/* ====== RESET & BASE ====== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --primary: #1a5cff;
  --primary-dark: #0d3fa8;
  --primary-light: #4a7dff;
  --secondary: #00d4ff;
  --accent: #ff6b35;
  --dark: #0a1628;
  --dark2: #111c35;
  --gray: #6b7a99;
  --light-gray: #f0f4ff;
  --white: #ffffff;
  --gradient: linear-gradient(135deg, #1a5cff, #00d4ff);
  --gradient-dark: linear-gradient(135deg, #0a1628, #111c35);
  --shadow: 0 10px 40px rgba(26, 92, 255, 0.1);
  --shadow-lg: 0 20px 60px rgba(26, 92, 255, 0.15);
  --radius: 16px;
  --radius-sm: 8px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
html { scroll-behavior: smooth; }
body {
  font-family: 'PingFang SC', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, sans-serif;
  color: #1a1a2e;
  background: var(--white);
  overflow-x: hidden;
  line-height: 1.6;
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; height: auto; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ====== PRELOADER ====== */
#preloader {
  position: fixed; inset: 0; z-index: 9999;
  background: var(--dark);
  display: flex; align-items: center; justify-content: center;
  transition: opacity 0.6s, visibility 0.6s;
  /* 兜底：即使 JS 异常，2.5s 后也自动撤场，避免一直卡在加载圈 */
  animation: preloaderAutoHide 0.6s ease 2.5s forwards;
}
#preloader.hidden { opacity: 0; visibility: hidden; }
@keyframes preloaderAutoHide { to { opacity: 0; visibility: hidden; } }
.loader { width: 60px; height: 60px; position: relative; }
.loader::before, .loader::after {
  content: ''; position: absolute; inset: 0;
  border-radius: 50%; border: 3px solid transparent;
}
.loader::before {
  border-top-color: var(--primary-light);
  animation: spin 1s linear infinite;
}
.loader::after {
  border-bottom-color: var(--secondary);
  animation: spin 0.8s linear infinite reverse;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ====== NAVBAR ====== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  padding: 16px 0;
  transition: var(--transition);
}
.navbar.scrolled {
  background: rgba(10, 22, 40, 0.95);
  backdrop-filter: blur(20px);
  padding: 10px 0;
  box-shadow: 0 2px 20px rgba(0,0,0,0.3);
}
.navbar .container { display: flex; align-items: center; justify-content: space-between; }
.nav-logo {
  display: flex; align-items: center; gap: 12px;
  font-size: 24px; font-weight: 800; color: var(--white);
}
.nav-logo .logo-icon {
  width: 42px; height: 42px;
  object-fit: contain;   /* PNG 按比例缩放塞进 42×42，不变形 */
  border-radius: 12px;   /* 想要直角就删这行 */
}
.nav-logo span { background: var(--gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.nav-links { display: flex; align-items: center; gap: 8px; }
.nav-links a {
  padding: 8px 20px; color: rgba(255,255,255,0.8);
  font-size: 15px; font-weight: 500; border-radius: 8px;
  transition: var(--transition); position: relative;
}
.nav-links a::after {
  content: ''; position: absolute; bottom: 2px; left: 50%;
  width: 0; height: 2px; background: var(--secondary);
  transition: var(--transition); transform: translateX(-50%); border-radius: 2px;
}
.nav-links a:hover, .nav-links a.active { color: var(--white); }
.nav-links a:hover::after, .nav-links a.active::after { width: 60%; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 5px; }
.nav-toggle span {
  width: 28px; height: 2px; background: var(--white);
  border-radius: 2px; transition: var(--transition);
}

