/* ============================================
   INFRASTRUCTURE ACADEMY - DESIGN SYSTEM
   Dark Navy/Purple Background + Gold Accents
   ============================================ */

/* Root Color Variables */
:root {
  /* Primary Colors */
  --color-bg-primary: #0a1628;
  --color-bg-secondary: #0f1f3a;
  --color-text-primary: #ffffff;
  --color-text-secondary: #e0e0e0;
  --color-accent-gold: #ffd700;
  --color-accent-gold-dark: #daa520;
  --color-accent-yellow: #ffff00;
  
  /* Typography */
  --font-primary: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --font-heading: 'Georgia', 'Times New Roman', serif;
  
  /* Spacing — 8px grid system */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

/* ============================================
   GLOBAL STYLES
   ============================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  line-height: 1.5;
  font-size: 16px;
  overflow-x: hidden;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1 {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: var(--spacing-sm);
  line-height: 1.2;
}

h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--spacing-sm);
  line-height: 1.25;
}

h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--spacing-xs);
}

h4 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  margin-bottom: var(--spacing-xs);
}

p {
  font-size: 1rem;
  line-height: 1.5;
  margin-bottom: 0.75em;
  color: var(--color-text-primary);
}

a {
  color: var(--color-accent-gold);
  text-decoration: none;
  transition: color 0.3s ease;
}

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

/* ============================================
   HEADER & NAVIGATION
   ============================================ */

header {
  background-color: var(--color-bg-secondary);
  border-bottom: 2px solid var(--color-accent-gold);
  padding: 0.4rem var(--spacing-sm);
  position: sticky;
  top: 0;
  z-index: 200000;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
  overflow: visible;
}

.header-content {
  max-width: 1600px;
  margin: 0 auto;
  text-align: center;
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  flex-wrap: nowrap;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex: 1;
  justify-content: center;
}

.header-text-group {
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* IAAI Logo — Gold iAAi Compass Image */
.iaai-logo-box {
  width: 40px;
  height: 40px;
  min-width: 40px;
  border: 2px solid var(--color-accent-gold);
  border-radius: 6px;
  object-fit: cover;
  flex-shrink: 0;
}

/* 8th Scholar Header Thumbnail */
.header-scholar-link {
  flex-shrink: 0;
  margin-left: 0;
}
.header-scholar-thumb {
  width: 40px;
  height: 40px;
  min-width: 40px;
  object-fit: cover;
  border-radius: 6px;
  border: 2px solid var(--color-accent-gold);
  transition: transform 0.2s;
}
.header-scholar-thumb:hover {
  transform: scale(1.05);
}

.header-title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 0;
}

.header-tagline {
  font-size: 0.65rem;
  letter-spacing: 0.25em;
  color: var(--color-accent-gold);
  opacity: 0.85;
  margin-top: -0.1rem;
  text-transform: uppercase;
}

.header-subtitle {
  display: none;
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  background: var(--color-bg-secondary);
  border: 2px solid var(--color-accent-gold);
  border-radius: 50%;
  color: var(--color-accent-gold);
  font-size: 1.2rem;
  cursor: pointer;
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s, background 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--color-accent-gold);
  color: var(--color-bg-primary);
}

/* Navigation Bar */
nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 4px;
  justify-content: center;
  overflow-x: auto;
  padding: 0.2rem 0;
}

/* Hamburger Menu Button */
.hamburger {
  display: none;
  flex-direction: column;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
  gap: 6px;
}

.hamburger span {
  width: 25px;
  height: 3px;
  background-color: var(--color-accent-gold);
  border-radius: 2px;
  transition: all 0.3s ease;
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

nav a {
  display: inline-block;
  padding: 0.2rem 0.5rem;
  color: var(--color-text-primary);
  background-color: transparent;
  border: 1px solid var(--color-accent-gold);
  border-radius: var(--radius-sm);
  font-size: 0.65rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: all 0.3s ease;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
}

nav a:hover {
  background-color: var(--color-accent-gold);
  color: var(--color-bg-primary);
  border-color: var(--color-accent-gold);
}

nav a.active {
  background-color: var(--color-accent-gold);
  color: var(--color-bg-primary);
  border-color: var(--color-accent-gold);
  font-weight: 700;
  box-shadow: 0 0 12px rgba(255, 215, 0, 0.6), 0 0 4px rgba(255, 215, 0, 0.3);
  text-shadow: none;
  animation: nav-glow 2.5s ease-in-out infinite;
}
@keyframes nav-glow {
  0%, 100% { box-shadow: 0 0 8px rgba(255, 215, 0, 0.5), 0 0 4px rgba(255, 215, 0, 0.3); }
  50% { box-shadow: 0 0 18px rgba(255, 215, 0, 0.9), 0 0 8px rgba(255, 215, 0, 0.6), 0 0 30px rgba(255, 215, 0, 0.3); }
}

