* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #f5f7fa;
  color: #172033;
  line-height: 1.6;
}

header {
  background: linear-gradient(135deg, #0f172a, #1e3a5f);
  color: white;
  padding: 35px 20px;
}

header h1 {
  max-width: 900px;
  margin: 0 auto;
  font-size: 38px;
  line-height: 1.15;
}

header p {
  max-width: 900px;
  margin: 10px auto 0;
  color: #dbe4f0;
  font-size: 18px;
}

nav {
  max-width: 900px;
  margin: 0 auto 30px;
}

nav a {
  color: white;
  text-decoration: none;
  margin-right: 20px;
  font-weight: bold;
}

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 30px 20px 50px;
}

h2 {
  color: #172033;
  font-size: 28px;
  margin-top: 35px;
}

h3 {
  color: #1e3a5f;
  font-size: 23px;
  margin-bottom: 8px;
}

p {
  font-size: 17px;
}

a {
  color: #1769aa;
  font-weight: bold;
}

section,
.card {
  background: white;
  border-radius: 16px;
  padding: 25px;
  margin: 20px 0;
  box-shadow: 0 4px 18px rgba(15, 23, 42, 0.08);
}

button,
.cta {
  display: inline-block;
  background: #1769aa;
  color: white;
  border: none;
  border-radius: 10px;
  padding: 13px 20px;
  font-size: 16px;
  font-weight: bold;
  text-decoration: none;
  cursor: pointer;
}

button:hover,
.cta:hover {
  background: #0f4f82;
}

ul {
  padding-left: 25px;
}

li {
  margin-bottom: 8px;
}

footer {
  background: #172033;
  color: #cbd5e1;
  text-align: center;
  padding: 25px 15px;
  margin-top: 30px;
}

@media (max-width: 600px) {
  header {
    padding: 25px 16px;
  }

  header h1 {
    font-size: 30px;
  }

  header p {
    font-size: 16px;
  }

  main {
    padding: 20px 14px 40px;
  }

  section,
  .card {
    padding: 20px;
  }

  h2 {
    font-size: 24px;
  }

  h3 {
    font-size: 21px;
  }

  p {
    font-size: 16px;
  }

  nav a {
    display: inline-block;
    margin-bottom: 8px;
  }
}