/* ============================================================
   Li Yang Studio — Main Stylesheet
   Cool Gray + Electric Teal | Clean, Modern, Tech-Forward
   ============================================================ */

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

:root {
  /* Primary */
  --teal: #0d9488;
  --teal-dark: #0f766e;
  --teal-light: #14b8a6;
  --teal-subtle: #ccfbf1;
  --teal-ghost: #f0fdfa;

  /* Neutral */
  --gray: #64748b;
  --gray-dark: #475569;
  --gray-light: #94a3b8;

  /* Backgrounds */
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-alt: #f1f5f9;

  /* Text */
  --heading: #0f172a;
  --body: #334155;
  --body-light: #64748b;
  --text-on-dark: #e2e8f0;

  /* Borders */
  --border: #e2e8f0;
  --border-light: #f1f5f9;

  /* Spacing */
  --section-pad: 100px;
  --container-max: 1200px;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.05);

  /* Radii */
  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Transitions */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --transition: 200ms var(--ease);
  --transition-slow: 350ms var(--ease);
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

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

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  color: var(--heading);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2.5rem, 5vw, 3.75rem); }
h2 { font-size: clamp(2rem, 4vw, 2.75rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.5rem); }
h4 { font-size: 1rem; }

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

a:hover {
  color: var(--teal-dark);
}

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

/* ---------- Container ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Section Shared ---------- */
section {
  padding: var(--section-pad) 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 64px;
}

.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--teal);
  background: var(--teal-ghost);
  padding: 6px 16px;
  border-radius: 100px;
  margin-bottom: 16px;
}

.section-title {
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 18px;
  color: var(--body-light);
  line-height: 1.6;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 600;
  padding: 14px 28px;
  border-radius: var(--radius);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background: var(--teal);
  color: #ffffff;
  border-color: var(--teal);
}

.btn-primary:hover {
  background: var(--teal-dark);
  border-color: var(--teal-dark);
  color: #ffffff;
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  background: transparent;
  color: var(--teal);
  border-color: var(--teal);
}

.btn-outline:hover {
  background: var(--teal);
  color: #ffffff;
  transform: translateY(-1px);
}

.btn-white {
  background: #ffffff;
  color: var(--teal);
  border-color: #ffffff;
}

.btn-white:hover {
  background: var(--teal-ghost);
  color: var(--teal);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-outline-white {
  background: transparent;
  color: #ffffff;
  border-color: #ffffff;
}

.btn-outline-white:hover {
  background: #ffffff;
  color: var(--teal);
  transform: translateY(-1px);
}

.btn-full {
  width: 100%;
}

/* ---------- Navigation ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition);
}

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

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--heading);
  font-size: 18px;
  font-weight: 500;
  letter-spacing: -0.01em;
}

.nav-logo strong {
  font-weight: 700;
  color: var(--teal);
}

.nav-logo:hover {
  color: var(--heading);
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 8px;
}

.nav-links a {
  display: block;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  color: var(--body);
  font-size: 15px;
  font-weight: 500;
  transition: all var(--transition);
}

.nav-links a:hover {
  color: var(--teal);
  background: var(--teal-ghost);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--heading);
  border-radius: 2px;
  transition: all var(--transition);
}

/* ---------- Hero ---------- */
.hero {
  padding: 160px 0 100px;
  background: linear-gradient(180deg, #ffffff 0%, var(--bg) 100%);
  overflow: hidden;
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.hero-badge {
  display: inline-block;
  font-size: 13px;
  font-weight: 500;
  color: var(--gray);
  background: var(--surface-alt);
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: 20px;
  border: 1px solid var(--border);
}

.hero-title {
  font-size: clamp(2.75rem, 5.5vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 24px;
}

.text-teal {
  color: var(--teal);
}

.hero-subtitle {
  font-size: 18px;
  color: var(--body-light);
  line-height: 1.7;
  max-width: 520px;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 56px;
}

.hero-stats {
  display: flex;
  gap: 48px;
}

.hero-stat {
  display: flex;
  flex-direction: column;
}

.hero-stat-number {
  font-size: 32px;
  font-weight: 800;
  color: var(--heading);
  letter-spacing: -0.02em;
}

.hero-stat-label {
  font-size: 14px;
  color: var(--gray);
}

/* Hero visual */
.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-graphic {
  position: relative;
  width: 400px;
  height: 300px;
}

.hero-lines {
  width: 100%;
  height: 100%;
}

.hero-lines line {
  stroke: var(--teal);
  stroke-width: 1.5;
  opacity: 0.25;
}

.hero-node {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 12px rgba(13, 148, 136, 0.4);
}

