/* ========================================
   观微光电 (Perceium) Design System
   Apple Pro Style - Titanium Edition
   ======================================== */

/* ----------------------------------------
   1. CSS Variables / Design Tokens
   ---------------------------------------- */
:root {
  /* Colors - Titanium Palette */
  --color-titanium-grey: #8E8E93;
  --color-deep-black: #1D1D1F;
  --color-light-grey: #F5F5F7;
  --color-real-black: #000000;
  --color-essential-white: #FFFFFF;

  /* Accent Colors */
  --color-sensing-blue: #0071E3;
  --color-sensing-blue-hover: #0077ED;
  --color-energy-orange: #FF9500;

  /* Semantic Colors */
  --color-text-primary: var(--color-deep-black);
  --color-text-secondary: var(--color-titanium-grey);
  --color-text-inverse: var(--color-essential-white);
  --color-background: var(--color-essential-white);
  --color-background-alt: var(--color-light-grey);
  --color-surface: var(--color-essential-white);
  --color-border: rgba(0, 0, 0, 0.08);

  /* Typography */
  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-display: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;

  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 2rem;
  --text-4xl: 2.5rem;
  --text-5xl: 3rem;
  --text-6xl: 4rem;
  --text-7xl: 5rem;

  /* Font Weights */
  --font-regular: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  /* Line Heights */
  --leading-tight: 1.1;
  --leading-snug: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.75;

  /* Letter Spacing */
  --tracking-tight: -0.02em;
  --tracking-normal: 0;
  --tracking-wide: 0.02em;
  --tracking-wider: 0.05em;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-2xl: 32px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;
  --transition-slower: 800ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Layout */
  --container-max-width: 1200px;
  --container-padding: var(--space-6);
  --section-padding: var(--space-24);
  --header-height: 52px;
}

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

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

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-regular);
  line-height: var(--leading-normal);
  color: var(--color-text-primary);
  background-color: var(--color-background);
  overflow-x: hidden;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--color-sensing-blue);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-sensing-blue-hover);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul,
ol {
  list-style: none;
}

/* ----------------------------------------
   3. Typography
   ---------------------------------------- */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-display);
  font-weight: var(--font-semibold);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--color-text-primary);
}

.headline-hero {
  font-size: clamp(var(--text-4xl), 8vw, var(--text-7xl));
  font-weight: var(--font-bold);
  letter-spacing: -0.03em;
  line-height: 1.05;
}

.headline-section {
  font-size: clamp(var(--text-3xl), 5vw, var(--text-5xl));
  font-weight: var(--font-semibold);
}

.headline-card {
  font-size: var(--text-2xl);
  font-weight: var(--font-semibold);
}

.subheadline {
  font-size: clamp(var(--text-lg), 2.5vw, var(--text-xl));
  font-weight: var(--font-regular);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

.body-text {
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
  color: var(--color-text-secondary);
}

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

.overline {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  letter-spacing: var(--tracking-wider);
  text-transform: uppercase;
  color: var(--color-text-secondary);
}

/* ----------------------------------------
   4. Layout Components
   ---------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.section {
  padding-top: var(--section-padding);
  padding-bottom: var(--section-padding);
}

.section-dark {
  background-color: var(--color-real-black);
  color: var(--color-text-inverse);
}

.section-dark h1,
.section-dark h2,
.section-dark h3,
.section-dark h4 {
  color: var(--color-text-inverse);
}

.section-dark .subheadline,
.section-dark .body-text,
.section-dark .caption {
  color: rgba(255, 255, 255, 0.7);
}

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

/* Bento Grid Layout */
.bento-grid {
  display: grid;
  gap: var(--space-4);
}

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

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

.bento-grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

@media (max-width: 1024px) {

  .bento-grid-3,
  .bento-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {

  .bento-grid-2,
  .bento-grid-3,
  .bento-grid-4 {
    grid-template-columns: 1fr;
  }
}

/* ----------------------------------------
   5. Card Component
   ---------------------------------------- */
.card {
  background-color: var(--color-surface);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

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

.card-dark {
  background-color: var(--color-deep-black);
  color: var(--color-text-inverse);
}

.card-dark h3,
.card-dark h4 {
  color: var(--color-text-inverse);
}

.card-glass {
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.card-featured {
  grid-column: span 2;
}