/* Tetrahedron Thumbnail — living pulse */
.header-tetra-thumb {
  width: 40px;
  height: 40px;
  object-fit: cover;
  border-radius: 4px;
  flex-shrink: 0;
  margin-right: 6px;
  animation: tetra-pulse 4s ease-in-out infinite;
  border: 1px solid rgba(255, 215, 0, 0.3);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.header-tetra-thumb:hover {
  transform: scale(1.15) rotate(5deg);
  box-shadow: 0 0 16px rgba(255, 215, 0, 0.7), 0 0 32px rgba(255, 215, 0, 0.3);
}
@keyframes tetra-pulse {
  0%, 100% { box-shadow: 0 0 4px rgba(255, 215, 0, 0.2); opacity: 0.9; }
  50% { box-shadow: 0 0 12px rgba(255, 215, 0, 0.6), 0 0 24px rgba(255, 215, 0, 0.2); opacity: 1; }
}

/* Second Nav Row — Campaign / Community */
.nav-row2 {
  display: flex;
  flex-wrap: nowrap;
  gap: 4px;
  justify-content: center;
  overflow: visible;
  padding: 0.15rem 0;
  border-top: 1px solid rgba(255, 215, 0, 0.15);
  margin-top: 0;
  position: relative;
  z-index: 200001;
}

.nav-row2 a {
  display: inline-block;
  padding: 0.15rem 0.45rem;
  color: var(--color-accent-gold);
  background-color: rgba(255, 215, 0, 0.06);
  border: 1px solid rgba(255, 215, 0, 0.25);
  border-radius: var(--radius-sm);
  font-size: 0.6rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: all 0.3s ease;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
}

.nav-row2 a:hover {
  background-color: rgba(255, 215, 0, 0.15);
  border-color: var(--color-accent-gold);
  color: #fff;
}

.nav-row2 a.active {
  background-color: var(--color-accent-gold);
  color: var(--color-bg-primary);
  border-color: var(--color-accent-gold);
  font-weight: 700;
  box-shadow: 0 0 12px rgba(255, 215, 0, 0.6), 0 0 4px rgba(255, 215, 0, 0.3);
  text-shadow: none;
  animation: nav-glow 2.5s ease-in-out infinite;
}

/* Relay Navigation Buttons */
.relay-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  justify-content: center;
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-md);
  border-top: 2px solid var(--color-accent-gold);
  border-bottom: 2px solid var(--color-accent-gold);
}

.relay-nav button {
  min-width: 40px;
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: transparent;
  color: var(--color-accent-gold);
  border: 1px solid var(--color-accent-gold);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s ease;
}

.relay-nav button:hover {
  background-color: var(--color-accent-gold);
  color: var(--color-bg-primary);
}

.relay-nav button.active {
  background-color: var(--color-accent-yellow);
  color: var(--color-bg-primary);
  border-color: var(--color-accent-yellow);
}

/* ============================================
   MAIN CONTENT
   ============================================ */

main {
  max-width: 1600px;
  margin: 0 auto;
  padding: var(--spacing-md) var(--spacing-lg);
  min-height: calc(100vh - 300px);
}

.container {
  background-color: var(--color-bg-secondary);
  border: 2px solid var(--color-accent-gold);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

/* No double padding: content-box inside container uses reduced padding */
.container .content-box {
  padding: var(--spacing-sm) var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.content-box {
  background-color: rgba(15, 31, 58, 0.5);
  border: 2px solid var(--color-accent-gold);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

/* Two-Column Layout */
.two-column {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.column-left {
  grid-column: 1;
}

