/* ============================================================
   PengFei Lighting - B2B Solar & LED Street Light Website
   Design System: Modern, Clean, Professional
   ============================================================ */

/* --- CSS Variables --- */
:root {
  --primary: #0A66C2;
  --primary-dark: #084E96;
  --primary-light: #E8F0FE;
  --accent: #F59E0B;
  --accent-dark: #D97706;
  --dark: #0F172A;
  --dark-2: #1E293B;
  --dark-3: #334155;
  --text: #475569;
  --text-light: #94A3B8;
  --bg: #FFFFFF;
  --bg-alt: #F8FAFC;
  --bg-dark: #0F172A;
  --border: #E2E8F0;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 20px 60px rgba(0, 0, 0, 0.15);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Inter', -apple-system, system-ui, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

ul {
  list-style: none;
}

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

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

.section {
  padding: 100px 0;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}

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

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.25rem;
}

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

.logo-icon {
  font-size: 1.5rem;
}

.logo-accent {
  color: var(--primary);
}

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

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--dark-3);
  transition: var(--transition);
  position: relative;
}

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--primary);
  border-radius: 1px;
}

.nav-btn {
  background: var(--primary);
  color: white !important;
  padding: 10px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  transition: var(--transition);
}

.nav-btn:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  margin: 5px 0;
  background: var(--dark);
  transition: var(--transition);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 32px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  border-color: var(--border);
  color: var(--dark);
  background: white;
}

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

.btn-light {
  background: white;
  color: var(--primary);
  font-weight: 700;
}

.btn-light:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-outline-light {
  border-color: rgba(255, 255, 255, 0.4);
  color: white;
}

.btn-outline-light:hover {
  border-color: white;
  background: rgba(255, 255, 255, 0.1);
}

/* --- 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 50%, #0A66C2 100%);
}

.hero-gradient {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(245, 158, 11, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 30%, rgba(10, 102, 194, 0.3) 0%, transparent 50%);
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  padding: 8px 20px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 100px;
  color: rgba(255, 255, 255, 0.9);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 32px;
  backdrop-filter: blur(10px);
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  color: white;
  line-height: 1.15;
  margin-bottom: 24px;
}

.hero-highlight {
  background: linear-gradient(135deg, var(--accent), #FCD34D);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: rgba(255, 255, 255, 0.75);
  max-width: 680px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

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

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  max-width: 800px;
  margin: 0 auto;
  padding: 32px;
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
}

.stat {
  text-align: center;
}

.stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: white;
}

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

.stat-label {
  display: block;
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.6);
  margin-top: 4px;
}

/* --- Section Headers --- */
.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-tag {
  display: inline-block;
  padding: 6px 16px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  font-weight: 800;
  color: var(--dark);
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-light);
  max-width: 600px;
  margin: 0 auto;
}

/* --- Category Cards --- */
.category-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.category-card {
  position: relative;
  padding: 32px 24px;
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  cursor: pointer;
  overflow: hidden;
}

.category-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition);
}

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

.category-card:hover::before {
  transform: scaleX(1);
}

.category-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.category-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 8px;
}

.category-card p {
  font-size: 0.85rem;
  color: var(--text-light);
  line-height: 1.5;
  flex: 1;
}

.category-count {
  display: inline-block;
  margin-top: 16px;
  font-size: 0.8rem;
  color: var(--primary);
  font-weight: 600;
}

.category-arrow {
  position: absolute;
  bottom: 24px;
  right: 24px;
  font-size: 1.2rem;
  color: var(--primary);
  opacity: 0;
  transform: translateX(-8px);
  transition: var(--transition);
}

.category-card:hover .category-arrow {
  opacity: 1;
  transform: translateX(0);
}

/* --- Product Cards --- */
.product-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.product-card {
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
  cursor: pointer;
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.product-card-img {
  height: 220px;
  background: var(--bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
}

.product-card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.product-card:hover .product-card-img img {
  transform: scale(1.05);
}

.product-card-img .placeholder {
  font-size: 3rem;
  opacity: 0.3;
}

.product-card-body {
  padding: 20px;
}

.product-card-body h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--dark);
  margin-bottom: 8px;
  line-height: 1.4;
}

.product-card-body p {
  font-size: 0.85rem;
  color: var(--text-light);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.product-card-specs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 12px;
}

.spec-tag {
  padding: 4px 10px;
  background: var(--bg-alt);
  border-radius: 6px;
  font-size: 0.75rem;
  color: var(--dark-3);
  font-weight: 500;
}

