SOURCE

<p>
<span class="text-1">H</span><span class="text-2">E</span><span class="text-3">L</span><span class="text-4">L</span><span class="text-5">O</span>
</p>

@mixin text3d($color: #ffd300, $x: 1, $y: -1,  $darken: 1, $depth: 12) {
    $all: ();
    @for $i from 0 through $depth {
        $all: append($all, append($i*1px $i*1px 0, darken($color, ($i+14%)*$darken)), comma);
    }
    color: $color;
    text-shadow: $all
}

@for $i from 1 through 5 {
    .text-#{$i} {
        @include text3d  ($color: rgba(random(255), random(255), random(255), 1), $depth: 5);
    }
}

p {
    font-size: 100px;
    margin: 0;
}