style.css

html {
    box-sizing: border-box;
}

body {
    background: linear-gradient(to right, red, white, green);
}

h1 {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 50px;
    text-align: center;
    margin-top: auto;
    font-weight: lighter;
    text-shadow: 2px 5px 10px;
    padding: 10px;
}

ul {
    list-style-type: none;
    padding-left: 20px;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 20px auto
}

li {
    font-size: 20px;
    padding: 25px;
    border: 2px solid gray;
    border-radius: 5px;
    margin-bottom: 5px;
    text-align: center;
}

.la {
    background-image: url(images/Lasaña.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
}

.pi {
    background-image: url(images/margarita.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
}

.ri {
    background-image: url(images/risotto.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
}