/* ============================================================
   Guangzhou Cui Yang Technology Co., Ltd.
   "Urban Concrete" — Raw industrial concrete aesthetic
   Greyscale monochrome with safety yellow/orange accents
   ============================================================ */

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

:root {
  --bg:          #F5F5F0;
  --surface:     #FFFFFF;
  --alt:         #E8E8E0;
  --text:        #1A1A1A;
  --secondary:   #6B6B6B;
  --muted:       #999999;
  --yellow:      #EAB308;
  --orange:      #F97316;
  --dark:        #1A1A1A;
  --dark-text:   #F5F5F0;
  --dark-second: #BBBBBB;
  --border:      #CCCCCC;
  --font-body:   'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'Bebas Neue', 'Arial Narrow', Impact, sans-serif;
}

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

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

/* --- CONCRETE TEXTURE OVERLAY --- */
.concrete-texture {
  position: relative;
}
.concrete-texture::before {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  opacity: 0.04;
  background-image:
    repeating-linear-gradient(0deg, transparent, transparent 2px, rgba(0,0,0,0.03) 2px, rgba(0,0,0,0.03) 4px),
    repeating-linear-gradient(90deg, transparent, transparent 2px, rgba(0,0,0,0.03) 2px, rgba(0,0,0,0.03) 4px);
}
.concrete-texture > * { position: relative; z-index: 2; }

/* --- TYPOGRAPHY --- */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  line-height: 1.1;
}
h1 { font-size: clamp(3.5rem, 10vw, 7rem); }
h2 { font-size: clamp(2rem, 5vw, 3.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.75rem); }
h4 { font-size: 1.125rem; }

p { margin-bottom: 1rem; }
a { color: var(--text); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--yellow); }

/* --- UTILITY --- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}
.section { padding: 6rem 0; }
.accent-underline {
  display: inline-block;
  width: 60px;
  height: 4px;
  background: var(--yellow);
  margin-top: 0.5rem;
}
.accent-underline.orange { background: var(--orange); }
.accent-underline.full { width: 100%; }

/* --- HEADER / NAV --- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  font-family: var(--font-display);
  font-size: 1.35rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text);
  white-space: nowrap;
}
.logo span { color: var(--yellow); }
.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}
.nav-links a {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
  color: var(--secondary);
}
.nav-links a:hover { color: var(--text); }

/* --- HAMBURGER (mobile) --- */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 26px;
  height: 2px;
  background: var(--text);
  transition: transform 0.3s, opacity 0.3s;
}
.hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* --- HERO --- */
.hero {
  padding: 10rem 0 6rem;
  background: var(--bg);
  text-align: center;
}
.hero-badge {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.75rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--secondary);
  border: 1px solid var(--border);
  padding: 0.4rem 1.2rem;
  margin-bottom: 2rem;
}
.hero h1 {
  margin-bottom: 0.25rem;
  color: var(--text);
}
.hero h1 .highlight {
  position: relative;
  display: inline-block;
}
.hero h1 .highlight::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 0; right: 0;
  height: 4px;
  background: var(--yellow);
}
.hero p.subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--secondary);
  max-width: 600px;
  margin: 1.5rem auto 2.5rem;
}
.btn {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 1rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.85rem 2.5rem;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
}
.btn-primary {
  background: var(--yellow);
  color: var(--text);
}
.btn-primary:hover { background: var(--orange); color: var(--text); }
.btn-outline {
  background: transparent;
  color: var(--text);
  border: 2px solid var(--border);
}
.btn-outline:hover { border-color: var(--yellow); color: var(--yellow); }

.hero-scroll {
  margin-top: 3rem;
  display: inline-block;
  cursor: pointer;
}
.hero-scroll svg { display: block; width: 24px; height: 24px; color: var(--muted); }
.hero-scroll:hover svg { color: var(--yellow); }

/* --- SERVICES --- */
.services {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.section-header { margin-bottom: 3rem; }
.section-header h2 { margin-bottom: 0.5rem; }
.section-header p { color: var(--secondary); max-width: 520px; }

.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
}
.service-card {
  background: var(--surface);
  padding: 3rem 2rem 2.5rem;
  border: 1px solid var(--border);
  border-top-width: 5px;
}
.service-card:nth-child(1) { border-top-color: var(--yellow); }
.service-card:nth-child(2) { border-top-color: var(--orange); }
.service-card:nth-child(3) { border-top-color: var(--yellow); }
.service-card .icon {
  width: 48px;
  height: 48px;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--alt);
}
.service-card .icon svg { width: 24px; height: 24px; color: var(--text); }
.service-card h3 { margin-bottom: 0.75rem; }
.service-card p { color: var(--secondary); font-size: 0.95rem; margin-bottom: 0; }

/* --- ABOUT --- */
.about { padding: 0; }
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 500px;
}
.about-left {
  background: var(--dark);
  color: var(--dark-text);
  padding: 5rem 3rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.about-left h2 { color: var(--dark-text); margin-bottom: 1rem; }
.about-left .accent-text { color: var(--yellow); }
.about-left p { color: var(--dark-second); margin-bottom: 0; }
.about-right {
  background: var(--bg);
  padding: 5rem 3rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.about-right p { color: var(--text); }
.about-right .contact-info {
  margin-top: 1.5rem;
}
.about-right .contact-info .row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--secondary);
}
.about-right .contact-info .row svg { width: 16px; height: 16px; flex-shrink: 0; color: var(--yellow); }

