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

body {
    background: #333;
    overflow: hidden;
}

object {
    position: absolute;
    pointer-events: none;
}

#ship, #explosion {
    width: 100px;
}

#ufo {
    width: 80px;
}

#missile, #laser {
    width: 50px;
}

#target {
    width: 100px;
    display: inline;
    z-index: 2;
    opacity: 0.5;
    transform: translate(-50%, -50%);
}

.overlay {
    position: relative;
    width: 100vw;
    padding: 0 1rem;

    background: rgba(0, 0, 0, 0.5);
    color: white;
    z-index: 1;

    display: flex;
    justify-content: space-between;
    align-items: center;
}

.overlay .score {
    font-size: 2rem;
}

#score {
    color: royalblue;
}

@keyframes scale {
    0% {
        transform: scale(1);
    }
    100% {
        transform: scale(1.1);
    }
}

.overlay .header {
    font-size: 3rem;
    font-weight: bold;
    color: white;
}

.overlay .controls {
    font-size: 1.25rem;
    display: flex;
    gap: 1.5rem;
}

.overlay .controls span {
    color: royalblue;
}

#scene .container {
    position: absolute;
    top: 50vh;
    width: 100vw;
    padding: 2rem;

    background: rgba(0, 0, 0, 0.5);
    font-size: 2rem;
    color: white;
    transform: translate(0, -50%);
    border-style: none;
    z-index: 400;
    cursor: pointer;

    transition: top 1s linear;

    display: flex;
    justify-content: center;
    align-items: center;
}

#scene .container h1 {
    animation-name: scale;
    animation-duration: 1s;
    animation-timing-function: ease-in-out;
    animation-iteration-count: infinite;
    animation-direction: alternate-reverse;
}

#scene.playing .container {
    display: none;
}

#scene object {
    display: none;
}

#scene.playing object {
    display: inline;
}