:root {
  --blue: #005bac;
  --blue-dark: #004a8f;
  --blue-light: #e8f2fa;
  --text: #222;
  --text-muted: #666;
  --border: #e0e0e0;
  --bg-gray: #f5f7fa;
  --bg-dark: #1a2d4a;
  --wrap: 1200px;
  --header-h: 72px;
  --top-h: 36px;
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  font-size: 14px;
  color: var(--text);
  line-height: 1.7;
  background: #fff;
  -webkit-font-smoothing: antialiased;
}

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

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

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 20px;
}

/* Top bar */
.site-top {
  background: var(--bg-dark);
  height: var(--top-h);
  display: flex;
  align-items: center;
}

.site-top__inner {
  display: flex;
  justify-content: flex-end;
}

.site-top__nav {
  display: flex;
  gap: 24px;
}

.site-top__nav a {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.75);
  transition: color 0.2s;
}

.site-top__nav a:hover {
  color: #fff;
}

@media (max-width: 640px) {
  .site-top__nav {
    gap: 12px;
    font-size: 11px;
  }
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  height: var(--header-h);
  background: #fff;
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.3s;
}

.site-header.is-scrolled {
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

.site-header__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-header__brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.site-header__brand img {
  width: 42px;
  height: 42px;
}

.site-header__brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.3;
}

.site-header__brand-text strong {
  font-size: 18px;
  color: var(--blue);
  letter-spacing: 0.04em;
}

.site-header__brand-text span {
  font-size: 11px;
  color: var(--text-muted);
  display: none;
}

@media (min-width: 900px) {
  .site-header__brand-text span {
    display: block;
  }
}

.site-header__nav {
  display: flex;
  align-items: center;
  gap: 0;
}

.site-header__nav a {
  padding: 8px 18px;
  font-size: 15px;
  color: var(--text);
  position: relative;
  transition: color 0.2s;
}

.site-header__nav a:hover,
.site-header__nav a.is-active {
  color: var(--blue);
}

.site-header__nav a.is-active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 18px;
  right: 18px;
  height: 2px;
  background: var(--blue);
}

.site-header__menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.site-header__menu-btn span {
  width: 22px;
  height: 2px;
  background: var(--text);
  transition: transform 0.3s, opacity 0.3s;
}

.site-header__menu-btn.is-open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.site-header__menu-btn.is-open span:nth-child(2) {
  opacity: 0;
}

.site-header__menu-btn.is-open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 900px) {
  .site-header__menu-btn {
    display: flex;
  }

  .site-header__nav {
    position: fixed;
    top: calc(var(--top-h) + var(--header-h));
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.3s, opacity 0.3s;
  }

  .site-header__nav.is-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .site-header__nav a {
    padding: 14px 20px;
    border-bottom: 1px solid var(--border);
  }

  .site-header__nav a.is-active::after {
    display: none;
  }
}

/* Banner */
.banner {
  position: relative;
  height: clamp(420px, 56vh, 560px);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.banner__bg {
  position: absolute;
  inset: 0;
}

.banner__bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.banner__bg:not(.has-image) {
  background: linear-gradient(135deg, #002d62 0%, #005bac 50%, #1a2d4a 100%);
}

.banner__bg:not(.has-image) img {
  display: none;
}

.banner__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    135deg,
    rgba(0, 45, 98, 0.82) 0%,
    rgba(0, 91, 172, 0.65) 50%,
    rgba(26, 45, 74, 0.75) 100%
  );
}

.banner__content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: #fff;
  padding: 40px 20px 60px;
}

.banner__title {
  font-size: clamp(24px, 4.5vw, 40px);
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.35;
  text-shadow: 0 2px 16px rgba(0, 0, 0, 0.25);
}

.banner__tagline {
  font-size: clamp(16px, 2.5vw, 22px);
  margin-top: 16px;
  font-weight: 400;
  opacity: 0.92;
  letter-spacing: 0.12em;
}

.banner__scroll {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  margin-top: 48px;
  color: rgba(255, 255, 255, 0.8);
  font-size: 12px;
  letter-spacing: 0.2em;
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(6px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .banner__scroll {
    animation: none;
  }
}

/* Block sections */
.block {
  padding: 72px 0;
}

.block--intro {
  background: #fff;
}

.block--timeline {
  background: var(--bg-dark);
  color: #fff;
}

.block--services {
  background: var(--bg-gray);
}

.block--system {
  background: #fff;
}

.block--cases {
  background: linear-gradient(180deg, var(--blue-dark) 0%, var(--bg-dark) 100%);
  color: #fff;
}

