/* ============================================================
   Ya Zheng — Computer Systems Design
   Steel Gray + Amber Yellow  |  Industrial-Chic
   ============================================================ */

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

:root {
  --primary:   #64748b;
  --primary-d: #475569;
  --primary-l: #94a3b8;
  --accent:    #d97706;
  --accent-d:  #b45309;
  --accent-l:  #f59e0b;
  --bg:        #f8fafc;
  --surface:   #ffffff;
  --heading:   #0f172a;
  --body:      #334155;
  --muted:     #64748b;
  --border:    #e2e8f0;
  --radius:    6px;
  --shadow:    0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 6px rgba(0,0,0,.05), 0 2px 4px rgba(0,0,0,.04);
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--body);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--accent-d);
  text-decoration: none;
  transition: color .2s;
}
a:hover { color: var(--accent); }

h1, h2, h3, h4, h5, h6 {
  color: var(--heading);
  line-height: 1.2;
  font-weight: 700;
}
h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.4rem); }
h3 { font-size: clamp(1.2rem, 2.2vw, 1.5rem); }
h4 { font-size: 1.125rem; }

/* --- Utility ---------------------------------------------- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 5rem 0;
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent-d);
  margin-bottom: 0.75rem;
}

.section-title {
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 640px;
  margin-bottom: 3rem;
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0);
  border: 0;
}

/* --- Header / Nav ----------------------------------------- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 800;
  font-size: 1.3rem;
  color: var(--heading);
}
.logo-icon {
  width: 36px;
  height: 36px;
  background: var(--primary);
  color: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  font-size: 1.1rem;
  font-weight: 800;
}
.nav { display: flex; align-items: center; gap: 2rem; }
.nav a {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--body);
  padding: 0.35rem 0;
  border-bottom: 2px solid transparent;
  transition: border-color .2s, color .2s;
}
.nav a:hover { color: var(--accent-d); border-bottom-color: var(--accent); }
.nav-cta {
  background: var(--accent);
  color: #ffffff !important;
  padding: 0.45rem 1.2rem !important;
  border-radius: var(--radius);
  transition: background .2s !important;
  border-bottom: none !important;
}
.nav-cta:hover { background: var(--accent-d); }

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.menu-toggle span {
  display: block;
  width: 24px;
  height: 2.5px;
  background: var(--heading);
  border-radius: 2px;
}

/* --- Hero ------------------------------------------------- */
.hero {
  position: relative;
  overflow: hidden;
  background: var(--surface);
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(135deg, var(--primary) 0%, var(--primary-d) 100%);
  clip-path: polygon(0 0, 100% 0, 100% 78%, 0 92%);
  z-index: 0;
}
.hero-bg-accent {
  position: absolute;
  top: 12%;
  right: 8%;
  width: 200px;
  height: 200px;
  border: 3px solid var(--accent);
  border-radius: 50%;
  opacity: .25;
  z-index: 0;
}
.hero .container {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  padding-top: 5rem;
  padding-bottom: 5rem;
}
.hero-content { color: #ffffff; }
.hero-content .hero-badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent-l);
  background: rgba(255,255,255,.1);
  padding: 0.35rem 1rem;
  border-radius: 100px;
  margin-bottom: 1.25rem;
}
.hero-content h1 {
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  color: #ffffff;
  margin-bottom: 1.25rem;
  line-height: 1.15;
}
.hero-content h1 span { color: var(--accent-l); }
.hero-content p {
  font-size: 1.15rem;
  color: #e2e8f0;
  margin-bottom: 2rem;
  max-width: 520px;
  line-height: 1.75;
}
.hero-buttons { display: flex; gap: 1rem; flex-wrap: wrap; }
.btn { display: inline-flex; align-items: center; gap: 0.4rem; font-size: 0.95rem; font-weight: 600; padding: 0.7rem 1.6rem; border-radius: var(--radius); cursor: pointer; border: none; transition: background .2s, transform .15s; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: #ffffff; }
.btn-primary:hover { background: var(--accent-d); color: #ffffff; }
.btn-outline { background: transparent; color: #ffffff; border: 2px solid rgba(255,255,255,.4); }
.btn-outline:hover { border-color: #ffffff; color: #ffffff; }
.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}
.hero-card {
  background: var(--surface);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 20px 50px rgba(0,0,0,.15);
  width: 100%;
  max-width: 420px;
}
.hero-card-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; margin-bottom: 1.5rem; }
.hero-stat-value { font-size: 1.8rem; font-weight: 800; color: var(--heading); }
.hero-stat-label { font-size: 0.8rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.06em; }
.hero-card-bar {
  height: 8px;
  background: var(--border);
  border-radius: 4px;
  margin-bottom: 0.5rem;
  overflow: hidden;
}
.hero-card-bar-fill { height: 100%; width: 94%; background: var(--accent); border-radius: 4px; }
.hero-card-bar2 .hero-card-bar-fill { width: 88%; background: var(--primary); }
.hero-card-row { display: flex; justify-content: space-between; font-size: 0.8rem; color: var(--muted); margin-bottom: 1.5rem; }
.hero-card-icon-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0.75rem; }
.hero-card-icon-item {
  aspect-ratio: 1;
  background: var(--bg);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  color: var(--primary);
}

