/* ============================================
   云梦智能 - Enterprise Website Styles
   Apple-inspired: minimal whitespace, precise typography, subtle motion
   ============================================ */

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

:root {
  --color-bg: #fafafa;
  --color-bg-dark: #0a0a0a;
  --color-bg-elevated: #ffffff;
  --color-text-primary: #1d1d1f;
  --color-text-secondary: #6e6e73;
  --color-text-on-dark: #f5f5f7;
  --color-text-on-dark-secondary: #a1a1a6;
  --color-accent: #0071e3;
  --color-accent-hover: #0077ED;
  --color-border: #d2d2d7;
  --color-border-light: #e8e8ed;
  --color-surface: #f5f5f7;
  --color-card-shadow: rgba(0, 0, 0, 0.04);
  --font-stack: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  --max-width: 1120px;
  --nav-height: 48px;
  --section-padding: 120px;
  --transition-smooth: cubic-bezier(0.25, 0.1, 0.25, 1);
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-stack);
  font-size: 17px;
  line-height: 1.47059;
  color: var(--color-text-primary);
  background: var(--color-bg);
  overflow-x: hidden;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: opacity 0.2s var(--transition-smooth);
}

a:hover {
  opacity: 0.8;
}

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

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  letter-spacing: -0.022em;
}

.eyebrow {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: 8px;
}

.section-headline {
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.07143;
  font-weight: 700;
  letter-spacing: -0.04em;
}

.section-subhead {
  font-size: clamp(19px, 2.5vw, 28px);
  line-height: 1.21053;
  font-weight: 500;
  letter-spacing: -0.021em;
  color: var(--color-text-secondary);
  margin-top: 16px;
}

.section-copy {
  font-size: 17px;
  line-height: 1.64706;
  color: var(--color-text-secondary);
  max-width: 680px;
}

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

.section {
  padding: var(--section-padding) 0;
}

.section--dark {
  background: var(--color-bg-dark);
  color: var(--color-text-on-dark);
}

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

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  background: rgba(250, 250, 250, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--color-border-light);
  transition: background 0.3s var(--transition-smooth);
}

.nav--dark {
  background: rgba(10, 10, 10, 0.8);
  border-bottom-color: rgba(255, 255, 255, 0.08);
}

.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__logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 16px;
  font-weight: 600;
  color: var(--color-text-primary);
  text-decoration: none;
}

.nav__logo img {
  height: 28px;
  width: auto;
}

.nav--dark .nav__logo {
  color: var(--color-text-on-dark);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav__link {
  font-size: 13px;
  font-weight: 400;
  color: var(--color-text-primary);
  text-decoration: none;
  transition: color 0.2s var(--transition-smooth);
}

.nav__link:hover {
  color: var(--color-accent);
  opacity: 1;
}

.nav--dark .nav__link {
  color: var(--color-text-on-dark-secondary);
}

.nav--dark .nav__link:hover {
  color: var(--color-text-on-dark);
}

.nav__cta {
  font-size: 13px;
  font-weight: 500;
  color: #fff;
  background: var(--color-accent);
  padding: 7px 16px;
  border-radius: 980px;
  text-decoration: none;
  transition: background 0.2s var(--transition-smooth);
}

.nav__cta:hover {
  background: var(--color-accent-hover);
  opacity: 1;
}

.nav__toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav__toggle span {
  display: block;
  width: 18px;
  height: 1.5px;
  background: var(--color-text-primary);
  margin: 4px 0;
  transition: all 0.3s var(--transition-smooth);
}

.nav--dark .nav__toggle span {
  background: var(--color-text-on-dark);
}

/* --- Hero --- */
.hero {
  padding-top: calc(var(--nav-height) + 80px);
  padding-bottom: 100px;
  text-align: center;
  background: var(--color-bg-dark);
  color: var(--color-text-on-dark);
  position: relative;
  overflow: hidden;
}

.hero__eyebrow {
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text-on-dark-secondary);
  margin-bottom: 16px;
}

.hero__headline {
  font-size: clamp(36px, 6vw, 72px);
  line-height: 1.05;
  font-weight: 700;
  letter-spacing: -0.04em;
  max-width: 900px;
  margin: 0 auto 24px;
  background: linear-gradient(135deg, #f5f5f7 0%, #a1a1a6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subhead {
  font-size: clamp(17px, 2vw, 21px);
  line-height: 1.47059;
  color: var(--color-text-on-dark-secondary);
  max-width: 680px;
  margin: 0 auto 40px;
}

.hero__actions {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 17px;
  font-weight: 500;
  padding: 14px 28px;
  border-radius: 980px;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s var(--transition-smooth);
  min-width: 160px;
}

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

.btn--primary:hover {
  background: var(--color-accent-hover);
  opacity: 1;
}

.btn--secondary {
  background: transparent;
  color: var(--color-accent);
  border: 1.5px solid rgba(255, 255, 255, 0.2);
}

.btn--secondary:hover {
  border-color: var(--color-accent);
  opacity: 1;
}

.btn--dark-outline {
  background: transparent;
  color: var(--color-text-primary);
  border: 1.5px solid var(--color-border);
}

.btn--dark-outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  opacity: 1;
}

.btn--small {
  font-size: 14px;
  padding: 10px 20px;
  min-width: auto;
}

/* --- Stats Bar --- */
.stats-bar {
  background: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border-light);
  padding: 48px 0;
}

.stats-bar__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  text-align: center;
}

