/* ===== CSS Variables & Reset ===== */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #3b82f6;
  --primary-bg: #eff6ff;
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --gray-900: #0f172a;
  --white: #ffffff;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-md: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
  --shadow-lg: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.04);
  --radius: 12px;
  --radius-sm: 8px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  color: var(--gray-700);
  background: var(--white);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition);
}

ul, ol { list-style: none; }

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

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

/* ===== Header & Navigation ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--gray-200);
  transition: var(--transition);
}

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

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

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--gray-900);
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-weight: 800;
  font-size: 1rem;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.nav-links {
  display: flex;
  gap: 8px;
}

.nav-links a {
  padding: 8px 18px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--gray-600);
  position: relative;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--primary);
  background: var(--primary-bg);
}

.nav-links a.active {
  color: var(--primary);
  background: var(--primary-bg);
  font-weight: 600;
}

/* Mobile menu toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border: none;
  background: none;
  z-index: 1001;
}

.menu-toggle span {
  width: 24px;
  height: 2.5px;
  background: var(--gray-700);
  border-radius: 2px;
  transition: var(--transition);
}

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

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

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

/* ===== Hero / Banner ===== */
.hero {
  padding: 140px 0 100px;
  background: linear-gradient(135deg, #f0f4ff 0%, #e8f0fe 30%, #dbeafe 60%, #eff6ff 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 700px;
  height: 700px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.06) 0%, transparent 70%);
  border-radius: 50%;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.04) 0%, transparent 70%);
  border-radius: 50%;
}

.hero .container {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 900px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  background: rgba(37, 99, 235, 0.08);
  border: 1px solid rgba(37, 99, 235, 0.15);
  border-radius: 50px;
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  animation: fadeInUp 0.6s ease;
}

.hero-badge svg {
  width: 16px;
  height: 16px;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  color: var(--gray-900);
  line-height: 1.3;
  margin-bottom: 20px;
  letter-spacing: -0.5px;
  animation: fadeInUp 0.6s ease 0.1s both;
}

.hero h1 .highlight {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.15rem;
  color: var(--gray-500);
  max-width: 680px;
  margin: 0 auto 36px;
  animation: fadeInUp 0.6s ease 0.2s both;
}

.hero-btns {
  display: flex;
  gap: 16px;
  justify-content: center;
  animation: fadeInUp 0.6s ease 0.3s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: var(--white);
  box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(37, 99, 235, 0.4);
}

.btn-outline {
  background: var(--white);
  color: var(--gray-700);
  border: 1.5px solid var(--gray-300);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-bg);
}

/* ===== Section Styles ===== */
.section {
  padding: 100px 0;
}

.section-alt {
  background: var(--gray-50);
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 60px;
}

.section-header .tag {
  display: inline-block;
  padding: 4px 14px;
  background: var(--primary-bg);
  color: var(--primary);
  font-size: 0.8rem;
  font-weight: 700;
  border-radius: 50px;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 16px;
}

.section-header h2 {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--gray-900);
  margin-bottom: 16px;
  letter-spacing: -0.3px;
}

.section-header p {
  color: var(--gray-500);
  font-size: 1.05rem;
}

/* ===== About / Company Intro ===== */
.about-content {
  background: var(--white);
  border-radius: var(--radius);
  border: 1px solid var(--gray-200);
  padding: 48px;
  box-shadow: var(--shadow);
  line-height: 2;
  color: var(--gray-600);
  font-size: 1.05rem;
  position: relative;
}

.about-content::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  border-radius: var(--radius) var(--radius) 0 0;
}

/* ===== Feature / Advantage Cards ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 36px 32px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.feature-card:hover {
  border-color: rgba(37, 99, 235, 0.2);
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.feature-card:hover::after {
  transform: scaleX(1);
}

.feature-icon {
  width: 52px;
  height: 52px;
  background: var(--primary-bg);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--primary);
  font-size: 1.4rem;
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--gray-500);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ===== Service Tags / Range ===== */
.service-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
  margin-top: 40px;
}

.service-tags .tag-item {
  padding: 10px 24px;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: 50px;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--gray-700);
  transition: var(--transition);
}

.service-tags .tag-item:hover {
  background: var(--primary-bg);
  border-color: rgba(37, 99, 235, 0.2);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

/* ===== Service Detail Cards ===== */
.service-detail-grid {
  display: grid;
  gap: 28px;
}

.service-detail-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 40px;
  display: flex;
  gap: 32px;
  transition: var(--transition);
  position: relative;
}

.service-detail-card:hover {
  border-color: rgba(37, 99, 235, 0.15);
  box-shadow: var(--shadow-md);
}

.service-detail-card .service-number {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-weight: 800;
  font-size: 1.3rem;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.service-detail-card .service-info h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 12px;
}

.service-detail-card .service-info p {
  color: var(--gray-500);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* ===== Process / Timeline ===== */
.process-timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.process-timeline::before {
  content: '';
  position: absolute;
  top: 0;
  left: 35px;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--primary), var(--primary-light), var(--gray-200));
  border-radius: 3px;
}

.process-item {
  display: flex;
  gap: 32px;
  padding-bottom: 48px;
  position: relative;
}

.process-item:last-child {
  padding-bottom: 0;
}

.process-step {
  flex-shrink: 0;
  width: 72px;
  height: 72px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-weight: 800;
  font-size: 1.4rem;
  box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
  z-index: 1;
  position: relative;
}

.process-content {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 28px 32px;
  flex: 1;
  transition: var(--transition);
}

.process-content:hover {
  border-color: rgba(37, 99, 235, 0.15);
  box-shadow: var(--shadow-md);
}

