/* ============================================
   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 */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  
  /* 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: 1.6;
  font-size: 16px;
}

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

h1 {
  font-family: var(--font-heading);
  font-size: 3.5rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: var(--spacing-lg);
  line-height: 1.2;
}

h2 {
  font-family: var(--font-heading);
  font-size: 2.5rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--spacing-md);
  line-height: 1.3;
}

h3 {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--spacing-md);
}

h4 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: bold;
  color: var(--color-accent-gold);
  margin-bottom: var(--spacing-sm);
}

p {
  font-size: 1rem;
  line-height: 1.8;
  margin-bottom: var(--spacing-md);
  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: 3px solid var(--color-accent-gold);
  padding: var(--spacing-md) var(--spacing-xl);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  text-align: center;
}

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

.header-subtitle {
  display: none;
}

/* Navigation Bar */
nav {
  display: flex;
  flex-wrap: nowrap;
  gap: var(--spacing-xs);
  justify-content: center;
  overflow-x: auto;
  padding: var(--spacing-sm) 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(10px, 10px);
}

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

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

nav a {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-sm);
  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: 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-yellow);
  color: var(--color-bg-primary);
  border-color: var(--color-accent-yellow);
}

/* 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: 1400px;
  margin: 0 auto;
  padding: var(--spacing-xl);
  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-lg);
  margin-bottom: var(--spacing-lg);
}

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

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

.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-lg);
  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-md);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin: var(--spacing-lg) 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-lg) 0;
}

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

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

footer {
  background-color: var(--color-bg-secondary);
  border-top: 3px solid var(--color-accent-gold);
  padding: var(--spacing-xl);
  margin-top: var(--spacing-2xl);
  text-align: center;
}

.footer-content {
  max-width: 1400px;
  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 {
    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: var(--spacing-sm);
  }
  
  .header-title {
    font-size: 1.25rem;
    margin-bottom: 0;
    flex: 1;
  }
  
  header {
    display: flex;
    flex-direction: column;
    padding: var(--spacing-md) var(--spacing-lg);
  }
  
  .header-subtitle {
    font-size: 0.85rem;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
  
  .hamburger {
    display: flex;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
  }
  
  .hamburger span {
    width: 24px;
    height: 3px;
    background-color: var(--color-accent-gold);
    display: block;
    transition: all 0.3s ease;
  }
  
  .hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
  }
  
  .hamburger.active span:nth-child(2) {
    opacity: 0;
  }
  
  .hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(8px, -8px);
  }
  
  nav {
    position: static;
    display: grid !important;
    grid-template-columns: repeat(3, 1fr) !important;
    background-color: var(--color-bg-secondary);
    border-bottom: 3px solid var(--color-accent-gold);
    gap: 1px;
    padding: 2px 1px;
    width: 100%;
    box-sizing: border-box;
    max-height: 500px;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }
  
  nav.collapsed {
    max-height: 0;
    padding: 0;
  }
  
  nav a {
    text-align: center;
    border: 1px solid var(--color-accent-gold);
    border-radius: var(--radius-sm);
    padding: 2px 0;
    font-size: 0.6rem;
    white-space: nowrap;
    text-overflow: ellipsis;
    box-sizing: border-box;
    line-height: 1.2;
    margin: 0;
    display: flex !important;
    align-items: center;
    justify-content: center;
  }
  
  nav a:last-child {
    border-bottom: none;
  }
  
  .card-grid {
    grid-template-columns: 1fr;
  }
  
  .relay-nav {
    gap: 4px;
  }
  
  .relay-nav button {
    min-width: 35px;
    padding: 4px 6px;
    font-size: 0.75rem;
  }
}

@media (max-width: 480px) {
  header {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  main {
    padding: var(--spacing-md);
  }
  
  .header-title {
    font-size: 1rem;
  }
  
  .header-subtitle {
    font-size: 0.75rem;
  }
  
  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: calc(33.33% - 2px);
    padding: 1px 0;
    font-size: 0.55rem;
    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);
}