.sec2{
    width: 100%;
    height: 450px;
}
.main-slider{
    width: 70%;
    height: 400px;
    position: absolute;
    left: 50%;
    top: 60%;
    transform: translate(-50%, -50%);
    background-image: url(./picture/slide-1.jpg);
    background-size: 100% 100%;
    box-shadow: 1px 2px 10px 5px black;
    animation: img-slider 9s infinite linear;
    opacity: 0.5;
}
@keyframes img-slider{
    0%{opacity: 1;
        background-image: url(./picture/slide-1.jpg);}
    100%{opacity: 1;
        background-image: url(./picture/slide-3.png);}
}


/* Responsive styles */
@media (max-width: 768px) {
    .sec2 {
        width: 100%;
        height: 200px;
    }

    .main-slider{
        width: 100%;
        height: 200px;
        /* left: 10%; */
        top: 133%;
    }
}