.column-right {
  grid-column: 2;
}

/* ============================================
   CARDS & BOXES
   ============================================ */

.card {
  background-color: var(--color-bg-secondary);
  border: 2px solid var(--color-accent-gold);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  text-align: center;
  transition: all 0.3s ease;
}

.card:hover {
  box-shadow: 0 0 20px rgba(255, 215, 0, 0.3);
  transform: translateY(-5px);
}

.card-title {
  font-size: 1.5rem;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  margin-bottom: var(--spacing-sm);
}

.card-subtitle {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--spacing-md);
  margin: var(--spacing-md) 0;
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  background-color: var(--color-accent-gold);
  color: var(--color-bg-primary);
  border: 2px solid var(--color-accent-gold);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: bold;
  text-transform: uppercase;
  letter-spacing: 1px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
}

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

.btn-secondary {
  background-color: transparent;
  color: var(--color-accent-gold);
  border: 2px solid var(--color-accent-gold);
}

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

/* ============================================
   SEPARATOR LINES
   ============================================ */

.separator {
  height: 2px;
  background: linear-gradient(to right, var(--color-accent-gold), transparent, var(--color-accent-gold));
  margin: var(--spacing-sm) 0;
}

.separator-thick {
  height: 3px;
  background-color: var(--color-accent-gold);
  margin: var(--spacing-sm) 0;
}

/* ============================================
   FOOTER
   ============================================ */

footer {
  background-color: var(--color-bg-secondary);
  border-top: 3px solid var(--color-accent-gold);
  padding: var(--spacing-md);
  margin-top: var(--spacing-lg);
  text-align: center;
}

.footer-content {
  max-width: 1600px;
  margin: 0 auto;
}

.footer-copyright {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

.footer-links {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

.footer-links a {
  color: var(--color-accent-gold);
  margin: 0 var(--spacing-sm);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 1024px) {
  .two-column {
    grid-template-columns: 1fr;
  }
  
  .column-left,
  .column-right {
    grid-column: 1;
  }
  
  h1 {
    font-size: 2.5rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  nav {
    gap: var(--spacing-xs);
  }
  
  nav a {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.75rem;
  }
}

@media (max-width: 768px) {
  header {
    display: flex;
    flex-direction: column;
    padding: var(--spacing-md) var(--spacing-lg);
  }
  
  main {
    padding: var(--spacing-lg);
  }
  
  .header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    margin-bottom: 0;
    flex-wrap: nowrap;
    gap: 0.35rem;
    position: relative;
  }
  
  .header-brand {
    gap: 0.5rem;
    justify-content: flex-start;
    flex: 1;
    min-width: 0;
    max-width: 100%;
    overflow: hidden;
  }
  
  .header-text-group {
    min-width: 0;
    overflow: hidden;
    align-items: flex-start;
  }
  
  .iaai-logo-box {
    width: 36px;
    height: 36px;
    min-width: 36px;
  }
  
  .header-scholar-thumb {
    width: 36px;
    height: 36px;
    min-width: 36px;
  }
  
  .header-title {
    font-size: 0.85rem;
    margin-bottom: 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    min-width: 0;
    letter-spacing: 0.5px;
    max-width: calc(100vw - 170px);
  }
  
  .header-tagline {
    font-size: 0.45rem;
    letter-spacing: 0.1em;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: calc(100vw - 170px);
  }
  
  .header-subtitle {
    display: none;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
  
  .hamburger {
    display: flex;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 300001;
  }
  
  .hamburger span {
    width: 24px;
    height: 3px;
    background-color: var(--color-accent-gold);
    display: block;
    transition: all 0.3s ease;
    border-radius: 2px;
  }
  
  .hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
  }
  
  .hamburger.active span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
  }
  
  .hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
  }
  
  nav {
    display: flex;
    flex-direction: column;
    background-color: var(--color-bg-secondary);
    border-top: 1px solid var(--color-accent-gold);
    gap: 0;
    padding: 0;
    width: 100%;
    box-sizing: border-box;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.3s ease;
  }
  
  nav.open {
    max-height: 35vh;
    overflow-y: auto;
    padding: var(--spacing-xs) 0;
    border-bottom: 2px solid var(--color-accent-gold);
  }

