:root {
  --ink: #082735;
  --ink-deep: #051d27;
  --ink-soft: #123c4d;
  --paper: #f4f2ec;
  --paper-soft: #edf2f2;
  --white: #ffffff;
  --sky: #96d7e6;
  --sky-strong: #57b6d3;
  --blue: #217b9b;
  --coral: #c94f35;
  --coral-dark: #a83c28;
  --text: #183643;
  --muted: #596b73;
  --line: rgba(8, 39, 53, 0.14);
  --line-light: rgba(255, 255, 255, 0.18);
  --shadow: 0 24px 60px rgba(4, 28, 38, 0.14);
  --header-height: 78px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 20px);
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: hidden;
  color: var(--text);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  font-size: 16px;
  line-height: 1.72;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body.menu-open,
body.dialog-open {
  overflow: hidden;
}

img {
  display: block;
  max-width: 100%;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

button,
input,
textarea,
select {
  font: inherit;
}

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

button {
  color: inherit;
}

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

h1,
h2,
h3,
strong {
  font-weight: 650;
}

h1,
h2,
h3 {
  line-height: 1.12;
  letter-spacing: -0.035em;
  text-wrap: balance;
}

:focus-visible {
  outline: 3px solid var(--coral);
  outline-offset: 4px;
}

.shell {
  width: min(1440px, calc(100% - clamp(40px, 7vw, 120px)));
  margin-inline: auto;
}

.section {
  padding-block: clamp(88px, 8vw, 132px);
}

.skip-link {
  position: fixed;
  z-index: 5000;
  top: 12px;
  left: 12px;
  padding: 12px 18px;
  background: var(--white);
  color: var(--ink);
  transform: translateY(-160%);
  transition: transform 160ms ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.button {
  display: inline-flex;
  min-height: 50px;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  padding: 12px 21px;
  cursor: pointer;
  font-size: 15px;
  font-weight: 650;
  line-height: 1.2;
  letter-spacing: 0.01em;
  transition: color 180ms ease, background 180ms ease, border-color 180ms ease, transform 180ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  background: var(--coral);
  color: var(--white);
}

.button-primary:hover {
  background: var(--coral-dark);
}

.button-secondary {
  border-color: rgba(255, 255, 255, 0.42);
  background: transparent;
  color: var(--white);
}

.button-secondary:hover {
  border-color: var(--white);
  background: rgba(255, 255, 255, 0.08);
}

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

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

.site-header {
  position: sticky;
  z-index: 1000;
  top: 0;
  height: var(--header-height);
  border-bottom: 1px solid rgba(8, 39, 53, 0.1);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(18px);
}

.header-shell {
  display: grid;
  height: 100%;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(24px, 3vw, 48px);
}

.brand {
  display: inline-flex;
  align-items: center;
}

.brand img {
  width: clamp(174px, 13vw, 210px);
  height: auto;
}

.desktop-nav {
  display: flex;
  min-width: 0;
  align-items: stretch;
  justify-content: flex-end;
  gap: clamp(14px, 1.3vw, 24px);
}

.desktop-nav > a,
.desktop-nav summary {
  position: relative;
  display: flex;
  min-height: 54px;
  align-items: center;
  color: #294653;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  list-style: none;
  white-space: nowrap;
}

.desktop-nav summary::-webkit-details-marker {
  display: none;
}

.desktop-nav > a::after,
.desktop-nav summary::after {
  position: absolute;
  right: 0;
  bottom: 5px;
  left: 0;
  height: 2px;
  background: var(--coral);
  content: "";
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 180ms ease;
}

.desktop-nav > a:hover::after,
.desktop-nav > a:focus-visible::after,
.desktop-nav > a[aria-current="page"]::after,
.nav-group:hover summary::after,
.nav-group[open] summary::after {
  transform: scaleX(1);
  transform-origin: left;
}

.nav-group {
  position: relative;
}

.nav-panel {
  position: absolute;
  top: calc(100% - 1px);
  left: 50%;
  display: grid;
  width: 258px;
  padding: 12px;
  border-top: 3px solid var(--coral);
  background: var(--white);
  box-shadow: var(--shadow);
  transform: translateX(-50%);
}

.nav-panel a {
  display: flex;
  min-height: 46px;
  align-items: center;
  border-bottom: 1px solid var(--line);
  padding: 8px 10px;
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
}

.nav-panel a:last-child {
  border-bottom: 0;
}

.nav-panel a:hover,
.nav-panel a:focus-visible {
  background: var(--paper-soft);
  color: var(--ink);
}

.header-phone {
  display: grid;
  min-height: 50px;
  align-content: center;
  border-left: 1px solid var(--line);
  padding-left: clamp(20px, 2vw, 34px);
  line-height: 1.15;
}