.block--contact {
  background: var(--blue-light);
}

.block-head {
  text-align: center;
  margin-bottom: 48px;
}

.block-head__cn {
  font-size: clamp(26px, 3.5vw, 32px);
  font-weight: 700;
  color: var(--blue);
  letter-spacing: 0.08em;
}

.block-head__en {
  font-size: 13px;
  color: var(--text-muted);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-top: 8px;
}

.block-head--light .block-head__cn {
  color: #fff;
}

.block-head--light .block-head__en {
  color: rgba(255, 255, 255, 0.55);
}

/* Intro */
.intro {
  display: grid;
  gap: 40px;
  align-items: start;
}

@media (min-width: 900px) {
  .intro {
    grid-template-columns: 1.2fr 1fr;
    gap: 56px;
  }

  .intro--no-media {
    grid-template-columns: 1fr;
    max-width: 800px;
    margin: 0 auto;
  }
}

.intro__lead {
  font-size: 15px;
  line-height: 2;
  color: var(--text);
  text-indent: 2em;
}

.intro__more {
  font-size: 14px;
  line-height: 2;
  color: var(--text-muted);
  margin-top: 16px;
  text-indent: 2em;
}

.intro__quotes {
  display: grid;
  gap: 16px;
  margin-top: 32px;
}

@media (min-width: 640px) {
  .intro__quotes {
    grid-template-columns: 1fr 1fr;
  }
}

.intro__quote {
  padding: 20px 24px;
  background: var(--bg-gray);
  border-left: 3px solid var(--blue);
}

.intro__quote span {
  display: block;
  font-size: 12px;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: 0.1em;
  margin-bottom: 8px;
}

.intro__quote p {
  font-size: 14px;
  font-weight: 500;
  line-height: 1.6;
}

.intro__media {
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
}

.intro__media img {
  width: 100%;
  aspect-ratio: 7 / 5;
  object-fit: cover;
}

/* Timeline */
.timeline {
  max-width: 900px;
  margin: 0 auto;
}

.timeline__year {
  display: none;
}

.timeline__year.is-active {
  display: block;
}

.timeline__tabs {
  display: flex;
  justify-content: center;
  gap: 0;
  margin-bottom: 0;
  border-bottom: 2px solid rgba(255, 255, 255, 0.15);
}

.timeline__tab {
  padding: 16px 40px;
  background: transparent;
  border: none;
  color: rgba(255, 255, 255, 0.5);
  font-size: 24px;
  font-weight: 700;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
  font-family: var(--font);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
}

.timeline__tab:hover {
  color: rgba(255, 255, 255, 0.85);
}

.timeline__tab.is-active {
  color: #fff;
  border-bottom-color: var(--blue);
}

.timeline__list {
  list-style: none;
  padding: 32px 0 0;
}

.timeline__list li {
  font-size: 14px;
  line-height: 1.9;
  color: rgba(255, 255, 255, 0.85);
  padding: 12px 0 12px 24px;
  position: relative;
  border-bottom: 1px dashed rgba(255, 255, 255, 0.12);
}

.timeline__list li:last-child {
  border-bottom: none;
}

.timeline__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20px;
  width: 8px;
  height: 8px;
  background: var(--blue);
  border-radius: 50%;
}

/* Service cards */
.service-grid {
  display: grid;
  gap: 24px;
}

@media (min-width: 640px) {
  .service-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .service-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.service-card {
  background: #fff;
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
  transition: transform 0.25s, box-shadow 0.25s;
  display: flex;
  flex-direction: column;
}

.service-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 91, 172, 0.15);
}

.service-card__img {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--bg-gray);
}

.service-card__img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s;
}

.service-card:hover .service-card__img img {
  transform: scale(1.05);
}

.service-card--no-img .service-card__body {
  padding-top: 28px;
}

.service-card__body {
  padding: 24px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.service-card__num {
  font-size: 32px;
  font-weight: 800;
  color: var(--blue-light);
  line-height: 1;
  margin-bottom: 8px;
}

.service-card__title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
}

.service-card__desc {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.8;
  flex: 1;
}

.service-card__link {
  display: inline-block;
  margin-top: 16px;
  font-size: 13px;
  color: var(--blue);
  font-weight: 600;
  transition: color 0.2s;
}

.service-card__link:hover {
  color: var(--blue-dark);
}

.service-card__link::after {
  content: " →";
}

/* System cards */
.system-grid {
  display: grid;
  gap: 24px;
}

@media (min-width: 768px) {
  .system-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.system-card {
  padding: 32px 28px;
  background: var(--bg-gray);
  border: 1px solid var(--border);
  border-top: 3px solid var(--blue);
  border-radius: 4px;
  transition: box-shadow 0.2s;
}

