.slider {
position: relative;
 max-width: 1200px;
 margin: auto;
 height: 400px;
z-index:9;
 cursor: pointer;
}

.slider img {
    width: 100%;
    display: none;
}

.slider img.active {
    display: block;
}

button.prev, button.next {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background-color: rgba(0,0,0,0.5);
    color: white;
    border: none;
    padding: 10px;
    cursor: pointer;
}

button.prev {
    left: 10px;
}

button.next {
    right: 10px;
}