:root {
  --primary-color: #004d99;
  --accent-color: #00ccff;
}

body {
  font-family: 'Roboto', sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f8f8f8;
  color: #333;
}

header {
  background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
  color: #fff;
  padding: 1.5em 1em;
  text-align: center;
}

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

nav a {
  color: inherit;
  margin: 0 0.5em;
  font-weight: 700;
}

.hero {
  text-align: center;
  padding: 3em 1em;
}

.btn {
  display: inline-block;
  background-color: var(--primary-color);
  color: #fff;
  padding: 0.75em 1.5em;
  text-decoration: none;
  border-radius: 4px;
}

.btn:hover {
  background-color: var(--accent-color);
}

.placeholder {
  padding: 2em 1em;
}

main {
  max-width: 800px;
  margin: 2em auto;
  padding: 0 1em;
  background-color: #fff;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

footer {
  text-align: center;
  padding: 1em;
  background-color: #f1f1f1;
}