:root {
  --navy: #16304f;
  --navy-2: #1d3c63;
  --navy-dark: #0e2138;
  --gold: #c9974b;
  --grey-bg: #f4f6f8;
  --text: #2a3440;
  --text-light: #5d6b7a;
  --white: #ffffff;
  --header-h: 72px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  color: var(--text);
  line-height: 1.7;
  background: var(--white);
}

img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: background .3s, box-shadow .3s;
}
.header-inner {
  max-width: 1320px;
  margin: 0 auto;
  padding: 0 24px;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand img { height: 36px; filter: brightness(0) invert(1); transition: filter .3s; }
.site-header.scrolled { background: var(--white); box-shadow: 0 2px 16px rgba(14, 33, 56, .1); }
.site-header.scrolled .brand img { filter: none; }

.nav { display: flex; gap: 32px; }
.nav a {
  color: var(--white);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: .02em;
  position: relative;
  padding: 6px 0;
  transition: color .3s;
}
.nav a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--gold);
  transition: width .25s;
}
.nav a:hover::after { width: 100%; }
.site-header.scrolled .nav a { color: var(--navy); }

.header-actions { display: flex; align-items: center; gap: 16px; }
.lang-switch {
  border: 1px solid rgba(255, 255, 255, .7);
  background: transparent;
  color: var(--white);
  font-size: 13px;
  font-weight: 600;
  padding: 5px 14px;
  border-radius: 3px;
  cursor: pointer;
  letter-spacing: .05em;
  transition: all .3s;
}
.lang-switch:hover { background: var(--gold); border-color: var(--gold); }
.site-header.scrolled .lang-switch { color: var(--navy); border-color: var(--navy); }
.site-header.scrolled .lang-switch:hover { background: var(--navy); color: var(--white); }

.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 6px; }
.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--white);
  margin: 5px 0;
  transition: all .3s;
}
.site-header.scrolled .nav-toggle span { background: var(--navy); }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background: url("../assets/img/hero.jpg") center/cover no-repeat;
}
.hero-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(100deg, rgba(14, 33, 56, .82) 0%, rgba(14, 33, 56, .55) 45%, rgba(14, 33, 56, .25) 100%);
}
.hero-content { position: relative; z-index: 1; color: var(--white); padding-top: var(--header-h); }
.hero-kicker {
  display: inline-block;
  font-size: 15px;
  letter-spacing: .12em;
  color: var(--gold);
  border-left: 3px solid var(--gold);
  padding-left: 12px;
  margin-bottom: 24px;
}
.hero-title {
  font-size: clamp(34px, 5.2vw, 64px);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: .01em;
}
.hero-subtitle {
  font-size: clamp(20px, 2.6vw, 30px);
  font-weight: 600;
  margin-top: 18px;
}
.hero-desc {
  font-size: clamp(14px, 1.5vw, 17px);
  color: rgba(255, 255, 255, .82);
  margin-top: 12px;
  letter-spacing: .04em;
}
.hero-cta { margin-top: 40px; display: flex; gap: 16px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  padding: 13px 34px;
  font-size: 15px;
  font-weight: 600;
  border-radius: 3px;
  letter-spacing: .04em;
  transition: all .3s;
}
.btn-primary { background: var(--gold); color: var(--white); }
.btn-primary:hover { background: #b5843c; transform: translateY(-2px); }
.btn-ghost { border: 1px solid rgba(255, 255, 255, .75); color: var(--white); }
.btn-ghost:hover { background: var(--white); color: var(--navy); }

.hero-scroll {
  position: absolute;
  bottom: 32px; left: 50%;
  transform: translateX(-50%);
  width: 26px; height: 42px;
  border: 2px solid rgba(255, 255, 255, .6);
  border-radius: 14px;
  z-index: 1;
}
.hero-scroll span {
  position: absolute;
  top: 8px; left: 50%;
  width: 4px; height: 8px;
  margin-left: -2px;
  background: var(--white);
  border-radius: 2px;
  animation: scrollHint 1.8s infinite;
}
@keyframes scrollHint {
  0% { opacity: 1; transform: translateY(0); }
  70% { opacity: 0; transform: translateY(14px); }
  100% { opacity: 0; }
}