/* --- METRICS --- */
.metrics {
  background: var(--bg);
  text-align: center;
}
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}
.metric-item {
  padding: 2rem;
}
.metric-number {
  font-family: var(--font-display);
  font-size: clamp(3rem, 6vw, 5rem);
  line-height: 1;
  color: var(--text);
  margin-bottom: 0.5rem;
}
.metric-item .accent-underline { margin: 0.5rem auto 1rem; }
.metric-label {
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--secondary);
}

/* --- PROCESS --- */
.process { background: var(--surface); border-top: 1px solid var(--border); }
.process-blocks {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
}
.process-block {
  display: grid;
  grid-template-columns: 80px 1fr;
  align-items: center;
  gap: 2rem;
  padding: 2rem 2.5rem;
  border-bottom: 1px solid var(--border);
}
.process-block:last-child { border-bottom: none; }
.process-block:nth-child(1) { background: #FFFFFF; }
.process-block:nth-child(2) { background: #F8F8F4; }
.process-block:nth-child(3) { background: #EEEEE8; }
.process-block:nth-child(4) { background: #E4E4DC; }

.step-circle {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.5rem;
  flex-shrink: 0;
}
.step-circle.yellow { background: var(--yellow); color: var(--text); }
.step-circle.orange { background: var(--orange); color: #FFFFFF; }

.process-block .block-content h3 { margin-bottom: 0.25rem; }
.process-block .block-content p { color: var(--secondary); margin-bottom: 0; font-size: 0.95rem; }

/* --- TAGS --- */
.tags {
  background: var(--bg);
  text-align: center;
}
.tags-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  max-width: 900px;
  margin: 0 auto;
}
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  border: 2px solid var(--border);
  padding: 0.6rem 1.4rem;
  font-family: var(--font-display);
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text);
  transition: border-color 0.2s, background 0.2s;
}
.tag:hover { border-color: var(--yellow); background: var(--surface); }
.tag .dot {
  width: 8px;
  height: 8px;
  background: var(--yellow);
  flex-shrink: 0;
}

/* --- CTA --- */
.cta {
  background: var(--yellow);
  color: var(--text);
  text-align: center;
  padding: 5rem 0;
}
.cta h2 { margin-bottom: 1rem; }
.cta p { color: var(--text); max-width: 500px; margin: 0 auto 2rem; font-size: 1.05rem; }
.cta .btn { background: var(--dark); color: var(--yellow); }
.cta .btn:hover { background: var(--text); color: var(--yellow); }

/* --- FOOTER --- */
.site-footer {
  background: var(--dark);
  color: var(--dark-second);
  padding: 3rem 0 2rem;
  font-size: 0.9rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}
.footer-col h4 {
  color: var(--dark-text);
  font-family: var(--font-body);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: 0.8rem;
  margin-bottom: 1rem;
}
.footer-col p, .footer-col li { color: var(--dark-second); margin-bottom: 0.4rem; }
.footer-col ul { list-style: none; }
.footer-col a { color: var(--dark-second); }
.footer-col a:hover { color: var(--yellow); }
.footer-bottom {
  border-top: 1px solid #333;
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}
.footer-bottom-links { display: flex; gap: 1.5rem; }
.footer-bottom-links a { color: var(--dark-second); font-size: 0.8rem; }
.footer-bottom-links a:hover { color: var(--yellow); }

/* --- LEGAL PAGES --- */
.legal-hero {
  padding: 8rem 0 3rem;
  background: var(--bg);
  text-align: center;
}
.legal-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 2rem 5rem;
}
.legal-content h3 {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin: 2rem 0 0.75rem;
  color: var(--text);
}
.legal-content p, .legal-content ul {
  color: var(--secondary);
  font-size: 0.95rem;
  margin-bottom: 1rem;
}
.legal-content ul { padding-left: 1.5rem; }
.legal-content ul li { margin-bottom: 0.4rem; }
.legal-content .last-updated {
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

/* --- FADE-IN ANIMATION --- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease-out, transform 0.7s ease-out;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* --- RESPONSIVE --- */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0; right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 1.5rem 2rem;
    gap: 1rem;
  }
  .hamburger { display: flex; }

  .hero { padding: 8rem 0 4rem; }

  .services-grid { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .about-left, .about-right { padding: 3rem 2rem; }
  .metrics-grid { grid-template-columns: 1fr; gap: 1rem; }

  .process-block {
    grid-template-columns: 60px 1fr;
    gap: 1.25rem;
    padding: 1.5rem;
  }
  .step-circle { width: 48px; height: 48px; font-size: 1.2rem; }

  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
}

@media (max-width: 480px) {
  .container { padding: 0 1rem; }
  .section { padding: 4rem 0; }
  h1 { font-size: 2.5rem; }
}