.header-phone span {
  margin-bottom: 5px;
  color: var(--muted);
  font-size: 11px;
  letter-spacing: 0.12em;
}

.header-phone strong {
  color: var(--ink);
  font-size: 15px;
  letter-spacing: 0.025em;
}

.menu-toggle,
.mobile-menu {
  display: none;
}

.hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  border-bottom: 1px solid rgba(8, 39, 53, 0.1);
  background: #f3f4f1;
  color: var(--ink);
}

.hero::before {
  position: absolute;
  z-index: -1;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(247, 249, 247, 0.99) 0%, rgba(247, 249, 247, 0.97) 28%, rgba(247, 249, 247, 0.82) 39%, rgba(247, 249, 247, 0.34) 49%, rgba(247, 249, 247, 0) 61%),
    linear-gradient(0deg, rgba(7, 29, 38, 0.08), transparent 22%);
  content: "";
  pointer-events: none;
}

.hero-grid {
  display: grid;
  min-height: clamp(680px, calc(100svh - var(--header-height)), 780px);
  grid-template-columns: minmax(0, 620px) minmax(0, 1fr);
  align-items: center;
  padding-block: clamp(64px, 6vw, 92px);
}

.hero-copy {
  position: relative;
  z-index: 2;
  max-width: 590px;
}

.hero h1 {
  margin-bottom: 30px;
  color: var(--ink);
  font-size: clamp(64px, 5.6vw, 92px);
  letter-spacing: -0.04em;
  line-height: 0.96;
}

.hero h1 span {
  display: inline-block;
  margin-top: 16px;
  color: #187e9f;
  font-size: 0.59em;
  letter-spacing: -0.035em;
  line-height: 1.08;
}

.hero-summary {
  max-width: 570px;
  margin-bottom: 30px;
  color: #415b65;
  font-size: clamp(16px, 1.1vw, 18px);
  line-height: 1.78;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 34px;
}

.hero .button-secondary {
  border-color: rgba(8, 39, 53, 0.28);
  background: rgba(255, 255, 255, 0.7);
  color: var(--ink);
}

.hero .button-secondary:hover {
  border-color: rgba(8, 39, 53, 0.5);
  background: rgba(255, 255, 255, 0.88);
}

.hero-capabilities {
  display: grid;
  max-width: 590px;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 0;
  padding: 0;
  border-top: 1px solid rgba(8, 39, 53, 0.18);
  list-style: none;
}

.hero-capabilities li {
  min-height: 54px;
  border-right: 1px solid rgba(8, 39, 53, 0.14);
  padding: 15px 12px 0 0;
  color: #385866;
  font-size: 13px;
  font-weight: 650;
  letter-spacing: 0.025em;
}

.hero-capabilities li:not(:first-child) {
  padding-left: 14px;
}

.hero-capabilities li:last-child {
  border-right: 0;
}

.hero-art {
  position: absolute;
  z-index: -2;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  overflow: visible;
}

.hero-art img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 58% center;
}

.hero-assembly {
  position: absolute;
  z-index: 3;
  top: 50%;
  right: clamp(22px, 3vw, 54px);
  width: clamp(170px, 14vw, 210px);
  border: 1px solid rgba(210, 238, 246, 0.28);
  background: rgba(5, 25, 34, 0.68);
  box-shadow: 0 20px 48px rgba(4, 21, 29, 0.16);
  color: #f7fbfc;
  transform: translateY(-50%);
  backdrop-filter: blur(8px);
}

.hero-assembly > strong {
  display: block;
  padding: 15px 16px 13px;
  border-bottom: 1px solid rgba(210, 238, 246, 0.2);
  color: #c8edf5;
  font-size: 12px;
  font-weight: 750;
  letter-spacing: 0.12em;
}

.hero-assembly ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.hero-assembly li {
  position: relative;
  min-height: 38px;
  padding: 11px 15px 9px 28px;
  border-bottom: 1px solid rgba(210, 238, 246, 0.14);
  font-size: 12px;
  font-weight: 650;
  letter-spacing: 0.04em;
}

.hero-assembly li:last-child {
  border-bottom: 0;
}

.hero-assembly li::before {
  position: absolute;
  top: 17px;
  left: 15px;
  width: 7px;
  height: 1px;
  background: #79d3e7;
  content: "";
}

.hero-assembly small {
  display: block;
  padding: 11px 15px 12px;
  border-top: 1px solid rgba(210, 238, 246, 0.14);
  color: rgba(231, 246, 249, 0.72);
  font-size: 10px;
  line-height: 1.5;
}

@media (max-width: 1180px) and (min-width: 821px) {
  .hero::before {
    background:
      linear-gradient(90deg, rgba(247, 249, 247, 0.99) 0%, rgba(247, 249, 247, 0.98) 39%, rgba(247, 249, 247, 0.9) 51%, rgba(247, 249, 247, 0.46) 64%, rgba(247, 249, 247, 0) 76%),
      linear-gradient(0deg, rgba(7, 29, 38, 0.08), transparent 22%);
  }