.card-image {
  width: 100%;
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-6);
  object-fit: cover;
}

.card-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--space-4);
}

/* ----------------------------------------
   6. Button Components
   ---------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-base);
  font-weight: var(--font-medium);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

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

.btn-primary:hover {
  background-color: var(--color-sensing-blue-hover);
  color: var(--color-essential-white);
  transform: scale(1.02);
}

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

.btn-secondary:hover {
  background-color: var(--color-sensing-blue);
  color: var(--color-essential-white);
}

.btn-text {
  color: var(--color-sensing-blue);
  padding: var(--space-2) 0;
}

.btn-text::after {
  content: ' →';
  transition: transform var(--transition-fast);
}

.btn-text:hover::after {
  transform: translateX(4px);
}

/* ----------------------------------------
   7. Navigation
   ---------------------------------------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.nav-scrolled {
  background: rgba(255, 255, 255, 0.92);
}

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

.nav-logo {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
}

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

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-primary);
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-sensing-blue);
}

.nav-cta {
  padding: var(--space-2) var(--space-5);
  font-size: var(--text-sm);
}

.nav-mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
}

.nav-mobile-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-text-primary);
  transition: transform var(--transition-fast);
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    padding: var(--space-4);
    border-bottom: 1px solid var(--color-border);
  }

  .nav-menu.active {
    display: flex;
  }

  .nav-link {
    display: block;
    padding: var(--space-4);
    border-bottom: 1px solid var(--color-border);
  }

  .nav-cta {
    margin-top: var(--space-4);
  }

  .nav-mobile-toggle {
    display: flex;
  }
}

/* ----------------------------------------
   8. Hero Section
   ---------------------------------------- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding-top: calc(var(--header-height) + var(--space-16));
  padding-bottom: var(--space-16);
  background-color: var(--color-real-black);
  color: var(--color-text-inverse);
  overflow: hidden;
}

.hero-content {
  max-width: 900px;
  margin: 0 auto;
}

.hero-logo {
  font-size: clamp(var(--text-6xl), 12vw, 8rem);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-8);
  background: linear-gradient(135deg, #FFFFFF 0%, #8E8E93 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: fadeInUp 1s ease-out;
}

.hero-title {
  margin-bottom: var(--space-6);
  animation: fadeInUp 1s ease-out 0.2s backwards;
}

.hero-subtitle {
  max-width: 600px;
  margin: 0 auto var(--space-10);
  animation: fadeInUp 1s ease-out 0.4s backwards;
}

.hero-cta {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 1s ease-out 0.6s backwards;
}

/* ----------------------------------------
   9. Feature Sections
   ---------------------------------------- */
.feature-intro {
  text-align: center;
  max-width: 800px;
  margin: 0 auto var(--space-16);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-6);
}

.feature-item {
  text-align: center;
  padding: var(--space-8);
}

.feature-number {
  font-size: var(--text-5xl);
  font-weight: var(--font-bold);
  color: var(--color-sensing-blue);
  margin-bottom: var(--space-2);
}

.feature-label {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
}

/* Comparison Section */
.comparison-container {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-8);
  align-items: center;
}

@media (max-width: 768px) {
  .comparison-container {
    grid-template-columns: 1fr;
  }
}

.comparison-image {
  width: 100%;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

.comparison-content h3 {
  margin-bottom: var(--space-4);
}

.comparison-list {
  margin-top: var(--space-6);
}

.comparison-list li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
}

.comparison-list li::before {
  content: '✓';
  color: var(--color-sensing-blue);
  font-weight: var(--font-bold);
}

/* ----------------------------------------
   10. Team Section
   ---------------------------------------- */
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-8);
}

.team-card {
  text-align: center;
  padding: var(--space-8);
  background-color: var(--color-background-alt);
  border-radius: var(--radius-xl);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.team-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
}

.team-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto var(--space-6);
  border: 4px solid var(--color-essential-white);
  box-shadow: var(--shadow-md);
}

.team-name {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-2);
}

.team-role {
  font-size: var(--text-sm);
  color: var(--color-sensing-blue);
  font-weight: var(--font-medium);
  margin-bottom: var(--space-4);
}

