:root {
  --bg: #050814;
  --bg-alt: #070a18;
  --bg-soft: #0b1025;
  --card: #10152b;
  --accent: #3f7afe;
  --accent-soft: rgba(63, 122, 254, 0.12);
  --accent-strong: rgba(63, 122, 254, 0.3);
  --text: #f5f7ff;
  --text-muted: #a0a4c0;
  --border-subtle: rgba(255, 255, 255, 0.06);
  --shadow-soft: 0 24px 80px rgba(0, 0, 0, 0.7);
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-full: 999px;
  --nav-height: 72px;
}

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

html,
body {
  margin: 0;
  padding: 0;
  scroll-behavior: smooth;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Montserrat", sans-serif;
  background: radial-gradient(circle at top, #121b3f 0, #050814 55%, #000 100%);
  color: var(--text);
}

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

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

.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(3, 6, 22, 0.9);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-subtle);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.logo-mark {
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: radial-gradient(circle at 0 0, #7cf3ff, #3f7afe 40%, #121b3f);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 16px;
  color: #fff;
}

.logo-text {
  display: inline-flex;
  flex-direction: column;
  font-size: 15px;
  font-weight: 600;
}

.logo-sub {
  font-size: 11px;
  font-weight: 400;
  color: var(--text-muted);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 14px;
}

.main-nav a {
  position: relative;
  color: var(--text-muted);
  padding-bottom: 2px;
  transition: color 0.2s ease;
}

.main-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, #3f7afe, #7cf3ff);
  transition: width 0.22s ease;
}

.main-nav a:hover,
.main-nav a.active {
  color: #fff;
}

.main-nav a:hover::after,
.main-nav a.active::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: 999px;
  border: 1px solid var(--border-subtle);
  background: rgba(12, 16, 40, 0.9);
  display: none;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 6px;
  padding: 0;
}

.nav-toggle span {
  width: 18px;
  height: 2px;
  border-radius: 999px;
  background: var(--text);
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(4px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  transform: translateY(-4px) rotate(-45deg);
}

/* Hero */
.hero {
  padding: 78px 0 56px;
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1.1fr);
  gap: 52px;
  align-items: center;
}

.hero-content h1 {
  font-size: 40px;
  line-height: 1.2;
  margin: 0 0 18px;
}

.gradient-text {
  background: linear-gradient(120deg, #7cf3ff, #3f7afe);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-subtitle {
  margin: 0 0 24px;
  color: var(--text-muted);
  font-size: 15px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 24px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border-radius: var(--radius-full);
  font-size: 14px;
  font-weight: 500;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s,
    border-color 0.15s, color 0.15s;
}

.btn-primary {
  background: linear-gradient(135deg, #3f7afe, #7cf3ff);
  color: #020412;
  box-shadow: 0 14px 30px rgba(34, 87, 255, 0.35);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 50px rgba(34, 87, 255, 0.5);
}

.btn-outline {
  background: transparent;
  border-color: var(--accent-strong);
  color: #d3d7ff;
  background-image: radial-gradient(
    circle at 0 0,
    rgba(124, 243, 255, 0.2),
    transparent 55%
  );
}

.btn-outline:hover {
  background-color: rgba(8, 13, 40, 0.8);
}

.btn-full {
  width: 100%;
}

.hero-metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.metric-item {
  min-width: 120px;
}

.metric-value {
  font-size: 20px;
  font-weight: 600;
}

.metric-label {
  font-size: 12px;
  color: var(--text-muted);
}

.hero-visual {
  position: relative;
}

.hero-gallery {
  border-radius: 22px;
  padding: 10px;
  background:
    radial-gradient(circle at 0 0, rgba(124, 243, 255, 0.38), transparent 55%),
    linear-gradient(145deg, rgba(10, 16, 42, 0.95), rgba(5, 8, 22, 0.98));
  border: 1px solid rgba(124, 243, 255, 0.36);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.9);
  margin-bottom: 18px;
  position: relative;
  overflow: hidden;
}

.hero-gallery-main {
  border-radius: 18px;
  overflow: hidden;
}

.hero-illustration {
  width: 100%;
  border-radius: 18px;
  display: block;
  animation: float-slow 10s ease-in-out infinite;
}

.hero-visual-caption {
  position: absolute;
  left: 16px;
  bottom: 12px;
  max-width: 260px;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(3, 5, 14, 0.86);
  border: 1px solid rgba(124, 243, 255, 0.36);
  font-size: 11px;
  color: #d8f8ff;
  backdrop-filter: blur(10px);
}

.hero-gallery-strip {
  position: absolute;
  right: 16px;
  bottom: 16px;
  display: flex;
  gap: 8px;
}

.hero-thumb {
  width: 72px;
  height: 54px;
  border-radius: 12px;
  border: 1px solid rgba(124, 243, 255, 0.4);
  overflow: hidden;
  background: #020412;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.7);
}

