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

:root {
  --bg: #ffffff;
  --bg-secondary: #f7f7f5;
  --bg-tertiary: #f1f1ef;
  --text-primary: #37352f;
  --text-secondary: #787774;
  --text-tertiary: #9b9a97;
  --border: #e9e9e7;
  --border-strong: #d4d4d2;
  --accent: #2383e2;
  --accent-hover: #1b6ec2;
  --accent-light: #e8f0fe;
  --white: #ffffff;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.08);
  --radius: 6px;
  --radius-lg: 10px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
  --max-width: 1100px;
  --nav-height: 56px;
}

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

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

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}

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

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

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
}

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

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 15px;
}

.nav-brand:hover {
  color: var(--text-primary);
}

.nav-logo {
  height: 28px;
  width: auto;
}

.nav-brand-text {
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-link {
  padding: 6px 12px;
  font-size: 14px;
  color: var(--text-secondary);
  border-radius: var(--radius);
  transition: all 0.15s ease;
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-secondary);
}

.nav-link.active {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

.nav-cta {
  background: var(--accent);
  color: var(--white) !important;
  margin-left: 8px;
}

.nav-cta:hover {
  background: var(--accent-hover);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
  transition: all 0.2s ease;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 500;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all 0.15s ease;
  text-decoration: none;
  line-height: 1.4;
}

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

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

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-ghost {
  background: transparent;
  color: var(--accent);
}

.btn-ghost:hover {
  background: var(--accent-light);
}

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

.btn-white:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.btn-full {
  width: 100%;
}

.btn-large {
  padding: 14px 32px;
  font-size: 16px;
}

/* ===== Hero ===== */
.hero {
  padding-top: calc(var(--nav-height) + 64px);
  padding-bottom: 48px;
  border-bottom: 1px solid var(--border);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.hero-badge {
  display: inline-block;
  padding: 4px 12px;
  font-size: 13px;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-light);
  border-radius: 100px;
  margin-bottom: 16px;
}

.hero-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.025em;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.hero-desc {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 28px;
  max-width: 520px;
}

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

.hero-visual {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--bg-secondary);
}

.hero-image {
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* ===== Stats Bar ===== */
.stats-bar {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: 32px 0;
}

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

.stat-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat-number {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.stat-label {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ===== Sections ===== */
.section {
  padding: 80px 0;
}

.section-light {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 48px;
}

.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 12px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.section-actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 32px;
}

/* ===== Pillars (Who is Yunmeng) ===== */
.pillars-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.pillar-card {
  padding: 24px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: all 0.2s ease;
}

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

.pillar-icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  border-radius: var(--radius);
  margin-bottom: 16px;
  color: var(--text-secondary);
}

.pillar-card h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.pillar-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== Capabilities ===== */
.capabilities-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.capability-card {
  padding: 28px;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid transparent;
  transition: all 0.2s ease;
}

.capability-card:hover {
  background: var(--bg);
  border-color: var(--border);
  box-shadow: var(--shadow-md);
}

.capability-number {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
  margin-bottom: 12px;
}

.capability-card h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.capability-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

.capabilities-grid .capability-card:nth-child(4),
.capabilities-grid .capability-card:nth-child(5) {
  grid-column: span 1;
}

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

/* ===== Standard ===== */
.standard-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.standard-card {
  padding: 32px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  text-align: center;
}

.standard-icon {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  color: var(--text-primary);
}

.standard-card h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.standard-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ===== Products ===== */
.products-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.product-card {
  padding: 32px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  position: relative;
}

.product-highlight {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.product-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  padding: 3px 10px;
  font-size: 12px;
  font-weight: 600;
  background: var(--accent);
  color: var(--white);
  border-radius: 100px;
}

.product-header h3 {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 6px;
}

.product-subtitle {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.product-features {
  list-style: none;
  margin-bottom: 28px;
}

.product-features li {
  padding: 8px 0;
  font-size: 14px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.product-features li:last-child {
  border-bottom: none;
}

.product-features li::before {
  content: "";
  display: inline-block;
  width: 5px;
  height: 5px;
  background: var(--accent);
  border-radius: 50%;
  margin-top: 8px;
  flex-shrink: 0;
}

.product-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

/* ===== Partners ===== */
.partners-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.partner-card {
  padding: 32px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  text-align: center;
}

.partner-logo {
  height: 40px;
  width: auto;
  margin: 0 auto 20px;
  opacity: 0.85;
}

.partner-card h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 12px;
}

.partner-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ===== About ===== */
.about-content {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 48px;
  margin-bottom: 64px;
}