  .nav-row2 {
    display: flex;
    flex-direction: column;
    background-color: var(--color-bg-secondary);
    border-top: 1px solid rgba(255, 215, 0, 0.3);
    gap: 0;
    padding: 0;
    width: 100%;
    box-sizing: border-box;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.3s ease;
  }

  .nav-row2.open {
    max-height: 25vh;
    overflow-y: auto;
    padding: var(--spacing-xs) 0;
    border-bottom: 2px solid var(--color-accent-gold);
  }

  .nav-row2 a {
    width: 100%;
    text-align: center;
    border: none;
    border-bottom: 1px solid rgba(255, 215, 0, 0.1);
    border-radius: 0;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.8rem;
    white-space: nowrap;
    box-sizing: border-box;
    line-height: 1.4;
    margin: 0;
    display: block;
    letter-spacing: 1px;
    background-color: rgba(255, 215, 0, 0.03);
  }
  
  nav a {
    width: 100%;
    text-align: center;
    border: none;
    border-bottom: 1px solid rgba(255, 215, 0, 0.15);
    border-radius: 0;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.85rem;
    white-space: nowrap;
    box-sizing: border-box;
    line-height: 1.4;
    margin: 0;
    display: block;
    letter-spacing: 1px;
  }
  
  nav a:last-child {
    border-bottom: none;
  }
  
  nav a:hover {
    background-color: rgba(255, 215, 0, 0.1);
  }
  nav a.active {
    background-color: var(--color-accent-gold) !important;
    color: var(--color-bg-primary) !important;
    font-weight: 700;
    box-shadow: 0 0 12px rgba(255, 215, 0, 0.6);
  }
  
  .card-grid {
    grid-template-columns: 1fr;
  }
  
  .relay-nav {
    gap: 4px;
  }
  
  .relay-nav button {
    min-width: 35px;
    padding: 4px 6px;
    font-size: 0.75rem;
  }

  /* Mobile nav-grouped styles — CRITICAL: must override JS-injected desktop styles */
  #nav-grouped {
    display: flex !important;
    flex-direction: column !important;
    flex-wrap: nowrap !important;
    max-height: 0 !important;
    overflow: hidden !important;
    transition: max-height 0.4s ease, padding 0.3s ease;
    padding: 0 !important;
    width: 100% !important;
    gap: 0 !important;
    position: relative;
    z-index: 200000;
    background: #0a1628;
  }

  #nav-grouped.open {
    max-height: 100vh !important;
    overflow-y: scroll !important;
    -webkit-overflow-scrolling: touch;
    padding: 0.5rem 0 !important;
    border-bottom: 2px solid var(--color-accent-gold);
    z-index: 200000;
  }

  #nav-grouped > a,
  #nav-grouped > .nav-group {
    width: 100%;
    text-align: center;
  }

  #nav-grouped > a {
    display: block !important;
    border-radius: 0 !important;
    border: none !important;
    border-bottom: 1px solid rgba(255,215,0,0.1) !important;
    padding: 0.6rem 1rem !important;
    font-size: 0.8rem !important;
  }

  #nav-grouped > .nav-group .nav-group-label {
    display: block;
    width: 100%;
    border-radius: 0;
    border: none;
    border-bottom: 1px solid rgba(255,215,0,0.1);
    padding: 0.6rem 1rem;
    font-size: 0.8rem;
    text-align: center;
  }

  #nav-grouped > .nav-group .nav-group-dropdown {
    position: static !important;
    transform: none !important;
    min-width: 100% !important;
    border-radius: 0 !important;
    border: none !important;
    box-shadow: none !important;
    margin-top: 0 !important;
    background: rgba(10,22,40,0.95) !important;
  }

  #nav-grouped > .nav-group.open .nav-group-dropdown {
    display: flex !important;
    flex-direction: column !important;
  }

  #nav-grouped .lang-selector {
    display: none !important;
  }
}

@media (max-width: 480px) {
  header {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  main {
    padding: var(--spacing-md);
  }
  
  .iaai-logo-box {
    width: 28px;
    height: 28px;
    min-width: 28px;
  }
  
  .header-tetra-thumb {
    width: 28px !important;
    height: 28px !important;
    margin-right: 2px !important;
  }
  
  .header-scholar-thumb {
    width: 28px !important;
    height: 28px !important;
    min-width: 28px;
  }
  
