@import url("https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=Noto+Sans+HK:wght@300;400;500;700&display=swap");

:root {
  --paper: #fcfcfc;
  --ink: #111111;
  --muted: #6b6b66;
  --line: #d9d9d2;
  --soft: #f1f1ec;
  --blue: #2d7ff9;
  --night: #0a0a0a;
  --night-line: #292929;
  --radius: 8px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Inter", "Noto Sans HK", ui-sans-serif, system-ui, sans-serif;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}

::selection {
  background: var(--ink);
  color: #ffffff;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
}

.sr-only,
.skip-link {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link:focus {
  position: fixed;
  top: 16px;
  left: 16px;
  z-index: 100;
  width: auto;
  height: auto;
  padding: 12px 16px;
  clip: auto;
  background: #ffffff;
  border: 1px solid var(--ink);
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 24px clamp(20px, 4vw, 64px);
  mix-blend-mode: difference;
  color: #ffffff;
  transition: padding 240ms ease, background 240ms ease;
}

.site-header.is-scrolled {
  padding-top: 14px;
  padding-bottom: 14px;
  background: rgba(10, 10, 10, 0.72);
  backdrop-filter: blur(16px);
  mix-blend-mode: normal;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-size: 12px;
  font-weight: 600;
}

.brand-name,
.desktop-nav,
.hero-navline,
.section-kicker,
.scroll-cue,
.spec-title,
.chapter-panel span,
.process-list span,
.site-footer {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.desktop-nav a {
  opacity: 0.82;
}

.desktop-nav a:hover {
  opacity: 1;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.menu-button {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  border: 0;
  background: transparent;
  color: currentColor;
  cursor: pointer;
}

.menu-button span:not(.sr-only) {
  display: block;
  height: 2px;
  width: 30px;
  background: currentColor;
  transform-origin: center;
  transition: transform 220ms ease;
}

.menu-button[aria-expanded="true"] span:first-child {
  transform: translateY(4px) rotate(45deg);
}

.menu-button[aria-expanded="true"] span:nth-child(2) {
  transform: translateY(-4px) rotate(-45deg);
}

.mobile-menu {
  position: fixed;
  inset: 70px 12px auto 12px;
  z-index: 49;
  display: grid;
  gap: 18px;
  padding: 22px;
  background: rgba(252, 252, 252, 0.96);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 18px 40px rgba(17, 17, 17, 0.14);
}

.mobile-menu[hidden] {
  display: none;
}

.hero {
  position: relative;
  min-height: 100vh;
  padding: 82px clamp(20px, 4vw, 64px) 44px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(17, 17, 17, 0.05) 1px, transparent 1px),
    linear-gradient(0deg, rgba(17, 17, 17, 0.04) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: linear-gradient(to bottom, black, transparent 76%);
  pointer-events: none;
}

.hero-wordmark {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 2px;
  padding-top: 8px;
  border-top: 1px solid rgba(17, 17, 17, 0.18);
  font-size: clamp(42px, 8.6vw, 132px);
  line-height: 0.86;
  font-weight: 600;
  letter-spacing: 0;
  animation: wordRise 900ms cubic-bezier(0.16, 1, 0.3, 1) both;
}

.hero-wordmark span:last-child {
  font-size: clamp(32px, 6.2vw, 96px);
}

.hero-navline {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 0.5fr 1fr 1fr;
  gap: 20px;
  margin-top: 14px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(17, 17, 17, 0.18);
  color: var(--muted);
}

.hero-grid {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: minmax(390px, 0.95fr) minmax(300px, 1fr) minmax(210px, 0.55fr);
  gap: clamp(24px, 3.2vw, 48px);
  align-items: center;
  flex: 1;
  padding-top: clamp(16px, 3vh, 34px);
}

.section-kicker {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 22px;
  color: var(--muted);
  font-weight: 600;
}

