style.css

:root {
    --color1: rgb(199, 196, 20);
    --cloor2: rgb(0, 0, 0);
    --color3: rgb(255, 4, 25);
}

html, body {
    margin: 0;
    padding: 0;
}

body {
    background-image: url(https://images.unsplash.com/photo-1597840900616-664e930c29df?w=1600&h=1600);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;   
}

section {
    padding: 16px;
    text-align: center;
}

h1 {
    background-color: var(--cloor2);
    font-family: 'Faster One', cursive;
    font-size: 64px;
    margin-top: 12px;
    color: var(--color1);
}

.scores, .grid {
    margin: auto;
    width: 400px;
    display: flex;
    align-items: center;
    opacity: 0.8;
}

.scores {
    color: black;
    text-align: center;
    background-color: var(--color1);
    justify-content: space-around;
    font-family: 'Press Start 2P', cursive;
    line-height: 2.5em;
    border: solid 6px black;
    border-bottom: none;
}

.grid {
    height: 400px;
    border: solid 6px var(--color1);
    border-top: none;
    flex-wrap: wrap;
    justify-content: center;
    background-color: var(--cloor2);
}

.square {
    width: 40px;
    height: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.snake {
    background-color: var(--color1);
    border-radius: 20px;
    text-align: center;
    font-size: 40px;
}

.fire {
    font-size: 40px;
}

.end {
    margin-top: 40px;
    font-size: 60px;
    color: var(--color3);
    position: absolute;
    top: auto;
    left: auto;
    display: none;
    animation: blinker 2s linear infinite;
}

@keyframes blinker {
    50% {
      opacity: 0;
    }
  }

.show {
    display: unset;
}

button {
    margin-top: 12px;
    padding: 16px;
    cursor: pointer;
    font-family: 'Press Start 2P', cursive;
    color: var(--color1);
    font-size: 24px;
    background-color: var(--cloor2);
    border: none;
}

button:focus {
    border: none;
    outline: none;
}