.product-card-footer {
  padding: 16px 20px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.product-card-footer .view-btn {
  color: var(--primary);
  font-weight: 600;
  font-size: 0.85rem;
}

.section-cta {
  text-align: center;
  margin-top: 48px;
}

/* --- Advantage Cards --- */
.advantage-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.advantage-card {
  padding: 32px;
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: var(--transition);
}

.advantage-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}

.advantage-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.advantage-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 8px;
}

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

/* --- CTA Section --- */
.cta-section {
  padding: 80px 0;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
}

.cta-content {
  text-align: center;
  color: white;
}

.cta-content h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.cta-content p {
  font-size: 1.1rem;
  opacity: 0.85;
  margin-bottom: 32px;
}

.cta-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
}

/* --- Footer --- */
.footer {
  background: var(--bg-dark);
  color: rgba(255, 255, 255, 0.7);
  padding: 64px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  color: white;
  font-weight: 700;
  font-size: 1.1rem;
}

.footer-desc {
  font-size: 0.85rem;
  line-height: 1.6;
}

.footer-col h4 {
  color: white;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 16px;
}

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

.footer-col ul li a {
  font-size: 0.85rem;
  transition: var(--transition);
}

.footer-col ul li a:hover {
  color: var(--accent);
}

.footer-col ul li {
  font-size: 0.85rem;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 24px;
  text-align: center;
  font-size: 0.8rem;
}

/* --- Products Page --- */
.page-header {
  padding: 120px 0 60px;
  background: linear-gradient(135deg, #0F172A 0%, #1E3A5F 100%);
  text-align: center;
}

.page-header h1 {
  color: white;
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.page-header p {
  color: rgba(255, 255, 255, 0.7);
  font-size: 1.1rem;
}

.filter-bar {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 40px;
  padding: 16px;
  background: white;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.filter-btn {
  padding: 8px 20px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: white;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--dark-3);
  transition: var(--transition);
  font-family: var(--font);
}

.filter-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.filter-btn.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* --- Product Detail Page --- */
.product-detail {
  padding: 100px 0 60px;
}

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

.product-detail-img {
  background: var(--bg-alt);
  border-radius: var(--radius-lg);
  padding: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 400px;
  border: 1px solid var(--border);
}

.product-detail-img img {
  max-height: 400px;
  object-fit: contain;
}

.product-detail-info h1 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--dark);
  margin-bottom: 12px;
}

.product-detail-info .model {
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 20px;
}

.product-detail-info .description {
  font-size: 1rem;
  line-height: 1.8;
  margin-bottom: 24px;
}

.specs-table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 24px;
}

.specs-table th,
.specs-table td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.specs-table th {
  font-weight: 600;
  color: var(--dark);
  background: var(--bg-alt);
  width: 40%;
}

.product-actions {
  display: flex;
  gap: 12px;
  margin-top: 32px;
}

/* --- About Page --- */
.about-hero {
  text-align: center;
}

.about-hero h2 {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 16px;
}

.about-hero p {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text);
  max-width: 800px;
  margin: 0 auto;
}

.timeline {
  max-width: 600px;
  margin: 48px auto 0;
}

.timeline-item {
  display: flex;
  gap: 24px;
  padding-bottom: 32px;
  border-left: 2px solid var(--border);
  padding-left: 24px;
  position: relative;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -7px;
  top: 0;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--primary);
  border: 2px solid white;
}

.timeline-year {
  font-weight: 700;
  color: var(--primary);
  min-width: 48px;
}

.timeline-text {
  font-size: 0.9rem;
  color: var(--text);
}

/* --- Contact Page --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--dark);
  margin-bottom: 6px;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.9rem;
  font-family: var(--font);
  transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(10, 102, 194, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.contact-info-card {
  padding: 32px;
  background: var(--bg-alt);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  margin-bottom: 16px;
}

.contact-info-card h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 16px;
}

.contact-info-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  margin-bottom: 16px;
  font-size: 0.9rem;
}

.contact-info-item .icon {
  font-size: 1.2rem;
}

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

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate {
  animation: fadeInUp 0.6s ease forwards;
  opacity: 0;
}

/* --- Responsive --- */
@media (max-width: 992px) {
  .category-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
  }

  .product-detail-grid {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-toggle {
    display: block;
  }

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

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

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

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

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .filter-bar {
    flex-wrap: wrap;
  }
}