  .hero-copy,
  .hero-capabilities {
    max-width: 520px;
  }

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

  .hero-capabilities li:nth-child(2n) {
    border-right: 0;
  }

  .hero-capabilities li:nth-child(n + 3) {
    border-top: 1px solid rgba(8, 39, 53, 0.14);
  }
}

.fact-band {
  background: var(--coral);
  color: var(--white);
}

.fact-shell {
  display: grid;
  grid-template-columns: 0.8fr 1fr 1.05fr 0.85fr 1.45fr;
}

.fact-shell > div {
  display: grid;
  min-height: 132px;
  align-content: center;
  border-left: 1px solid rgba(255, 255, 255, 0.25);
  padding: 22px clamp(18px, 2.4vw, 38px);
}

.fact-shell > div:last-child {
  border-right: 1px solid rgba(255, 255, 255, 0.25);
}

.fact-shell strong {
  margin-bottom: 5px;
  font-size: clamp(25px, 2vw, 34px);
  line-height: 1.1;
  letter-spacing: -0.035em;
}

.fact-shell sup {
  font-size: 0.52em;
}

.fact-shell span {
  color: rgba(255, 255, 255, 0.78);
  font-size: 13px;
}

.section-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.18fr) minmax(330px, 0.62fr);
  align-items: end;
  gap: clamp(44px, 8vw, 120px);
  margin-bottom: clamp(50px, 5vw, 76px);
}

.section-intro h2,
.acoustic h2,
.process h2,
.knowledge h2,
.contact h2 {
  margin-bottom: 0;
  color: var(--ink);
  font-size: clamp(42px, 4vw, 66px);
}

.section-intro p {
  margin-bottom: 5px;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.9;
}

.noise {
  background: var(--paper);
}

.capability-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.9fr) minmax(320px, 0.82fr);
  gap: clamp(22px, 3vw, 42px);
}

.noise-paths {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.path-card {
  display: grid;
  min-height: 286px;
  align-content: start;
  background: var(--white);
  padding: clamp(28px, 3vw, 48px);
  transition: background 180ms ease, color 180ms ease;
}

.path-card h3 {
  margin: 0 0 14px;
  font-size: clamp(24px, 2vw, 31px);
}

.path-card p {
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 15px;
}

.path-card strong {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--line);
  padding-top: 18px;
  color: var(--ink);
  font-size: 14px;
}

.path-card i {
  font-style: normal;
}

.path-card:hover {
  background: #f9fbfa;
}

.path-card-dark,
.path-card-blue {
  color: var(--white);
}

.path-card-dark {
  background: var(--ink);
}

.path-card-blue {
  background: var(--blue);
}

.path-card-dark:hover,
.path-card-blue:hover {
  background: var(--ink-soft);
}

.path-card-dark p,
.path-card-blue p {
  color: rgba(255, 255, 255, 0.7);
}

.path-card-dark strong,
.path-card-blue strong {
  border-color: rgba(255, 255, 255, 0.2);
  color: var(--white);
}

.noise-aside {
  display: flex;
  min-height: 573px;
  flex-direction: column;
  background: #dfecef;
  padding: clamp(32px, 3.4vw, 56px);
}

.noise-aside > p {
  margin-bottom: 30px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 650;
  letter-spacing: 0.12em;
}

.noise-aside h3 {
  margin-bottom: 42px;
  color: var(--ink);
  font-size: clamp(28px, 2.5vw, 40px);
}

.noise-aside ul {
  margin: 0 0 40px;
  padding: 0;
  list-style: none;
}

.noise-aside li {
  display: grid;
  grid-template-columns: 38px 1fr;
  gap: 14px;
  border-top: 1px solid rgba(8, 39, 53, 0.16);
  padding: 17px 0;
  font-size: 14px;
}

.noise-aside li span {
  color: var(--blue);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.noise-aside > a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  border-top: 1px solid rgba(8, 39, 53, 0.22);
  padding-top: 22px;
  color: var(--ink);
  font-size: 14px;
  font-weight: 650;
}

.acoustic {
  background: var(--ink);
  color: var(--white);
}

.acoustic-shell {
  display: grid;
  grid-template-columns: minmax(0, 0.94fr) minmax(0, 1.06fr);
  align-items: center;
  gap: clamp(48px, 7vw, 112px);
}

.acoustic-photo {
  position: relative;
  overflow: hidden;
  aspect-ratio: 1852 / 778;
  margin: 0;
  background: #0a2835;
}

.acoustic-photo img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  filter: saturate(0.72) contrast(1.04) brightness(0.78);
}

