/* ============================================
   云梦智能官网 - Apple 风格样式表
   大留白、精确层级、柔和光感、产品级质感
   ============================================ */

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

:root {
  /* Apple-inspired color system */
  --color-bg: #fbfbfd;
  --color-bg-secondary: #f5f5f7;
  --color-surface: #ffffff;
  --color-text-primary: #1d1d1f;
  --color-text-secondary: #6e6e73;
  --color-text-tertiary: #86868b;
  --color-accent: #0071e3;
  --color-accent-hover: #0077ed;
  --color-border: #d2d2d7;
  --color-border-light: #e8e8ed;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3.5rem;
  --font-size-6xl: 4.5rem;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-5xl: 8rem;

  /* Layout */
  --max-width: 1120px;
  --header-height: 48px;

  /* Effects */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.1);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
  --transition-slow: 0.4s ease;
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

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

ul {
  list-style: none;
}

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

/* --- Header --- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(251, 251, 253, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: 1000;
}

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

.logo {
  display: flex;
  align-items: center;
  height: 28px;
}

.logo img {
  height: 100%;
  width: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav-link {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-text-primary);
}

.nav-dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  padding-top: var(--space-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: all var(--transition-fast);
}

.nav-dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu li {
  background: var(--color-surface);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-md);
  margin-bottom: 2px;
}

.dropdown-menu a {
  display: block;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  white-space: nowrap;
  transition: color var(--transition-fast);
}

.dropdown-menu a:hover {
  color: var(--color-text-primary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 30px;
  height: 30px;
  padding: 0;
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 100%;
  height: 1.5px;
  background: var(--color-text-primary);
  transition: all var(--transition-fast);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-sm) var(--space-lg);
  font-size: var(--font-size-sm);
  font-weight: 500;
  border-radius: 980px;
  transition: all var(--transition-fast);
  cursor: pointer;
  white-space: nowrap;
}

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

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

.btn-secondary {
  background: transparent;
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
}

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

.btn-text {
  background: transparent;
  color: var(--color-accent);
  padding: var(--space-sm) 0;
}

.btn-text:hover {
  text-decoration: underline;
}

.btn-large {
  padding: var(--space-md) var(--space-2xl);
  font-size: var(--font-size-base);
}

/* --- Section --- */
.section {
  padding: var(--space-5xl) 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto var(--space-4xl);
}

.section-title {
  font-size: var(--font-size-4xl);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.015em;
  color: var(--color-text-primary);
  margin-bottom: var(--space-lg);
}

.section-subtitle {
  font-size: var(--font-size-lg);
  line-height: 1.6;
  color: var(--color-text-secondary);
}

.highlight {
  color: var(--color-accent);
}

.section-actions {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  margin-top: var(--space-3xl);
}

/* --- Hero --- */
.hero {
  padding-top: calc(var(--header-height) + var(--space-5xl));
  padding-bottom: var(--space-5xl);
  background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4xl);
  align-items: center;
}

.hero-content {
  max-width: 540px;
}

.hero-title {
  font-size: var(--font-size-5xl);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  margin-bottom: var(--space-lg);
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  line-height: 1.6;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
}

.hero-actions {
  display: flex;
  gap: var(--space-md);
}

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

.hero-image {
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 480px;
}

/* --- Stats Bar --- */
.section-stats {
  padding: var(--space-4xl) 0;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border-light);
}

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

.stat-number {
  font-size: var(--font-size-4xl);
  font-weight: 600;
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-xs);
}

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

/* --- Features Grid (Module 2) --- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
}

.feature-card {
  background: var(--color-surface);
  padding: var(--space-2xl);
  border-radius: var(--radius-lg);
  text-align: center;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
}

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

.feature-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--space-lg);
  color: var(--color-accent);
}

.feature-icon svg {
  width: 100%;
  height: 100%;
}

.feature-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

.feature-desc {
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text-secondary);
}

/* --- Why Grid (Module 3) --- */
.section-why {
  background: var(--color-bg-secondary);
}

.why-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.why-card {
  background: var(--color-surface);
  padding: var(--space-2xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.why-card:hover {
  box-shadow: var(--shadow-md);
}