/* ====== HERO SECTION ====== */
.hero {
  position: relative; min-height: 100vh;
  display: flex; align-items: center;
  background: var(--dark);
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(26,92,255,0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(0,212,255,0.1) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(106,17,203,0.08) 0%, transparent 50%);
}
.hero-particles {
  position: absolute; inset: 0; overflow: hidden;
}
.particle {
  position: absolute; width: 4px; height: 4px;
  background: rgba(255,255,255,0.3); border-radius: 50%;
  animation: float 15s infinite;
}
@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); opacity: 0.3; }
  50% { transform: translateY(-100px) scale(1.5); opacity: 1; }
}
.hero-grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
}
.hero .container { position: relative; z-index: 2; text-align: center; padding: 120px 20px 80px; }
.hero-badge {
  display: inline-block; padding: 8px 24px;
  background: rgba(26,92,255,0.2); border: 1px solid rgba(26,92,255,0.3);
  border-radius: 50px; color: var(--secondary); font-size: 14px;
  margin-bottom: 30px; letter-spacing: 2px;
}
.hero h1 {
  font-size: clamp(36px, 6vw, 68px); font-weight: 800;
  color: var(--white); margin-bottom: 24px; line-height: 1.2;
}
.hero h1 .highlight {
  background: var(--gradient); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero p {
  font-size: clamp(16px, 2vw, 20px); color: rgba(255,255,255,0.7);
  max-width: 680px; margin: 0 auto 40px; line-height: 1.8;
}
.hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 36px; border-radius: 50px;
  font-size: 16px; font-weight: 600;
  cursor: pointer; transition: var(--transition); border: none;
}
.btn-primary {
  background: var(--gradient); color: var(--white);
  box-shadow: 0 8px 30px rgba(26,92,255,0.3);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 12px 40px rgba(26,92,255,0.4); }
.btn-outline {
  background: transparent; color: var(--white);
  border: 2px solid rgba(255,255,255,0.3);
}
.btn-outline:hover { border-color: var(--white); transform: translateY(-3px); }

.hero-scroll {
  position: absolute; bottom: 40px; left: 50%; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  color: rgba(255,255,255,0.4); font-size: 12px; letter-spacing: 2px;
  animation: bounce 2s infinite;
}
.hero-scroll .scroll-line {
  width: 1px; height: 30px;
  background: linear-gradient(to bottom, var(--secondary), transparent);
}
@keyframes bounce { 0%,100%{transform:translateX(-50%) translateY(0)} 50%{transform:translateX(-50%) translateY(-8px)} }

/* ====== SECTION COMMON ====== */
.section { padding: 100px 0; position: relative; }
.section-header { text-align: center; margin-bottom: 60px; }
.section-tag {
  display: inline-block; padding: 6px 20px;
  background: rgba(26,92,255,0.08);
  border-radius: 50px; color: var(--primary); font-size: 14px; font-weight: 600;
  margin-bottom: 16px; letter-spacing: 1px;
}
.section-header h2 {
  font-size: clamp(28px, 3.5vw, 40px); font-weight: 800;
  color: var(--dark); margin-bottom: 16px;
}
.section-header p {
  font-size: 17px; color: var(--gray);
  max-width: 600px; margin: 0 auto;
}

/* ====== ABOUT SECTION ====== */
.about-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 60px; align-items: center;
}
.about-content h3 { font-size: 32px; font-weight: 800; margin-bottom: 20px; color: var(--dark); }
.about-content h3 span { color: var(--primary); }
.about-content p { color: var(--gray); font-size: 16px; line-height: 1.8; margin-bottom: 16px; }
.about-stats {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 40px;
}
.stat-item { text-align: center; padding: 24px; background: var(--light-gray); border-radius: var(--radius); transition: var(--transition); }
.stat-item:hover { transform: translateY(-5px); box-shadow: var(--shadow); }
.stat-item .num { font-size: 36px; font-weight: 800; background: var(--gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.stat-item .label { font-size: 14px; color: var(--gray); margin-top: 4px; }
.about-image {
  position: relative; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.about-image img { width: 100%; display: block; }
.about-image::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(26,92,255,0.2), transparent);
}
.about-image .exp-badge {
  position: absolute; bottom: 30px; right: 30px;
  width: 100px; height: 100px; background: var(--gradient);
  border-radius: 50%; display: flex; flex-direction: column;
  align-items: center; justify-content: center; color: var(--white);
  font-weight: 700; font-size: 14px; line-height: 1.3;
  box-shadow: 0 8px 30px rgba(26,92,255,0.4);
  animation: pulse 2s infinite;
}
@keyframes pulse { 0%,100%{transform:scale(1)} 50%{transform:scale(1.05)} }
.about-image .exp-badge strong { font-size: 28px; }

