The best way to do it, would be use HTML
<h2>Stay <span class="pure">Pure</span></h2>
and CSS
.pure {
font-weight: bold;
}
but it could be that you'll have some problem with certain template elements that do not accept HTML code.
In that case you are force to use javascript, search for specific selectors and inject the required HTML, but it could be laborious to find all selectors that you need.
e.g. just a concept
<script>
function pure_replace() {
const el = document.getElementById('text');
text = text.toLowerCase().replace('pure', '<span class="pure">Pure</span>')
el.innerHTML = text;
}
</script>
<body onload="pure_replace()">
