/* ============================================
   Black Gold Engineering — Styles
   ============================================ */

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

:root {
  --black: #1C1C1C;
  --gold: #C5962C;
  --gold-light: #d4a94a;
  --white: #FFFFFF;
  --gray-light: #F5F5F5;
  --gray-mid: #E0E0E0;
  --gray-text: #6B6B6B;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --header-height: 72px;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
}

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--black);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

/* --- Container --- */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Header --- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(28, 28, 28, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  height: var(--header-height);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

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

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

.main-nav {
  display: flex;
  gap: 32px;
}

.main-nav a {
  font-size: 0.875rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.75);
  letter-spacing: 0.02em;
  transition: color 0.2s ease;
}

.main-nav a:hover {
  color: var(--gold);
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 28px;
  height: 28px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--white);
  border-radius: 1px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.hamburger.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

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

.hamburger.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* --- Hero --- */
.hero {
  position: relative;
  min-height: 100vh;
  background: linear-gradient(135deg, #1C1C1C 0%, #2a2a2a 40%, #1C1C1C 100%);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(197, 150, 44, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 30%, rgba(197, 150, 44, 0.05) 0%, transparent 50%);
  pointer-events: none;
}

.hero-overlay {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 120px 24px 80px;
  text-align: center;
}

.hero-content {
  max-width: 700px;
}

.hero-logo {
  width: 200px;
  height: auto;
  margin: 0 auto 24px;
}

.hero h1 {
  font-size: 2rem;
  font-weight: 300;
  color: var(--white);
  letter-spacing: 0.04em;
  margin-bottom: 16px;
}

.hero-tagline {
  font-size: 1.125rem;
  font-weight: 400;
  color: rgba(255, 255, 255, 0.65);
  line-height: 1.6;
}

.scroll-indicator {
  position: absolute;
  bottom: 40px;
  color: rgba(255, 255, 255, 0.4);
  animation: bounce 2s ease infinite;
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(8px); }
  60% { transform: translateY(4px); }
}

/* --- Sections --- */
.section {
  padding: 100px 0;
}

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

.section-heading {
  font-size: 2rem;
  font-weight: 600;
  text-align: center;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.section-subheading {
  font-size: 1.0625rem;
  color: var(--gray-text);
  text-align: center;
  margin-bottom: 56px;
  font-weight: 400;
}

.section-heading + .section-subheading {
  margin-top: 0;
}

.section-heading:last-child,
.section-heading + :not(.section-subheading) {
  margin-bottom: 56px;
}

/* --- Services --- */
.services-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  margin-top: 56px;
}

.service-card {
  padding: 36px 32px;
  background: var(--white);
  border: 1px solid var(--gray-mid);
  border-radius: 8px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.section-alt .service-card {
  background: var(--white);
}

.service-card:hover {
  border-color: var(--gold);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}

.service-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--black);
}

.service-card p {
  font-size: 0.9375rem;
  color: var(--gray-text);
  line-height: 1.6;
}

/* --- Products --- */
.product-card {
  max-width: 600px;
  margin: 56px auto 0;
  padding: 48px 40px;
  background: var(--white);
  border: 1px solid var(--gray-mid);
  border-radius: 8px;
  text-align: center;
}

.section-alt .product-card {
  background: var(--white);
}

.product-card h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--black);
}

.product-card p {
  font-size: 1rem;
  color: var(--gray-text);
  line-height: 1.7;
  margin-bottom: 28px;
}

/* --- Button --- */
.btn {
  display: inline-block;
  padding: 12px 32px;
  font-family: var(--font);
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.15s ease;
}

.btn:active {
  transform: scale(0.98);
}

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

.btn-primary:hover {
  background: var(--gold-light);
}

/* --- About --- */
.about-content {
  max-width: 680px;
  margin: 56px auto 0;
  text-align: center;
}

.about-content p {
  font-size: 1.0625rem;
  color: var(--gray-text);
  line-height: 1.8;
}

/* --- Team --- */
.team-card {
  max-width: 560px;
  margin: 56px auto 0;
  text-align: center;
}

.team-avatar {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  background: var(--black);
  color: var(--gold);
  font-size: 1.5rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 24px;
  letter-spacing: 0.04em;
}

.team-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--black);
}

.team-card p {
  font-size: 0.9375rem;
  color: var(--gray-text);
  line-height: 1.7;
}

/* --- Contact --- */
.contact-form {
  max-width: 560px;
  margin: 0 auto;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 6px;
  color: var(--black);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  font-family: var(--font);
  font-size: 0.9375rem;
  border: 1px solid var(--gray-mid);
  border-radius: 6px;
  background: var(--white);
  color: var(--black);
  transition: border-color 0.2s ease;
  outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--gold);
}

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

.contact-form .btn {
  width: 100%;
  padding: 14px;
  font-size: 1rem;
}

/* --- Footer --- */
.site-footer {
  background: var(--black);
  padding: 40px 0;
  text-align: center;
}

.footer-logo {
  height: 32px;
  width: auto;
  margin: 0 auto 8px;
}

.site-footer p {
  font-size: 0.8125rem;
  color: rgba(255, 255, 255, 0.45);
}

/* --- Fade-in Animation --- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ============================================
   Responsive
   ============================================ */

/* Tablet */
@media (max-width: 1024px) {
  .services-grid {
    gap: 24px;
  }

  .section {
    padding: 80px 0;
  }
}

/* Mobile */
@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }

  .hamburger {
    display: flex;
  }

  .main-nav {
    position: fixed;
    top: 0;
    right: 0;
    width: 280px;
    height: 100vh;
    background: rgba(28, 28, 28, 0.97);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    flex-direction: column;
    padding: 96px 32px 32px;
    gap: 0;
    transform: translateX(100%);
    transition: transform 0.3s ease;
  }

  .main-nav.open {
    transform: translateX(0);
  }

  .main-nav a {
    font-size: 1.125rem;
    padding: 16px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    color: rgba(255, 255, 255, 0.8);
  }

  .hero-logo {
    width: 160px;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

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

  .section {
    padding: 64px 0;
  }

  .section-heading {
    font-size: 1.625rem;
  }

  .services-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

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

  .product-card {
    padding: 36px 28px;
  }

  .form-row {
    grid-template-columns: 1fr;
    gap: 0;
  }
}

/* Small mobile */
@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .hero-logo {
    width: 140px;
  }

  .hero h1 {
    font-size: 1.25rem;
  }
}