/* ========================================
   KuanYou Culture - Main Stylesheet
   Modern static site for Kuanyou (Beijing)
   Cultural Exchange Co., Ltd.
   ======================================== */

/* ----- Fonts ----- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Noto+Sans+SC:wght@300;400;500;700;900&display=swap');

/* ----- CSS Custom Properties ----- */
:root {
  --color-primary: #B91C1C;
  --color-primary-dark: #991B1B;
  --color-primary-light: #EF4444;
  --color-dark: #111827;
  --color-dark-2: #1F2937;
  --color-dark-3: #374151;
  --color-light: #F9FAFB;
  --color-light-2: #F3F4F6;
  --color-white: #FFFFFF;
  --color-text: #111827;
  --color-text-secondary: #6B7280;
  --color-text-light: #9CA3AF;
  --color-border: #E5E7EB;
  --font-cn: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-en: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --max-width: 1200px;
  --header-height: 72px;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-sm: 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,.07), 0 2px 4px rgba(0,0,0,.04);
  --shadow-lg: 0 10px 25px rgba(0,0,0,.1), 0 4px 10px rgba(0,0,0,.06);
  --shadow-xl: 0 20px 40px rgba(0,0,0,.12);
  --transition: .3s cubic-bezier(.4,0,.2,1);
}

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

body {
  font-family: var(--font-cn);
  color: var(--color-text);
  line-height: 1.7;
  background: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.en body,
.en {
  font-family: var(--font-en);
}

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

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

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
}

.section-dark {
  background: var(--color-dark);
  color: var(--color-white);
}

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

.section-label {
  display: inline-block;
  font-size: .8125rem;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 12px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 16px;
  letter-spacing: -.02em;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  line-height: 1.6;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-header .section-subtitle {
  margin: 0 auto;
}

/* ----- Buttons ----- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: .9375rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: var(--transition);
  line-height: 1.4;
}

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

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: var(--color-white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background: transparent;
  color: var(--color-white);
  border: 2px solid rgba(255,255,255,.3);
}

.btn-outline:hover {
  border-color: var(--color-white);
  color: var(--color-white);
  background: rgba(255,255,255,.08);
}

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

.btn-outline-dark:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-sm {
  padding: 8px 20px;
  font-size: .875rem;
}

/* ========================================
   HEADER
   ======================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255,255,255,.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(229,231,235,.5);
  z-index: 1000;
  transition: var(--transition);
}

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

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.logo img {
  height: 34px;
  width: auto;
}

.logo-text {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-dark);
  letter-spacing: -.01em;
}

.logo-text span {
  color: var(--color-primary);
}

/* ----- Navigation ----- */
.nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav a {
  padding: 8px 16px;
  font-size: .9375rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  transition: var(--transition);
  position: relative;
}

.nav a:hover,
.nav a.active {
  color: var(--color-text);
  background: var(--color-light-2);
}

.nav a.active::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: 12px;
  padding-left: 12px;
  border-left: 1px solid var(--color-border);
}

.lang-switch a {
  padding: 4px 10px;
  font-size: .8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .03em;
  color: var(--color-text-light);
  border-radius: 4px;
}

.lang-switch a.active {
  color: var(--color-primary);
  background: rgba(185,28,28,.08);
}

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

/* ----- Mobile menu ----- */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-dark);
  border-radius: 2px;
  transition: var(--transition);
  transform-origin: center;
}

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

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

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

/* ========================================
   HERO
   ======================================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  background: linear-gradient(135deg, var(--color-dark) 0%, #1e293b 50%, var(--color-dark-2) 100%);
  overflow: hidden;
  padding-top: var(--header-height);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(185,28,28,.15) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(185,28,28,.08) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(59,130,246,.05) 0%, transparent 50%);
  pointer-events: none;
}

.hero-particles {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

.hero-particles span {
  position: absolute;
  width: 2px;
  height: 2px;
  background: rgba(255,255,255,.15);
  border-radius: 50%;
  animation: float 20s infinite;
}

