style.css

body {
    background-blend-mode: overlay;
    background-image: url('images/back.jpg');
    background-repeat: no-repeat;
    background-size: cover;
    background-color: rgba(61, 26, 26, 0.9);
    text-align: center;
    color: rgb(181, 168, 168);
    height: 100vh;
    background-position: center;
}

a {
    color: white;
    text-decoration: none;
}

a:hover {
    color: red;
    text-decoration: none;
}

.box {
    background-color: rgba(0, 0, 0, 0.5);
    border-radius: 15%;
}

.da01 {
    background-image: url('images/da01.jpg');
    background-blend-mode: overlay;
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    border: 3px solid black;
    width: 95%;
    height: 95%;
    border-radius: 15%;
    opacity: 50%;
}

@media (max-width:600px) {
    .da01 {
        margin-top: 5%;
        width: 95%;
        height: 50%;
    }
    .box {
        width: 100vw;
        height: 83vh;

    }
    .da02 {
        width: 95%;
        height: 50%;
        display: flex;
        flex-direction: column;
    }
}

@media (min-width:600px) {
    .da01 {
        width: 40%;
        height: 95%;
    }
    .box {
        width: 80vw;
        height: 80vh;

    }
    .da02 {
        width: 40%;
        height: 95%;
        display: flex;
        flex-direction: column;
    }
}