/* ============================================
   MUJI-Inspired Design System for Clouddream
   Natural, whitespace, low saturation, quiet
   ============================================ */

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

:root {
  /* MUJI-inspired palette */
  --color-bg: #F5F2EC;
  --color-bg-alt: #EDE9E1;
  --color-surface: #FAFAF7;
  --color-surface-raised: #FFFFFF;
  --color-text: #2C2A25;
  --color-text-secondary: #7A7568;
  --color-text-tertiary: #A09A8C;
  --color-primary: #5C6B4F;
  --color-primary-hover: #4A5640;
  --color-accent: #8B7355;
  --color-accent-hover: #756047;
  --color-border: #DDD8CE;
  --color-border-light: #E8E4DC;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Noto Sans Mono", monospace;

  /* 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;

  /* Layout */
  --max-width: 1120px;
  --header-height: 64px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  letter-spacing: 0.01em;
}

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

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

ul, ol {
  list-style: none;
}

/* --- Header --- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(245, 242, 236, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-light);
  transition: box-shadow var(--transition-base);
}

.site-header.scrolled {
  box-shadow: 0 1px 8px rgba(44, 42, 37, 0.04);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.logo-img {
  height: 32px;
  width: auto;
}

.logo-text {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text);
  letter-spacing: 0.04em;
}

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

.nav-link {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  padding: var(--space-xs) 0;
  position: relative;
  transition: color var(--transition-fast);
  letter-spacing: 0.02em;
}

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-primary);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.dropdown-list {
  position: absolute;
  top: 100%;
  left: -50%;
  padding-top: var(--space-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: all var(--transition-fast);
}

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

.dropdown-list {
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border-light);
  border-radius: 4px;
  padding: var(--space-xs) 0;
  min-width: 160px;
  box-shadow: 0 4px 16px rgba(44, 42, 37, 0.06);
}

.dropdown-link {
  display: block;
  padding: var(--space-sm) var(--space-lg);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.dropdown-link:hover {
  background: var(--color-bg);
  color: var(--color-text);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: var(--color-text);
  transition: all var(--transition-fast);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 450;
  letter-spacing: 0.02em;
  padding: 0.7rem 1.6rem;
  border-radius: 3px;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: none;
}

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

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

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

.btn-secondary:hover {
  border-color: var(--color-text-tertiary);
  color: var(--color-text);
}

.btn-text {
  background: none;
  color: var(--color-accent);
  padding: var(--space-xs) 0;
  position: relative;
}

.btn-text::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

.btn-text:hover::after {
  width: 100%;
}

.btn-large {
  padding: 0.9rem 2.4rem;
  font-size: 0.95rem;
}

/* --- Sections --- */
.section {
  padding: var(--space-4xl) var(--space-xl);
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-eyebrow {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-md);
  font-weight: 400;
}

.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 400;
  line-height: 1.35;
  color: var(--color-text);
  margin-bottom: var(--space-lg);
  letter-spacing: 0.01em;
}

.section-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  max-width: 560px;
  line-height: 1.8;
}

/* --- Hero --- */
.hero {
  padding-top: calc(var(--header-height) + var(--space-4xl));
  padding-bottom: var(--space-4xl);
  padding-left: var(--space-xl);
  padding-right: var(--space-xl);
  min-height: 85vh;
  display: flex;
  align-items: center;
}

.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
}

.hero-eyebrow {
  font-size: 0.8rem;
  color: var(--color-text-tertiary);
  letter-spacing: 0.08em;
  margin-bottom: var(--space-xl);
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 400;
  line-height: 1.3;
  color: var(--color-text);
  margin-bottom: var(--space-xl);
  letter-spacing: 0.01em;
  max-width: 720px;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--color-text-secondary);
  line-height: 1.85;
  max-width: 520px;
  margin-bottom: var(--space-2xl);
}

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

/* --- Stats --- */
.stats {
  background: var(--color-bg-alt);
  padding: var(--space-3xl) var(--space-xl);
}

.stats-grid {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
}

.stat-item {
  text-align: center;
  padding: var(--space-lg) var(--space-md);
}

.stat-value {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 400;
  color: var(--color-primary);
  letter-spacing: 0.02em;
  margin-bottom: var(--space-xs);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--color-text-tertiary);
  letter-spacing: 0.06em;
}

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

.about-header {
  margin-bottom: var(--space-3xl);
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.about-item {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border-light);
}

.about-item-title {
  font-size: 1.05rem;
  font-weight: 500;
  margin-bottom: var(--space-sm);
  color: var(--color-text);
  letter-spacing: 0.02em;
}

.about-item-desc {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.75;
}

.about-actions {
  display: flex;
  gap: var(--space-xl);
  padding-top: var(--space-lg);
}

/* --- Features --- */
.features-header {
  margin-bottom: var(--space-3xl);
}

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

.feature-card {
  padding: var(--space-xl);
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border-light);
  border-radius: 4px;
  transition: all var(--transition-base);
}