/* ---------- Stats ---------- */
.stats {
  position: relative;
  background: url("../assets/img/city-blue.jpg") center/cover no-repeat;
  padding: 72px 0;
}
.stats-overlay { position: absolute; inset: 0; background: rgba(22, 48, 79, .9); }
.stats-grid {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  text-align: center;
  color: var(--white);
}
.stat-num { font-size: clamp(34px, 4vw, 52px); font-weight: 800; line-height: 1.1; }
.stat-num small { font-size: .4em; font-weight: 600; margin-left: 4px; color: var(--gold); }
.stat-label { margin-top: 8px; font-size: 15px; color: rgba(255, 255, 255, .8); }

/* ---------- Sections ---------- */
.section { padding: 96px 0; }
.section-grey { background: var(--grey-bg); }

.section-head { margin-bottom: 56px; }
.kicker {
  display: inline-block;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--gold);
  text-transform: uppercase;
  margin-bottom: 12px;
  position: relative;
  padding-left: 34px;
}
.kicker::before {
  content: "";
  position: absolute;
  left: 0; top: 50%;
  width: 24px; height: 2px;
  background: var(--gold);
}
.section-head h2 {
  font-size: clamp(26px, 3.2vw, 38px);
  color: var(--navy);
  font-weight: 700;
  line-height: 1.3;
}
.section-head-light h2 { color: var(--white); }

.sub-title {
  font-size: 22px;
  color: var(--navy);
  margin-bottom: 32px;
  font-weight: 700;
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 56px;
  align-items: start;
}
.about-text p { margin-bottom: 18px; color: var(--text-light); font-size: 16px; }
.about-locs { margin-top: 28px; border-top: 1px solid #e3e8ee; }
.about-locs li {
  display: flex;
  gap: 20px;
  padding: 14px 0;
  border-bottom: 1px solid #e3e8ee;
  font-size: 15px;
}
.about-locs strong { color: var(--navy); min-width: 110px; font-weight: 700; }
.about-locs span { color: var(--text-light); }

.about-img { display: grid; gap: 20px; }
.about-img img {
  width: 100%;
  border-radius: 4px;
  box-shadow: 0 12px 32px rgba(14, 33, 56, .14);
}

.timeline-wrap { margin-top: 80px; }
.timeline {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 12px;
  position: relative;
}
.timeline::before {
  content: "";
  position: absolute;
  top: 17px; left: 0; right: 0;
  height: 2px;
  background: #dfe5ec;
}
.tl-item { position: relative; padding-top: 48px; }
.tl-item::before {
  content: "";
  position: absolute;
  top: 11px; left: 0;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--white);
  border: 3px solid var(--navy);
}
.tl-year { font-weight: 800; color: var(--navy); font-size: 18px; }
.tl-item p { font-size: 13.5px; color: var(--text-light); margin-top: 6px; line-height: 1.55; }

/* ---------- Services cards ---------- */
.cards-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.card {
  background: var(--white);
  padding: 40px 28px;
  border-radius: 4px;
  border-top: 3px solid transparent;
  box-shadow: 0 4px 20px rgba(14, 33, 56, .06);
  transition: transform .3s, box-shadow .3s, border-color .3s;
}
.card:hover {
  transform: translateY(-8px);
  box-shadow: 0 16px 40px rgba(14, 33, 56, .14);
  border-top-color: var(--gold);
}
.card-icon {
  width: 56px; height: 56px;
  border-radius: 4px;
  background: var(--navy);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
}
.card-icon svg { width: 28px; height: 28px; fill: var(--white); }
.card h3 { font-size: 18px; color: var(--navy); margin-bottom: 12px; }
.card p { font-size: 14.5px; color: var(--text-light); }