  .header-scholar-link {
    flex-shrink: 0;
    margin-left: 0 !important;
  }
  
  .header-title {
    font-size: 0.65rem;
    white-space: nowrap;
    letter-spacing: 0.3px;
    max-width: calc(100vw - 120px);
    display: inline-flex !important;
    align-items: center;
    gap: 4px;
    overflow: visible;
  }
  
  .header-tagline {
    display: none;
  }
  
  .header-subtitle {
    display: none;
  }
  
  h1 {
    font-size: 1.5rem;
  }
  
  h2 {
    font-size: 1.25rem;
  }
  
  p {
    font-size: 0.95rem;
  }
  
  .container,
  .content-box {
    padding: var(--spacing-md);
  }
  
  nav a {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.8rem;
    margin: 0;
    display: block;
  }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */

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

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

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

.mt-lg {
  margin-top: var(--spacing-lg);
}

.mb-lg {
  margin-bottom: var(--spacing-lg);
}

.pt-lg {
  padding-top: var(--spacing-lg);
}

.pb-lg {
  padding-bottom: var(--spacing-lg);
}

.hidden {
  display: none;
}

.visible {
  display: block;
}

.flex {
  display: flex;
}

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

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

.gap-md {
  gap: var(--spacing-md);
}


/* ============================================
   LANGUAGE TOGGLE (EN/CN)
   ============================================ */

/* Language Selector Dropdown */
.lang-selector {
  position: relative;
  display: inline-flex;
  margin-left: 1rem;
  vertical-align: middle;
  z-index: 10000;
}

.lang-current {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: rgba(15, 31, 58, 0.9);
  border: 1px solid rgba(255, 215, 0, 0.5);
  border-radius: 4px;
  color: var(--color-accent-gold);
  font-family: var(--font-primary);
  font-size: 0.7rem;
  font-weight: 600;
  padding: 3px 8px;
  cursor: pointer;
  transition: all 0.2s;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.lang-current:hover {
  background: rgba(255, 215, 0, 0.15);
  border-color: var(--color-accent-gold);
}

.lang-globe {
  font-size: 0.75rem;
}

/* Dropdown panel */
.lang-dropdown {
  display: none;
  position: fixed;
  top: auto;
  right: 10px;
  min-width: 200px;
  max-height: 80vh;
  overflow-y: auto;
  background: #0f1f3a;
  border: 1px solid rgba(255, 215, 0, 0.4);
  border-radius: 6px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  z-index: 99999;
}

.lang-dropdown.lang-dropdown-open {
  display: block;
}

.lang-option {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 10px 14px;
  background: none;
  border: none;
  border-bottom: 1px solid rgba(255, 215, 0, 0.1);
  color: var(--color-text-primary);
  font-family: var(--font-primary);
  font-size: 0.85rem;
  cursor: pointer;
  transition: background 0.15s;
  text-align: left;
}

.lang-option:last-child {
  border-bottom: none;
}

.lang-option:hover {
  background: rgba(255, 215, 0, 0.1);
}

.lang-option-active {
  background: rgba(255, 215, 0, 0.08);
}

.lang-option-label {
  font-weight: 700;
  color: var(--color-accent-gold);
  min-width: 45px;
}

.lang-option-name {
  color: var(--color-text-secondary);
  font-size: 0.8rem;
  flex: 1;
}

.lang-coming-badge {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: #0a1628;
  background: rgba(255, 215, 0, 0.7);
  padding: 2px 6px;
  border-radius: 3px;
  white-space: nowrap;
}

.lang-option-coming {
  opacity: 0.7;
}

.lang-option-coming:hover {
  opacity: 1;
}

.lang-check {
  color: var(--color-accent-gold);
  font-size: 0.9rem;
  margin-left: auto;
}

/* Toast notification for Coming Soon */
.lang-toast {
  position: fixed;
  bottom: -80px;
  left: 50%;
  transform: translateX(-50%);
  background: #0f1f3a;
  border: 1px solid var(--color-accent-gold);
  color: var(--color-text-primary);
  padding: 14px 24px;
  border-radius: 8px;
  font-family: var(--font-primary);
  font-size: 0.9rem;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  z-index: 9999;
  transition: bottom 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  max-width: 500px;
  text-align: center;
  line-height: 1.5;
}

