body
{
    background-color: lightgray;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.Contenedor
{
margin: auto;
background-color: #fff;
width: 800px;
padding: 30px;
}


ul,li
{
padding: 0;
margin: 0;
list-style: none;
}

ul.slider
{
    position: relative;
    width: 800px;
    height: 300px;
}

ul.slider li
{
    position: absolute;
    left: 0px;
    top: 0px;
    opacity: 0;
    width: inherit;
    height: inherit;
    transition: opacity .5s;
    background-color: #fff;
}

ul.slider li img
{
width: 100%;
height: 300px;
object-fit: cover;
}

ul.slider li:first-child
{
    opacity: 1;
}

ul.slider li:target
{
    opacity: 1;
}

.menu 
{
text-align: center;
margin: 20px;
}

.menu li
{
    display: inline-block;
    text-align: center;
}

.menu li a
{
    display: inline-block;
    color: #fff;
    text-decoration: none;
    background-color: grey;
    padding: 10px;
    width: 20px;
    height: 20px;
    text-align: center;
    font-size: 20px;
    border-radius: 100%;
}