/* --- About ------------------------------------------------ */
.about {
  background: var(--surface);
}
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}
.about-image-wrap {
  position: relative;
}
.about-image {
  width: 100%;
  border-radius: 12px;
  box-shadow: var(--shadow-md);
}
.about-accent-box {
  position: absolute;
  bottom: -20px;
  right: -20px;
  background: var(--accent);
  color: #ffffff;
  padding: 1.25rem 1.5rem;
  border-radius: 10px;
  font-weight: 700;
  font-size: 0.95rem;
  text-align: center;
  box-shadow: var(--shadow-md);
}
.about-text .about-highlight {
  color: var(--accent-d);
  font-weight: 700;
}
.about-text p {
  margin-bottom: 1.25rem;
  font-size: 1.05rem;
  color: var(--body);
}
.about-stats { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1.5rem; margin-top: 2rem; }
.about-stat h4 { font-size: 1.6rem; color: var(--accent-d); }
.about-stat p { font-size: 0.85rem; color: var(--muted); margin-bottom: 0; }

/* --- Services --------------------------------------------- */
.services { background: var(--bg); }
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.service-card {
  background: var(--surface);
  border-radius: 10px;
  padding: 2rem;
  border: 1px solid var(--border);
  transition: box-shadow .25s, transform .25s;
}
.service-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}
.service-icon {
  width: 52px;
  height: 52px;
  background: var(--bg);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  color: var(--accent);
  margin-bottom: 1.25rem;
}
.service-card h3 { margin-bottom: 0.75rem; color: var(--heading); }
.service-card p { font-size: 0.95rem; color: var(--body); margin-bottom: 1rem; }
.service-tags { display: flex; flex-wrap: wrap; gap: 0.35rem; }
.service-tag {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--primary);
  background: var(--bg);
  padding: 0.2rem 0.6rem;
  border-radius: 100px;
}

/* --- Industries ------------------------------------------- */
.industries { background: var(--surface); }
.industries-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}
.industry-card {
  background: var(--bg);
  border-radius: 10px;
  padding: 1.75rem 1.5rem;
  text-align: center;
  border: 1px solid var(--border);
  transition: box-shadow .25s, border-color .25s;
}
.industry-card:hover { box-shadow: var(--shadow-md); border-color: var(--accent); }
.industry-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
  color: var(--primary);
}
.industry-card h4 { margin-bottom: 0.4rem; color: var(--heading); }
.industry-card p { font-size: 0.85rem; color: var(--muted); }

/* --- Process ---------------------------------------------- */
.process { background: var(--bg); }
.process-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}
.process-card {
  background: var(--surface);
  border-radius: 10px;
  padding: 2rem;
  border: 1px solid var(--border);
  position: relative;
}
.process-number {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--accent);
  opacity: .2;
  position: absolute;
  top: 1rem;
  right: 1.5rem;
  line-height: 1;
}
.process-card h3 { margin-bottom: 0.75rem; color: var(--heading); }
.process-card p { font-size: 0.95rem; color: var(--body); }

/* --- Capabilities ----------------------------------------- */
.capabilities { background: var(--surface); }
.capabilities-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1rem;
}
.capability-item {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 1rem;
  text-align: center;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--body);
  border: 1px solid var(--border);
  transition: border-color .2s, color .2s;
}
.capability-item:hover {
  border-color: var(--accent);
  color: var(--accent-d);
}
.capability-icon {
  display: block;
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--primary);
}

/* --- Why Ya Zheng ----------------------------------------- */
.why-us { background: var(--bg); }
.why-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.why-card {
  background: var(--surface);
  border-radius: 10px;
  padding: 2rem;
  border: 1px solid var(--border);
}
.why-card .why-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 0.5rem;
}
.why-card h3 { margin-bottom: 0.75rem; }
.why-card p { font-size: 0.95rem; color: var(--body); }

