/* ========== Reset & Base ========== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #1a56db;
  --primary-dark: #1244ab;
  --primary-light: #e8effc;
  --accent: #f59e0b;
  --text: #1f2937;
  --text-light: #6b7280;
  --text-lighter: #9ca3af;
  --bg: #ffffff;
  --bg-light: #f9fafb;
  --bg-dark: #111827;
  --border: #e5e7eb;
  --radius: 8px;
  --radius-lg: 16px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,.07), 0 2px 4px rgba(0,0,0,.06);
  --shadow-lg: 0 10px 25px rgba(0,0,0,.1), 0 6px 10px rgba(0,0,0,.08);
  --transition: .3s ease;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

ul {
  list-style: none;
}

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

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 32px;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.btn-primary:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(26,86,219,.3);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,.6);
}

.btn-outline:hover {
  background: #fff;
  color: var(--primary);
  border-color: #fff;
  transform: translateY(-2px);
}

.btn-block {
  width: 100%;
}

/* ========== Header ========== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,.95);
  backdrop-filter: blur(12px);
  transition: all var(--transition);
}

.header.scrolled {
  box-shadow: var(--shadow);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text);
}

.logo-img {
  height: 40px;
  width: auto;
}

.logo-text {
  white-space: nowrap;
}

.nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: .9375rem;
  font-weight: 500;
  color: var(--text-light);
  transition: color var(--transition);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: width var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary);
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: all var(--transition);
  border-radius: 2px;
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ========== Hero ========== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 120px 0 80px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 40%, #1a56db 100%);
  z-index: 0;
}

.hero-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(245,158,11,.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(59,130,246,.2) 0%, transparent 40%),
    radial-gradient(circle at 60% 80%, rgba(16,185,129,.1) 0%, transparent 40%);
}

.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: #fff;
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -.02em;
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--accent), #fbbf24);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 1.125rem;
  color: rgba(255,255,255,.8);
  max-width: 640px;
  margin: 0 auto 36px;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 64px;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  padding: 32px 48px;
  background: rgba(255,255,255,.08);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,.12);
}

.stat-item {
  text-align: center;
}

.stat-num {
  font-size: 2.5rem;
  font-weight: 800;
  color: #fff;
  font-variant-numeric: tabular-nums;
}

.stat-suffix {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent);
}

.stat-label {
  display: block;
  font-size: .875rem;
  color: rgba(255,255,255,.6);
  margin-top: 4px;
}

/* ========== Section Common ========== */
.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-tag {
  display: inline-block;
  padding: 4px 16px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 20px;
  font-size: .875rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 12px;
  letter-spacing: -.01em;
}

.section-desc {
  font-size: 1.0625rem;
  color: var(--text-light);
  max-width: 560px;
  margin: 0 auto;
}

/* ========== Products ========== */
.products {
  padding: 100px 0;
  background: var(--bg-light);
}

.products-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.product-card {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: all var(--transition);
  border: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.product-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
}

.product-card.featured {
  border-color: var(--primary);
  background: linear-gradient(to bottom, var(--primary-light), #fff);
}

.product-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  background: var(--accent);
  color: #fff;
  font-size: .75rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 20px;
}

.product-icon {
  width: 56px;
  height: 56px;
  color: var(--primary);
  margin-bottom: 20px;
}

.product-icon svg {
  width: 100%;
  height: 100%;
}

.product-name {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
}

.product-desc {
  font-size: .9375rem;
  color: var(--text-light);
  line-height: 1.7;
  margin-bottom: 16px;
}

.product-features {
  margin-bottom: 20px;
}

.product-features li {
  font-size: .875rem;
  color: var(--text-light);
  padding: 4px 0;
  padding-left: 20px;
  position: relative;
}

.product-features li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 6px;
  background: var(--primary);
  border-radius: 50%;
}

.product-link {
  font-size: .9375rem;
  font-weight: 600;
  color: var(--primary);
  transition: all var(--transition);
}

.product-link:hover {
  color: var(--primary-dark);
  gap: 8px;
}

/* ========== Advantages ========== */
.advantages {
  padding: 100px 0;
  background: var(--bg);
}

.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.advantage-card {
  padding: 36px 28px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  transition: all var(--transition);
  position: relative;
}

.advantage-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.advantage-num {
  font-size: 3rem;
  font-weight: 900;
  color: var(--primary-light);
  line-height: 1;
  margin-bottom: 16px;
  transition: color var(--transition);
}

.advantage-card:hover .advantage-num {
  color: var(--primary);
}

.advantage-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
}

.advantage-desc {
  font-size: .9375rem;
  color: var(--text-light);
  line-height: 1.7;
}

/* ========== Cases ========== */
.cases {
  padding: 100px 0;
  background: var(--bg-light);
}

.cases-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.case-item {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  border: 1px solid var(--border);
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
}

.case-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
}

.case-quote {
  font-size: 3rem;
  font-weight: 700;
  color: var(--primary-light);
  line-height: 1;
  margin-bottom: 8px;
  font-family: Georgia, serif;
}

.case-feedback {
  font-size: .9375rem;
  color: var(--text-light);
  line-height: 1.8;
  flex: 1;
  margin-bottom: 20px;
}