.hero-node-1 { top: 30px; left: 200px; background: var(--teal-dark); width: 14px; height: 14px; }
.hero-node-2 { top: 80px; left: 350px; }
.hero-node-3 { top: 150px; left: 100px; }
.hero-node-4 { top: 180px; left: 300px; background: var(--teal-light); width: 14px; height: 14px; }
.hero-node-5 { top: 250px; left: 50px; }
.hero-node-6 { top: 250px; left: 380px; }

/* ---------- About ---------- */
.about {
  background: var(--surface);
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.about-card {
  padding: 32px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--bg);
  transition: all var(--transition-slow);
}

.about-card:hover {
  border-color: var(--teal);
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.about-icon {
  margin-bottom: 20px;
}

.about-card h3 {
  margin-bottom: 12px;
  font-size: 18px;
}

.about-card p {
  font-size: 15px;
  color: var(--body-light);
  line-height: 1.65;
}

/* ---------- Services ---------- */
.services {
  background: var(--bg);
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.service-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px;
  transition: all var(--transition-slow);
  position: relative;
  overflow: hidden;
}

.service-card:hover {
  border-color: var(--teal);
  box-shadow: var(--shadow-xl);
  transform: translateY(-4px);
}

.service-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--teal);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-slow);
}

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

.service-number {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--teal);
  margin-bottom: 12px;
  letter-spacing: 0.05em;
}

.service-card h3 {
  margin-bottom: 16px;
  font-size: 20px;
}

.service-card > p {
  font-size: 15px;
  color: var(--body-light);
  line-height: 1.65;
  margin-bottom: 20px;
}

.service-features {
  list-style: none;
  padding: 0;
  border-top: 1px solid var(--border-light);
  padding-top: 16px;
}

.service-features li {
  font-size: 14px;
  color: var(--gray);
  padding: 5px 0;
  padding-left: 20px;
  position: relative;
}

.service-features li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 12px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--teal);
  opacity: 0.5;
}

/* ---------- Industries ---------- */
.industries {
  background: var(--surface);
}

.industries-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.industry-card {
  padding: 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border-light);
  background: var(--bg);
  transition: all var(--transition);
}

.industry-card:hover {
  border-color: var(--teal);
  box-shadow: var(--shadow-md);
}

.industry-icon {
  margin-bottom: 16px;
}

.industry-card h3 {
  font-size: 16px;
  margin-bottom: 8px;
}

.industry-card p {
  font-size: 14px;
  color: var(--body-light);
  line-height: 1.6;
}

/* ---------- Process ---------- */
.process {
  background: var(--bg);
}

.process-timeline {
  max-width: 880px;
  margin: 0 auto;
}

.process-step {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 28px;
  padding-bottom: 40px;
}

.process-step:last-child {
  padding-bottom: 0;
}

.process-marker {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.process-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--teal);
  color: #ffffff;
  font-weight: 700;
  font-size: 20px;
  flex-shrink: 0;
  box-shadow: 0 0 0 4px var(--teal-subtle);
}

.process-line {
  width: 2px;
  flex: 1;
  background: var(--border);
  margin-top: 8px;
}

.process-step:last-child .process-line {
  display: none;
}

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

.process-card:hover {
  border-color: var(--teal);
  box-shadow: var(--shadow-lg);
}

.process-phase {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--teal);
  margin-bottom: 8px;
  display: block;
}

.process-card h3 {
  font-size: 24px;
  margin-bottom: 12px;
}

.process-card > p {
  font-size: 15px;
  color: var(--body-light);
  line-height: 1.65;
  margin-bottom: 20px;
}

.process-deliverables {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  border-top: 1px solid var(--border-light);
  padding-top: 16px;
}

.process-deliverables li {
  font-size: 14px;
  color: var(--gray);
  padding-left: 18px;
  position: relative;
}

.process-deliverables li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 7px;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background: var(--teal);
  opacity: 0.4;
}

/* ---------- Capabilities ---------- */
.capabilities {
  background: var(--surface);
}

.capabilities-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.capability-group {
  padding: 28px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  background: var(--bg);
}

.capability-group h3 {
  font-size: 17px;
  color: var(--teal);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--teal-subtle);
}

.capability-list {
  list-style: none;
}

.capability-list li {
  font-size: 15px;
  color: var(--body);
  padding: 7px 0;
  padding-left: 16px;
  position: relative;
}

.capability-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 13px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--teal);
  opacity: 0.5;
}

/* ---------- Why Li Yang ---------- */
.why-us {
  background: var(--bg);
}

.why-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.why-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px;
  transition: all var(--transition-slow);
}

.why-card:hover {
  border-color: var(--teal);
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.why-number {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  color: var(--teal);
  margin-bottom: 12px;
}

.why-card h3 {
  font-size: 20px;
  margin-bottom: 12px;
}

.why-card p {
  font-size: 15px;
  color: var(--body-light);
  line-height: 1.65;
}

