/* RESET */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  /* GLOBAL */
  body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f2f2f2;
  }
  
  /* NAVIGATION */
  header {
    width: 100%;
    background-color: #003366;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }
  nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 2rem;
  }
  nav .logo {
    color: #ffffff;
    font-size: 1.5rem;
    font-weight: bold;
  }
  nav ul {
    list-style: none;
    display: flex;
    gap: 1rem;
  }
  nav ul li a {
    text-decoration: none;
    color: #ffffff;
    padding: 0.5rem 1rem;
    transition: background 0.3s;
  }
  nav ul li a:hover,
  nav ul li a.active {
    background-color: #1f5baa;
    border-radius: 4px;
  }
  
  /* HERO SECTION */
  .hero {
    width: 100%;
    background: url('https://images.unsplash.com/photo-1473654729523-203e25dfda10?ixlib=rb-4.0.3&auto=format&fit=crop&w=1280&q=80')
      center/cover no-repeat;
    min-height: 50vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    color: #fff;
  }
  .hero::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 51, 102, 0.5);
    top: 0;
    left: 0;
  }
  .hero-content {
    position: relative;
    text-align: center;
    max-width: 600px;
    padding: 1rem;
  }
  .hero-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
  }
  .hero-content p {
    font-size: 1.2rem;
    margin-bottom: 1rem;
  }
  .cta-btn {
    background-color: #ffd700;
    color: #333;
    padding: 0.8rem 1.5rem;
    text-decoration: none;
    font-weight: bold;
    border-radius: 4px;
    transition: background 0.3s;
  }
  .cta-btn:hover {
    background-color: #ffc300;
  }
  
  /* MAIN CALCULATOR SECTION */
  main {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem 2rem;
    background-color: #ffffff;
    border-radius: 8px;
    box-shadow: 0px 2px 6px rgba(0, 0, 0, 0.1);
  }
  main h2 {
    text-align: center;
    padding: 1.5rem 0 1rem;
  }
  main p {
    text-align: center;
    margin-bottom: 2rem;
  }
  
  /* MULTI-STEP FORM */
  form {
    width: 100%;
    padding: 1rem 2rem;
  }
  .step-indicators {
    display: flex;
    justify-content: center;
    margin-bottom: 1.5rem;
  }
  .step-indicator {
    width: 35px;
    height: 35px;
    line-height: 35px;
    border-radius: 50%;
    background-color: #d3d3d3;
    color: #333;
    text-align: center;
    margin: 0 5px;
    font-weight: bold;
    transition: background 0.3s;
  }
  .step-indicator.active {
    background-color: #003366;
    color: #fff;
  }
  .form-step {
    display: none;
    opacity: 0;
    transition: opacity 0.5s ease-in-out;
  }
  .form-step.active {
    display: block;
    opacity: 1;
  }
  .form-group {
    margin-bottom: 1rem;
  }
  .form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
  }
  .form-group input[type='number'],
  .form-group select {
    width: 100%;
    padding: 0.6rem;
    border: 1px solid #ccc;
    border-radius: 4px;
  }
  .button-group {
    display: flex;
    justify-content: space-between;
    margin-top: 1.5rem;
  }
  .prev-btn,
  .next-btn,
  #calculateBtn,
  #resetBtn {
    background-color: #003366;
    color: #ffffff;
    border: none;
    padding: 0.7rem 1.2rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.3s;
  }
  .prev-btn:hover,
  .next-btn:hover,
  #calculateBtn:hover,
  #resetBtn:hover {
    background-color: #1f5baa;
  }
  
  /* RESULTS SECTION */
  #results {
    text-align: center;
    padding: 1.5rem 2rem;
    margin-top: 2rem;
    border-top: 1px solid #ccc;
  }
  #results.hidden {
    display: none;
  }
  .results-summary {
    margin: 1rem 0;
  }
  #footprintValue {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
  }
  #funFact {
    font-size: 1rem;
    color: #555;
    margin-bottom: 1rem;
  }
  .disclaimer {
    font-size: 0.9rem;
    color: #555;
    margin-bottom: 1rem;
    font-style: italic;
  }
  /* CHART CONTAINER */
  .chart-container {
    margin: 1rem auto;
    max-width: 600px;
    padding: 1rem;
  }
  /* COMPARISONS */
  .comparisons {
    text-align: left;
    margin-top: 2rem;
    background-color: #f9f9f9;
    border-radius: 8px;
    padding: 1rem;
    box-shadow: 0px 1px 3px rgba(0, 0, 0, 0.1);
  }
  .comparisons.hidden {
    display: none;
  }
  .comparisons h3 {
    margin-bottom: 1rem;
  }
  .comparisons ul {
    list-style: disc;
    margin-left: 1.5rem;
  }
  .comparisons li {
    margin-bottom: 0.5rem;
    line-height: 1.4;
  }
  
  /* RECOMMENDATIONS */
  #recommendations {
    text-align: left;
    margin-top: 2rem;
    background-color: #f8f8f8;
    border-radius: 8px;
    padding: 1rem;
    box-shadow: 0px 1px 3px rgba(0, 0, 0, 0.1);
  }
  #recommendations.hidden {
    display: none;
  }
  #recommendations h3 {
    margin-bottom: 1rem;
  }
  #recommendations ul {
    list-style: disc;
    margin-left: 1.5rem;
  }
  #recommendations li {
    margin-bottom: 0.5rem;
  }
  
  /* ABOUT SECTION */
  #about {
    max-width: 800px;
    margin: 2rem auto;
    padding: 1rem;
    background-color: #ffffff;
    border-radius: 8px;
    box-shadow: 0px 2px 6px rgba(0, 0, 0, 0.1);
  }
  #about h2 {
    text-align: center;
    margin-bottom: 1rem;
  }
  
  /* FOOTER */
  footer {
    text-align: center;
    background-color: #003366;
    color: #fff;
    padding: 1rem 0;
    margin-top: 2rem;
    font-size: 0.9rem;
  }