:root {
  --primary-color: #2c3e50; /* Slate Blue */
  --secondary-color: #34495e; /* Darker Slate */
  --bg-color: #ffffff; /* White */
  --text-color: #333333;
  --link-color: #2980b9;
  --font-family: 'Helvetica Neue', Arial, sans-serif;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
}

header {
  background-color: var(--primary-color);
  color: #fff;
  padding: 1rem;
}

header a {
  color: #fff;
  text-decoration: none;
}

header nav ul {
  list-style: none;
  display: flex;
  gap: 1rem;
}

main {
  padding: 2rem;
  max-width: 800px;
  margin: 0 auto;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--primary-color);
  margin-bottom: 1rem;
}

a {
  color: var(--link-color);
}

.ad-container-leaderboard {
  min-height: 250px;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #f4f4f4;
  margin: 1rem 0;
}

@media (min-width: 768px) {
  .ad-container-leaderboard {
    min-height: 90px;
  }
}

footer {
  background-color: var(--secondary-color);
  color: #fff;
  text-align: center;
  padding: 1rem;
  margin-top: 2rem;
}

footer a {
  color: #fff;
  margin: 0 0.5rem;
}

.cta {
  background-color: #ecf0f1;
  padding: 1rem;
  border-radius: 5px;
  margin-top: 2rem;
}

.cta h3 {
  margin-top: 0;
}