.feature-card:hover {
  border-color: var(--color-border);
  box-shadow: 0 2px 12px rgba(44, 42, 37, 0.04);
}

.feature-icon {
  width: 40px;
  height: 40px;
  color: var(--color-primary);
  margin-bottom: var(--space-lg);
}

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

.feature-title {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: var(--space-sm);
  color: var(--color-text);
  letter-spacing: 0.01em;
}

.feature-desc {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.75;
}

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

.capabilities-header {
  margin-bottom: var(--space-3xl);
}

.capabilities-list {
  display: flex;
  flex-direction: column;
}

.capability-item {
  display: flex;
  gap: var(--space-2xl);
  padding: var(--space-2xl) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.capability-item:first-child {
  border-top: 1px solid var(--color-border-light);
}

.capability-number {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--color-text-tertiary);
  letter-spacing: 0.08em;
  padding-top: 0.15rem;
  flex-shrink: 0;
  width: 2rem;
}

.capability-title {
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: var(--space-sm);
  color: var(--color-text);
  letter-spacing: 0.02em;
}

.capability-desc {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.75;
  max-width: 560px;
}

/* --- Partners --- */
.partners-header {
  margin-bottom: var(--space-3xl);
}

.partners-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
}

.partner-card {
  padding: var(--space-2xl);
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border-light);
  border-radius: 4px;
}

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

.partner-logo img {
  height: 100%;
  width: auto;
  object-fit: contain;
}

.partner-desc {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
}

/* --- CTA --- */
.cta {
  background: var(--color-bg-alt);
}

.cta-inner {
  text-align: center;
  max-width: 560px;
  margin: 0 auto;
}

.cta-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 400;
  line-height: 1.4;
  color: var(--color-text);
  margin-bottom: var(--space-md);
  letter-spacing: 0.01em;
}

.cta-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
  line-height: 1.75;
}

/* --- Footer --- */
.site-footer {
  background: var(--color-text);
  color: var(--color-bg);
  padding: var(--space-3xl) var(--space-xl) var(--space-xl);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-top {
  display: flex;
  justify-content: space-between;
  gap: var(--space-3xl);
  padding-bottom: var(--space-2xl);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-brand {
  flex: 1;
}

.footer-logo {
  height: 28px;
  width: auto;
  margin-bottom: var(--space-md);
  opacity: 0.85;
}

.footer-brand-desc {
  font-size: 0.85rem;
  color: rgba(245, 242, 236, 0.55);
  line-height: 1.7;
}

.footer-links {
  display: flex;
  gap: var(--space-3xl);
}

.footer-col-title {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(245, 242, 236, 0.4);
  margin-bottom: var(--space-md);
}

.footer-col-list li {
  margin-bottom: var(--space-sm);
}

.footer-col-list a {
  font-size: 0.875rem;
  color: rgba(245, 242, 236, 0.65);
  transition: color var(--transition-fast);
}

.footer-col-list a:hover {
  color: rgba(245, 242, 236, 0.9);
}

.footer-bottom {
  padding-top: var(--space-xl);
}

.footer-copy {
  font-size: 0.8rem;
  color: rgba(245, 242, 236, 0.3);
}

/* --- Responsive: Tablet --- */
@media (max-width: 900px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .footer-top {
    flex-direction: column;
    gap: var(--space-2xl);
  }
}

/* --- Responsive: Mobile --- */
@media (max-width: 640px) {
  :root {
    --space-4xl: 4rem;
    --space-3xl: 2.5rem;
  }

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

  .nav-toggle {
    display: flex;
  }

  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg);
    padding: var(--space-xl) var(--space-md);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    z-index: 99;
  }

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

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

  .nav-link {
    font-size: 1.1rem;
  }

  .dropdown-list {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    background: transparent;
    border: none;
    box-shadow: none;
    padding: var(--space-xs) 0 0 var(--space-md);
  }

  .dropdown-link {
    padding: var(--space-xs) 0;
    font-size: 0.95rem;
  }

  .hero {
    min-height: auto;
    padding-top: calc(var(--header-height) + var(--space-3xl));
    padding-bottom: var(--space-3xl);
  }

  .hero-title {
    font-size: 1.75rem;
  }

  .hero-desc {
    font-size: 0.95rem;
  }

  .section {
    padding: var(--space-3xl) var(--space-md);
  }

  .section-title {
    font-size: 1.5rem;
  }

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

  .stat-value {
    font-size: 1.5rem;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .about-item {
    padding: var(--space-lg) 0;
  }

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

  .capability-item {
    flex-direction: column;
    gap: var(--space-sm);
  }

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

  .footer-links {
    flex-direction: column;
    gap: var(--space-xl);
  }

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

  .btn {
    width: 100%;
    text-align: center;
  }

  .about-actions {
    flex-direction: column;
    gap: var(--space-md);
  }
}

/* --- Subtle animations --- */
@media (prefers-reduced-motion: no-preference) {
  .section {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity var(--transition-slow), transform var(--transition-slow);
  }

  .section.visible {
    opacity: 1;
    transform: translateY(0);
  }
}