/* ============================================
   FOUNTAINHEAD ALLOYS - Main Stylesheet
   Industrial Blue/Steel Theme
   Mobile-First Responsive Design
   ============================================ */

/* --- CSS Variables --- */
:root {
  --primary: #1a3a5c;
  --primary-dark: #0f2440;
  --primary-light: #2a5a8c;
  --accent: #3498db;
  --accent-light: #5dade2;
  --steel: #4a5568;
  --steel-light: #718096;
  --steel-dark: #2d3748;
  --silver: #c0c7d0;
  --bg-light: #f7f9fc;
  --bg-white: #ffffff;
  --text-dark: #1a202c;
  --text-body: #4a5568;
  --text-light: #718096;
  --gold: #d4a843;
  --success: #27ae60;
  --border: #e2e8f0;
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
  --shadow-xl: 0 20px 40px -10px rgba(0,0,0,0.15);
  --radius: 8px;
  --radius-lg: 12px;
  --transition: all 0.3s ease;
  --max-width: 1200px;
}

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

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--text-body);
  line-height: 1.6;
  background: var(--bg-white);
  -webkit-font-smoothing: antialiased;
}

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

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

a:hover {
  color: var(--primary);
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-dark);
  font-weight: 700;
  line-height: 1.3;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

/* --- Utility Classes --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1rem;
}

.section {
  padding: 4rem 0;
}

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

.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-accent { color: var(--accent); }
.text-white { color: #fff; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

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

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

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #fff;
}

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

.btn-white:hover {
  background: var(--bg-light);
  color: var(--primary);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 1rem 2.25rem;
  font-size: 1.05rem;
}

.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-header h2 {
  margin-bottom: 0.75rem;
  position: relative;
  display: inline-block;
}

.section-header h2::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
}

.section-header p {
  color: var(--text-light);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 1rem auto 0;
}

/* --- Top Bar --- */
.top-bar {
  background: var(--primary-dark);
  color: #fff;
  padding: 0.5rem 0;
  font-size: 0.85rem;
}

.top-bar-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.top-bar a {
  color: var(--silver);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.top-bar a:hover {
  color: #fff;
}

.top-bar-left {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.top-bar-right {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.top-bar-right a {
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(255,255,255,0.1);
}

.top-bar-right a:hover {
  background: var(--accent);
}

/* --- Header / Navigation --- */
.header {
  background: var(--bg-white);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  max-width: var(--max-width);
  margin: 0 auto;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo img {
  height: 50px;
  width: auto;
}

.logo-text {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1.2;
}

.logo-text span {
  display: block;
  font-size: 0.7rem;
  font-weight: 400;
  color: var(--steel-light);
  text-transform: uppercase;
  letter-spacing: 2px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 0;
}

.nav a {
  padding: 0.5rem 1rem;
  color: var(--steel-dark);
  font-weight: 500;
  font-size: 0.9rem;
  position: relative;
}

.nav a:hover,
.nav a.active {
  color: var(--accent);
}

.nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 1rem;
  right: 1rem;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transition: transform 0.3s ease;
}

.nav a:hover::after,
.nav a.active::after {
  transform: scaleX(1);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background: #fff;
  box-shadow: var(--shadow-lg);
  border-radius: var(--radius);
  padding: 0.5rem 0;
  min-width: 220px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: var(--transition);
  z-index: 100;
}

.nav-dropdown:hover .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.nav-dropdown-menu a {
  display: block;
  padding: 0.5rem 1.25rem;
  font-size: 0.85rem;
}

.nav-dropdown-menu a:hover {
  background: var(--bg-light);
}

.nav-dropdown-menu a::after {
  display: none;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

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

/* CTA in header */
.header-cta {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.header-phone {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--primary);
  font-weight: 600;
  font-size: 0.95rem;
}

/* --- Hero Section --- */
.hero {
  position: relative;
  background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 50%, var(--primary-light) 100%);
  color: #fff;
  padding: 6rem 0;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(52,152,219,0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(212,168,67,0.1) 0%, transparent 40%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 700px;
}

.hero-badge {
  display: inline-block;
  background: rgba(255,255,255,0.15);
  backdrop-filter: blur(10px);
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
  border: 1px solid rgba(255,255,255,0.2);
}

.hero h1 {
  color: #fff;
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 1.25rem;
  line-height: 1.15;
}

.hero h1 .highlight {
  color: var(--gold);
}

.hero p {
  font-size: 1.15rem;
  line-height: 1.7;
  opacity: 0.9;
  margin-bottom: 2rem;
  max-width: 550px;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  gap: 3rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255,255,255,0.15);
}

