/* ============================================
   CSS Variables & Reset
   ============================================ */
:root {
  --bg:        #f0f4f8;
  --bg-2:      #e8eef5;
  --bg-card:   #ffffff;
  --bg-nav:    rgba(255,255,255,0.92);
  --border:    #d1dce8;
  --blue:      #2563eb;
  --blue-dim:  #1d4ed8;
  --blue-light:#eff6ff;
  --blue-glow: rgba(37, 99, 235, 0.12);
  --text:      #1e293b;
  --text-muted:#64748b;
  --white:     #ffffff;
  --radius:    12px;
  --shadow:    0 2px 12px rgba(30,41,59,0.08);
  --shadow-lg: 0 8px 32px rgba(30,41,59,0.12);
  --transition: 0.22s ease;
}

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

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }

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

/* ============================================
   Layout
   ============================================ */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 96px 0;
}

.section-alt {
  background: var(--bg-2);
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 10px;
  color: var(--text);
}

.section-sub {
  text-align: center;
  color: var(--text-muted);
  margin-bottom: 56px;
  font-size: 1rem;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-block;
  padding: 13px 32px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

.btn-primary {
  background: var(--blue);
  color: var(--white);
  box-shadow: 0 4px 16px rgba(37,99,235,0.25);
}
.btn-primary:hover {
  background: var(--blue-dim);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(37,99,235,0.35);
}

.btn-outline {
  background: transparent;
  color: var(--blue);
  border: 2px solid var(--blue);
}
.btn-outline:hover {
  background: var(--blue-light);
  text-decoration: none;
  transform: translateY(-2px);
}

/* ============================================
   Navigation
   ============================================ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: var(--bg-nav);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  height: 64px;
  box-shadow: 0 1px 8px rgba(30,41,59,0.06);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--blue);
  letter-spacing: 0.04em;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 32px;
  align-items: center;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.95rem;
  transition: color var(--transition);
  font-weight: 500;
}
.nav-links a:hover { color: var(--blue); text-decoration: none; }

.btn-nav {
  background: var(--blue) !important;
  color: var(--white) !important;
  padding: 8px 20px;
  border-radius: 6px;
  font-size: 0.9rem !important;
  box-shadow: 0 2px 8px rgba(37,99,235,0.2);
}
.btn-nav:hover { background: var(--blue-dim) !important; }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.4rem;
  cursor: pointer;
}

/* ============================================
   Hero
   ============================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding-top: 64px;
  background: linear-gradient(135deg, #f0f4f8 0%, #e8f0ff 60%, #f0f4f8 100%);
}

.hero-inner {
  position: relative;
  z-index: 2;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.hero-eyebrow {
  font-size: 0.82rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--blue);
  margin-bottom: 20px;
  font-weight: 700;
}

.hero-title {
  font-size: clamp(2.2rem, 5.5vw, 3.8rem);
  font-weight: 800;
  color: var(--text);
  line-height: 1.2;
  margin-bottom: 32px;
}

.hero-title span {
  color: var(--blue);
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  list-style: none;
  margin-bottom: 48px;
}

.hero-tags li {
  background: var(--white);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 7px 18px;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 500;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.hero-tags li:hover {
  border-color: var(--blue);
  color: var(--blue);
  background: var(--blue-light);
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* Subtle dot grid background */
.hero-bg-grid {
  position: absolute;
  inset: 0;
  z-index: 1;
  background-image: radial-gradient(circle, rgba(37,99,235,0.08) 1px, transparent 1px);
  background-size: 32px 32px;
  mask-image: radial-gradient(ellipse 80% 70% at 70% 50%, black 30%, transparent 100%);
}

/* ============================================
   Services
   ============================================ */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
}

.service-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 24px;
  transition: var(--transition);
  text-align: center;
  box-shadow: var(--shadow);
}

.service-card:hover {
  border-color: var(--blue);
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.service-icon {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.service-card h3 {
  color: var(--text);
  font-size: 1.05rem;
  margin-bottom: 10px;
  font-weight: 700;
}

.service-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* ============================================
   Cases (Tabs + Grid)
   ============================================ */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 40px;
}

.tab {
  background: var(--white);
  border: 1.5px solid var(--border);
  color: var(--text-muted);
  padding: 9px 22px;
  border-radius: 24px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

.tab:hover {
  border-color: var(--blue);
  color: var(--blue);
}

.tab.active {
  background: var(--blue);
  border-color: var(--blue);
  color: var(--white);
  font-weight: 700;
  box-shadow: 0 4px 12px rgba(37,99,235,0.25);
}

.cases-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
  min-height: 200px;
}

.no-images {
  grid-column: 1 / -1;
  text-align: center;
  color: var(--text-muted);
  padding: 80px 0;
  font-size: 0.95rem;
}