.lang-toast strong {
  color: var(--color-accent-gold);
}

.lang-toast-show {
  bottom: 30px;
}

/* Mobile: position selector in header area */
@media (max-width: 768px) {
  .lang-selector {
    position: absolute;
    top: 50%;
    right: 52px;
    transform: translateY(-50%);
    z-index: 99999;
    margin-left: 0;
  }

  .lang-current {
    font-size: 0.6rem;
    padding: 2px 6px;
  }

  .lang-globe {
    font-size: 0.75rem;
  }

  .lang-dropdown {
    right: 0;
    min-width: 180px;
  }
}

@media (max-width: 480px) {
  .lang-selector {
    top: 50%;
    right: 48px;
    transform: translateY(-50%);
  }

  .lang-current {
    font-size: 0.55rem;
    padding: 2px 5px;
  }
}

/* ============================================
   RTL (RIGHT-TO-LEFT) SUPPORT — Arabic
   When html[dir="rtl"] is set by i18n.js
   ============================================ */

/* Global text alignment */
[dir="rtl"] body {
  text-align: right;
  direction: rtl;
}

/* Navigation */
[dir="rtl"] .nav-links {
  flex-direction: row-reverse;
}

[dir="rtl"] .hamburger-menu {
  right: auto;
  left: 20px;
}

[dir="rtl"] .mobile-nav {
  text-align: right;
}

[dir="rtl"] .mobile-nav a {
  text-align: right;
}

/* Header */
[dir="rtl"] header .container,
[dir="rtl"] .header-content {
  flex-direction: row-reverse;
}

[dir="rtl"] .site-title {
  text-align: right;
}

/* Language selector — keep LTR positioning */
[dir="rtl"] .lang-selector-container {
  left: 20px;
  right: auto;
}

[dir="rtl"] .lang-dropdown {
  left: 0;
  right: auto;
}

/* Hero sections */
[dir="rtl"] .hero-content,
[dir="rtl"] .hero-text {
  text-align: right;
}

/* Cards and grid items */
[dir="rtl"] .relay-card,
[dir="rtl"] .feature-card,
[dir="rtl"] .volume-card,
[dir="rtl"] .book-card {
  text-align: right;
}

/* Lists */
[dir="rtl"] ul, [dir="rtl"] ol {
  padding-right: 1.5em;
  padding-left: 0;
}

/* Blockquotes */
[dir="rtl"] blockquote {
  border-right: 4px solid var(--color-accent-gold);
  border-left: none;
  padding-right: 1rem;
  padding-left: 0;
}

/* Flex containers that should reverse */
[dir="rtl"] .breadcrumb,
[dir="rtl"] .meta-info,
[dir="rtl"] .tag-list {
  flex-direction: row-reverse;
}

/* Back/forward arrows */
[dir="rtl"] .back-link::before {
  content: '→';
}

/* Footer */
[dir="rtl"] footer {
  text-align: right;
}

[dir="rtl"] .footer-links {
  flex-direction: row-reverse;
}

/* Tables */
[dir="rtl"] table {
  direction: rtl;
}

[dir="rtl"] th, [dir="rtl"] td {
  text-align: right;
}

/* Chapter/relay pages */
[dir="rtl"] .chapter-header {
  text-align: right;
}

[dir="rtl"] .chapter-nav {
  flex-direction: row-reverse;
}

[dir="rtl"] .chapter-content {
  text-align: right;
}

/* Relay grid */
[dir="rtl"] .relay-grid {
  direction: rtl;
}

/* Sidebar navigation */
[dir="rtl"] .sidebar {
  right: 0;
  left: auto;
}

/* Margins and paddings that need flipping */
[dir="rtl"] .ml-auto { margin-left: 0; margin-right: auto; }
[dir="rtl"] .mr-auto { margin-right: 0; margin-left: auto; }

/* Arabic font enhancement */
[dir="rtl"] body {
  font-family: 'Segoe UI', 'Tahoma', 'Arial', 'Noto Sans Arabic', sans-serif;
  line-height: 1.8;
}

[dir="rtl"] h1, [dir="rtl"] h2, [dir="rtl"] h3, [dir="rtl"] h4 {
  font-family: 'Georgia', 'Noto Serif Arabic', serif;
}