/* ====== SERVICES ====== */
.services { background: var(--light-gray); }
.services-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px;
}
.service-card {
  background: var(--white); border-radius: var(--radius);
  padding: 40px 30px; text-align: center;
  transition: var(--transition); position: relative;
  overflow: hidden; border: 1px solid rgba(26,92,255,0.05);
}
.service-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0;
  height: 4px; background: var(--gradient);
  transform: scaleX(0); transform-origin: left;
  transition: var(--transition);
}
.service-card:hover { transform: translateY(-10px); box-shadow: var(--shadow-lg); }
.service-card:hover::before { transform: scaleX(1); }
.service-icon {
  width: 72px; height: 72px; margin: 0 auto 24px;
  background: var(--light-gray); border-radius: 20px;
  display: flex; align-items: center; justify-content: center;
  font-size: 32px; transition: var(--transition);
}
.service-card:hover .service-icon { background: var(--gradient); }
.service-card:hover .service-icon span { filter: brightness(0) invert(1); }
.service-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 12px; }
.service-card p { color: var(--gray); font-size: 15px; line-height: 1.7; margin-bottom: 20px; }
.service-link {
  color: var(--primary); font-weight: 600; font-size: 14px;
  display: inline-flex; align-items: center; gap: 6px;
}
.service-link:hover { gap: 10px; }

/* ====== SOLUTIONS ====== */
.solutions-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px;
}
.solution-card {
  background: var(--white); border-radius: var(--radius);
  padding: 40px 30px; border: 1px solid rgba(26,92,255,0.08);
  transition: var(--transition); position: relative;
}
.solution-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); border-color: var(--primary-light); }
.solution-card .icon-box {
  width: 56px; height: 56px; background: var(--light-gray);
  border-radius: 16px; display: flex; align-items: center; justify-content: center;
  font-size: 28px; margin-bottom: 20px;
}
.solution-card .icon-box.s1 { background: rgba(26,92,255,0.1); color: var(--primary); }
.solution-card .icon-box.s2 { background: rgba(0,212,255,0.1); color: var(--secondary); }
.solution-card .icon-box.s3 { background: rgba(255,107,53,0.1); color: var(--accent); }
.solution-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.solution-card .subtitle { color: var(--primary); font-size: 14px; margin-bottom: 16px; font-weight: 500; }
.solution-card p { color: var(--gray); font-size: 15px; line-height: 1.7; margin-bottom: 20px; }
.solution-card .features { display: flex; flex-direction: column; gap: 10px; }
.solution-card .features li {
  display: flex; align-items: center; gap: 10px;
  font-size: 14px; color: var(--dark);
}
.solution-card .features li::before {
  content: '✓'; width: 22px; height: 22px;
  background: rgba(26,92,255,0.1); color: var(--primary);
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  font-size: 12px; font-weight: 700; flex-shrink: 0;
}

/* ====== CASES ====== */
.cases-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px;
}
.case-card {
  border-radius: var(--radius); overflow: hidden;
  background: var(--white); border: 1px solid rgba(26,92,255,0.06);
  transition: var(--transition); cursor: pointer;
}
.case-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); }
.case-image {
  height: 220px; background: var(--gradient-dark);
  display: flex; align-items: center; justify-content: center;
  position: relative; overflow: hidden;
}
.case-image .placeholder-icon { font-size: 56px; opacity: 0.3; }
.case-image .case-cat {
  position: absolute; top: 16px; left: 16px;
  padding: 4px 14px; background: rgba(255,255,255,0.15);
  backdrop-filter: blur(10px); border-radius: 50px;
  color: var(--white); font-size: 12px; font-weight: 500;
}
.case-body { padding: 24px; }
.case-body h3 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.case-body p { color: var(--gray); font-size: 14px; line-height: 1.6; margin-bottom: 16px; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.case-body .case-meta { display: flex; justify-content: space-between; color: var(--gray); font-size: 13px; }

