body {
  font-family: 'Segoe UI', 'Roboto', Arial, sans-serif;
  background: #f7f9fb;
  color: #222;
  margin: 0;
  padding: 0;
}

html {
  scroll-padding-top: 56px; /* Offset for sticky navbar height */
}

.navbar {
  background: #222e50;
  padding: 0.5rem 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  position: sticky;
  top: 0;
  z-index: 100;
}
.navbar ul {
  list-style: none;
  display: flex;
  justify-content: center;
  margin: 0;
  padding: 0;
}
.navbar li {
  margin: 0 1.2rem;
}
.navbar a {
  color: #fff;
  text-decoration: none;
  font-weight: 500;
  font-size: 1.1rem;
  transition: color 0.2s;
  padding: 0.3rem 0.7rem;
  border-radius: 4px;
}
.navbar a:hover, .navbar a:focus {
  background: #4062bb;
  color: #fff;
}

main {
  max-width: 800px;
  margin: 2.5rem auto 2rem auto;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(34,46,80,0.07);
  padding: 2.5rem 2rem;
}
section {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid #e0e6ed;
}
section:last-child {
  border-bottom: none;
}

h1, h2 {
  color: #222e50;
  margin-top: 0;
}
h1 {
  font-size: 2.5rem;
  margin-bottom: 0.2em;
}
h2 {
  font-size: 1.5rem;
  margin-bottom: 0.7em;
  letter-spacing: 0.01em;
}

.introduction p {
  font-size: 1.1rem;
  margin: 0.3em 0;
}

ul {
  padding-left: 1.2em;
  margin: 0.5em 0 0.5em 0;
}
li {
  margin-bottom: 0.3em;
  font-size: 1.05rem;
}

strong {
  color: #4062bb;
}

a {
  color: #4062bb;
  text-decoration: underline;
}
a:hover {
  color: #23305e;
}

@media (max-width: 600px) {
  main {
    padding: 1.2rem 0.5rem;
  }
  h1 {
    font-size: 2rem;
  }
  h2 {
    font-size: 1.2rem;
  }
  .navbar ul {
    flex-direction: column;
    align-items: center;
  }
  .navbar li {
    margin: 0.5rem 0;
  }
}