:root {
    --primary: #2a3b4c;
    --secondary: #e67e22;
    --accent: #f39c12;
    --text: #333333;
    --light: #ecf0f1;
    --dark: #1a2530;
    --danger: #c0392b;
    --success: #27ae60;
    --gray: #95a5a6;
  }

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

  body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--text);
    background-color: #f5f5f5;
  }

  .container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
  }

  h1, h2, h3, h4, h5, h6 {
    font-family: 'Montserrat', sans-serif;
    margin-bottom: 1rem;
    color: var(--primary);
  }

  h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    text-transform: uppercase;
  }

  h2 {
    font-size: 2rem;
    position: relative;
    padding-bottom: 0.5rem;
    margin-bottom: 2rem;
  }

  h2::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background-color: var(--secondary);
  }

  h3 {
    font-size: 1.5rem;
    color: var(--primary);
  }

  p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
  }

  img {
    max-width: 100%;
    height: auto;
    border-radius: 5px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  }

  .bg-image {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: 0;
    opacity: 0.2;
  }

  /* Hero Section */
  .hero-section {
    position: relative;
    background-color: var(--dark);
    color: var(--light);
    padding: 120px 0;
    text-align: center;
    overflow: hidden;
  }

  .hero-section .container {
    position: relative;
    z-index: 1;
  }

  .hero-section h1 {
    color: var(--light);
    font-size: 3.5rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
    margin-bottom: 1rem;
  }

  .hero-subtitle {
    font-size: 1.5rem;
    color: var(--accent);
    font-weight: 500;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
  }

  /* Tanks Overview */
  .tanks-overview {
    padding: 80px 0;
    background-color: var(--light);
  }

  .tanks-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
  }

  .tank-type {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
  }

  .tank-type:hover {
    transform: translateY(-10px);
  }

  .tank-type img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 8px 8px 0 0;
  }

  .tank-type h3, .tank-type p {
    padding: 0 20px;
  }

  .tank-type h3 {
    margin-top: 20px;
    color: var(--primary);
  }

  .tank-type p {
    padding-bottom: 20px;
  }

  /* National Lines */
  .national-lines {
    padding: 80px 0;
    background-color: var(--primary);
    color: var(--light);
    position: relative;
  }

  .national-lines h2 {
    color: var(--light);
  }

  .nations-accordion {
    margin-top: 40px;
  }

  .nation-item {
    margin-bottom: 15px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    overflow: hidden;
  }

  .nation-header {
    padding: 15px 20px;
    background-color: rgba(0, 0, 0, 0.2);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .nation-header h3 {
    color: var(--light);
    margin: 0;
    font-size: 1.3rem;
    display: flex;
    justify-content: space-between;
    width: 100%;
  }

  .nation-content {
    padding: 20px;
    display: none;
  }

  .nation-content p:last-child {
    margin-bottom: 0;
  }

  .nation-item.active .nation-content {
    display: block;
  }

  .nation-item.active .nation-header i {
    transform: rotate(180deg);
  }

  /* Tank Mechanics */
  .tank-mechanics {
    padding: 80px 0;
    background-color: #f9f9f9;
  }

  .mechanics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 40px;
  }

  .mechanic-card {
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    text-align: center;
    transition: transform 0.3s ease;
  }

  .mechanic-card:hover {
    transform: translateY(-5px);
  }

  .mechanic-card i {
    font-size: 2.5rem;
    color: var(--secondary);
    margin-bottom: 20px;
  }

  .mechanic-card h3 {
    margin-bottom: 15px;
  }

  .mechanic-card p {
    font-size: 1rem;
    margin-bottom: 0;
  }

  /* Tank Tips */
  .tank-tips {
    padding: 80px 0;
    background-color: var(--dark);
    color: var(--light);
    position: relative;
  }

  .tank-tips h2 {
    color: var(--light);
  }

  .tips-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
  }

  .tip-box {
    background-color: rgba(255, 255, 255, 0.1);
    padding: 30px;
    border-radius: 8px;
    position: relative;
    overflow: hidden;
  }

  .tip-number {
    position: absolute;
    top: 10px;
    right: 10px;
    font-size: 3rem;
    font-weight: 900;
    color: rgba(255, 255, 255, 0.1);
    line-height: 1;
  }

  .tip-box h3 {
    color: var(--accent);
    margin-bottom: 15px;
    position: relative;
    z-index: 1;
  }

  .tip-box p {
    position: relative;
    z-index: 1;
    margin-bottom: 0;
  }

  /* Links */
  a {
    color: var(--secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
  }

  a:hover {
    color: var(--accent);
    text-decoration: underline;
  }

  /* Responsive */
  @media (max-width: 768px) {
    h1 {
      font-size: 2rem;
    }
    
    h2 {
      font-size: 1.5rem;
    }
    
    h3 {
      font-size: 1.2rem;
    }
    
    .hero-section {
      padding: 80px 0;
    }
    
    .hero-subtitle {
      font-size: 1.2rem;
    }
    
    .tanks-grid, 
    .mechanics-grid, 
    .tips-container {
      grid-template-columns: 1fr;
    }
    
    section {
      padding: 60px 0;
    }
  }

  /* Screen reader only class */
  .sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
  }