/* ====== NEWS ====== */
.news { background: var(--light-gray); }
.news-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px;
}
.news-card {
  background: var(--white); border-radius: var(--radius);
  overflow: hidden; border: 1px solid rgba(26,92,255,0.06);
  transition: var(--transition);
}
.news-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); }
.news-image {
  height: 200px; background: var(--gradient-dark);
  display: flex; align-items: center; justify-content: center;
  position: relative;
}
.news-image .placeholder-icon { font-size: 48px; opacity: 0.2; }
.news-image .news-date {
  position: absolute; bottom: 16px; right: 16px;
  background: rgba(0,0,0,0.5); backdrop-filter: blur(10px);
  padding: 6px 14px; border-radius: 8px;
  color: var(--white); font-size: 13px;
}
.news-body { padding: 24px; }
.news-body .news-cat {
  display: inline-block; padding: 3px 12px;
  background: rgba(26,92,255,0.08); color: var(--primary);
  border-radius: 50px; font-size: 12px; font-weight: 600;
  margin-bottom: 12px;
}
.news-body h3 { font-size: 16px; font-weight: 700; margin-bottom: 8px; line-height: 1.4; }
.news-body p { color: var(--gray); font-size: 14px; line-height: 1.6; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.news-body .read-more {
  color: var(--primary); font-size: 14px; font-weight: 600;
  display: inline-flex; align-items: center; gap: 4px; margin-top: 12px;
}

/* ====== PARTNERS ====== */
.partners-track {
  display: flex; gap: 40px; animation: scroll 30s linear infinite;
  align-items: center;
}
@keyframes scroll { 0%{transform:translateX(0)} 100%{transform:translateX(-50%)} }
.partner-item {
  flex-shrink: 0; height: 50px; padding: 0 30px;
  background: var(--light-gray); border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 700; color: var(--gray);
  opacity: 0.6; transition: var(--transition);
  text-decoration: none;
}
.partner-item:hover { opacity: 1; }
.partner-item img { filter: grayscale(100%); opacity: 0.7; transition: var(--transition); }
.partner-item:hover img { filter: grayscale(0); opacity: 1; }

.honors-scroll-track {
  display: flex; gap: 24px; animation: honorScroll 40s linear infinite;
  will-change: transform;
}
.honors-scroll-track:hover { animation-play-state: paused; }
.honors-scroll-card {
  flex-shrink: 0; width: 200px; background: var(--white); border-radius: 12px;
  overflow: hidden; border: 1px solid rgba(26,92,255,0.06);
  transition: var(--transition); cursor: pointer;
}
.honors-scroll-card:hover { transform: translateY(-4px); box-shadow: 0 12px 40px rgba(0,0,0,0.08); }
.honors-scroll-card .img-wrap {
  height: 150px; background: var(--light-gray); display: flex;
  align-items: center; justify-content: center; overflow: hidden;
}
.honors-scroll-card .img-wrap img { width: 100%; height: 100%; object-fit: contain; padding: 12px; transition: var(--transition); }
.honors-scroll-card:hover .img-wrap img { transform: scale(1.08); }
.honors-scroll-card .card-body { padding: 10px 14px 14px; }
.honors-scroll-card .card-body h4 { font-size: 13px; font-weight: 700; line-height: 1.3; margin: 0; }
.honors-scroll-card .card-body .cat { font-size: 11px; color: var(--primary); font-weight: 600; margin-bottom: 4px; }

@keyframes honorScroll {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

/* ====== CONTACT ====== */
.contact-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 50px;
}
.contact-info h3 { font-size: 28px; font-weight: 800; margin-bottom: 16px; }
.contact-info > p { color: var(--gray); margin-bottom: 30px; }
.contact-items { display: flex; flex-direction: column; gap: 20px; }
.contact-item {
  display: flex; align-items: center; gap: 16px;
  padding: 16px 20px; background: var(--light-gray);
  border-radius: 12px; transition: var(--transition);
}
.contact-item:hover { transform: translateX(5px); }
.contact-item .icon {
  width: 48px; height: 48px; background: var(--gradient);
  border-radius: 12px; display: flex; align-items: center;
  justify-content: center; color: var(--white); flex-shrink: 0;
}
.contact-item .info .label { font-size: 13px; color: var(--gray); }
.contact-item .info .value { font-size: 15px; font-weight: 600; }
.contact-form {
  background: var(--white); padding: 40px; border-radius: var(--radius);
  box-shadow: var(--shadow); border: 1px solid rgba(26,92,255,0.06);
}
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; color: var(--dark); }
.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 12px 16px; border: 2px solid #e8edf5;
  border-radius: 10px; font-size: 15px; transition: var(--transition);
  font-family: inherit; background: var(--light-gray);
  outline: none;
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
  border-color: var(--primary); box-shadow: 0 0 0 4px rgba(26,92,255,0.1);
}
.form-group textarea { height: 120px; resize: vertical; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.submit-btn {
  width: 100%; padding: 14px; background: var(--gradient);
  color: var(--white); border: none; border-radius: 12px;
  font-size: 16px; font-weight: 600; cursor: pointer;
  transition: var(--transition);
}
.submit-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(26,92,255,0.3); }