.hero-particles span:nth-child(1) { top: 10%; left: 10%; animation-delay: 0s; }
.hero-particles span:nth-child(2) { top: 30%; left: 80%; animation-delay: 2s; width: 3px; height: 3px; }
.hero-particles span:nth-child(3) { top: 60%; left: 20%; animation-delay: 4s; }
.hero-particles span:nth-child(4) { top: 80%; left: 70%; animation-delay: 6s; width: 4px; height: 4px; background: rgba(185,28,28,.2); }
.hero-particles span:nth-child(5) { top: 20%; left: 50%; animation-delay: 8s; }
.hero-particles span:nth-child(6) { top: 70%; left: 40%; animation-delay: 10s; }
.hero-particles span:nth-child(7) { top: 45%; left: 90%; animation-delay: 12s; width: 3px; height: 3px; }
.hero-particles span:nth-child(8) { top: 90%; left: 15%; animation-delay: 14s; }

@keyframes float {
  0%, 100% { transform: translateY(0) translateX(0); opacity: 1; }
  25% { transform: translateY(-20px) translateX(10px); opacity: .8; }
  50% { transform: translateY(-10px) translateX(-5px); opacity: .6; }
  75% { transform: translateY(-30px) translateX(15px); opacity: .9; }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 80px 24px;
  width: 100%;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  background: rgba(185,28,28,.15);
  border: 1px solid rgba(185,28,28,.25);
  border-radius: 100px;
  font-size: .8125rem;
  font-weight: 500;
  color: rgba(255,255,255,.8);
  margin-bottom: 32px;
  letter-spacing: .03em;
}

.hero-badge-dot {
  width: 6px;
  height: 6px;
  background: var(--color-primary-light);
  border-radius: 50%;
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: .4; }
}

.hero h1 {
  font-size: clamp(2.25rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.12;
  color: var(--color-white);
  margin: 0 0 24px;
  letter-spacing: -.03em;
}

.hero h1 .highlight {
  background: linear-gradient(135deg, var(--color-primary-light), #FCA5A5);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: clamp(1.0625rem, 1.5vw, 1.25rem);
  color: rgba(255,255,255,.65);
  max-width: 600px;
  line-height: 1.7;
  margin: 0 0 40px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 80px;
  padding-top: 40px;
  border-top: 1px solid rgba(255,255,255,.1);
}

.hero-stat-value {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--color-white);
  line-height: 1;
  margin-bottom: 6px;
}

.hero-stat-value .accent {
  color: var(--color-primary-light);
}

.hero-stat-label {
  font-size: .875rem;
  color: rgba(255,255,255,.5);
}

/* ========================================
   SERVICES SECTION
   ======================================== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.service-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 40px 32px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.service-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .4s ease;
}

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

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

.service-icon {
  width: 56px;
  height: 56px;
  background: rgba(185,28,28,.08);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
}

.service-icon svg {
  width: 28px;
  height: 28px;
  color: var(--color-primary);
}

.service-card h3 {
  font-size: 1.375rem;
  font-weight: 700;
  margin: 0 0 12px;
}

.service-card p {
  font-size: .9375rem;
  color: var(--color-text-secondary);
  margin: 0 0 20px;
  line-height: 1.7;
}

.service-link {
  font-size: .875rem;
  font-weight: 600;
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.service-link:hover {
  gap: 8px;
}

/* ========================================
   FEATURED PROJECTS
   ======================================== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.project-card {
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  transition: var(--transition);
}

.project-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.project-card-image {
  position: relative;
  padding-top: 66%;
  overflow: hidden;
  background: var(--color-light-2);
}

.project-card-image img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .5s ease;
}