.acoustic-copy {
  min-width: 0;
}

.acoustic-copy > p:first-child {
  margin-bottom: 26px;
  color: var(--sky);
  font-size: 13px;
  font-weight: 650;
  letter-spacing: 0.14em;
}

.acoustic h2 {
  margin-bottom: 28px;
  color: var(--white);
  font-size: clamp(40px, 3.7vw, 60px);
}

.acoustic-copy > p:nth-of-type(2) {
  max-width: 700px;
  margin-bottom: 42px;
  color: rgba(255, 255, 255, 0.72);
  font-size: 17px;
}

.acoustic-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line-light);
}

.acoustic-links a {
  display: grid;
  min-height: 104px;
  align-content: center;
  border-right: 1px solid var(--line-light);
  border-bottom: 1px solid var(--line-light);
  padding: 18px 24px;
  transition: background 180ms ease;
}

.acoustic-links a:nth-child(even) {
  border-right: 0;
}

.acoustic-links a:hover {
  background: rgba(255, 255, 255, 0.06);
}

.acoustic-links strong {
  margin-bottom: 4px;
  color: var(--white);
  font-size: 17px;
}

.acoustic-links span {
  color: rgba(255, 255, 255, 0.56);
  font-size: 13px;
}

.cases {
  background: var(--white);
}

.case-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(18px, 2vw, 28px);
}

.case-card {
  display: grid;
  grid-template-rows: auto 1fr;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--white);
}

.case-card img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  object-position: center;
  background: linear-gradient(135deg, #edf3f3, #dcebed);
  filter: saturate(0.84) contrast(1.02);
  transition: transform 360ms ease, filter 360ms ease;
}

.case-card:hover img {
  transform: scale(1.018);
  filter: saturate(0.96) contrast(1.02);
}

.case-card-copy {
  display: grid;
  align-content: start;
  min-height: 148px;
  padding: clamp(20px, 2.2vw, 30px);
}

.case-card-copy small {
  margin-bottom: 8px;
  color: var(--blue);
  font-size: 12px;
  letter-spacing: 0.12em;
}

.case-card-copy strong {
  color: var(--ink);
  font-size: clamp(18px, 1.45vw, 23px);
  line-height: 1.35;
}

.case-card-copy i {
  margin-top: 16px;
  color: var(--muted);
  font-size: 12px;
  font-style: normal;
}

.case-more {
  display: grid;
  grid-template-columns: minmax(260px, 0.72fr) minmax(520px, 1.35fr) auto;
  align-items: end;
  gap: clamp(30px, 4vw, 66px);
  margin-top: 14px;
  background: var(--paper-soft);
  padding: clamp(34px, 4.3vw, 64px);
}

.case-more h3 {
  margin-bottom: 10px;
  color: var(--ink);
  font-size: clamp(28px, 2.5vw, 40px);
}

.case-more p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

.case-more ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 28px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.case-more li {
  border-top: 1px solid var(--line);
}

.case-more li:nth-last-child(-n + 2) {
  border-bottom: 1px solid var(--line);
}

.case-more li a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 13px 0;
  font-size: 13px;
}

.case-more li span {
  color: var(--blue);
}

.client-proof {
  display: grid;
  grid-template-columns: minmax(260px, 0.65fr) minmax(0, 1.7fr);
  gap: clamp(48px, 7vw, 110px);
  margin-top: clamp(74px, 8vw, 124px);
  border-top: 1px solid var(--line);
  padding-top: clamp(48px, 5vw, 76px);
}

.client-proof-copy h3 {
  margin-bottom: 18px;
  color: var(--ink);
  font-size: clamp(34px, 3vw, 50px);
}

.client-proof-copy p {
  max-width: 420px;
  margin-bottom: 0;
  color: var(--muted);
}

.client-proof-link {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin-top: 28px;
  border-bottom: 1px solid var(--blue);
  padding-bottom: 8px;
  color: var(--blue);
  font-size: 14px;
  font-weight: 700;
}

.client-proof-link span {
  transition: transform 180ms ease;
}

.client-proof-link:hover span,
.client-proof-link:focus-visible span {
  transform: translateX(4px);
}

.client-logos {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  margin: 0;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
  padding: 0;
  list-style: none;
}

.client-logos-featured {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.client-logos li {
  display: grid;
  min-height: 112px;
  place-items: center;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: #fbfcfb;
  padding: 20px 14px;
}

.client-logos img {
  width: auto;
  max-width: 88%;
  height: auto;
  max-height: 48px;
  object-fit: contain;
}

.client-name {
  color: #b51e2e;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.process {
  background: var(--ink);
  color: var(--white);
}

.process-shell {
  display: grid;
  grid-template-columns: minmax(300px, 0.72fr) minmax(0, 1.28fr);
  gap: clamp(64px, 9vw, 144px);
}

.process-copy {
  align-self: start;
  position: sticky;
  top: calc(var(--header-height) + 46px);
}