.hero-stat h3 {
  color: var(--gold);
  font-size: 2rem;
  margin-bottom: 0.25rem;
}

.hero-stat p {
  font-size: 0.85rem;
  opacity: 0.7;
  margin: 0;
}

/* --- Features / Why Choose Us --- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.feature-card {
  background: #fff;
  padding: 2rem 1.5rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  text-align: center;
  transition: var(--transition);
  border: 1px solid var(--border);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--accent);
}

.feature-icon {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, var(--accent), var(--primary-light));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
  color: #fff;
  font-size: 1.5rem;
}

.feature-card h4 {
  margin-bottom: 0.5rem;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-light);
}

/* --- Products Section --- */
.products-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.product-card {
  background: #fff;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid var(--border);
}

.product-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
}

.product-img {
  width: 100%;
  height: 220px;
  object-fit: cover;
  background: var(--bg-light);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--steel-light);
  font-size: 3rem;
}

.product-body {
  padding: 1.5rem;
}

.product-body h3 {
  margin-bottom: 0.5rem;
  font-size: 1.15rem;
}

.product-body p {
  font-size: 0.9rem;
  color: var(--text-light);
  margin-bottom: 1rem;
}

.product-grades {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.grade-tag {
  background: var(--bg-light);
  color: var(--primary);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
}

/* --- About Preview --- */
.about-preview {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.about-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.about-img-placeholder {
  width: 100%;
  height: 400px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.2rem;
  font-weight: 600;
}

.about-text h2 {
  margin-bottom: 1rem;
}

.about-text p {
  margin-bottom: 1rem;
}

.about-list {
  list-style: none;
  margin: 1.5rem 0;
}

.about-list li {
  padding: 0.4rem 0;
  padding-left: 1.75rem;
  position: relative;
  font-size: 0.95rem;
}

.about-list li::before {
  content: '\2713';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

/* --- Certifications --- */
.cert-bar {
  background: var(--primary);
  color: #fff;
  padding: 2.5rem 0;
}

.cert-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  flex-wrap: wrap;
  text-align: center;
}

.cert-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.cert-icon {
  width: 50px;
  height: 50px;
  background: rgba(255,255,255,0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.cert-item span {
  font-size: 0.85rem;
  font-weight: 500;
}

/* --- CTA Banner --- */
.cta-banner {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary-light));
  color: #fff;
  padding: 4rem 0;
  text-align: center;
}

.cta-banner h2 {
  color: #fff;
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.cta-banner p {
  opacity: 0.85;
  font-size: 1.1rem;
  margin-bottom: 2rem;
}

.cta-buttons {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

/* --- Testimonials / Clients --- */
.clients-grid {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  flex-wrap: wrap;
  opacity: 0.6;
}

.clients-grid img {
  height: 50px;
  filter: grayscale(100%);
  transition: var(--transition);
}

.clients-grid img:hover {
  filter: grayscale(0%);
  opacity: 1;
}

/* --- Counter / Stats Bar --- */
.stats-bar {
  background: var(--bg-light);
  padding: 3rem 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  text-align: center;
}

.stat-item h3 {
  font-size: 2.5rem;
  color: var(--accent);
  margin-bottom: 0.25rem;
}

.stat-item p {
  color: var(--steel-light);
  font-size: 0.9rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* --- Footer --- */
.footer {
  background: var(--steel-dark);
  color: var(--silver);
  padding: 4rem 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 2rem;
}

.footer h4 {
  color: #fff;
  font-size: 1rem;
  margin-bottom: 1.25rem;
  position: relative;
  padding-bottom: 0.75rem;
}

.footer h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 30px;
  height: 2px;
  background: var(--accent);
}

.footer p {
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 1rem;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  color: var(--silver);
  font-size: 0.9rem;
  transition: var(--transition);
}

.footer-links a:hover {
  color: #fff;
  padding-left: 5px;
}

.footer-contact li {
  list-style: none;
  display: flex;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}

.footer-contact .icon {
  color: var(--accent);
  min-width: 20px;
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: 1.25rem 0;
  margin-top: 3rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.85rem;
}

.footer-social {
  display: flex;
  gap: 0.75rem;
}

.footer-social a {
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.1);
  border-radius: 50%;
  color: var(--silver);
  transition: var(--transition);
}

.footer-social a:hover {
  background: var(--accent);
  color: #fff;
}

/* --- Inner Page Hero --- */
.page-hero {
  background: linear-gradient(135deg, var(--primary-dark), var(--primary));
  color: #fff;
  padding: 4rem 0;
  text-align: center;
}

