body {
    background-color: #000;
    color: #f00;
    font-family: 'Courier New', Courier, monospace;
    text-align: center;
    padding-top: 20vh;
    margin: 0;
}

h1 {
    font-size: 4em;
    text-shadow: 0 0 10px #f00, 0 0 20px #900;
    animation: flicker 2s infinite;
}

@keyframes flicker {
    0%, 19%, 21%, 23%, 25%, 54%, 56%, 100% {
        opacity: 1;
    }
    20%, 22%, 24%, 55% {
        opacity: 0.4;
    }
}