.team-bio {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

/* ----------------------------------------
   11. Applications Section
   ---------------------------------------- */
.app-card {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-xl);
  aspect-ratio: 4/3;
}

.app-card-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

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

.app-card-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: var(--space-6);
  background: linear-gradient(to top, rgba(0, 0, 0, 0.8) 0%, transparent 100%);
  color: var(--color-text-inverse);
}

.app-card-title {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-2);
}

.app-card-desc {
  font-size: var(--text-sm);
  opacity: 0.8;
}

/* ----------------------------------------
   12. Roadmap Section
   ---------------------------------------- */
/* ----------------------------------------
   12. Roadmap Section
   ---------------------------------------- */
.roadmap {
  position: relative;
  padding-bottom: var(--space-12);
}

.roadmap-line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: linear-gradient(to bottom, var(--color-sensing-blue), var(--color-energy-orange));
  transform: translateX(-50%);
}

.roadmap-item {
  display: grid;
  grid-template-columns: 1fr 60px 1fr;
  gap: var(--space-4);
  margin-bottom: var(--space-12);
  align-items: center;
}

.roadmap-content {
  padding: var(--space-6);
  background-color: var(--color-background-alt);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

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

.roadmap-item:nth-child(odd) .roadmap-content {
  text-align: right;
}

.roadmap-dot {
  width: 20px;
  height: 20px;
  background-color: var(--color-sensing-blue);
  border-radius: 50%;
  border: 4px solid var(--color-background);
  box-shadow: var(--shadow-md);
  z-index: 1;
  justify-self: center;
  flex-shrink: 0;
}

.roadmap-phase {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--color-sensing-blue);
  margin-bottom: var(--space-2);
  letter-spacing: 0.05em;
}

.roadmap-title {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-3);
  line-height: var(--leading-tight);
}

.roadmap-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
  .roadmap-line {
    left: 20px;
  }

  .roadmap-item {
    grid-template-columns: 40px 1fr;
    align-items: start;
    gap: var(--space-4);
    margin-bottom: var(--space-8);
  }

  .roadmap-dot {
    order: -1;
    grid-column: 1;
    margin-top: 1.5rem;
    /* Align with content text roughly */
  }

  .roadmap-content {
    grid-column: 2;
    padding: var(--space-5);
    text-align: left !important;
  }

  .roadmap-item:nth-child(odd) .roadmap-content {
    text-align: left;
  }

  .roadmap-phase {
    font-size: var(--text-xs);
  }

  .roadmap-title {
    font-size: var(--text-lg);
    margin-bottom: var(--space-2);
  }

  .roadmap-desc {
    font-size: var(--text-xs);
    line-height: 1.6;
  }
}


/* ----------------------------------------
   13. Contact Section
   ---------------------------------------- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-8);
}

.contact-item {
  text-align: center;
  padding: var(--space-8);
}

.contact-icon {
  font-size: var(--text-3xl);
  margin-bottom: var(--space-4);
}

.contact-label {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
}

.contact-value {
  font-size: var(--text-lg);
  font-weight: var(--font-medium);
  color: var(--color-text-primary);
}

/* ----------------------------------------
   14. Footer
   ---------------------------------------- */
.footer {
  background-color: var(--color-real-black);
  color: var(--color-text-inverse);
  padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}

.footer-brand {
  max-width: 300px;
}

.footer-logo {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-4);
}

.footer-desc {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.6);
  line-height: var(--leading-relaxed);
}

.footer-links {
  display: flex;
  gap: var(--space-12);
  flex-wrap: wrap;
}

.footer-group h4 {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-4);
  color: var(--color-essential-white);
}

.footer-group a {
  display: block;
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.6);
  padding: var(--space-2) 0;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: var(--space-8);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.5);
}

/* ----------------------------------------
   15. Animations
   ---------------------------------------- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }

  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(30px);
  }

  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* Scroll Reveal */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--transition-slower), transform var(--transition-slower);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

.reveal-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity var(--transition-slower), transform var(--transition-slower);
}

.reveal-left.active {
  opacity: 1;
  transform: translateX(0);
}

.reveal-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity var(--transition-slower), transform var(--transition-slower);
}