/* ---------- Solutions ---------- */
.sol-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
  padding: 36px 0;
}
.sol-row + .sol-row { border-top: 1px solid #edf0f4; }
.sol-row-rev .sol-img { order: 2; }
.sol-row-rev .sol-text { order: 1; }
.sol-img img {
  width: 100%;
  height: 320px;
  object-fit: cover;
  border-radius: 4px;
  box-shadow: 0 12px 32px rgba(14, 33, 56, .12);
}
.sol-text h3 {
  font-size: 24px;
  color: var(--navy);
  margin-bottom: 16px;
  position: relative;
  padding-left: 18px;
}
.sol-text h3::before {
  content: "";
  position: absolute;
  left: 0; top: 6px; bottom: 6px;
  width: 4px;
  background: var(--gold);
  border-radius: 2px;
}
.sol-text p { color: var(--text-light); font-size: 15.5px; }

/* ---------- Advantages ---------- */
.adv-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.adv-item {
  background: var(--white);
  padding: 34px 30px;
  border-radius: 4px;
  border-left: 3px solid var(--navy);
  box-shadow: 0 4px 20px rgba(14, 33, 56, .06);
  transition: border-color .3s, transform .3s;
}
.adv-item:hover { border-left-color: var(--gold); transform: translateY(-4px); }
.adv-item h3 { color: var(--navy); font-size: 18px; margin-bottom: 10px; }
.adv-item p { font-size: 14.5px; color: var(--text-light); }

/* ---------- Team band ---------- */
.team-band {
  position: relative;
  background: url("../assets/img/city-dark.jpg") center/cover no-repeat;
  padding: 88px 0;
  text-align: center;
  color: var(--white);
}
.team-overlay { position: absolute; inset: 0; background: rgba(14, 33, 56, .85); }
.team-inner { position: relative; max-width: 820px; }
.team-inner h2 { font-size: clamp(24px, 3vw, 34px); margin-bottom: 18px; }
.team-inner p { color: rgba(255, 255, 255, .82); font-size: 16px; }
.team-badges { margin-top: 32px; display: flex; justify-content: center; gap: 14px; flex-wrap: wrap; }
.team-badges span {
  border: 1px solid var(--gold);
  color: var(--gold);
  font-weight: 700;
  letter-spacing: .08em;
  padding: 7px 22px;
  border-radius: 3px;
  font-size: 14px;
}

/* ---------- Certificates ---------- */
.certs-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.cert-card {
  background: var(--white);
  border-radius: 4px;
  padding: 16px 16px 0;
  box-shadow: 0 4px 20px rgba(14, 33, 56, .06);
  cursor: zoom-in;
  transition: transform .3s, box-shadow .3s;
}
.cert-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 36px rgba(14, 33, 56, .14);
}
.cert-img {
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fafbfc;
  border: 1px solid #eef1f5;
  border-radius: 3px;
  overflow: hidden;
}
.cert-img img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  transition: transform .4s;
}
.cert-card:hover .cert-img img { transform: scale(1.04); }
.cert-card figcaption {
  padding: 14px 4px;
  font-size: 13.5px;
  color: var(--text-light);
  text-align: center;
  line-height: 1.5;
}
.certs-hint {
  margin-top: 28px;
  text-align: center;
  font-size: 13px;
  color: var(--text-light);
  letter-spacing: .05em;
}

.lightbox {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: rgba(14, 33, 56, .9);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 40px;
  cursor: zoom-out;
}
.lightbox.open { display: flex; }
.lightbox img {
  max-width: 100%;
  max-height: 100%;
  border-radius: 4px;
  box-shadow: 0 24px 64px rgba(0, 0, 0, .5);
  animation: lightboxIn .25s ease;
}
@keyframes lightboxIn {
  from { opacity: 0; transform: scale(.94); }
  to { opacity: 1; transform: scale(1); }
}

/* ---------- Cases ---------- */
.cases-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.case {
  position: relative;
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 0 6px 24px rgba(14, 33, 56, .1);
}
.case img {
  width: 100%;
  height: 260px;
  object-fit: cover;
  transition: transform .5s;
}
.case:hover img { transform: scale(1.06); }
.case figcaption {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  padding: 36px 18px 14px;
  background: linear-gradient(transparent, rgba(14, 33, 56, .88));
  color: var(--white);
  font-size: 14px;
}

