style.css

/* ======================== */
/* 
    Ignore the following styles. They are not important to achieve the effect.
    I'm only using them for looks (overall page background/font styles/centering content).
*/
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300&display=swap');

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: #090221;
    display: grid;
    place-content: center;
    height: 100vh;
    padding: 5px;
    color: #fff;
}

/* ======================== */

.scene {
    width: 230px;
    height: 200px;
    background-color: #4695ea;
    border-radius: 4px;
    position: relative;
    overflow: hidden;
}

.scene img {
    position: absolute;
}

.city {
    bottom: -3px;
    width: 100%;
    height: 50%;
    object-fit: cover;
}

.plane {
    top: 50px;
    left: -50px;
    width: 45%;
    animation: plane-move 15s linear forwards;
}

.cloud {
    animation: clouds-move 22s linear forwards;
}

.cloud-1 {
    width: 70px;
    top: 0;
    left: 30px;
}

.cloud-2 {
    width: 35px;
    top: 20px;
    left: 125px;
}

.cloud-3 {
    width: 45px;
    top: 55px;
    left: 145px;
}

.boat {
    width: 30%;
    bottom: 0;
    right: -50px;
    animation: boat-move 20s linear forwards;
}

@keyframes plane-move {
    to {
        transform:
            translate(300px, -100px);
    }
}

@keyframes clouds-move {
    to {
        transform:
            translateX(-25px);
    }
}

@keyframes boat-move {
    to {
        transform:
            translateX(-300px);
    }
}