* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
.game {
    width: 600px;
    height: 200px;
    border: 1px solid #000000;
    margin: 50px auto;
    position: relative;
    overflow: hidden;
    background: url(../images/t-rex-background.png)
}
#dino {
    width: 50px;
    height: 50px;
    background-image: url(../images/dino.png);
    background-repeat: no-repeat;
    background-size: 40px 40px;
    position: relative;
    top: 150px;
}
.jump {
    animation: jump 0.3s linear;
}
@keyframes jump {
    0% {
        top: 150px;
    }
    30% {
        top: 130px;
    }
    50% {
        top: 80px;
    }
    80% {
        top: 130px;
    }
    100% {
        top: 150px;
    }
}
#cactus {
    width: 20px;
    height: 40px;
    background-image: url(../images/cactus.png);
    background-repeat: no-repeat;
    background-size: 20px 20px;
    position: relative;
    top: 120px;
    left: 580px;
    animation: block 1.7s infinite linear;
}
@keyframes block {
    0% {
        left: 580px;
    }
    100% {
        left: 0px;
    }
}
#cloud {
    width: 100px;
    height: 60px;
    background-image: url(../images/cloud.png);
    background-repeat: no-repeat;
    background-size: 80px 60px;
    position: relative;
    top: -40px;
    left: 520px;
    animation: cloud 3s infinite linear;
}
@keyframes cloud {
    0% {
        left: 520px;
    }
    100% {
        left: 0px;
    }
}
#birds {
    width: 100px;
    height: 200px;
    background-image: url(../images/birds.png);
    background-repeat: no-repeat;
    background-size: 100px 130px;
    position: relative;
    top: -70px;
    left: 320px;
    animation: birds 2s infinite linear;
}
@keyframes birds {
    0% {
        left: 520px;
    }
    100% {
        left: 0px;
    }
}