/* ====== FOOTER ====== */
.footer {
  background: var(--dark); color: rgba(255,255,255,0.6); padding: 72px 0 0;
}
.footer-grid {
  display: grid; grid-template-columns: 1.8fr 1fr 1fr; gap: 64px;
  padding-bottom: 48px; border-bottom: 1px solid rgba(255,255,255,0.08);
}
.footer-brand .nav-logo { margin-bottom: 20px; }
.footer-slogan { font-size: 15px; line-height: 1.9; color: rgba(255,255,255,0.5); max-width: 340px; }
.footer-col h4 {
  color: var(--white); font-size: 13px; font-weight: 600;
  letter-spacing: 2px; margin-bottom: 24px;
}
.footer-col ul li { margin-bottom: 14px; }
.footer-col ul li a { font-size: 14px; color: rgba(255,255,255,0.55); transition: var(--transition); }
.footer-col ul li a:hover { color: var(--white); padding-left: 4px; }
.footer-contact li { font-size: 14px; color: rgba(255,255,255,0.55); }
.footer-bottom {
  padding: 24px 0; text-align: center;
  font-size: 13px; color: rgba(255,255,255,0.35); letter-spacing: 0.5px;
}

/* ====== ANIMATIONS ====== */
.fade-in { opacity: 0; transform: translateY(30px); transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1); }
.fade-in.visible { opacity: 1; transform: translateY(0); }
.fade-in-left { opacity: 0; transform: translateX(-40px); transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1); }
.fade-in-left.visible { opacity: 1; transform: translateX(0); }
.fade-in-right { opacity: 0; transform: translateX(40px); transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1); }
.fade-in-right.visible { opacity: 1; transform: translateX(0); }
.fade-in-up { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1); }
.fade-in-up.visible { opacity: 1; transform: translateY(0); }

/* ====== RESPONSIVE ====== */
@media (max-width: 1024px) {
  .about-grid, .contact-grid { grid-template-columns: 1fr; }
  .services-grid, .solutions-grid, .cases-grid, .news-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .nav-links {
    position: fixed; top: 0; right: -100%; width: 280px; height: 100vh;
    background: rgba(10,22,40,0.98); backdrop-filter: blur(20px);
    flex-direction: column; padding: 80px 30px; transition: var(--transition);
  }
  .nav-links.active { right: 0; }
  .nav-toggle { display: flex; }
  .hero h1 { font-size: 32px; }
  .services-grid, .solutions-grid, .cases-grid, .news-grid { grid-template-columns: 1fr; }
  .section { padding: 60px 0; }
  .form-row { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: repeat(3, 1fr); gap: 10px; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero-buttons { flex-direction: column; align-items: center; }
  .contact-grid { grid-template-columns: 1fr; }

  /* WeChat browser fixes */
  .hero h1 { font-size: 28px; }
  .hero p { font-size: 15px; }
  .hero-badge { font-size: 12px; }
  .btn { padding: 12px 28px; font-size: 15px; }
  .section { padding: 50px 0; }
  .about-image { display: none; }
  .about-stats { grid-template-columns: repeat(3, 1fr); gap: 8px; }
  .stat-item { padding: 16px 10px; }
  .stat-item .num { font-size: 28px; }
  .stat-item .label { font-size: 12px; }
  .case-image { height: 180px; }
  .news-image { height: 160px; }
  .case-body { padding: 16px; }
  .news-body { padding: 16px; }
  .contact-form { padding: 24px; }
  .footer-grid { grid-template-columns: 1fr; }
  .page-hero { padding: 130px 0 60px; }
  .page-hero h1 { font-size: 30px; }
}