.project-card:hover .project-card-image img {
  transform: scale(1.05);
}

.project-card-body {
  padding: 20px 24px 24px;
}

.project-card-year {
  display: inline-block;
  padding: 2px 10px;
  background: rgba(185,28,28,.08);
  color: var(--color-primary);
  font-size: .75rem;
  font-weight: 600;
  border-radius: 4px;
  margin-bottom: 10px;
}

.project-tag {
  display: inline-block;
  padding: 2px 10px;
  background: var(--color-light-2);
  color: var(--color-text-secondary);
  font-size: .75rem;
  border-radius: 4px;
  margin-top: 8px;
}

.project-card h4 {
  font-size: 1.0625rem;
  font-weight: 700;
  margin: 0;
  line-height: 1.4;
}

.project-card p {
  font-size: .875rem;
  color: var(--color-text-secondary);
  margin: 8px 0 0;
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ========================================
   MEDIA PLATFORMS
   ======================================== */
.platforms-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.platform-card {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 24px;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.04);
  transition: var(--transition);
}

.platform-card:hover {
  background: rgba(255,255,255,.08);
  border-color: rgba(255,255,255,.2);
  transform: translateX(4px);
}

.platform-icon {
  width: 48px;
  height: 48px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(185,28,28,.15);
  border-radius: var(--radius-sm);
}

.platform-icon svg {
  width: 24px;
  height: 24px;
  color: var(--color-primary-light);
}

.platform-info h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 4px;
  color: var(--color-white);
}

.platform-info p {
  font-size: .8125rem;
  margin: 0;
  color: rgba(255,255,255,.5);
}

/* ========================================
   CTA SECTION
   ======================================== */
.cta-section {
  padding: 100px 0;
  background: linear-gradient(135deg, var(--color-dark) 0%, #1e293b 100%);
  text-align: center;
}

.cta-section h2 {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--color-white);
  margin: 0 0 16px;
}

.cta-section p {
  font-size: 1.125rem;
  color: rgba(255,255,255,.6);
  max-width: 500px;
  margin: 0 auto 32px;
}

/* ========================================
   FOOTER
   ======================================== */
.footer {
  background: var(--color-dark);
  color: var(--color-white);
  padding: 64px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,.08);
  margin-bottom: 32px;
}

.footer-brand img {
  height: 32px;
  width: auto;
  margin-bottom: 16px;
}

.footer-brand p {
  font-size: .875rem;
  color: rgba(255,255,255,.5);
  line-height: 1.7;
  max-width: 320px;
  margin: 0;
}

.footer h4 {
  font-size: .8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: rgba(255,255,255,.4);
  margin: 0 0 20px;
}

.footer ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer li {
  margin-bottom: 10px;
}

.footer a {
  font-size: .875rem;
  color: rgba(255,255,255,.65);
}

.footer a:hover {
  color: var(--color-white);
}

.footer-contact li {
  font-size: .875rem;
  color: rgba(255,255,255,.65);
  line-height: 1.6;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: .8125rem;
  color: rgba(255,255,255,.35);
}

.footer-bottom a {
  color: rgba(255,255,255,.35);
}

.footer-bottom a:hover {
  color: rgba(255,255,255,.6);
}

/* ========================================
   ABOUT PAGE
   ======================================== */
.page-hero {
  padding: calc(var(--header-height) + 80px) 0 80px;
  background: linear-gradient(135deg, var(--color-dark) 0%, #1e293b 100%);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, rgba(185,28,28,.1) 0%, transparent 70%);
  pointer-events: none;
}

.page-hero h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  color: var(--color-white);
  margin: 0 0 16px;
  position: relative;
}

.page-hero p {
  font-size: 1.125rem;
  color: rgba(255,255,255,.6);
  max-width: 600px;
  margin: 0 auto;
  position: relative;
}

/* About intro */
.about-intro {
  padding: 100px 0;
}

.about-intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.about-intro-text h2 {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 24px;
  line-height: 1.3;
}

.about-intro-text p {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin: 0 0 16px;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  padding: 40px;
  background: var(--color-light);
  border-radius: var(--radius-md);
}