.why-number {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-text-tertiary);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-md);
}

.why-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

.why-desc {
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text-secondary);
}

/* --- Capability Grid (Module 4) --- */
.capability-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.capability-card {
  background: var(--color-surface);
  padding: var(--space-2xl);
  border-radius: var(--radius-lg);
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.capability-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.capability-icon {
  width: 40px;
  height: 40px;
  margin: 0 auto var(--space-lg);
  color: var(--color-accent);
}

.capability-icon svg {
  width: 100%;
  height: 100%;
}

.capability-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

.capability-desc {
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text-secondary);
}

/* --- Partners (Module 5) --- */
.section-partners {
  background: var(--color-bg-secondary);
}

.partners-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
  max-width: 880px;
  margin: 0 auto;
}

.partner-card {
  background: var(--color-surface);
  padding: var(--space-2xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.partner-card:hover {
  box-shadow: var(--shadow-md);
}

.partner-logo {
  height: 48px;
  margin-bottom: var(--space-lg);
  display: flex;
  align-items: center;
}

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

.partner-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

.partner-desc {
  font-size: var(--font-size-sm);
  line-height: 1.6;
  color: var(--color-text-secondary);
}

/* --- CTA (Module 6) --- */
.section-cta {
  background: linear-gradient(180deg, var(--color-bg-secondary) 0%, var(--color-bg) 100%);
  padding: var(--space-5xl) 0;
}

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

.cta-title {
  font-size: var(--font-size-4xl);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.015em;
  margin-bottom: var(--space-md);
  color: var(--color-text-primary);
}

.cta-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
}

/* --- Footer --- */
.footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border-light);
  padding: var(--space-4xl) 0 var(--space-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-3xl);
  margin-bottom: var(--space-3xl);
}

.footer-logo {
  height: 32px;
  margin-bottom: var(--space-sm);
}

.footer-brand-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.footer-nav-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
}

.footer-nav-list li {
  margin-bottom: var(--space-xs);
}

.footer-nav-list a {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

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

.footer-contact-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.footer-qr {
  width: 100px;
  height: 100px;
  border-radius: var(--radius-sm);
}

.footer-bottom {
  padding-top: var(--space-xl);
  border-top: 1px solid var(--color-border-light);
}

.footer-copyright {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  text-align: center;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  :root {
    --font-size-5xl: 2.75rem;
    --font-size-4xl: 2rem;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    max-width: 100%;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .hero-image {
    max-width: 360px;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
  }

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

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

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

@media (max-width: 768px) {
  :root {
    --font-size-5xl: 2.25rem;
    --font-size-4xl: 1.75rem;
    --space-5xl: 5rem;
    --space-4xl: 3.5rem;
  }

  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(251, 251, 253, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: var(--space-xl);
    transform: translateX(100%);
    transition: transform var(--transition-base);
  }

  .nav.open {
    transform: translateX(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-lg);
  }

  .nav-link {
    font-size: var(--font-size-lg);
  }

  .dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    padding: var(--space-sm) 0 0 var(--space-md);
  }

  .dropdown-menu li {
    background: transparent;
    box-shadow: none;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-toggle.open .nav-toggle-bar:nth-child(1) {
    transform: rotate(45deg) translate(4px, 4px);
  }

  .nav-toggle.open .nav-toggle-bar:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle.open .nav-toggle-bar:nth-child(3) {
    transform: rotate(-45deg) translate(4px, -4px);
  }

  .section {
    padding: var(--space-4xl) 0;
  }

  .section-title {
    font-size: var(--font-size-3xl);
  }

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

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

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

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

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }

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

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

@media (max-width: 480px) {
  :root {
    --font-size-5xl: 1.875rem;
    --font-size-4xl: 1.5rem;
    --font-size-3xl: 1.375rem;
  }

  .container {
    padding: 0 var(--space-md);
  }

  .header-inner {
    padding: 0 var(--space-md);
  }

  .feature-card,
  .why-card,
  .capability-card,
  .partner-card {
    padding: var(--space-xl);
  }
}