.system-card:hover {
  box-shadow: 0 4px 20px rgba(0, 91, 172, 0.1);
}

.system-card__index {
  font-size: 36px;
  font-weight: 800;
  color: rgba(0, 91, 172, 0.15);
  line-height: 1;
  display: block;
  margin-bottom: 12px;
}

.system-card h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
}

.system-card p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.8;
}

/* Case cards */
.case-card {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 4px;
  padding: 40px;
  margin-bottom: 32px;
}

.case-card:last-child {
  margin-bottom: 0;
}

.case-card__head {
  display: grid;
  gap: 24px;
  margin-bottom: 32px;
}

@media (min-width: 900px) {
  .case-card__head {
    grid-template-columns: auto 1fr 280px;
    align-items: start;
    gap: 32px;
  }

  .case-card__head--no-img {
    grid-template-columns: auto 1fr;
  }
}

.case-card__num {
  font-size: 48px;
  font-weight: 800;
  color: rgba(255, 255, 255, 0.15);
  line-height: 1;
}

.case-card__info h3 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
}

.case-card__tagline {
  font-size: 16px;
  opacity: 0.9;
  margin-bottom: 12px;
}

.case-card__desc {
  font-size: 14px;
  opacity: 0.65;
  line-height: 1.9;
}

.case-card__hero {
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.case-card__hero img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.case-feats {
  display: grid;
  gap: 20px;
  margin-bottom: 28px;
}

@media (min-width: 768px) {
  .case-feats {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .case-feats {
    grid-template-columns: repeat(4, 1fr);
  }
}

.case-feat {
  background: rgba(255, 255, 255, 0.05);
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.case-feat--no-img {
  padding: 20px;
}

.case-feat--no-img h4 {
  padding: 0;
}

.case-feat--no-img p {
  padding: 0;
  margin-top: 8px;
}

.case-feat img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}

.case-feat h4 {
  font-size: 15px;
  font-weight: 700;
  padding: 14px 16px 4px;
}

.case-feat p {
  font-size: 12px;
  opacity: 0.6;
  padding: 0 16px 16px;
  line-height: 1.6;
}

.case-shots {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

@media (min-width: 640px) {
  .case-shots {
    grid-template-columns: repeat(4, 1fr);
  }
}

.case-shots__item {
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
}

.case-shots__item img {
  width: 100%;
  aspect-ratio: 9 / 19;
  object-fit: cover;
}

/* Contact */
.contact-bar {
  display: grid;
  gap: 20px;
  background: #fff;
  padding: 40px;
  border-radius: 4px;
  box-shadow: 0 4px 24px rgba(0, 91, 172, 0.08);
  border: 1px solid var(--border);
}

@media (min-width: 768px) {
  .contact-bar {
    grid-template-columns: repeat(2, 1fr);
  }
}

.contact-bar__item--wide {
  grid-column: 1 / -1;
}

.contact-bar__label {
  display: block;
  font-size: 12px;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: 0.08em;
  margin-bottom: 6px;
}

.contact-bar__item p {
  font-size: 15px;
  line-height: 1.7;
}

.contact-bar__item a {
  color: var(--blue);
}

.contact-bar__item a:hover {
  text-decoration: underline;
}

/* Footer */
.site-footer {
  background: var(--bg-dark);
  color: rgba(255, 255, 255, 0.7);
}

.site-footer__main {
  display: grid;
  gap: 32px;
  padding: 48px 20px;
}

@media (min-width: 768px) {
  .site-footer__main {
    grid-template-columns: 1.5fr 1fr 1fr;
    align-items: start;
  }
}

.site-footer__brand {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.site-footer__brand img {
  width: 36px;
  height: 36px;
}

.site-footer__brand strong {
  display: block;
  font-size: 18px;
  color: #fff;
  margin-bottom: 4px;
}

.site-footer__brand p {
  font-size: 12px;
  opacity: 0.7;
}

.site-footer__contact p {
  font-size: 13px;
  margin-bottom: 8px;
}

.site-footer__contact a {
  color: rgba(255, 255, 255, 0.85);
}

.site-footer__links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.site-footer__links a {
  font-size: 13px;
  transition: color 0.2s;
}

.site-footer__links a:hover {
  color: #fff;
}

.site-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  padding: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 12px;
  opacity: 0.55;
}

.site-footer__bottom a:hover {
  color: #fff;
}