.about-stat-value {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 6px;
}

.about-stat-label {
  font-size: .875rem;
  color: var(--color-text-secondary);
}

/* Timeline */
.timeline-section {
  padding: 100px 0;
  background: var(--color-light);
}

.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  display: flex;
  align-items: flex-start;
  margin-bottom: 48px;
  position: relative;
}

.timeline-item:nth-child(odd) {
  flex-direction: row-reverse;
}

.timeline-item-content {
  width: calc(50% - 40px);
  padding: 24px;
  background: var(--color-white);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  transition: var(--transition);
}

.timeline-item-content:hover {
  box-shadow: var(--shadow-md);
}

.timeline-year {
  font-size: .8125rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: .02em;
  margin-bottom: 8px;
}

.timeline-item-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 8px;
}

.timeline-item-content p {
  font-size: .875rem;
  color: var(--color-text-secondary);
  margin: 0;
  line-height: 1.6;
}

.timeline-dot {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 14px;
  height: 14px;
  background: var(--color-primary);
  border: 3px solid var(--color-white);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--color-primary);
  z-index: 1;
  margin-top: 28px;
}

/* ========================================
   SERVICES PAGE
   ======================================== */
.service-detail {
  padding: 100px 0;
}

.service-detail:not(:last-child) {
  border-bottom: 1px solid var(--color-border);
}

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

.service-detail-grid.reverse {
  direction: rtl;
}

.service-detail-grid.reverse > * {
  direction: ltr;
}

.service-detail-text h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0 0 20px;
}

.service-detail-text p {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin: 0 0 16px;
}

.service-detail-image {
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-light-2);
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-light);
  font-size: .875rem;
}

/* ========================================
   PROJECTS PAGE
   ======================================== */
.projects-page-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.projects-filter {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 20px;
  font-size: .875rem;
  font-weight: 500;
  border: 1px solid var(--color-border);
  border-radius: 100px;
  background: var(--color-white);
  cursor: pointer;
  transition: var(--transition);
  color: var(--color-text-secondary);
}

.filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.filter-btn.active {
  background: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}

/* ========================================
   CONTACT PAGE
   ======================================== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
}

.contact-info h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 0 0 32px;
}

.contact-item {
  display: flex;
  gap: 16px;
  margin-bottom: 28px;
}

.contact-item-icon {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  background: rgba(185,28,28,.08);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

.contact-item-icon svg {
  width: 20px;
  height: 20px;
  color: var(--color-primary);
}

.contact-item h4 {
  font-size: .9375rem;
  font-weight: 600;
  margin: 0 0 4px;
}

.contact-item p {
  font-size: .9375rem;
  color: var(--color-text-secondary);
  margin: 0;
  line-height: 1.5;
}

.social-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 8px;
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 44px;
  padding: 0 10px;
  border-radius: 8px;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  transition: all .3s ease;
}

.social-links a:hover {
  border-color: var(--color-primary);
  background: rgba(185,28,28,.05);
  transform: translateY(-2px);
}

.social-links a img {
  height: 28px;
  width: auto;
  display: block;
}

.social-wechat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  min-width: 44px;
  padding: 6px 10px 8px;
  border-radius: 8px;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  cursor: default;
}

.social-wechat img {
  height: 26px;
  width: auto;
  display: block;
}

.social-wechat span {
  font-size: .6875rem;
  color: var(--color-text-secondary);
  line-height: 1.2;
  white-space: nowrap;
}

/* ========================================
   TOAST NOTIFICATION
   ======================================== */
#toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  background: #333;
  color: #fff;
  padding: 14px 28px;
  border-radius: 8px;
  font-size: .9375rem;
  z-index: 9999;
  opacity: 0;
  transition: all .4s ease;
  pointer-events: none;
  white-space: nowrap;
  box-shadow: 0 4px 20px rgba(0,0,0,.25);
}

#toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ========================================
   SCROLL ANIMATIONS
   ======================================== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .6s ease, transform .6s ease;
}