.process h2 {
  margin-bottom: 26px;
  color: var(--white);
  font-size: clamp(40px, 3.6vw, 56px);
}

.process-copy p {
  max-width: 520px;
  margin-bottom: 34px;
  color: rgba(255, 255, 255, 0.68);
  font-size: 17px;
}

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

.process-list li {
  display: grid;
  grid-template-columns: 70px 1fr;
  gap: clamp(22px, 3vw, 44px);
  border-top: 1px solid var(--line-light);
  padding: 28px 0;
}

.process-list li:last-child {
  border-bottom: 1px solid var(--line-light);
}

.process-list > li > span {
  color: var(--sky);
  font-size: 14px;
  letter-spacing: 0.1em;
}

.process-list strong {
  display: block;
  margin-bottom: 7px;
  color: var(--white);
  font-size: clamp(21px, 1.8vw, 27px);
}

.process-list p {
  margin-bottom: 0;
  color: rgba(255, 255, 255, 0.58);
  font-size: 14px;
}

.knowledge {
  background: var(--paper);
}

.knowledge-grid {
  display: grid;
  grid-template-columns: minmax(300px, 0.78fr) minmax(0, 1.22fr);
  gap: clamp(64px, 9vw, 144px);
}

.knowledge h2 {
  margin-bottom: 28px;
}

.knowledge-intro > p {
  max-width: 520px;
  margin-bottom: 38px;
  color: var(--muted);
  font-size: 17px;
}

.knowledge-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.knowledge-links a {
  display: flex;
  min-height: 74px;
  align-items: center;
  justify-content: space-between;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 16px 19px;
  background: rgba(255, 255, 255, 0.44);
  font-size: 14px;
  font-weight: 650;
}

.knowledge-links span {
  color: var(--blue);
}

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

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

.faq-list summary {
  position: relative;
  padding: 24px 58px 24px 0;
  cursor: pointer;
  color: var(--ink);
  font-size: clamp(18px, 1.55vw, 23px);
  font-weight: 650;
  list-style: none;
}

.faq-list summary::-webkit-details-marker {
  display: none;
}

.faq-list summary::after {
  position: absolute;
  top: 50%;
  right: 6px;
  width: 28px;
  height: 28px;
  border: 1px solid var(--line);
  color: var(--blue);
  content: "+";
  font-size: 20px;
  font-weight: 400;
  line-height: 25px;
  text-align: center;
  transform: translateY(-50%);
}

.faq-list details[open] summary::after {
  content: "−";
}

.faq-list details p {
  max-width: 740px;
  margin-bottom: 26px;
  padding-right: 58px;
  color: var(--muted);
}

.contact {
  background: var(--coral);
  color: var(--white);
}

.contact-shell {
  display: grid;
  grid-template-columns: minmax(0, 1.18fr) minmax(360px, 0.82fr);
  gap: clamp(60px, 9vw, 144px);
}

.contact h2 {
  max-width: 850px;
  margin-bottom: 26px;
  color: var(--white);
}

.contact-copy > p {
  max-width: 780px;
  margin-bottom: 36px;
  color: rgba(255, 255, 255, 0.79);
  font-size: 17px;
}

.contact-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.contact-actions > * {
  display: grid;
  min-height: 146px;
  align-content: center;
  border: 1px solid rgba(255, 255, 255, 0.38);
  background: transparent;
  padding: 22px 26px;
  color: var(--white);
  cursor: pointer;
  text-align: left;
  transition: background 180ms ease, color 180ms ease;
}

.contact-actions > *:hover {
  background: var(--white);
  color: var(--ink);
}

.contact-actions span {
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: 0.12em;
}

.contact-actions strong {
  font-size: clamp(20px, 1.65vw, 27px);
}

.contact-actions i {
  margin-top: 10px;
  font-size: 12px;
  font-style: normal;
  opacity: 0.76;
}

.contact-prepare {
  background: var(--white);
  color: var(--ink);
  padding: clamp(32px, 4vw, 58px);
}

.contact-prepare h3 {
  margin-bottom: 22px;
  font-size: clamp(26px, 2.2vw, 36px);
}

.contact-prepare ul {
  margin: 0 0 24px;
  padding: 0;
  list-style: none;
}

.contact-prepare li {
  display: grid;
  grid-template-columns: 48px 1fr;
  border-top: 1px solid var(--line);
  padding: 16px 0;
}

.contact-prepare li span {
  color: var(--blue);
  font-size: 12px;
}

.contact-prepare li strong {
  font-size: 15px;
}

.contact-prepare > p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 13px;
}

.site-footer {
  background: var(--ink-deep);
  color: var(--white);
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(260px, 0.72fr) minmax(0, 1.28fr);
  align-items: end;
  gap: 80px;
  border-bottom: 1px solid var(--line-light);
  padding-block: 58px 42px;
}