.hero-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.card {
  border-radius: var(--radius-lg);
  padding: 16px 16px 14px;
  background: radial-gradient(circle at 0 -30%, rgba(124, 243, 255, 0.18), transparent 55%),
    linear-gradient(145deg, rgba(255, 255, 255, 0.03), rgba(5, 8, 20, 0.9));
  border: 1px solid rgba(124, 243, 255, 0.14);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.7);
}

.card h3,
.card h4 {
  margin: 0 0 8px;
  font-size: 15px;
}

.card p {
  margin: 0;
  font-size: 13px;
  color: var(--text-muted);
}

.card ul {
  margin: 0;
  padding-left: 18px;
  font-size: 13px;
  color: var(--text-muted);
}

.card-highlight {
  grid-column: span 2;
  background: radial-gradient(circle at 0 0, rgba(124, 243, 255, 0.25), transparent 60%),
    linear-gradient(145deg, #10152b, #1b2750);
}

.tag {
  display: inline-flex;
  margin-top: 8px;
  padding: 4px 10px;
  font-size: 11px;
  border-radius: var(--radius-full);
  background: rgba(2, 12, 44, 0.85);
  border: 1px solid rgba(124, 243, 255, 0.3);
  color: #d4f9ff;
}

/* Sections */
.section {
  padding: 56px 0;
}

.section-alt {
  background: radial-gradient(circle at top, #10152b 0, #050814 50%);
}

.section-header {
  text-align: center;
  margin-bottom: 32px;
}

.section-header.align-left {
  text-align: left;
}

.section-header h2 {
  margin: 0 0 10px;
  font-size: 26px;
}

.section-header p {
  margin: 0;
  color: var(--text-muted);
  font-size: 14px;
}

/* Fullwidth scene banners */
.section-fullwidth {
  padding: 0;
}

.scene-banners {
  display: flex;
  flex-direction: column;
}

.scene-banner {
  position: relative;
  min-height: 260px;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.scene-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    120deg,
    rgba(5, 8, 22, 0.92),
    rgba(5, 8, 22, 0.35)
  );
}

.scene-overlay {
  position: relative;
  max-width: 1120px;
  margin: 0 auto;
  padding: 40px 20px;
}

.scene-overlay h2 {
  margin: 0 0 8px;
  font-size: 24px;
}

.scene-overlay p {
  margin: 0;
  font-size: 13px;
  color: var(--text-muted);
}

/* 这里的背景图路径可替换为你们自己的大图 */
.scene-control {
  background-image: linear-gradient(
      90deg,
      rgba(15, 96, 215, 0.4),
      rgba(5, 8, 20, 0.2)
    ),
    url("./assets/scene-control.svg");
}

.scene-heating {
  background-image: linear-gradient(
      90deg,
      rgba(255, 140, 92, 0.45),
      rgba(5, 8, 20, 0.2)
    ),
    url("./assets/scene-heating.svg");
}

.scene-twin {
  background-image: linear-gradient(
      90deg,
      rgba(124, 243, 255, 0.5),
      rgba(5, 8, 20, 0.2)
    ),
    url("./assets/scene-twin.svg");
}

/* Solutions */
.solutions-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.solution-card {
  background: rgba(5, 8, 20, 0.95);
  border-radius: var(--radius-lg);
  padding: 18px 18px 16px;
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-soft);
  position: relative;
  overflow: hidden;
}

.solution-card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top left, rgba(124, 243, 255, 0.18), transparent 55%);
  opacity: 0.95;
  pointer-events: none;
}

.solution-card h3 {
  margin: 0 0 8px;
  font-size: 17px;
  position: relative;
  z-index: 1;
}

.solution-card p {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--text-muted);
  position: relative;
  z-index: 1;
}

.solution-card ul {
  margin: 0;
  margin-top: 6px;
  padding-left: 18px;
  font-size: 13px;
  color: var(--text-muted);
  position: relative;
  z-index: 1;
}

.solution-icon {
  position: absolute;
  right: 16px;
  top: 14px;
  font-size: 24px;
  font-weight: 600;
  color: rgba(124, 243, 255, 0.32);
  z-index: 0;
}

/* Industries */
.industries-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.industry-card {
  background: linear-gradient(145deg, rgba(10, 16, 42, 0.95), rgba(12, 24, 72, 0.98));
  border-radius: var(--radius-lg);
  padding: 18px 18px 14px;
  border: 1px solid rgba(124, 243, 255, 0.18);
}

.industry-card h3 {
  margin: 0 0 8px;
  font-size: 16px;
}

.industry-card p {
  margin: 0;
  font-size: 13px;
  color: var(--text-muted);
}

.industry-card .tag {
  margin-top: 10px;
}

/* Cases */
.cases-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.case-card {
  background: rgba(5, 8, 20, 0.95);
  border-radius: var(--radius-md);
  padding: 16px 16px 14px;
  border: 1px solid var(--border-subtle);
}