/* --- Contact ---------------------------------------------- */
.contact { background: var(--surface); }
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}
.contact-info h3 { margin-bottom: 0.5rem; }
.contact-info p { color: var(--muted); margin-bottom: 1.5rem; }
.contact-detail {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.25rem;
  align-items: flex-start;
}
.contact-detail-icon {
  width: 44px;
  height: 44px;
  background: var(--bg);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  color: var(--accent);
  flex-shrink: 0;
}
.contact-detail-text h4 { margin-bottom: 0.2rem; color: var(--heading); }
.contact-detail-text p { font-size: 0.95rem; color: var(--body); margin-bottom: 0; }
.contact-form-wrap {
  background: var(--bg);
  border-radius: 12px;
  padding: 2.5rem;
  border: 1px solid var(--border);
}
.contact-form { display: grid; gap: 1rem; }
.form-group { display: flex; flex-direction: column; gap: 0.3rem; }
.form-group label { font-size: 0.85rem; font-weight: 600; color: var(--heading); }
.form-group input,
.form-group select,
.form-group textarea {
  padding: 0.65rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--body);
  background: var(--surface);
  transition: border-color .2s;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-submit { margin-top: 0.5rem; }

/* --- CTA -------------------------------------------------- */
.cta {
  background: var(--primary);
  color: #ffffff;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 300px;
  height: 300px;
  border: 2px solid var(--accent);
  border-radius: 50%;
  opacity: .15;
}
.cta .container { position: relative; z-index: 1; }
.cta h2 { color: #ffffff; margin-bottom: 0.75rem; }
.cta p {
  font-size: 1.1rem;
  color: #e2e8f0;
  max-width: 560px;
  margin: 0 auto 2rem;
}
.cta .btn-primary { background: var(--accent); color: #ffffff; font-size: 1rem; padding: 0.85rem 2.2rem; }
.cta .btn-primary:hover { background: var(--accent-d); }

/* --- Footer ----------------------------------------------- */
.footer {
  background: var(--heading);
  color: #cbd5e1;
  padding: 4rem 0 2rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}
.footer-brand .logo { color: #ffffff; margin-bottom: 1rem; }
.footer-brand p {
  font-size: 0.9rem;
  color: #94a3b8;
  line-height: 1.7;
}
.footer-col h4 {
  color: #ffffff;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 1.25rem;
}
.footer-col a {
  display: block;
  font-size: 0.9rem;
  color: #94a3b8;
  margin-bottom: 0.6rem;
  transition: color .2s;
}
.footer-col a:hover { color: var(--accent-l); }
.footer-bottom {
  border-top: 1px solid #334155;
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.85rem;
  color: #64748b;
}

/* --- Legal Pages ------------------------------------------ */
.legal-page { background: var(--surface); min-height: calc(100vh - 64px - 350px); }
.legal-page .container { max-width: 800px; padding-top: 3rem; padding-bottom: 4rem; }
.legal-page h1 { margin-bottom: 2rem; }
.legal-page h2 { font-size: 1.3rem; margin-top: 2.5rem; margin-bottom: 0.75rem; }
.legal-page p { margin-bottom: 1rem; font-size: 1.05rem; color: var(--body); }
.legal-page ul { margin-bottom: 1rem; padding-left: 1.5rem; }
.legal-page li { margin-bottom: 0.5rem; font-size: 1.05rem; }
.legal-updated { color: var(--muted); font-size: 0.9rem; margin-bottom: 2rem; }

/* --- Mobile Nav State ------------------------------------- */
.nav.open { display: flex; }

/* --- Responsive ------------------------------------------- */
@media (max-width: 1024px) {
  .services-grid { grid-template-columns: repeat(2, 1fr); }
  .industries-grid { grid-template-columns: repeat(3, 1fr); }
  .capabilities-grid { grid-template-columns: repeat(4, 1fr); }
  .hero .container { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
  .about-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .nav {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1.5rem;
    gap: 1rem;
  }
  .menu-toggle { display: flex; }
  .services-grid { grid-template-columns: 1fr; }
  .industries-grid { grid-template-columns: repeat(2, 1fr); }
  .process-grid { grid-template-columns: repeat(2, 1fr); }
  .capabilities-grid { grid-template-columns: repeat(3, 1fr); }
  .why-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: 1fr; }
  .section { padding: 3rem 0; }
}

@media (max-width: 480px) {
  .industries-grid { grid-template-columns: 1fr; }
  .capabilities-grid { grid-template-columns: repeat(2, 1fr); }
  .process-grid { grid-template-columns: 1fr; }
}