.footer-brand img {
  width: 190px;
  height: auto;
  filter: brightness(0) invert(1);
}

.footer-brand p {
  margin: 15px 0 0;
  color: rgba(255, 255, 255, 0.55);
  font-size: 13px;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 16px 30px;
}

.footer-nav a {
  color: rgba(255, 255, 255, 0.7);
  font-size: 13px;
}

.footer-nav a:hover {
  color: var(--white);
}

.footer-bottom {
  display: flex;
  min-height: 84px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  color: rgba(255, 255, 255, 0.5);
  font-size: 12px;
}

.footer-bottom p {
  margin: 0;
}

.footer-bottom a {
  color: var(--sky);
  font-size: 16px;
  font-weight: 650;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 10px 20px;
}

.footer-bottom .icp-link {
  color: rgba(255, 255, 255, 0.62);
  font-size: 12px;
  font-weight: 500;
}

.footer-bottom .icp-link:hover {
  color: var(--white);
}

.mobile-contact-bar {
  display: none;
}

.wechat-dialog {
  width: min(440px, calc(100% - 32px));
  max-width: none;
  overscroll-behavior: contain;
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--ink);
}

.wechat-dialog::backdrop {
  background: rgba(5, 29, 39, 0.82);
  backdrop-filter: blur(6px);
}

.wechat-dialog-card {
  position: relative;
  display: grid;
  justify-items: center;
  background: var(--white);
  padding: 36px;
  box-shadow: var(--shadow);
  text-align: center;
}

.dialog-close {
  position: absolute;
  top: 12px;
  right: 12px;
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  border: 0;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  font-size: 28px;
}

.wechat-dialog-card > p {
  margin-bottom: 4px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 650;
  letter-spacing: 0.12em;
}

.wechat-dialog-card h2 {
  margin-bottom: 24px;
  font-size: 29px;
}

.wechat-dialog-card img {
  width: min(270px, 76vw);
  height: auto;
  border: 1px solid var(--line);
}

.wechat-dialog-card > span {
  max-width: 280px;
  margin-top: 18px;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 1180px) {
  .desktop-nav {
    gap: 13px;
  }

  .desktop-nav > a,
  .desktop-nav summary {
    font-size: 13px;
  }

  .header-phone span {
    display: none;
  }

  .case-more {
    grid-template-columns: 0.8fr 1.2fr;
  }

  .case-more > .button {
    grid-column: 1 / -1;
    justify-self: start;
  }
}

@media (max-width: 1100px) {
  :root {
    --header-height: 70px;
  }

  .header-shell {
    grid-template-columns: 1fr auto;
  }

  .desktop-nav,
  .header-phone {
    display: none;
  }

  .brand img {
    width: 170px;
  }

  .menu-toggle {
    display: flex;
    min-width: 78px;
    min-height: 46px;
    align-items: center;
    justify-content: flex-end;
    gap: 12px;
    border: 0;
    background: transparent;
    cursor: pointer;
  }

  .menu-toggle-label {
    font-size: 14px;
    font-weight: 650;
  }

  .menu-toggle-lines {
    display: grid;
    width: 24px;
    gap: 7px;
  }

  .menu-toggle-lines i {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--ink);
    transition: transform 180ms ease;
  }

  .menu-toggle[aria-expanded="true"] .menu-toggle-lines i:first-child {
    transform: translateY(4.5px) rotate(45deg);
  }

  .menu-toggle[aria-expanded="true"] .menu-toggle-lines i:last-child {
    transform: translateY(-4.5px) rotate(-45deg);
  }

  .mobile-menu {
    position: fixed;
    z-index: 999;
    top: var(--header-height);
    right: 0;
    left: 0;
    display: grid;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    border-top: 1px solid var(--line);
    background: var(--white);
    padding: 14px max(24px, calc((100vw - 880px) / 2));
    box-shadow: 0 24px 60px rgba(5, 29, 39, 0.2);
  }

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

  .mobile-menu > a,
  .mobile-menu summary {
    display: flex;
    min-height: 52px;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--line);
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    list-style: none;
  }

  .mobile-menu summary::-webkit-details-marker {
    display: none;
  }

  .mobile-menu summary::after {
    content: "+";
    font-size: 20px;
  }

  .mobile-menu details[open] summary::after {
    content: "−";
  }

  .mobile-menu details div {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    border-bottom: 1px solid var(--line);
    padding: 8px 0 14px 16px;
  }

  .mobile-menu details a {
    display: flex;
    min-height: 44px;
    align-items: center;
    color: var(--muted);
    font-size: 14px;
  }

  .mobile-menu .mobile-menu-phone {
    justify-content: center;
    margin-top: 14px;
    border: 0;
    background: var(--coral);
    color: var(--white);
  }

