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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #e3f2fd;
  color: #1a1a1a;
  line-height: 1.6;
  padding: 40px 20px;
}

header, main {
  max-width: 900px;
  margin: 0 auto 40px;
  background: white;
  padding: 30px 40px;
  border-radius: 15px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

h1 {
  font-size: 3rem;
  color: #0d47a1;
  margin-bottom: 25px;
  text-align: center;
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 25px;
  margin-bottom: 30px;
}

nav ul li a {
  text-decoration: none;
  color: #1565c0;
  font-weight: 700;
  font-size: 1.1rem;
  padding: 10px 18px;
  border-radius: 12px;
  background: #bbdefb;
  transition: background-color 0.3s ease, color 0.3s ease;
}

nav ul li a:hover,
nav ul li a:focus {
  background-color: #0d47a1;
  color: #fff;
  box-shadow: 0 4px 10px rgba(13, 71, 161, 0.5);
}

h2 {
  font-size: 2.2rem;
  color: #0d47a1;
  margin-bottom: 18px;
  border-bottom: 3px solid #1565c0;
  padding-bottom: 6px;
}

h3 {
  font-size: 1.5rem;
  color: #1565c0;
  margin-bottom: 15px;
  margin-top: 30px;
  text-align: center;  
}

p {
  font-size: 1.15rem;
  color: #333;
  margin-bottom: 20px;
  text-align: center;  
}

ul {
  margin-left: 25px;
  margin-bottom: 30px;
  color: #444;
  text-align: center;  
}

ul li {
  margin-bottom: 10px;
  font-weight: 600;
  text-align: center; 
}

img {
  max-width: 100%;
  border-radius: 15px;
  box-shadow: 0 8px 25px rgba(21, 101, 192, 0.4);
  margin-top: 30px;
  display: block;
  cursor: pointer;
  margin-left: auto;
  margin-right: auto;
}