タイピング効果を実現するピュアhtml+css

<div class="text">hello,world!</div>

:root {
    /* number of characters */
    --steps: 12;
    /* animation time */
    --duration: 2.5s;
    /* Font size */
    --fontSize: 50px;
    /* cursor size */
    --cursorSize: 20px;
}

.text {
    color: #333;;
    position: relative;
    display: inline-block;
    font-family: 'Courier New', Courier, monospace;
    font-size: var(--fontSize);
    line-height: 1;
}

.text::after {
    content: '';
    width: var(--cursorSize);
    height: var(--fontSize);
    background-color: black;
    z-index: 2;
    position: absolute;
    animation: blink 1s var(--duration) step-end infinite,
               moveCursor var(--duration) steps(var(--steps)) forwards;
}

.text::before {
    content: '';
    width: 100%;
    height: var(--fontSize);
    z-index: 1;
    position: absolute;
    background: linear-gradient(#fff, #fff) no-repeat top right;
    animation: showText var(--duration) steps(var(--steps)) forwards;
}

/* cursor blink animation */
@keyframes blink {
    0% {
        background-color: black;
    }
    50% {
        background-color: transparent;
    }
    100% {
        background-color: black;
    }
}

/* cursor movement animation */
@keyframes moveCursor {
    0% {
        left: 0%;
    }
    100% {
        left: 100%;
    }
}

/* Background movement animation */
@keyframes showText {
    0% {
        background-size: 100% 100%;
    }
    100% {
        background-size: 0% 100%;
    }
}