* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html {
    font-size: 90%;
    font-family: Arial;
}
body {
    width: 100vw;
    height: 100vh;
    background: #000000;
    color: #b0bdbf;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    touch-action: none;
}

#game {
    position: relative;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, #000000, #142020);
    overflow: hidden;
}

.hero {
    position: absolute;
    width: 70px;
    height: 70px;
    background: #005bcd;
    border-radius: 50%;
    touch-action: none;
}

.enemy {
    position: absolute;
    width: 80px;
    height: 80px;
}
.enemy img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.bullet {
    position: absolute;
    width: 5px;
    height: 30px;
    background: #00bfc4;
    border-top-right-radius: 50%;
    border-top-left-radius: 50%;
}

.blast {
    position: absolute;
    width: 120px;
    height: 120px;
    animation: blast 0.3s forwards;
}
.blast img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

@keyframes blast {
    0% {
        transform: scale(1);
        opacity: 1;
    }
    100% {
        transform: scale(2);
        opacity: 0;
    }
}

#score,
#gameOver {
    position: absolute;
    color: #fff;
    font-size: 20px;
    font-weight: bold;
}

#score {
    top: 10px;
    left: 10px;
}

#gameOver {
    top: 50%;
    left: 50%;
    background: #000;
    width: 300px;
    height: 300px;
    border-radius: 5px;
    transform: translate(-50%, -50%);
    font-size: 30px;
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}
#gameOver h3 {
    color: #a0a0a0;
    font-weight: 900;
    text-align: center;
}
#gameOver .start-again {
    outline: none;
    border: none;
    border-radius: 5px;
    background: #0054d7;
    color: #fff;
    font-weight: 800;
    margin: 1rem auto;
    padding: 0.6rem 1rem;
}