.process-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 10px;
}

.process-content p {
  color: var(--gray-500);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* ===== Case Study Cards ===== */
.cases-grid {
  display: grid;
  gap: 28px;
}

.case-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  overflow: hidden;
  transition: var(--transition);
}

.case-card:hover {
  border-color: rgba(37, 99, 235, 0.15);
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.case-header {
  padding: 28px 36px;
  background: linear-gradient(135deg, var(--primary-bg), #dbeafe);
  border-bottom: 1px solid var(--gray-200);
  display: flex;
  align-items: center;
  gap: 16px;
}

.case-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-size: 1.2rem;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.case-header h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--gray-900);
}

.case-body {
  padding: 32px 36px;
}

.case-body .case-section {
  margin-bottom: 20px;
}

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

.case-body .case-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.case-body .case-text {
  color: var(--gray-600);
  font-size: 0.95rem;
  line-height: 1.8;
}

.case-stats {
  display: flex;
  gap: 20px;
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--gray-100);
}

.case-stat {
  text-align: center;
  flex: 1;
}

.case-stat .stat-value {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
}

.case-stat .stat-label {
  font-size: 0.8rem;
  color: var(--gray-400);
  margin-top: 4px;
}

/* ===== Contact Info ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin-bottom: 40px;
}

.contact-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
  transition: var(--transition);
}

.contact-card:hover {
  border-color: rgba(37, 99, 235, 0.15);
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.contact-card .contact-icon {
  width: 56px;
  height: 56px;
  background: var(--primary-bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  color: var(--primary);
  font-size: 1.3rem;
}

.contact-card h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 8px;
}

.contact-card p {
  color: var(--gray-500);
  font-size: 0.92rem;
  line-height: 1.6;
}

.contact-tip {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 36px 40px;
  position: relative;
}

.contact-tip::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  border-radius: var(--radius) var(--radius) 0 0;
}

.contact-tip h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 12px;
}

.contact-tip p {
  color: var(--gray-500);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* ===== Page Header (inner pages) ===== */
.page-hero {
  padding: 130px 0 70px;
  background: linear-gradient(135deg, #f0f4ff 0%, #e8f0fe 50%, #dbeafe 100%);
  text-align: center;
  position: relative;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -15%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.05) 0%, transparent 70%);
  border-radius: 50%;
}

.page-hero h1 {
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--gray-900);
  margin-bottom: 12px;
  letter-spacing: -0.3px;
  position: relative;
  z-index: 1;
}

.page-hero p {
  color: var(--gray-500);
  font-size: 1.05rem;
  position: relative;
  z-index: 1;
}

/* ===== Footer ===== */
.footer {
  background: var(--gray-900);
  color: var(--gray-400);
  padding: 48px 0 0;
}

.footer-main {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 40px;
  padding-bottom: 36px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
  flex-wrap: wrap;
}

.footer-brand .footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.footer-brand .footer-logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-weight: 800;
  font-size: 0.9rem;
}

.footer-brand .footer-logo span {
  color: var(--white);
  font-weight: 700;
  font-size: 1.05rem;
}

.footer-brand p {
  max-width: 320px;
  font-size: 0.88rem;
  line-height: 1.7;
}

.footer-nav h4 {
  color: var(--white);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.footer-nav ul li {
  margin-bottom: 10px;
}

.footer-nav ul a {
  color: var(--gray-400);
  font-size: 0.88rem;
  transition: var(--transition);
}

.footer-nav ul a:hover {
  color: var(--primary-light);
}

.footer-contact h4 {
  color: var(--white);
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.footer-contact p {
  font-size: 0.88rem;
  margin-bottom: 8px;
  line-height: 1.6;
}

.footer-bottom {
  padding: 20px 0;
  text-align: center;
  font-size: 0.82rem;
  color: var(--gray-500);
}

.footer-bottom a {
  color: var(--gray-400);
  transition: var(--transition);
}

.footer-bottom a:hover {
  color: var(--primary-light);
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header .container {
    height: 64px;
  }

  .menu-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--white);
    flex-direction: column;
    padding: 80px 24px 24px;
    gap: 4px;
    box-shadow: var(--shadow-lg);
    transition: right 0.3s ease;
    z-index: 1000;
  }

  .nav-links.open {
    right: 0;
  }

  .nav-links a {
    padding: 12px 16px;
    font-size: 1rem;
  }

  .hero {
    padding: 110px 0 70px;
  }

  .hero h1 {
    font-size: 2rem;
  }

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

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

  .section {
    padding: 60px 0;
  }

  .section-header h2 {
    font-size: 1.7rem;
  }

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

  .about-content {
    padding: 28px;
  }

  .service-detail-card {
    flex-direction: column;
    padding: 28px;
    gap: 20px;
  }

  .process-timeline::before {
    display: none;
  }

  .process-item {
    flex-direction: column;
    gap: 16px;
  }

  .process-step {
    width: 56px;
    height: 56px;
    font-size: 1.1rem;
  }

  .process-content {
    padding: 24px;
  }

  .case-header {
    padding: 20px 24px;
  }

  .case-body {
    padding: 24px;
  }

  .case-stats {
    flex-direction: column;
    gap: 12px;
  }

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

  .contact-tip {
    padding: 24px;
  }

  .page-hero h1 {
    font-size: 1.8rem;
  }

  .footer-main {
    flex-direction: column;
    gap: 28px;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.6rem;
  }

  .logo {
    font-size: 1rem;
  }

  .btn {
    padding: 12px 24px;
    font-size: 0.9rem;
  }

  .feature-card {
    padding: 28px 24px;
  }
}