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

body {
  font-family: Arial, sans-serif;
  background: #0b0c1a;
  color: #e0e0e0;
  line-height: 1.6;
  position: relative;
  padding-bottom: 40px;
}

.marca-dagua {
  background: url('logo-marca-dagua.png') no-repeat center center;
  background-size: 45%;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0.04;
  z-index: 0;
  pointer-events: none;
}

header {
  background: #001122;
  padding: 30px 10px;
  text-align: center;
  color: #00aaff;
}

nav {
  text-align: center;
  margin-bottom: 20px;
}

nav a {
  color: #00c0ff;
  text-decoration: none;
  margin: 0 10px;
  font-weight: bold;
}

nav a:hover {
  text-decoration: underline;
}

main {
  padding: 20px;
  max-width: 900px;
  margin: auto;
  position: relative;
  z-index: 1;
}

section {
  margin-bottom: 30px;
}

h2 {
  color: #00aaff;
  margin-bottom: 10px;
  border-bottom: 2px solid #00aaff;
  padding-bottom: 6px;
  margin-top: 10px;
}

ul {
  list-style: inside disc;
  margin-left: 20px;
}

footer {
  text-align: center;
  padding: 15px;
  margin-top: 20px;
  background: #001122;
}