(--ink); }
.principle strong { font-size: 28px; }
.principle span { color: var(--muted); }

.boundaries { background: var(--pink); }
.boundary-inner { display: grid; grid-template-columns: .72fr 1.28fr; gap: 100px; padding: 110px 0; }
.boundary-list h2 { margin: 0 0 32px; font-size: 44px; letter-spacing: -0.05em; }
.boundary-list ul { margin: 0; padding: 0; list-style: none; }
.boundary-list li { margin: 13px 0; font-size: 19px; font-weight: 600; }
.boundary-list li::before { content: "×"; margin-right: 14px; color: var(--red); font-size: 24px; }
.boundary-note { position: relative; align-self: center; padding: 42px 46px; border: 3px solid var(--red); border-radius: 48% 52% 46% 54% / 44% 52% 48% 56%; color: var(--red); background: rgba(255,255,255,.38); transform: rotate(-1deg); }
.boundary-note::after { content: ""; position: absolute; inset: 7px -9px -7px 9px; border: 1px solid var(--red); border-radius: inherit; transform: rotate(2deg); pointer-events: none; }
.boundary-note p { margin: 0 0 10px; font-size: 24px; font-weight: 800; }
.boundary-note strong { font-size: 18px; }

.prompts { padding: 136px 0; }
.prompt-panel { position: relative; overflow: hidden; border-radius: 8px; color: #fff; background: var(--ink); box-shadow: 0 24px 60px rgba(0,0,0,.16); }
.prompt-panel ol { margin: 0; padding: 82px 48px 38px; list-style: none; counter-reset: prompt; }
.prompt-panel li { position: relative; padding: 22px 28px 22px 44px; border-bottom: 1px solid #464646; font-size: 17px; counter-increment: prompt; }
.prompt-panel li:last-child { border-bottom: 0; }
.prompt-panel li::before { content: "→"; position: absolute; left: 2px; color: var(--red); font-size: 24px; font-weight: 800; }
.copy-button { position: absolute; top: 22px; right: 24px; padding: 10px 16px; border: 1px solid #777; border-radius: 5px; color: #fff; background: transparent; cursor: pointer; font-size: 13px; font-weight: 700; }
.copy-button:hover { border-color: var(--red); color: var(--red); }
.copy-status { min-height: 30px; padding: 0 48px 26px; color: #ff9a9b; font-size: 13px; }
.closing { padding: 76px 0 128px; text-align: center; }
.closing h2 { margin: 0 auto 40px; font-size: clamp(38px, 5vw, 68px); line-height: 1.28; letter-spacing: -0.06em; }
.footer { display: flex; justify-content: space-between; padding: 26px 0 36px; border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; }

.reveal { opacity: 0; transform: translateY(24px); transition: opacity .65s ease, transform .65s ease; }
.reveal.is-visible { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .reveal { opacity: 1; transform: none; transition: none; } .button { transition: none; } }

@media (max-width: 1080px) {
  .site-header { gap: 24px; }
  .hero { grid-template-columns: 1fr; min-height: auto; }
  .hero__copy { max-width: 760px; padding-top: 20px; }
  .workbench { min-height: 680px; }
  .capability-layout { grid-template-columns: 1fr; }
  .process-board { max-width: 760px; margin: 0 auto; }
  .boundary-inner { gap: 50px; }
}

@media (max-width: 760px) {
  .site-header { grid-template-columns: 1fr auto; width: calc(100% - 30px); height: 66px; }
  .site-header > .button { display: none; }
  .brand { font-size: 17px; }
  .nav { gap: 16px; overflow-x: auto; font-size: 13px; scrollbar-width: none; }
  .nav a:nth-child(2), .nav a:nth-child(3) { display: none; }
  .section-shell, .hero { width: min(calc(100% - 30px), var(--max)); }
  .hero { padding: 52px 0 72px; }
  .hero__copy h1 { font-size: clamp(43px, 13vw, 66px); }
  .hero__copy p { margin: 22px 0 28px; font-size: 17px; }
  .hero__actions { align-items: stretch; }
  .hero__actions .button { flex: 1 1 100%; }
  .workbench { min-height: 720px; overflow: visible; }
  .source-shot { top: 100px; left: 2%; width: 29%; }
  .reason-note { top: 315px; left: 1%; width: 145px; }
  .master-label { top: 36px; left: 43%; }
  .master-shot { top: 72px; left: 40%; width: 42%; }
  .variants-label { top: 410px; right: 33%; }
  .variant-strip { top: 445px; width: 76%; right: 4%; }
  .route--one { top: 138px; left: 26%; width: 20%; }
  .route--two { display: none; }
  .annotation--top { right: 0; }
  .statement { padding: 58px 0 82px; }
  .section-heading { display: block; margin-bottom: 42px; }
  .section-heading p { margin-top: 18px; }
  .capabilities, .workflow, .prompts { padding: 88px 0; }
  .capability-layout { gap: 50px; }
  .capability-list li { grid-template-columns: 58px 1fr; }
  .capability-list span { font-size: 20px; }
  .capability-list strong { font-size: 16px; }
  .process-board { padding: 24px 15px; overflow: hidden; }
  .board-row { gap: 8px; }
  .board-row figure { width: 90px; }
  .board-master { width: 78px !important; }
  .board-note { padding: 10px; font-size: 12px; }
  .board-arrow { font-size: 20px; }
  .mini-variants img { width: 47px; }
  .data-paper { padding: 9px; }
  .timeline::before { left: 26px; transform: none; }
  .step, .step--reverse { grid-template-columns: 54px 1fr; gap: 16px; min-height: 0; padding: 52px 0; }
  .step__number, .step--reverse .step__number { grid-column: 1; grid-row: 1; width: 48px; height: 48px; }
  .step__copy, .step--reverse .step__copy { grid-column: 2; grid-row: 1; padding: 0; }
  .step__visual, .step--reverse .step__visual { grid-column: 2; grid-row: 2; margin: 24px 0 0; }
  .step__copy h3 { font-size: 25px; }
  .principle { grid-template-columns: 1fr; gap: 10px; }
  .principle strong { font-size: 24px; }
  .boundary-inner { grid-template-columns: 1fr; padding: 78px 0; }
  .boundary-list h2 { font-size: 38px; }
  .boundary-note { padding: 34px 30px; border-radius: 30px; transform: none; }
  .boundary-note p { font-size: 21px; }
  .prompt-panel ol { padding: 76px 20px 26px; }
  .prompt-panel li { padding: 18px 4px 18px 36px; font-size: 15px; }
  .copy-status { padding: 0 20px 22px; }
  .footer { gap: 20px; }
}

@media (max-width: 430px) {
  .nav a:nth-child(4) { display: none; }
  .workbench { min-height: 665px; }
  .reason-note { top: 280px; }
  .master-shot { width: 44%; }
  .variant-strip { top: 415px; width: 82%; }
  .variants-label { top: 384px; }
  .annotation--bottom { bottom: 6px; }
  .process-board { margin-inline: -2px; }
  .board-note { display: none; }
  .board-line { width: 80%; }
  .ratios img { width: 125px; }
  .final-strip img { width: 84px; }
}