.case-img-wrap {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  cursor: pointer;
  aspect-ratio: 4/3;
  background: var(--bg-2);
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.case-img-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.case-img-wrap:hover {
  border-color: var(--blue);
  box-shadow: var(--shadow-lg);
}

.case-img-wrap:hover img {
  transform: scale(1.06);
}

.case-img-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(37,99,235,0.45);
  opacity: 0;
  transition: opacity 0.3s;
  font-size: 2rem;
}

.case-img-wrap:hover .case-img-overlay {
  opacity: 1;
}

/* ============================================
   Workflow
   ============================================ */
.workflow-steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
}

.step {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  flex: 1;
  min-width: 180px;
  max-width: 220px;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

.step:hover {
  border-color: var(--blue);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.step-num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--blue);
  margin-bottom: 12px;
  font-family: monospace;
}

.step h3 {
  color: var(--text);
  font-size: 1rem;
  margin-bottom: 10px;
  font-weight: 700;
}

.step p {
  color: var(--text-muted);
  font-size: 0.88rem;
  line-height: 1.6;
}

.step-arrow {
  font-size: 2rem;
  color: var(--blue);
  align-self: center;
  opacity: 0.4;
  padding: 0 4px;
}

/* ============================================
   About
   ============================================ */
.about-inner {
  display: flex;
  gap: 56px;
  align-items: center;
  flex-wrap: wrap;
}

.avatar-placeholder {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), #60a5fa);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 800;
  color: var(--white);
  flex-shrink: 0;
  box-shadow: 0 8px 24px rgba(37,99,235,0.25);
}

.about-text {
  flex: 1;
  min-width: 280px;
}

.about-text h3 {
  font-size: 1.4rem;
  color: var(--text);
  margin-bottom: 16px;
  font-weight: 700;
}

.about-text p {
  color: var(--text-muted);
  margin-bottom: 12px;
}

.about-stats {
  display: flex;
  gap: 40px;
  margin-top: 32px;
  flex-wrap: wrap;
}

.stat { text-align: center; }

.stat-num {
  display: block;
  font-size: 2rem;
  font-weight: 800;
  color: var(--blue);
  font-family: monospace;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ============================================
   Contact
   ============================================ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
  max-width: 860px;
  margin: 0 auto;
}

.contact-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 24px;
  text-align: center;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

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

.contact-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.contact-item h3 {
  color: var(--text);
  margin-bottom: 8px;
  font-weight: 700;
}

.contact-item p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.contact-item a {
  font-size: 0.95rem;
  font-weight: 500;
}

.wechat-id {
  margin-top: 6px;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.04em;
}

.qr-img {
  margin: 14px auto 0;
  width: 140px;
  height: 140px;
  border-radius: 8px;
  border: 1px solid var(--border);
  object-fit: contain;
  background: var(--bg-2);
}

.qr-placeholder {
  margin: 14px auto 0;
  width: 140px;
  height: 140px;
  border-radius: 8px;
  border: 2px dashed var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.78rem;
  text-align: center;
  line-height: 1.6;
  background: var(--bg-2);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  padding: 28px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.88rem;
}

/* ============================================
   Lightbox
   ============================================ */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: rgba(15,23,42,0.92);
  align-items: center;
  justify-content: center;
}

.lightbox.active { display: flex; }

.lightbox-img {
  max-width: 90vw;
  max-height: 85vh;
  border-radius: 8px;
  object-fit: contain;
  box-shadow: 0 0 60px rgba(0,0,0,0.6);
}

.lightbox-close,
.lightbox-prev,
.lightbox-next {
  position: absolute;
  background: rgba(255,255,255,0.12);
  border: none;
  color: #fff;
  font-size: 1.4rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
}

.lightbox-close:hover,
.lightbox-prev:hover,
.lightbox-next:hover {
  background: rgba(255,255,255,0.25);
}

.lightbox-close { top: 20px; right: 20px; font-size: 1.1rem; }
.lightbox-prev  { left: 16px; font-size: 1.8rem; }
.lightbox-next  { right: 16px; font-size: 1.8rem; }

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  .nav-links { display: none; flex-direction: column; }
  .nav-links.open {
    display: flex;
    position: absolute;
    top: 64px; left: 0; right: 0;
    background: var(--white);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px;
    gap: 16px;
    box-shadow: var(--shadow-lg);
  }
  .nav-toggle { display: block; }

  .hero { min-height: 90vh; }
  .hero-title { font-size: 2rem; }

  .workflow-steps { flex-direction: column; align-items: center; }
  .step { max-width: 100%; width: 100%; }
  .step-arrow { transform: rotate(90deg); }

  .about-inner { justify-content: center; text-align: center; }
  .about-stats { justify-content: center; }

  .lightbox-prev { left: 8px; }
  .lightbox-next { right: 8px; }
}

@media (max-width: 480px) {
  .section { padding: 72px 0; }
  .services-grid { grid-template-columns: 1fr 1fr; }
  .cases-grid { grid-template-columns: 1fr 1fr; }
}