.section-kicker span {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
}

.section-kicker span::after {
  content: "";
  display: inline-block;
  width: 56px;
  height: 1px;
  background: currentColor;
  opacity: 0.25;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 680px;
  margin-bottom: 18px;
  font-size: clamp(40px, 5.3vw, 76px);
  line-height: 1.02;
  font-weight: 500;
  letter-spacing: 0;
}

h1 span {
  display: block;
}

h2 {
  max-width: 1080px;
  margin-bottom: 28px;
  font-size: clamp(32px, 5.2vw, 76px);
  line-height: 1.06;
  font-weight: 500;
  letter-spacing: 0;
}

h3 {
  font-size: clamp(24px, 3vw, 40px);
  line-height: 1.1;
  font-weight: 500;
  letter-spacing: 0;
}

.hero-lede {
  max-width: 520px;
  color: #3f3f3a;
  font-size: clamp(16px, 1.35vw, 19px);
  line-height: 1.65;
}

.cta-row,
.contact-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.button {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 13px 20px;
  border-radius: 6px;
  border: 1px solid var(--ink);
  font-size: 15px;
  font-weight: 600;
  overflow: hidden;
  transition: transform 220ms ease, box-shadow 220ms ease, background 220ms ease, color 220ms ease;
}

.button:hover {
  transform: translateY(-1px);
  box-shadow: 4px 4px 0 rgba(17, 17, 17, 0.24);
}

.button-dark {
  background: var(--ink);
  color: #ffffff;
}

.button-light {
  background: #ffffff;
  color: var(--ink);
}

.hero-visual {
  margin: 0;
  align-self: stretch;
  min-height: 440px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.hero-visual svg {
  width: 100%;
  height: auto;
  filter: drop-shadow(0 34px 45px rgba(17, 17, 17, 0.14));
}

.hero-visual figcaption {
  margin-top: 12px;
  color: var(--muted);
  font-size: 12px;
}

.water-line {
  stroke-dasharray: 22 18;
  animation: waterMove 2200ms linear infinite;
}

.diagram-labels path,
.measurement path {
  stroke: #111111;
  stroke-width: 1.5;
  fill: none;
}

.diagram-labels text,
.measurement text {
  fill: #111111;
  font-size: 15px;
  font-family: "Inter", "Noto Sans HK", sans-serif;
}

.measurement text {
  writing-mode: vertical-rl;
  font-size: 12px;
}

.hero-spec {
  align-self: end;
  padding-top: 24px;
  border-top: 1px solid rgba(17, 17, 17, 0.24);
}

.spec-title {
  margin-bottom: 22px;
  color: var(--muted);
  font-weight: 600;
}

.hero-spec dl {
  display: grid;
  gap: 24px;
  margin: 0;
}

.hero-spec dt {
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 12px;
}

.hero-spec dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.55;
}

.scroll-cue {
  position: absolute;
  left: clamp(20px, 4vw, 64px);
  bottom: 28px;
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--muted);
  font-weight: 600;
}

.scroll-cue span {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: linear-gradient(90deg, transparent 44%, var(--muted) 44%, var(--muted) 48%, transparent 48%, transparent 55%, var(--muted) 55%, var(--muted) 59%, transparent 59%);
}

.intent-section,
.process-section,
.faq-section,
.contact-section {
  padding: clamp(86px, 12vw, 150px) clamp(20px, 4vw, 64px);
}

.intent-section {
  min-height: 82vh;
}

.intent-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 42px 0 78px;
}

.intent-actions a {
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #ffffff;
  font-size: 13px;
  font-weight: 600;
  transition: background 180ms ease, color 180ms ease, border 180ms ease;
}

.intent-actions a:hover {
  background: var(--ink);
  color: #ffffff;
  border-color: var(--ink);
}

.compare-band {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.compare-band article {
  padding: clamp(26px, 4vw, 52px);
}

.compare-band article:first-child {
  border-right: 1px solid var(--line);
}

.compare-band span {
  display: block;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 600;
}

