:root {
  --primary-color: #1a202c;
  --background-light: #f7fafc;
  --spacing-unit: 1.5rem;
}

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

body {
  font-family: 'Roboto', sans-serif;
  line-height: 1.7;
  color: var(--primary-color);
  background-color: var(--background-light);
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--spacing-unit);
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: #0056b3;
  color: white;
  padding: 8px;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
}

header {
  background: #0056b3;
  color: white;
  text-align: center;
  padding: calc(2 * var(--spacing-unit));
  border-radius: 0 0 8px 8px;
}

h1 {
  font-size: 2.2rem;
}

.center-text {
  font-size: 1.1rem;
  margin: var(--spacing-unit) 0;
}

nav {
  background-color: var(--primary-color);
  padding: 1rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-menu {
  list-style: none;
  display: flex;
  justify-content: center;
}

.nav-menu li a {
  color: white;
  text-decoration: none;
  padding: 0.75rem 1.5rem;
  transition: background 0.3s;
}

.nav-menu li a:hover {
  background: #0056b3;
  border-radius: 4px;
}

.hamburger {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 1.5rem;
  cursor: pointer;
}

main {
  display: grid;
  gap: var(--spacing-unit);
  padding: var(--spacing-unit);
}

.hero {
  background: #e2e8f0;
  padding: var(--spacing-unit);
  border-radius: 8px;
}

h2 {
  color: #0056b3;
  font-size: 1.6rem;
  margin-bottom: var(--spacing-unit);
  text-align: center;
}

p, ul {
  margin-bottom: var(--spacing-unit);
  font-size: 1rem;
}

ul {
  list-style: disc;
  padding-left: 1.5rem;
}

.image-container, .chart-container {
  text-align: center;
  margin: var(--spacing-unit) 0;
}

img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
}



.share-buttons a {
  background: #0056b3;
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 6px;
  text-decoration: none;
  transition: background 0.3s;
}

.share-buttons a:hover {
  background: #003d82;
}

footer {
  background: var(--primary-color);
  color: white;
  text-align: center;
  padding: var(--spacing-unit);
  margin-top: var(--spacing-unit);
}

footer p {
  font-size: 0.9rem;
  margin: 0.5rem 0;
}

footer a {
  color: #ffffff;
  text-decoration: none;
}

.back-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: #0056b3;
  color: white;
  border: none;
  padding: 0.75rem;
  border-radius: 50%;
  cursor: pointer;
  display: none;
}

@media (max-width: 768px) {
  h1 {
    font-size: 1.8rem;
  }

  h2 {
    font-size: 1.4rem;
  }

  .hamburger {
    display: block;
  }

  .nav-menu {
    display: none;
    flex-direction: column;
    background: var(--primary-color);
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
  }

  .nav-menu.active {
    display: flex;
  }

  .nav-menu li a {
    padding: 1rem;
  }

  .back-to-top {
    display: block;
  }
    .center {
    text-align: center;
    margin: 0 auto;
  }

}