  .hero-grid {
    min-height: 650px;
    grid-template-columns: minmax(0, 560px) minmax(0, 1fr);
    padding-block: 56px;
  }

  .hero-copy {
    max-width: 540px;
  }

  .fact-shell {
    grid-template-columns: repeat(3, 1fr);
  }

  .fact-shell > div:nth-child(4),
  .fact-shell > div:nth-child(5) {
    border-top: 1px solid rgba(255, 255, 255, 0.25);
  }

  .fact-shell > div:nth-child(4) {
    grid-column: 1 / span 1;
  }

  .fact-shell > div:nth-child(5) {
    grid-column: 2 / -1;
  }

  .section-intro {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .section-intro p {
    max-width: 720px;
  }

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

  .noise-aside {
    min-height: auto;
  }

  .acoustic-shell {
    grid-template-columns: minmax(0, 0.94fr) minmax(0, 1.06fr);
    gap: 32px;
  }

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

  .case-more,
  .client-proof,
  .process-shell,
  .knowledge-grid,
  .contact-shell {
    grid-template-columns: 1fr;
  }

  .process-copy {
    position: static;
  }

  .process-copy p {
    max-width: 720px;
  }

  .client-proof {
    gap: 36px;
  }

  .client-proof-copy p {
    max-width: 720px;
  }

  .contact-shell {
    gap: 42px;
  }
}

@media (max-width: 820px) {
  .hero::before {
    display: none;
  }

  .hero-grid {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 36px;
    padding-block: 54px 0;
  }

  .acoustic-shell {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .acoustic-copy {
    display: contents;
  }

  .acoustic-copy > p:first-child {
    order: 1;
  }

  .acoustic-copy > h2 {
    order: 2;
  }

  .acoustic-copy > p:nth-of-type(2) {
    order: 3;
  }

  .acoustic-photo {
    order: 4;
    width: min(100%, 680px);
    aspect-ratio: 1852 / 778;
    margin: 0 auto 34px;
  }

  .acoustic-links {
    order: 5;
  }

  .hero-copy {
    max-width: 650px;
  }

  .hero-art {
    position: relative;
    z-index: 0;
    inset: auto;
    justify-self: center;
    width: min(100%, 560px);
    height: auto;
    aspect-ratio: 2 / 1;
    overflow: hidden;
  }

  .hero-art img {
    object-position: center;
  }

  .hero-assembly {
    top: auto;
    right: 50%;
    bottom: 20px;
    width: min(calc(100% - 40px), 520px);
    transform: translateX(50%);
  }

  .hero-assembly > strong {
    padding: 12px 14px 10px;
  }

  .hero-assembly ul {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .hero-assembly li {
    min-height: 36px;
    border-right: 1px solid rgba(210, 238, 246, 0.14);
    padding: 10px 8px 9px 21px;
    font-size: 11px;
  }

  .hero-assembly li:nth-child(3n) {
    border-right: 0;
  }

  .hero-assembly li:nth-last-child(-n + 3) {
    border-bottom: 0;
  }

  .hero-assembly li::before {
    top: 16px;
    left: 10px;
    width: 6px;
  }

  .hero-assembly small {
    padding: 9px 14px 10px;
    font-size: 9px;
  }
}

@media (max-width: 680px) {
  :root {
    --header-height: 68px;
  }

  body {
    padding-bottom: calc(62px + env(safe-area-inset-bottom));
    font-size: 15px;
  }

  .shell {
    width: calc(100% - 32px);
  }

  .section {
    padding-block: 72px;
  }

  .brand img {
    width: 148px;
  }

  .menu-toggle {
    min-width: 68px;
    min-height: 48px;
  }

  .hero-grid {
    width: calc(100% - 32px);
    min-height: auto;
    gap: 28px;
    padding-block: 42px 0;
  }

  .hero h1 {
    margin-bottom: 24px;
    font-size: clamp(44px, 12vw, 54px);
  }

  .hero h1 span {
    margin-top: 10px;
    font-size: 0.62em;
    line-height: 1.16;
  }

  .hero-summary {
    margin-bottom: 22px;
    font-size: 16px;
    line-height: 1.72;
  }

  .hero-actions {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
    margin-bottom: 24px;
  }

  .hero-actions .button {
    width: 100%;
    min-height: 52px;
  }

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

  .hero-capabilities li {
    min-height: 48px;
    padding: 13px 10px 0 0;
    font-size: 13px;
    text-align: left;
  }

  .hero-capabilities li:not(:first-child) {
    padding-left: 10px;
  }

  .hero-capabilities li:nth-child(2n) {
    border-right: 0;
  }

  .hero-capabilities li:nth-child(n + 3) {
    border-top: 1px solid rgba(8, 39, 53, 0.14);
  }

  .hero-art {
    width: 100%;
    margin-inline: 0;
    aspect-ratio: 1122 / 1402;
  }