.reveal-right.active {
  opacity: 1;
  transform: translateX(0);
}

/* Stagger delays */
.stagger-1 {
  transition-delay: 0.1s;
}

.stagger-2 {
  transition-delay: 0.2s;
}

.stagger-3 {
  transition-delay: 0.3s;
}

.stagger-4 {
  transition-delay: 0.4s;
}

.stagger-5 {
  transition-delay: 0.5s;
}

.stagger-6 {
  transition-delay: 0.6s;
}

/* ----------------------------------------
   16. Utility Classes
   ---------------------------------------- */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

.mb-4 {
  margin-bottom: var(--space-4);
}

.mb-6 {
  margin-bottom: var(--space-6);
}

.mb-8 {
  margin-bottom: var(--space-8);
}

.mb-12 {
  margin-bottom: var(--space-12);
}

.mb-16 {
  margin-bottom: var(--space-16);
}

.mt-4 {
  margin-top: var(--space-4);
}

.mt-8 {
  margin-top: var(--space-8);
}

.mt-12 {
  margin-top: var(--space-12);
}

.pt-header {
  padding-top: var(--header-height);
}

.flex {
  display: flex;
}

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

.flex-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.flex-wrap {
  flex-wrap: wrap;
}

.gap-4 {
  gap: var(--space-4);
}

.gap-8 {
  gap: var(--space-8);
}

.hidden {
  display: none;
}

@media (max-width: 768px) {
  .hidden-mobile {
    display: none;
  }
}

@media (min-width: 769px) {
  .hidden-desktop {
    display: none;
  }
}

/* ----------------------------------------
   17. Tab Component
   ---------------------------------------- */
.tab-nav {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  margin-bottom: var(--space-8);
  padding: var(--space-1);
  background: var(--color-background-alt);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  width: fit-content;
  margin-left: auto;
  margin-right: auto;
}

.tab-btn {
  padding: var(--space-2) var(--space-6);
  border-radius: var(--radius-full);
  font-weight: var(--font-medium);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

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

.tab-btn.active {
  background: var(--color-surface);
  color: var(--color-text-primary);
  box-shadow: var(--shadow-sm);
}

.tab-content {
  display: none;
  animation: fadeIn 0.4s ease-out;
}

.tab-content.active {
  display: block;
}

@media (max-width: 768px) {
  .tab-nav {
    width: 100%;
    overflow-x: auto;
    justify-content: flex-start;
    padding: var(--space-2);
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .tab-nav::-webkit-scrollbar {
    display: none;
  }

  .tab-btn {
    flex: 0 0 auto;
  }
}

/* ----------------------------------------
   18. Industrialization Section
   ---------------------------------------- */
.milestone-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-6);
}

.milestone-card {
  background: var(--color-surface);
  padding: var(--space-6);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
  min-height: 200px;
}

.milestone-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  bottom: 0;
  background: var(--color-sensing-blue);
}

.milestone-year {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-sensing-blue);
  margin-bottom: var(--space-2);
  opacity: 0.1;
  /* Subtle watermark */
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  z-index: 0;
}

.milestone-card:hover .milestone-year {
  opacity: 0.3;
  transition: opacity var(--transition-base);
}

.time-title {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-4);
  position: relative;
  z-index: 1;
}

.milestone-list {
  list-style: none;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  position: relative;
  z-index: 1;
}

.milestone-list li {
  margin-bottom: var(--space-2);
  padding-left: var(--space-3);
  position: relative;
}

.milestone-list li::before {
  content: '•';
  color: var(--color-sensing-blue);
  position: absolute;
  left: 0;
}

/* Supply Chain */
.supply-chain-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-4);
}

.chain-card {
  background: var(--color-surface);
  padding: var(--space-6);
  border-radius: var(--radius-lg);
  text-align: center;
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  align-items: center;
  transition: transform var(--transition-fast);
}

.chain-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-sensing-blue);
}

.chain-icon {
  height: 48px;
  width: auto;
  margin-bottom: var(--space-4);
}

.chain-card h4 {
  font-size: var(--text-base);
  margin-bottom: var(--space-2);
}

.chain-partners {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
  line-height: 1.4;
}

.chain-tag {
  margin-top: auto;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(0, 113, 227, 0.1);
  color: var(--color-sensing-blue);
  font-weight: var(--font-bold);
}

.chain-tag.tag-out {
  background: rgba(0, 0, 0, 0.05);
  color: var(--color-text-secondary);
}