.stat-item__number {
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 700;
  letter-spacing: -0.04em;
  color: var(--color-text-primary);
  line-height: 1;
}

.stat-item__label {
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-top: 8px;
}

.stat-item__divider {
  width: 32px;
  height: 1px;
  background: var(--color-border);
  margin: 12px auto 0;
}

/* --- Feature Cards --- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 64px;
}

.feature-card {
  background: var(--color-bg-elevated);
  border-radius: 20px;
  padding: 40px 32px;
  transition: transform 0.4s var(--transition-smooth), box-shadow 0.4s var(--transition-smooth);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px var(--color-card-shadow);
}

.feature-card__icon {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 22px;
}

.feature-card__title {
  font-size: 21px;
  font-weight: 600;
  letter-spacing: -0.021em;
  margin-bottom: 10px;
}

.feature-card__copy {
  font-size: 15px;
  line-height: 1.5;
  color: var(--color-text-secondary);
}

/* --- Standardization Section --- */
.standard-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 64px;
}

.standard-card {
  padding: 40px 32px;
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  transition: background 0.3s var(--transition-smooth);
}

.standard-card:hover {
  background: rgba(255, 255, 255, 0.06);
}

.standard-card__number {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-text-on-dark-secondary);
  letter-spacing: 0.04em;
  margin-bottom: 16px;
}

.standard-card__title {
  font-size: 21px;
  font-weight: 600;
  letter-spacing: -0.021em;
  margin-bottom: 12px;
  color: var(--color-text-on-dark);
}

.standard-card__copy {
  font-size: 15px;
  line-height: 1.5;
  color: var(--color-text-on-dark-secondary);
}

/* --- Partners --- */
.partners {
  padding: 80px 0;
  text-align: center;
}

.partners__logos {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 64px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.partners__logo {
  height: 40px;
  width: auto;
  opacity: 0.7;
  transition: opacity 0.3s var(--transition-smooth);
}

.partners__logo:hover {
  opacity: 1;
}

/* --- CTA Section --- */
.cta-section {
  text-align: center;
  padding: 120px 0;
  background: var(--color-bg-dark);
  color: var(--color-text-on-dark);
}

.cta-section__headline {
  font-size: clamp(28px, 4vw, 48px);
  font-weight: 700;
  letter-spacing: -0.04em;
  margin-bottom: 16px;
}

.cta-section__copy {
  font-size: 19px;
  color: var(--color-text-on-dark-secondary);
  margin-bottom: 32px;
}

/* --- Footer --- */
.footer {
  background: var(--color-surface);
  padding: 48px 0 32px;
  border-top: 1px solid var(--color-border-light);
}

.footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 40px;
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text-primary);
}

.footer__brand img {
  height: 24px;
  width: auto;
}

.footer__nav {
  display: flex;
  gap: 48px;
}

.footer__col-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 12px;
}

.footer__col-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer__col-links a {
  font-size: 13px;
  color: var(--color-text-secondary);
  text-decoration: none;
}

.footer__col-links a:hover {
  color: var(--color-text-primary);
  opacity: 1;
}

.footer__bottom {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--color-border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer__copyright {
  font-size: 12px;
  color: var(--color-text-secondary);
}

.footer__legal {
  font-size: 12px;
  color: var(--color-text-secondary);
}

/* --- Scroll Animations --- */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s var(--transition-smooth), transform 0.8s var(--transition-smooth);
}

.animate-on-scroll.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.animate-on-scroll.delay-1 { transition-delay: 0.1s; }
.animate-on-scroll.delay-2 { transition-delay: 0.2s; }
.animate-on-scroll.delay-3 { transition-delay: 0.3s; }
.animate-on-scroll.delay-4 { transition-delay: 0.4s; }
.animate-on-scroll.delay-5 { transition-delay: 0.5s; }

/* --- Mobile Navigation --- */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(250, 250, 250, 0.98);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  z-index: 999;
  padding: 40px 24px;
  opacity: 0;
  transform: translateY(-10px);
  transition: opacity 0.3s var(--transition-smooth), transform 0.3s var(--transition-smooth);
  pointer-events: none;
}

.mobile-menu.is-open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.mobile-menu__links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.mobile-menu__link {
  font-size: 28px;
  font-weight: 600;
  color: var(--color-text-primary);
  text-decoration: none;
  letter-spacing: -0.021em;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  :root {
    --section-padding: 80px;
  }

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

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

  .nav__links {
    display: none;
  }

  .nav__cta {
    display: none;
  }

  .nav__toggle {
    display: block;
  }

  .mobile-menu {
    display: block;
  }

  .hero {
    padding-top: calc(var(--nav-height) + 48px);
    padding-bottom: 64px;
  }

  .hero__headline {
    font-size: clamp(28px, 8vw, 40px);
  }

  .hero__subhead {
    font-size: 17px;
  }

  .hero__actions {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 280px;
  }

  .stats-bar__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }

  .features-grid,
  .standard-grid {
    grid-template-columns: 1fr;
    margin-top: 40px;
  }

  .feature-card,
  .standard-card {
    padding: 32px 24px;
  }

  .partners__logos {
    gap: 32px;
  }

  .footer__inner {
    flex-direction: column;
  }

  .footer__nav {
    flex-direction: column;
    gap: 32px;
  }

  .footer__bottom {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .stats-bar__grid {
    grid-template-columns: 1fr;
  }

  .section-headline {
    font-size: 28px;
  }

  .section-subhead {
    font-size: 17px;
  }
}