.compare-band p,
.compare-band li,
.process-list p,
.faq-list p,
.contact-section p {
  color: #454540;
  font-size: 16px;
  line-height: 1.75;
}

.compare-band ul {
  margin: 26px 0 0;
  padding-left: 18px;
}

.system-section {
  position: relative;
  overflow: hidden;
  padding: clamp(110px, 14vw, 190px) clamp(20px, 4vw, 64px) 0;
  background: var(--night);
  color: #ffffff;
}

.system-ornament {
  position: absolute;
  top: -58px;
  left: 50%;
  width: min(1050px, 150vw);
  color: rgba(255, 255, 255, 0.16);
  transform: translateX(-50%);
  pointer-events: none;
}

.system-heading {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.35fr);
  gap: clamp(30px, 5vw, 76px);
  align-items: end;
  margin-bottom: clamp(70px, 9vw, 120px);
}

.system-heading .section-kicker span,
.system-section .section-kicker span {
  color: #ffffff;
}

.system-heading .section-kicker,
.system-heading p {
  color: #a7a7a0;
}

.system-heading p:not(.section-kicker) {
  font-size: 15px;
  line-height: 1.8;
}

.chapter-layout {
  display: grid;
  grid-template-columns: 0.95fr 1.35fr;
  border-top: 1px solid var(--night-line);
}

.chapter-visuals {
  position: relative;
  min-height: 560px;
  border-right: 1px solid var(--night-line);
}

.chapter-panel {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: clamp(28px, 4vw, 56px);
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 360ms ease, transform 360ms ease;
  pointer-events: none;
}

.chapter-panel::before {
  content: "";
  position: absolute;
  inset: 18%;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background:
    linear-gradient(90deg, transparent 49%, rgba(255, 255, 255, 0.14) 49%, rgba(255, 255, 255, 0.14) 50%, transparent 50%),
    linear-gradient(0deg, transparent 49%, rgba(255, 255, 255, 0.14) 49%, rgba(255, 255, 255, 0.14) 50%, transparent 50%);
  background-size: 42px 42px;
  transform: skewY(-6deg);
}

.chapter-panel.active {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.chapter-panel span,
.chapter-panel h3,
.chapter-panel p {
  position: relative;
  z-index: 1;
}

.chapter-panel span {
  margin-bottom: auto;
  color: #777770;
}

.chapter-panel h3 {
  margin-bottom: 18px;
  font-size: clamp(34px, 5vw, 66px);
}

.chapter-panel p {
  max-width: 440px;
  color: #bdbdb6;
  font-size: 16px;
  line-height: 1.75;
}

.chapter-list {
  display: grid;
}

.chapter-list button {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 104px;
  padding: 28px clamp(26px, 4vw, 52px);
  border: 0;
  border-bottom: 1px solid var(--night-line);
  background: transparent;
  color: #555555;
  text-align: left;
  font-size: clamp(22px, 3.5vw, 46px);
  line-height: 1.1;
  cursor: pointer;
  transition: color 220ms ease, background 220ms ease;
}

.chapter-list button::after {
  content: "+";
  font-size: 24px;
  color: #777777;
}

.chapter-list button:hover,
.chapter-list button.active {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.03);
}

.chapter-list button.active::after {
  content: "view";
  font-size: 12px;
  text-transform: uppercase;
  color: #bdbdb6;
}

.process-section {
  background: var(--paper);
}

.process-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  margin: 56px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.process-list li {
  min-height: 320px;
  padding: 30px;
  border-right: 1px solid var(--line);
}

.process-list li:last-child {
  border-right: 0;
}

.process-list span {
  display: block;
  margin-bottom: 74px;
  color: var(--muted);
}

.process-list h3 {
  font-size: 26px;
}

.proof-section {
  display: grid;
  grid-template-columns: minmax(0, 0.8fr) minmax(260px, 1fr);
  gap: clamp(30px, 5vw, 70px);
  padding: clamp(80px, 10vw, 130px) clamp(20px, 4vw, 64px);
  background: #eeeeea;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.proof-section h2 {
  font-size: clamp(30px, 4vw, 56px);
}