/* ====== WECHAT BROWSER OPTIMIZATION ====== */
/* 微信内置浏览器特殊优化 */
@media (max-width: 414px) {
  .container { padding: 0 16px; }
  .navbar { padding: 12px 0; }
  .navbar.scrolled { padding: 8px 0; }
  .nav-logo { font-size: 20px; }
  .nav-logo .logo-icon { width: 36px; height: 36px; font-size: 16px; border-radius: 10px; }

  .hero { min-height: 90vh; }
  .hero .container { padding: 100px 16px 60px; }
  .hero h1 { font-size: 26px; line-height: 1.4; }
  .hero p { font-size: 14px; line-height: 1.6; }
  .hero-badge { font-size: 11px; padding: 6px 16px; }
  .hero-buttons { flex-direction: column; gap: 12px; }
  .hero-buttons .btn { width: 100%; justify-content: center; padding: 14px 20px; font-size: 15px; }
  .hero-scroll { display: none; }

  .section { padding: 40px 0; }
  .section-header { margin-bottom: 30px; }
  .section-header h2 { font-size: 24px; }
  .section-header p { font-size: 14px; }
  .section-tag { font-size: 12px; padding: 4px 14px; }

  .about-grid { grid-template-columns: 1fr; gap: 30px; }
  .about-content h3 { font-size: 22px; }
  .about-content p { font-size: 14px; }
  .about-image { display: none; }
  .about-stats { grid-template-columns: repeat(3, 1fr); gap: 8px; }
  .stat-item { padding: 14px 8px; }
  .stat-item .num { font-size: 24px; }
  .stat-item .label { font-size: 11px; }

  .services-grid, .solutions-grid, .cases-grid, .news-grid { grid-template-columns: 1fr; gap: 20px; }
  .service-card { padding: 30px 20px; }
  .service-icon { width: 60px; height: 60px; font-size: 26px; }
  .service-card h3 { font-size: 18px; }
  .service-card p { font-size: 14px; }

  .solution-card { padding: 28px 20px; }
  .solution-card h3 { font-size: 18px; }
  .solution-card p { font-size: 14px; }
  .solution-card .features li { font-size: 13px; }

  .case-image { height: 200px; }
  .case-body h3 { font-size: 16px; }
  .case-body p { font-size: 13px; }
  .case-body .case-meta { font-size: 12px; flex-direction: column; gap: 4px; }

  .news-image { height: 200px; }
  .news-body h3 { font-size: 15px; }

  .contact-grid { grid-template-columns: 1fr; gap: 30px; }
  .contact-info h3 { font-size: 22px; }
  .contact-item { padding: 12px 16px; }
  .contact-item .icon { width: 42px; height: 42px; }
  .contact-item .info .value { font-size: 14px; }
  .contact-form { padding: 20px; }
  .form-row { grid-template-columns: 1fr; gap: 0; }
  .form-group input, .form-group textarea { font-size: 14px; padding: 10px 14px; }

  .footer { padding: 40px 0 0; }
  .footer-grid { grid-template-columns: 1fr; gap: 30px; }
  .footer-col h4 { font-size: 15px; }
  .footer-bottom { font-size: 12px; }

  .page-hero { padding: 110px 0 50px; }
  .page-hero h1 { font-size: 28px; }
  .page-hero p { font-size: 14px; }
  .partners-track { gap: 20px; }
  .partner-item { height: 40px; padding: 0 20px; font-size: 14px; }

  .back-to-top { width: 42px; height: 42px; bottom: 20px; right: 20px; font-size: 18px; }
}

/* ====== BACK TO TOP ====== */
.back-to-top {
  position: fixed; bottom: 30px; right: 30px; z-index: 999;
  width: 48px; height: 48px; background: var(--gradient);
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  color: var(--white); cursor: pointer; opacity: 0; visibility: hidden;
  transition: var(--transition); box-shadow: 0 4px 20px rgba(26,92,255,0.3);
  border: none; font-size: 20px;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-3px); }