.case-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.case-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: .875rem;
  flex-shrink: 0;
}

.case-company {
  font-size: .9375rem;
  font-weight: 600;
  color: var(--text);
}

.case-industry-tag {
  font-size: .8125rem;
  color: var(--text-lighter);
  margin-top: 2px;
}

/* ========== About ========== */
.about {
  padding: 100px 0;
  background: var(--bg);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.about-content .section-tag {
  margin-bottom: 16px;
}

.about-content .section-title {
  text-align: left;
  margin-bottom: 24px;
}

.about-text {
  font-size: .9375rem;
  color: var(--text-light);
  line-height: 1.8;
  margin-bottom: 16px;
}

.about-highlights {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 28px;
}

.highlight-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .9375rem;
  font-weight: 500;
  color: var(--text);
}

.highlight-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  font-size: .75rem;
  flex-shrink: 0;
}

.about-visual {
  position: relative;
}

.about-image-box {
  position: relative;
  width: 100%;
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, var(--primary), #3b82f6);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.about-pattern {
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%23ffffff' fill-opacity='0.08'%3E%3Cpath d='M20 0L40 20L20 40L0 20z'/%3E%3C/g%3E%3C/svg%3E");
}

.about-text-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: #fff;
}

.overlay-num {
  font-size: 4rem;
  font-weight: 900;
  line-height: 1;
}

.overlay-label {
  font-size: 1.125rem;
  opacity: .8;
  margin-top: 8px;
}

/* ========== Contact ========== */
.contact {
  padding: 100px 0;
  background: var(--bg-light);
}

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 48px;
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.info-card {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 20px;
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.info-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  color: var(--primary);
}

.info-icon svg {
  width: 100%;
  height: 100%;
}

.info-card h4 {
  font-size: .9375rem;
  font-weight: 600;
  margin-bottom: 4px;
  color: var(--text);
}

.info-card p {
  font-size: .875rem;
  color: var(--text-light);
}

.contact-form {
  background: #fff;
  padding: 36px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-size: .875rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 6px;
}

.required {
  color: #ef4444;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: .9375rem;
  color: var(--text);
  background: var(--bg);
  transition: border-color var(--transition);
  font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(26,86,219,.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-lighter);
}

.form-group textarea {
  resize: vertical;
}

/* ========== Footer ========== */
.footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,.7);
  padding: 64px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255,255,255,.1);
}

.footer-brand .logo {
  color: #fff;
  margin-bottom: 16px;
}

.footer-desc {
  font-size: .875rem;
  line-height: 1.7;
  color: rgba(255,255,255,.5);
}

.footer-links h4 {
  font-size: .9375rem;
  font-weight: 600;
  color: #fff;
  margin-bottom: 16px;
}

.footer-links a,
.footer-links p {
  display: block;
  font-size: .875rem;
  color: rgba(255,255,255,.5);
  margin-bottom: 8px;
  transition: color var(--transition);
}

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

.footer-bottom {
  padding: 24px 0;
  text-align: center;
  font-size: .8125rem;
  color: rgba(255,255,255,.3);
}

.footer-bottom a {
  color: rgba(255,255,255,.3);
  transition: color var(--transition);
}

.footer-bottom a:hover {
  color: rgba(255,255,255,.6);
}

/* ========== Back to Top ========== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: all var(--transition);
  box-shadow: var(--shadow-md);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--primary-dark);
  transform: translateY(-4px);
}

.back-to-top svg {
  width: 20px;
  height: 20px;
}

/* ========== Animations ========== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity .6s ease, transform .6s ease;
}

.fade-in-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========== Responsive ========== */
@media (max-width: 1024px) {
  .products-grid,
  .advantages-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .cases-list {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .about-content .section-title {
    text-align: center;
  }

  .about-content .section-tag {
    text-align: center;
    display: block;
  }

  .about-text {
    text-align: center;
  }

  .about-highlights {
    max-width: 400px;
    margin: 28px auto 0;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
}

@media (max-width: 768px) {
  .nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    box-shadow: var(--shadow-lg);
    transform: translateY(-120%);
    opacity: 0;
    transition: all var(--transition);
  }

  .nav.open {
    transform: translateY(0);
    opacity: 1;
  }

  .nav-toggle {
    display: flex;
  }

  .hero-title {
    font-size: 2rem;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .hero-stats {
    flex-wrap: wrap;
    gap: 24px;
    padding: 24px;
  }

  .stat-item {
    flex: 1 1 40%;
  }

  .stat-num {
    font-size: 2rem;
  }

  .products-grid,
  .advantages-grid,
  .cases-list {
    grid-template-columns: 1fr;
  }

  .section-title {
    font-size: 1.75rem;
  }

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

  .form-row {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 1.625rem;
  }

  .container {
    padding: 0 16px;
  }

  .hero-stats {
    gap: 16px;
    padding: 20px 16px;
  }

  .stat-num {
    font-size: 1.5rem;
  }

  .stat-suffix {
    font-size: 1rem;
  }

  .contact-form {
    padding: 24px 20px;
  }
}