.case-card h3 {
  margin: 0 0 8px;
  font-size: 15px;
}

.case-card p {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--text-muted);
}

.case-card ul {
  margin: 0;
  padding-left: 18px;
  font-size: 13px;
  color: var(--text-muted);
}

/* About */
.about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.9fr);
  gap: 28px;
  align-items: flex-start;
}

.about-highlights {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-top: 20px;
}

.about-highlights h3 {
  margin: 0 0 6px;
  font-size: 15px;
}

.about-highlights p {
  margin: 0;
  font-size: 13px;
  color: var(--text-muted);
}

.timeline {
  background: rgba(5, 8, 20, 0.95);
  border-radius: var(--radius-lg);
  padding: 16px 18px 14px;
  border: 1px solid var(--border-subtle);
}

.timeline h3 {
  margin: 0 0 10px;
  font-size: 16px;
}

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

.timeline li {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 8px;
  padding: 8px 0;
  border-bottom: 1px dashed rgba(255, 255, 255, 0.08);
  font-size: 13px;
  color: var(--text-muted);
}

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

.time {
  color: #d7ddff;
  font-weight: 500;
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1.1fr);
  gap: 28px;
  align-items: flex-start;
}

.contact-info p {
  font-size: 13px;
  margin: 0 0 6px;
  color: var(--text-muted);
}

.contact-form {
  background: rgba(5, 8, 20, 0.95);
  border-radius: var(--radius-lg);
  padding: 18px 18px 14px;
  border: 1px solid var(--border-subtle);
}

.form-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.form-group {
  margin-bottom: 10px;
}

.form-group label {
  display: block;
  font-size: 12px;
  margin-bottom: 4px;
  color: #c3c7ea;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 8px 10px;
  border-radius: 10px;
  border: 1px solid rgba(124, 243, 255, 0.2);
  background: rgba(10, 14, 32, 0.9);
  color: var(--text);
  font-size: 13px;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease,
    background-color 0.15s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: rgba(124, 243, 255, 0.75);
  box-shadow: 0 0 0 1px rgba(124, 243, 255, 0.5);
  background-color: rgba(8, 14, 38, 0.95);
}

.form-group textarea {
  resize: vertical;
  min-height: 90px;
}

.form-tip {
  margin: 8px 0 0;
  font-size: 11px;
  color: var(--text-muted);
}

/* Footer */
.site-footer {
  padding: 20px 0 26px;
  border-top: 1px solid var(--border-subtle);
  background: rgba(2, 4, 14, 0.96);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  font-size: 12px;
  color: var(--text-muted);
}

.footer-logo .logo-mark {
  width: 28px;
  height: 28px;
  font-size: 14px;
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 12px;
}

.footer-links a:hover {
  color: #fff;
}

.footer-copy {
  margin: 4px 0 0;
}

.footer-icp {
  margin-top: 4px;
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
}

.footer-icp a {
  color: var(--text-muted);
}

.footer-icp a:hover {
  color: #ffffff;
}

/* Back to top */
.back-to-top {
  position: fixed;
  right: 18px;
  bottom: 22px;
  width: 40px;
  height: 40px;
  border-radius: 999px;
  border: 1px solid rgba(124, 243, 255, 0.4);
  background: radial-gradient(circle at 0 0, rgba(124, 243, 255, 0.4), #050814);
  color: #fff;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.8);
  z-index: 40;
}

.back-to-top.show {
  display: flex;
}

@keyframes float-slow {
  0% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-6px);
  }
  100% {
    transform: translateY(0px);
  }
}

/* Responsive */
@media (max-width: 960px) {
  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero-visual {
    order: -1;
  }

  .solutions-grid,
  .industries-grid,
  .cases-grid,
  .about-grid,
  .contact-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .about-highlights {
    grid-template-columns: minmax(0, 1fr);
  }

  .timeline li {
    grid-template-columns: 60px minmax(0, 1fr);
  }
}

@media (max-width: 768px) {
  .header-inner {
    gap: 10px;
  }

  .main-nav {
    position: fixed;
    inset: calc(var(--nav-height) + 4px) 12px auto 12px;
    background: rgba(5, 8, 20, 0.98);
    border-radius: 16px;
    border: 1px solid var(--border-subtle);
    padding: 10px 14px 12px;
    flex-direction: column;
    gap: 10px;
    transform-origin: top;
    transform: scaleY(0.9);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.18s ease, transform 0.18s ease;
  }

  .main-nav.open {
    opacity: 1;
    pointer-events: auto;
    transform: scaleY(1);
  }

  .nav-toggle {
    display: inline-flex;
  }
}

@media (max-width: 600px) {
  .hero {
    padding-top: 48px;
  }

  .hero-content h1 {
    font-size: 30px;
  }

  .metric-item {
    min-width: 100px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}