  .hero-assembly {
    bottom: 14px;
    width: calc(100% - 28px);
  }

  .hero-assembly > strong {
    font-size: 11px;
  }

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

  .fact-shell > div {
    min-height: 104px;
    border-top: 1px solid rgba(255, 255, 255, 0.25);
    padding: 18px 16px;
  }

  .fact-shell > div:nth-child(1),
  .fact-shell > div:nth-child(2) {
    border-top: 0;
  }

  .fact-shell > div:nth-child(5) {
    grid-column: 1 / -1;
  }

  .fact-shell strong {
    font-size: 25px;
  }

  .fact-shell span {
    font-size: 12px;
  }

  .section-intro {
    margin-bottom: 38px;
  }

  .section-intro h2,
  .acoustic h2,
  .process h2,
  .knowledge h2,
  .contact h2 {
    font-size: clamp(34px, 9.5vw, 44px);
  }

  .section-intro p,
  .acoustic-copy > p:nth-of-type(2),
  .process-copy p,
  .knowledge-intro > p,
  .contact-copy > p {
    font-size: 15px;
  }

  .noise-paths {
    grid-template-columns: 1fr;
  }

  .path-card {
    min-height: 284px;
    padding: 28px;
  }

  .path-card h3 {
    margin-top: 36px;
  }

  .noise-aside {
    padding: 30px 26px;
  }

  .acoustic-photo {
    height: auto;
    aspect-ratio: 1852 / 778;
  }

  .acoustic-shell {
    gap: 0;
  }

  .acoustic-links {
    grid-template-columns: 1fr;
  }

  .acoustic-links a,
  .acoustic-links a:nth-child(even) {
    min-height: 90px;
    border-right: 0;
    padding-inline: 0;
  }

  .case-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .case-card-copy {
    min-height: auto;
    padding: 20px;
  }

  .case-more {
    gap: 28px;
    padding: 30px 24px;
  }

  .case-more ul {
    grid-template-columns: 1fr;
  }

  .case-more li:nth-last-child(-n + 2) {
    border-bottom: 0;
  }

  .case-more li:last-child {
    border-bottom: 1px solid var(--line);
  }

  .case-more > .button {
    width: 100%;
  }

  .client-proof {
    margin-top: 72px;
    padding-top: 44px;
  }

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

  .client-logos li {
    min-height: 94px;
    padding: 16px 10px;
  }

  .client-logos img {
    max-height: 44px;
  }

  .client-name {
    font-size: 15px;
  }

  .process-shell,
  .knowledge-grid {
    gap: 46px;
  }

  .process-list li {
    grid-template-columns: 42px 1fr;
    gap: 16px;
    padding: 22px 0;
  }

  .knowledge-links {
    grid-template-columns: 1fr;
  }

  .faq-list summary {
    padding: 21px 48px 21px 0;
    font-size: 18px;
  }

  .faq-list details p {
    padding-right: 20px;
  }

  .contact-actions {
    grid-template-columns: 1fr;
  }

  .contact-actions > * {
    min-height: 132px;
  }

  .contact-prepare {
    padding: 30px 24px;
  }

  .footer-main {
    grid-template-columns: 1fr;
    gap: 36px;
    padding-block: 50px 34px;
  }

  .footer-nav {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    justify-content: start;
    gap: 14px 24px;
  }

  .footer-bottom {
    min-height: 110px;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
  }

  .footer-legal {
    justify-content: flex-start;
  }

  .mobile-contact-bar {
    position: fixed;
    z-index: 1200;
    right: 0;
    bottom: 0;
    left: 0;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    min-height: calc(62px + env(safe-area-inset-bottom));
    padding-bottom: env(safe-area-inset-bottom);
    background: var(--white);
    box-shadow: 0 -8px 28px rgba(5, 29, 39, 0.16);
  }

  .mobile-contact-bar > * {
    display: grid;
    min-height: 62px;
    place-items: center;
    border: 0;
    background: var(--ink);
    color: var(--white);
    cursor: pointer;
    font-size: 15px;
    font-weight: 650;
  }

  .mobile-contact-bar > *:last-child {
    background: var(--coral);
  }

  .wechat-dialog-card {
    padding: 34px 24px 28px;
  }
}

@media (max-width: 360px) {
  .shell {
    width: calc(100% - 24px);
  }

  .brand img {
    width: 136px;
  }

  .menu-toggle-label {
    display: none;
  }

  .menu-toggle {
    min-width: 48px;
  }

  .hero h1 {
    font-size: 42px;
  }

  .hero-grid {
    padding-block: 38px 0;
  }

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

  .path-card,
  .noise-aside,
  .case-more,
  .contact-prepare {
    padding-inline: 22px;
  }

  .client-logos li {
    min-height: 86px;
  }
}

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

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