/* ---------- Clients ---------- */
.client-group { margin-bottom: 36px; }
.client-group:last-child { margin-bottom: 0; }
.client-cat {
  font-size: 15px;
  font-weight: 700;
  color: var(--navy);
  letter-spacing: .08em;
  margin-bottom: 16px;
  position: relative;
  padding-left: 16px;
}
.client-cat::before {
  content: "";
  position: absolute;
  left: 0; top: 3px; bottom: 3px;
  width: 4px;
  background: var(--gold);
  border-radius: 2px;
}
.clients-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
}
.client-card {
  background: var(--white);
  border-radius: 4px;
  padding: 22px 12px;
  text-align: center;
  box-shadow: 0 4px 16px rgba(14, 33, 56, .06);
  border-bottom: 3px solid transparent;
  transition: transform .3s, box-shadow .3s, border-color .3s;
}
.client-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 28px rgba(14, 33, 56, .12);
  border-bottom-color: var(--gold);
}
.client-cn {
  display: block;
  font-size: 17px;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.4;
}
.client-en {
  display: block;
  margin-top: 4px;
  font-size: 12.5px;
  color: var(--text-light);
  letter-spacing: .04em;
}

/* ---------- Contact ---------- */
.contact {
  background: linear-gradient(135deg, var(--navy-dark) 0%, var(--navy-2) 100%);
  padding: 96px 0;
  color: var(--white);
}
.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.contact-card {
  background: rgba(255, 255, 255, .06);
  border: 1px solid rgba(255, 255, 255, .12);
  border-radius: 4px;
  padding: 30px 26px;
  transition: background .3s, border-color .3s;
}
.contact-card:hover { background: rgba(255, 255, 255, .1); border-color: var(--gold); }
.contact-card h3 {
  font-size: 14px;
  letter-spacing: .1em;
  color: var(--gold);
  margin-bottom: 10px;
  text-transform: uppercase;
}
.contact-card p { font-size: 15.5px; word-break: break-all; }
.contact-card a:hover { color: var(--gold); }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--navy-dark);
  padding: 28px 0;
  color: rgba(255, 255, 255, .6);
  font-size: 14px;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-logo { height: 28px; filter: brightness(0) invert(.7); }

/* ---------- Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .7s ease, transform .7s ease;
}
.reveal.visible { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .timeline { grid-template-columns: repeat(4, 1fr); row-gap: 36px; }
  .timeline::before { display: none; }
  .cards-4 { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }
  .certs-grid { grid-template-columns: repeat(3, 1fr); }
  .clients-grid { grid-template-columns: repeat(4, 1fr); }
}

@media (max-width: 900px) {
  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    background: var(--white);
    flex-direction: column;
    gap: 0;
    padding: 12px 24px 20px;
    box-shadow: 0 12px 24px rgba(14, 33, 56, .12);
    display: none;
  }
  .nav.open { display: flex; }
  .nav a { color: var(--navy) !important; padding: 12px 0; border-bottom: 1px solid #eef1f5; }
  .nav-toggle { display: block; }
  .nav-toggle span { background: var(--navy); }
  .site-header { background: var(--white); box-shadow: 0 2px 16px rgba(14, 33, 56, .1); }
  .site-header .brand img { filter: none; }
  .site-header .nav a { color: var(--navy); }
  .site-header .lang-switch { color: var(--navy); border-color: var(--navy); }

  .about-grid, .sol-row { grid-template-columns: 1fr; gap: 32px; }
  .sol-row-rev .sol-img { order: 0; }
  .sol-row-rev .sol-text { order: 0; }
  .adv-grid { grid-template-columns: 1fr 1fr; }
  .cases-grid { grid-template-columns: 1fr 1fr; }
  .certs-grid { grid-template-columns: 1fr 1fr; }
  .clients-grid { grid-template-columns: repeat(3, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 560px) {
  .section { padding: 64px 0; }
  .timeline { grid-template-columns: repeat(2, 1fr); }
  .cards-4, .adv-grid, .cases-grid, .certs-grid, .contact-grid { grid-template-columns: 1fr; }
  .clients-grid { grid-template-columns: 1fr 1fr; }
  .sol-img img { height: 220px; }
  .hero-cta .btn { width: 100%; text-align: center; }
}