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

.fade-in-delay-1 { transition-delay: .1s; }
.fade-in-delay-2 { transition-delay: .2s; }
.fade-in-delay-3 { transition-delay: .3s; }

/* ========================================
   RESPONSIVE
   ======================================== */
@media (max-width: 1024px) {
  .services-grid,
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
  .about-intro-grid {
    gap: 48px;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  .section {
    padding: 64px 0;
  }
  .section-title {
    font-size: 1.75rem;
  }
  .section-header {
    margin-bottom: 40px;
  }
  /* Mobile nav */
  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--color-white);
    flex-direction: column;
    padding: 80px 24px 24px;
    gap: 4px;
    box-shadow: var(--shadow-xl);
    transition: right .3s ease;
    align-items: stretch;
  }
  .nav.open {
    right: 0;
  }
  .nav a {
    padding: 12px 16px;
    font-size: 1rem;
  }
  .lang-switch {
    margin: 16px 0 0;
    padding: 16px 0 0;
    border-left: none;
    border-top: 1px solid var(--color-border);
  }
  .menu-toggle {
    display: flex;
  }
  /* Mobile overlay */
  .nav-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.5);
    z-index: 998;
  }
  .nav-overlay.open {
    display: block;
  }
  /* Hero */
  .hero-content {
    padding: 60px 24px;
  }
  .hero h1 {
    font-size: 2rem;
  }
  .hero-stats {
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-top: 48px;
    padding-top: 24px;
  }
  .hero-stat-value {
    font-size: 1.75rem;
  }
  .hero-stat-label {
    font-size: .75rem;
  }
  /* Grids become single column */
  .services-grid,
  .projects-grid,
  .platforms-grid,
  .about-intro-grid,
  .service-detail-grid,
  .contact-grid,
  .projects-page-grid {
    grid-template-columns: 1fr;
  }
  .service-detail-grid.reverse {
    direction: ltr;
  }
  /* Timeline */
  .timeline::before {
    left: 24px;
  }
  .timeline-item,
  .timeline-item:nth-child(odd) {
    flex-direction: row;
    padding-left: 56px;
  }
  .timeline-item-content {
    width: 100%;
  }
  .timeline-dot {
    left: 24px;
  }
  /* About */
  .about-intro {
    padding: 64px 0;
  }
  .about-stats {
    padding: 24px;
    gap: 20px;
  }
  .about-stat-value {
    font-size: 1.75rem;
  }
  /* Footer */
  .footer {
    padding: 48px 0 24px;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }
  .cta-section {
    padding: 64px 0;
  }
  .cta-section h2 {
    font-size: 1.75rem;
  }
  .hero-actions {
    flex-direction: column;
  }
  .hero-actions .btn {
    width: 100%;
    justify-content: center;
  }
}

/* ======== Peiyuan 22-Period List ======== */
.peiyuan-list {
  max-width: 800px;
  margin: 0 auto;
}
.peiyuan-item {
  display: flex;
  gap: 16px;
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
  align-items: flex-start;
}
.peiyuan-item:last-child {
  border-bottom: none;
}
.peiyuan-badge {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .8125rem;
  font-weight: 700;
  font-family: var(--font-en);
}
.peiyuan-content {
  flex: 1;
  font-size: .9375rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
}
.peiyuan-content strong {
  color: var(--color-text);
  font-weight: 600;
}
.peiyuan-works {
  font-size: .8125rem;
  color: var(--color-primary);
  font-weight: 500;
}

@media (max-width: 768px) {
  .peiyuan-item {
    gap: 12px;
    padding: 16px 0;
  }
  .peiyuan-badge {
    width: 32px;
    height: 32px;
    font-size: .75rem;
  }
  .peiyuan-content {
    font-size: .875rem;
  }
}
  .container {
    padding: 0 16px;
  }
  .project-card-image {
    padding-top: 56%;
  }
}