/* ============================================
   NAVIGATION OPTIMISATION — GROUPED DROPDOWNS
   Reduces 22 visible links to 6 grouped items
   ============================================ */

/* Nav Group — dropdown container */
.nav-group {
  position: relative;
  display: inline-block;
  flex-shrink: 0;
}

.nav-group-label {
  display: inline-block;
  padding: 0.3rem 0.7rem;
  color: var(--color-text-primary);
  background-color: transparent;
  border: 1px solid var(--color-accent-gold);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.3s ease;
  user-select: none;
}

.nav-group-label::after {
  content: ' ▾';
  font-size: 0.6rem;
  opacity: 0.7;
}

.nav-group-label:hover {
  background-color: rgba(255, 215, 0, 0.15);
  border-color: var(--color-accent-gold);
}

.nav-group-label.active {
  background-color: var(--color-accent-gold);
  color: var(--color-bg-primary);
  font-weight: 700;
  box-shadow: 0 0 12px rgba(255, 215, 0, 0.6), 0 0 4px rgba(255, 215, 0, 0.3);
  text-shadow: none;
  animation: nav-glow 2.5s ease-in-out infinite;
}

.nav-group-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  min-width: 200px;
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-accent-gold);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.6);
  z-index: 300000;
  padding: 0.4rem 0;
  margin-top: 4px;
}

.nav-group:hover .nav-group-dropdown,
.nav-group.open .nav-group-dropdown {
  display: block;
}

.nav-group-dropdown a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--color-text-primary);
  font-size: 0.8rem;
  font-weight: 500;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border: none;
  border-bottom: 1px solid rgba(255, 215, 0, 0.1);
  transition: background 0.2s;
  white-space: nowrap;
}

.nav-group-dropdown a:last-child {
  border-bottom: none;
}

.nav-group-dropdown a:hover {
  background: rgba(255, 215, 0, 0.12);
  color: var(--color-accent-gold);
}

.nav-group-dropdown a.active {
  background: rgba(255, 215, 0, 0.2);
  color: var(--color-accent-gold);
  font-weight: 700;
  border-left: 3px solid var(--color-accent-gold);
  padding-left: calc(1rem - 3px);
}

/* ============================================
   SCROLL PROGRESS BAR
   ============================================ */

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent-gold), #ffff00, var(--color-accent-gold));
  z-index: 10002;
  transition: width 0.1s linear;
  box-shadow: 0 0 8px rgba(255, 215, 0, 0.5);
}

/* ============================================
   FLOATING SECTION TOC (Table of Contents)
   ============================================ */

.floating-toc {
  position: fixed;
  right: 1.5rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 999;
  display: flex;
  flex-direction: column;
  gap: 6px;
  align-items: flex-end;
}

.floating-toc-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(255, 215, 0, 0.25);
  border: 1px solid rgba(255, 215, 0, 0.4);
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
}

.floating-toc-dot:hover {
  background: rgba(255, 215, 0, 0.6);
  transform: scale(1.3);
}

.floating-toc-dot.active {
  background: var(--color-accent-gold);
  box-shadow: 0 0 8px rgba(255, 215, 0, 0.6);
  transform: scale(1.2);
}

.floating-toc-dot:hover::before {
  content: attr(data-label);
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-accent-gold);
  color: var(--color-accent-gold);
  font-size: 0.7rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 4px;
  white-space: nowrap;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

/* ============================================
   READING COLUMN CONSTRAINT
   ============================================ */

.reading-column {
  max-width: 800px;
  margin: 0 auto;
}

/* ============================================
   MOBILE: Hide floating TOC, adjust dropdowns
   ============================================ */

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

  .nav-group-dropdown {
    position: fixed;
    top: auto;
    bottom: 0;
    left: 0;
    right: 0;
    transform: none;
    min-width: 100%;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    max-height: 50vh;
    overflow-y: auto;
    z-index: 300000;
    background: var(--color-bg-secondary);
    border-top: 2px solid var(--color-accent-gold);
    box-shadow: 0 -8px 32px rgba(0, 0, 0, 0.8);
  }

  .nav-group-dropdown a {
    padding: 0.75rem 1.2rem;
    font-size: 0.85rem;
    text-align: center;
  }
}