*{
    padding: 0;
    margin: 0;
}        

body{
    height: 100vh;
    background: #495057;
    display: flex;
    align-items: center;
}

.contenedor {
    width: 100%;
    height: 500px;
    margin: 0 auto;
    background-color: aliceblue;
    position: relative;
    background: linear-gradient(#B7D6C7 transparent) #ffe2D1;
    transition: background-color 1s linear;
    overflow: hidden;
}

.mediodia {
    background-color: #ffdcf3;
}

.tarde {
    background-color: #ffadad;
}

.noche {
    background-color: #aca8c7;
}

.dino {
    width: 84px;
    height: 84px;
    position: absolute;
    bottom: 22px;
    left: 42px;
    z-index: 2;
    background: url(../img/dino.png) repeat-x 0px 0px;
    background-size: 336px 84px;
    background-position-x: 0px; 

}

.dino-corriendo{
    animation: animarDino 0.25s steps(2) infinite;
}

.dino-estrellado{
    background-position-x: -252px;
}

.suelo{
    width: 200%;
    height: 42px;
    position: absolute;
    bottom: 0px;
    left: 0px;
    background: url(../img/suelo.png) repeat-x 0px 0px;
    background-size: 50% 42px;
}

.score{
    width: 100px;
    height: 30px;
    position: absolute;
    top: 5px;
    right: 15px;
    z-index: 10;
    color: #0c0a0a;
    font-family: Verdana;
    font-size: 30px;
    font-weight: bold;
    text-align: right;
}

.cactus{
    width: 46px;
    height: 96px;
    position: absolute;
    bottom: 16px;
    left: 600px;
    z-index: 1;
    background: url(../img/cactus1.png) no-repeat;
}

.cactus2{
    width: 98px;
    height: 66px;
    background: url(../img/cactus2.png) no-repeat;
}

.nube{
    width: 92px;
    height: 26px;
    position: absolute;
    z-index: 0;
    background: url(../img/nube.png) no-repeat;
    background-size: 92px 26px;
}

.game-over{
    display: none;
    position: absolute;
    width: 100%;
    text-align: center;
    color: #e63946;
    font-size: 40px;
    font-family: Verdana;
    font-weight: 700;
}

.btn-general{
    margin-top: 1.4rem;
    margin-left: -4.2rem;
    width: 100%;
}

.res-button{
    cursor: pointer;
    font-size: 1rem;
    font-weight: bold;
    font-family: Verdana;
    position: absolute;
    text-align: center;
    background-color: #0c0a0a;
    color: lightgreen;
    border: 3px solid lightgreen;
    border-radius: 1rem;
    padding: .5rem;
    transition: 1.5s all;
}

.res-button:hover{
    color: lightskyblue;
    border: 3px solid lightskyblue;
    transform: scale(1.1);
}

@keyframes animarDino {
    from{
        background-position-x: -84px;
    }
    to{
        background-position-x: -252px;
    }
}