body {
    margin: 0;
    font-family: Arial, sans-serif;
    color: #fff;
    background: url('../images/background.gif') no-repeat center center fixed;
    background-size: cover;
    animation: gradientBG 15s ease infinite;
}
@keyframes gradientBG {
    0% {background-position: 0% 50%;}
    50% {background-position: 100% 50%;}
    100% {background-position: 0% 50%;}
}
header {
    background: rgba(0, 0, 0, 0.7);
    padding: 30px;
    text-align: center;
    font-size: 1.5em;
}
h1 {
    font-size: 3em;
    margin: 0;
}
nav {
    margin-top: 15px;
    font-size: 1.2em;
}
nav a {
    color: #fff;
    margin: 0 15px;
    text-decoration: none;
    border-bottom: 2px solid transparent;
    transition: border-color 0.3s;
}
nav a:hover {
    border-bottom: 2px solid #fff;
}
section {
    padding: 60px;
    text-align: center;
}
footer {
    background: rgba(0, 0, 0, 0.8);
    padding: 20px;
    text-align: center;
    font-size: 1em;
    position: absolute;
    bottom: 0;
    width: 100%;
}