/* ---------- Contact ---------- */
.contact {
  background: var(--surface);
}

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 64px;
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.contact-item h4 {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--gray);
  margin-bottom: 6px;
}

.contact-item a,
.contact-item address,
.contact-item p {
  font-size: 16px;
  color: var(--body);
  font-style: normal;
  line-height: 1.6;
}

.contact-item a {
  color: var(--teal);
}

.contact-item a:hover {
  color: var(--teal-dark);
}

.contact-form {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 40px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

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

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 6px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  font-family: var(--font-sans);
  font-size: 16px;
  color: var(--body);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--teal);
  box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.12);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--gray-light);
}

.form-note {
  margin-top: 12px;
  font-size: 14px;
  color: var(--gray);
  text-align: center;
}

.form-note a {
  color: var(--teal);
  text-decoration: underline;
}

/* ---------- CTA ---------- */
.cta {
  background: linear-gradient(135deg, var(--teal-dark) 0%, var(--teal) 50%, var(--teal-light) 100%);
  padding: 80px 0;
}

.cta-content {
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
}

.cta-content h2 {
  color: #ffffff;
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  margin-bottom: 16px;
}

.cta-content p {
  color: #d8dce4;
  font-size: 18px;
  line-height: 1.6;
  margin-bottom: 32px;
}

.cta-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--heading);
  color: var(--text-on-dark);
  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: 10px;
  color: #ffffff;
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 16px;
}

.footer-logo:hover {
  color: var(--teal-light);
}

.footer-desc {
  font-size: 15px;
  color: var(--gray-light);
  line-height: 1.6;
  max-width: 320px;
}

.footer-links-group h4 {
  color: #ffffff;
  font-size: 14px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 16px;
}

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

.footer-links-group li {
  margin-bottom: 8px;
}

.footer-links-group a {
  font-size: 15px;
  color: var(--gray-light);
  transition: color var(--transition);
}

.footer-links-group a:hover {
  color: var(--teal-light);
}

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

.footer-bottom p {
  font-size: 14px;
  color: var(--gray);
}

/* ---------- Legal Pages ---------- */
.legal-hero {
  padding: 140px 0 40px;
  background: linear-gradient(180deg, #ffffff 0%, var(--bg) 100%);
  text-align: center;
}

.legal-hero h1 {
  margin-bottom: 8px;
}

.legal-date {
  font-size: 15px;
  color: var(--gray);
}

.legal-content {
  padding: 0 0 100px;
}

.legal-body {
  max-width: 800px;
  margin: 0 auto;
}

.legal-body h2 {
  font-size: 1.5rem;
  margin-top: 40px;
  margin-bottom: 16px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.legal-body h2:first-of-type {
  border-top: none;
  padding-top: 0;
  margin-top: 0;
}

.legal-body h3 {
  font-size: 1.15rem;
  margin-top: 24px;
  margin-bottom: 10px;
  color: var(--heading);
}

.legal-body p {
  margin-bottom: 16px;
  line-height: 1.7;
}

.legal-body ul {
  margin-bottom: 16px;
  padding-left: 24px;
}

.legal-body li {
  margin-bottom: 6px;
  line-height: 1.6;
}

.legal-body strong {
  color: var(--heading);
}

/* ---------- Animations ---------- */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-up {
  animation: fadeUp 0.6s var(--ease) both;
}

/* ---------- Mobile Navigation ---------- */
@media (max-width: 1024px) {
  .about-grid { grid-template-columns: repeat(2, 1fr); }
  .services-grid { grid-template-columns: repeat(2, 1fr); }
  .industries-grid { grid-template-columns: repeat(3, 1fr); }
  .why-grid { grid-template-columns: repeat(2, 1fr); }
  .capabilities-grid { grid-template-columns: repeat(2, 1fr); }
  .hero .container { grid-template-columns: 1fr; }
  .hero-visual { display: none; }
  .contact-grid { grid-template-columns: 1fr; gap: 40px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  :root { --section-pad: 64px; }

  .nav-links {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--surface);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-slow);
  }

  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-toggle { display: flex; }

  .hero { padding: 120px 0 64px; }
  .hero-stats { gap: 24px; flex-wrap: wrap; }
  .hero-actions { flex-direction: column; }

  .about-grid { grid-template-columns: 1fr; }
  .services-grid { grid-template-columns: 1fr; }
  .industries-grid { grid-template-columns: repeat(2, 1fr); }
  .why-grid { grid-template-columns: 1fr; }
  .capabilities-grid { grid-template-columns: 1fr; }
  .process-deliverables { grid-template-columns: 1fr; }

  .form-row { grid-template-columns: 1fr; }
  .contact-form { padding: 24px; }

  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 480px) {
  .industries-grid { grid-template-columns: 1fr; }
  .cta { padding: 48px 0; }
}