.about-text p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 16px;
}

.about-text p:last-child {
  margin-bottom: 0;
}

.about-stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.about-stat {
  padding: 20px;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  text-align: center;
  border: 1px solid var(--border);
}

.about-stat-number {
  display: block;
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.about-stat-label {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ===== Timeline ===== */
.timeline {
  margin-bottom: 64px;
}

.timeline-title {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 32px;
  text-align: center;
}

.timeline-items {
  position: relative;
  padding-left: 32px;
}

.timeline-items::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--border-strong);
}

.timeline-item {
  position: relative;
  padding-bottom: 24px;
  display: flex;
  gap: 20px;
  align-items: baseline;
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 8px;
  width: 9px;
  height: 9px;
  background: var(--bg);
  border: 2px solid var(--border-strong);
  border-radius: 50%;
}

.timeline-year {
  font-size: 14px;
  font-weight: 600;
  font-family: var(--font-mono);
  color: var(--text-tertiary);
  min-width: 52px;
  flex-shrink: 0;
}

.timeline-item p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ===== Team ===== */
.team-section {
  margin-bottom: 0;
}

.team-title {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 32px;
  text-align: center;
}

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

.team-card {
  text-align: center;
  padding: 24px 16px;
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}

.team-photo {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 12px;
  background: var(--bg-tertiary);
}

.team-card h4 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 4px;
}

.team-role {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ===== CTA ===== */
.cta-section {
  padding: 80px 0;
  background: var(--text-primary);
  color: var(--white);
  text-align: center;
}

.cta-content {
  max-width: 560px;
  margin: 0 auto;
}

.cta-title {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.cta-desc {
  font-size: 16px;
  color: rgba(255,255,255,0.7);
  margin-bottom: 32px;
}

.cta-actions {
  margin-bottom: 32px;
}

.cta-qr {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.qr-image {
  width: 120px;
  height: 120px;
  border-radius: var(--radius);
  background: var(--white);
  padding: 8px;
}

.qr-label {
  font-size: 13px;
  color: rgba(255,255,255,0.6);
}

/* ===== Footer ===== */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand .footer-logo {
  height: 28px;
  width: auto;
  margin-bottom: 12px;
}

.footer-brand p {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

.footer-desc {
  font-size: 13px !important;
  color: var(--text-tertiary) !important;
}

.footer-links h4 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.footer-links a,
.footer-links p {
  display: block;
  font-size: 14px;
  color: var(--text-secondary);
  padding: 4px 0;
}

.footer-links a:hover {
  color: var(--text-primary);
}

.footer-qr {
  width: 80px;
  height: 80px;
  margin-top: 8px;
  border-radius: var(--radius);
}

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

.footer-bottom p {
  font-size: 13px;
  color: var(--text-tertiary);
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-visual {
    order: -1;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }

  .pillars-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .capabilities-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .standard-grid {
    grid-template-columns: 1fr;
  }

  .products-grid {
    grid-template-columns: 1fr;
  }

  .partners-grid {
    grid-template-columns: 1fr;
  }

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

  .about-stats {
    grid-template-columns: repeat(2, 1fr);
  }

  .team-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
  }
}

@media (max-width: 640px) {
  :root {
    --nav-height: 52px;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--white);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all 0.2s ease;
  }

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

  .nav-link {
    width: 100%;
    padding: 10px 12px;
  }

  .nav-cta {
    margin-left: 0;
    margin-top: 8px;
    text-align: center;
  }

  .hero {
    padding-top: calc(var(--nav-height) + 40px);
    padding-bottom: 32px;
  }

  .hero-title {
    font-size: 24px;
  }

  .hero-desc {
    font-size: 15px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .hero-actions .btn {
    width: 100%;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }

  .stat-number {
    font-size: 22px;
  }

  .section {
    padding: 48px 0;
  }

  .section-header {
    margin-bottom: 32px;
  }

  .pillars-grid {
    grid-template-columns: 1fr;
  }

  .capabilities-grid {
    grid-template-columns: 1fr;
  }

  .products-grid {
    grid-template-columns: 1fr;
  }

  .team-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .cta-section {
    padding: 48px 0;
  }

  .cta-title {
    font-size: 22px;
  }
}

/* ===== Animations ===== */
@media (prefers-reduced-motion: no-preference) {
  .pillar-card,
  .capability-card,
  .standard-card,
  .product-card,
  .partner-card,
  .team-card {
    transition: transform 0.2s ease, box-shadow 0.2s ease;
  }

  .pillar-card:hover,
  .capability-card:hover,
  .standard-card:hover,
  .product-card:hover,
  .partner-card:hover {
    transform: translateY(-2px);
  }
}