Create a CSS animated diagonal line

Can someone help me in replicating the animated red line on the Mahindra?

I have tried using the CSS but it didn't work.

I have replicated the existing CSS but I'm having no luck, it seems such a simple thing but I can't make it work.

Edit: I have got it working, but only on hover, is there a way to do it automatically?

Here's my code:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-css -->

.content {
    position: absolute;
    width: 60%;
    left: calc(5% + 0.75rem);
    transform: translate(0, 0%);
    top: 20%;
    color: #000;
    z-index: 2;
}

.content:before {
    content: "";
    display: block;
    position: absolute;
    width: 120px;
    height: 8px;
    background: #dd052b;
    left: 0;
    top: 50px;
    transform: rotate(-20deg) skew(-20deg) translate(-120%, 0);
    clip-path: inset(0 100% 0 0);
}

.content:after {
    content: "";
    display: block;
    position: absolute;
    width: 120px;
    height: 8px;
    background: #dd052b;
    left: 0;
    bottom: auto;
    top: 50px;
    transform: rotate(-20deg) skew(-20deg) translate(200%, 0%);
    clip-path: inset(0 100% 0 0);
}

.content:hover:after {
    clip-path: inset(0 0% 0 0);
    transition: all 0.6s linear;
    transition-delay: 1s;
}

.content:hover:before {
    clip-path: inset(0 0% 0 0);
    transition: all 0.6s linear;
    transition-delay: 0s;
}

<!-- language: lang-html -->

<div class="content text-center text-lg-start active">
    <small style="transform: translate3d(0px, 0px, 0px); opacity: 1; visibility: inherit;">ABOUT US</small>
    <h1 class="heading font-medium font-size-tb" style="transform: translate3d(0px, 0px, 0px); opacity: 1; visibility: inherit;">Planet, People, Trust</h1>
    <p style="transform: translate3d(0px, 0px, 0px); opacity: 1; visibility: inherit;">Committed to drive positive change across global markets and communities.</p>
</div>

<!-- end snippet -->

Basically, you had ::after and ::before and you overrode them on :hover. Since you want it to be "automatic", you should use CSS animations.

I've created an animation. Also added animation-delay: 750ms; property to make ::after wait 750ms before it starts (so ::before will work for 1000ms and after 750ms ::after will start). Also added opacity: 0; to ::after to hide it during showing ::before and changed it to 1 at the end of animation, as well as I added animation-fill-mode: forwards; to keep the last state of ::after.

Also, I removed a lot of not needed stuff (unless you were using them for some other purpose), so here's the final code:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-css -->

.content {
    position: absolute;
    width: 60%;
    left: calc(5% + 0.75rem);
    transform: translate(0, 0%);
    top: 20%;
}

@keyframes animation {
    0% {
        clip-path: inset(0 100% 0 0);
    }
    100% {
        clip-path: inset(0 0% 0 0);
        opacity: 1;
    }
}

.content:before {
    content: "";
    position: absolute;
    width: 120px;
    height: 8px;
    background: #dd052b;
    top: 50px;
    animation: animation 1s;
    transform: rotate(-20deg) skew(-20deg) translate(-120%, 0);
}

.content:after {
    opacity: 0;
    content: "";
    position: fixed;
    width: 120px;
    height: 8px;
    background: #dd052b;
    top: 50px;
    animation: animation 1s;
    animation-delay: 750ms;
    animation-fill-mode: forwards;
    transform: rotate(-20deg) skew(-20deg) translate(200%, 0%);
}

<!-- language: lang-html -->

<div class="content">
    <small>ABOUT US</small>
    <h1>Planet, People, Trust</h1>
    <p>Committed to drive positive change across global markets and communities.</p>
</div>

<!-- end snippet -->