/* Base styles - mobile first */
body {
    font-family: 'Roboto', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f5f9ff;
    color: #333;
    line-height: 1.6;
  }
  
  header {
    background: linear-gradient(135deg, #0066cc, #00ccff);
    color: white;
    padding: 1.5rem 2rem;
    text-align: center;
  }
  
  nav {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    background: #004080;
    padding: 1rem;
    gap: 0.5rem;
    justify-items: center;
    flex-wrap: wrap;
  }
  
  nav a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    background-color: transparent;
    transition: background 0.3s;
  }
  
  nav a:hover {
    background: #3399ff;
  }
  
  main {
    padding: 2rem;
    max-width: 1200px;
    margin: auto;
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  /* Layout adjusts at tablet and desktop sizes */
  @media (min-width: 600px) {
    main {
      grid-template-columns: repeat(2, 1fr);
    }
  }
  
  @media (min-width: 1000px) {
    main {
      grid-template-columns: repeat(3, 1fr);
    }
  }
  
  /* Sections stay consistent */
  section {
    background: white;
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }
  
  h1, h2 {
    color: #004080;
  }
  
  img, .responsive-image {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 1.5rem auto;
    border-radius: 8px;
  }
  
  /* Hero always spans full width */
  .hero {
    background: url('https://images.unsplash.com/photo-1507525428034-b723cf961d3e') no-repeat center center / cover;
    color: white;
    padding: 4rem 2rem;
    text-align: center;
    border-radius: 12px;
    margin-bottom: 2rem;
    grid-column: 1 / -1; /* full width */
  }
  
  .hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
  }
  
  .hero p {
    font-size: 1.2rem;
  }
  
  footer {
    background: #00264d;
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: 2rem;
    grid-column: 1 / -1;
  }