.proof-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.proof-grid p {
  margin: 0;
  min-height: 126px;
  padding: 22px;
  background: #f8f8f4;
  color: #3f3f3a;
  font-size: 15px;
  line-height: 1.65;
}

.faq-section {
  max-width: 1180px;
}

.faq-list {
  margin-top: 46px;
  border-top: 1px solid var(--line);
}

details {
  border-bottom: 1px solid var(--line);
}

summary {
  cursor: pointer;
  padding: 24px 0;
  font-size: clamp(20px, 2.4vw, 30px);
  font-weight: 500;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  content: "+";
  float: right;
  color: var(--muted);
}

details[open] summary::after {
  content: "-";
}

.faq-list p {
  max-width: 840px;
  padding-bottom: 28px;
}

.contact-section {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 36px;
  align-items: end;
  background: var(--ink);
  color: #ffffff;
}

.contact-section .section-kicker,
.contact-section p {
  color: #c7c7c0;
}

.contact-section .section-kicker span {
  color: #ffffff;
}

.contact-section h2 {
  margin-bottom: 18px;
}

.contact-section .button-light {
  border-color: #ffffff;
}

.site-footer {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 18px;
  padding: 26px clamp(20px, 4vw, 64px);
  background: var(--night);
  color: #8f8f88;
  border-top: 1px solid var(--night-line);
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  color: #ffffff;
}

@keyframes wordRise {
  from {
    opacity: 0;
    transform: translateY(36px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes waterMove {
  to {
    stroke-dashoffset: -80;
  }
}

@media (max-width: 1120px) {
  .hero-grid {
    grid-template-columns: 1fr 1fr;
  }

  .hero-spec {
    grid-column: 1 / -1;
    align-self: auto;
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 24px;
  }

  .hero-spec dl {
    grid-template-columns: repeat(3, 1fr);
  }

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

  .process-list li:nth-child(2) {
    border-right: 0;
  }
}

@media (max-width: 820px) {
  .site-header {
    padding: 16px 20px;
    mix-blend-mode: normal;
    color: var(--ink);
    background: rgba(252, 252, 252, 0.86);
    backdrop-filter: blur(14px);
  }

  .desktop-nav {
    display: none;
  }

  .menu-button {
    display: flex;
  }

  .hero {
    padding-top: 94px;
    min-height: auto;
  }

  .hero-navline {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .hero-grid,
  .system-heading,
  .chapter-layout,
  .proof-section,
  .contact-section,
  .site-footer {
    grid-template-columns: 1fr;
  }

  .hero-visual {
    min-height: 0;
  }

  .hero-spec {
    display: block;
  }

  .hero-spec dl {
    grid-template-columns: 1fr;
  }

  .scroll-cue {
    display: none;
  }

  .compare-band {
    grid-template-columns: 1fr;
  }

  .compare-band article:first-child,
  .chapter-visuals {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .chapter-visuals {
    min-height: 440px;
  }

  .chapter-list button {
    min-height: 84px;
  }

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

@media (max-width: 620px) {
  .brand-name {
    display: none;
  }

  .hero-wordmark {
    font-size: clamp(42px, 17vw, 84px);
  }

  h1 {
    font-size: clamp(44px, 14vw, 70px);
  }

  h2 {
    font-size: clamp(30px, 10vw, 48px);
  }

  .hero-copy {
    order: 1;
  }

  .hero-visual {
    order: 2;
  }

  .hero-spec {
    order: 3;
  }

  .cta-row,
  .contact-actions {
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .intent-section,
  .process-section,
  .faq-section,
  .contact-section {
    padding-top: 74px;
    padding-bottom: 74px;
  }

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

  .process-list li {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .process-list li:last-child {
    border-bottom: 0;
  }

  .process-list span {
    margin-bottom: 34px;
  }

  .diagram-labels text,
  .measurement text {
    font-size: 18px;
  }
}

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