.page-hero h1 {
  color: #fff;
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

.breadcrumb {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  opacity: 0.8;
}

.breadcrumb a {
  color: var(--silver);
}

.breadcrumb a:hover {
  color: #fff;
}

/* --- Contact Page --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

.contact-form {
  background: #fff;
  padding: 2rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-dark);
  margin-bottom: 0.4rem;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: inherit;
  transition: var(--transition);
  background: var(--bg-light);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
  background: #fff;
  box-shadow: 0 0 0 3px rgba(52,152,219,0.1);
}

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

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

.contact-info-cards {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.info-card {
  background: #fff;
  padding: 1.5rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  border-left: 3px solid var(--accent);
}

.info-card-icon {
  width: 45px;
  height: 45px;
  background: var(--bg-light);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  font-size: 1.1rem;
  flex-shrink: 0;
}

.info-card h4 {
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
}

.info-card p {
  font-size: 0.9rem;
  color: var(--text-light);
}

/* --- Products Inner Page --- */
.product-detail-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.product-detail-card {
  background: #fff;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: var(--transition);
}

.product-detail-card:hover {
  box-shadow: var(--shadow-xl);
}

.product-detail-body {
  padding: 1.5rem;
}

.specs-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
}

.specs-table th,
.specs-table td {
  padding: 0.6rem 0.75rem;
  text-align: left;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--border);
}

.specs-table th {
  background: var(--bg-light);
  font-weight: 600;
  color: var(--primary);
}

.specs-table tr:hover td {
  background: var(--bg-light);
}

/* --- Facilities Page --- */
.facilities-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.facility-card {
  background: #fff;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.facility-img-placeholder {
  width: 100%;
  height: 200px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 600;
}

.facility-body {
  padding: 1.25rem;
}

.facility-body h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

.facility-body p {
  font-size: 0.9rem;
  color: var(--text-light);
}

/* --- Quality / Certifications Page --- */
.quality-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.quality-card {
  background: #fff;
  padding: 2rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  border-left: 4px solid var(--accent);
}

.quality-card h3 {
  margin-bottom: 0.75rem;
}

.quality-card ul {
  list-style: none;
  margin-top: 1rem;
}

.quality-card ul li {
  padding: 0.35rem 0;
  padding-left: 1.5rem;
  position: relative;
  font-size: 0.9rem;
}

.quality-card ul li::before {
  content: '\2713';
  position: absolute;
  left: 0;
  color: var(--success);
  font-weight: 700;
}

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

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

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }

/* --- RESPONSIVE --- */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .products-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .facilities-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  html { font-size: 15px; }

  h1 { font-size: 2rem; }
  h2 { font-size: 1.6rem; }

  .top-bar { display: none; }

  .header-inner {
    padding: 0.5rem 1rem;
  }

  .menu-toggle {
    display: block;
  }

  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: #fff;
    flex-direction: column;
    padding: 4rem 1.5rem 2rem;
    box-shadow: -5px 0 15px rgba(0,0,0,0.1);
    transition: right 0.3s ease;
    z-index: 999;
    overflow-y: auto;
  }

  .nav.open {
    right: 0;
  }

  .nav a {
    padding: 0.75rem 0;
    font-size: 1rem;
    border-bottom: 1px solid var(--border);
    width: 100%;
  }

  .nav a::after { display: none; }

  .nav-dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    padding-left: 1rem;
    display: none;
  }

  .nav-dropdown.open .nav-dropdown-menu {
    display: block;
  }

  .header-cta { display: none; }

  .hero { padding: 3rem 0; }
  .hero h1 { font-size: 2rem; }
  .hero-stats { gap: 1.5rem; }
  .hero-stat h3 { font-size: 1.5rem; }

  .about-preview { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .quality-grid { grid-template-columns: 1fr; }
  .product-detail-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }
  .products-grid { grid-template-columns: 1fr; }
  .facilities-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }

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

  .cert-inner { gap: 1.5rem; }
  .hero-buttons { flex-direction: column; }
}

@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
  .hero-stats { flex-direction: column; gap: 1rem; }
  .container { padding: 0 0.75rem; }
  .section { padding: 2.5rem 0; }
}

/* --- Mobile Menu Overlay --- */
.nav-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.4);
  z-index: 998;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.nav-overlay.active {
  opacity: 1;
  visibility: visible;
}

/* --- Back to Top --- */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  background: var(--accent);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  cursor: pointer;
  border: none;
  z-index: 99;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--primary);
  transform: translateY(-3px);
}