design-themes/theme_treehouse/views/snippets/s_features.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>

<template id="s_features" inherit_id="website.s_features">
    <!-- Section -->
    <xpath expr="//section" position="attributes">
        <attribute name="class" add="pt48 pb48" remove="pt32 pb32" separator=" "/>
    </xpath>
    <!-- Icons -->
    <xpath expr="(//i)[1]" position="attributes">
        <attribute name="class" add="fa-2x fa-leaf m-4 rounded-circle" remove="fa-3x fa-gear m-3 rounded" separator=" "/>
    </xpath>
    <xpath expr="(//i)[2]" position="attributes">
        <attribute name="class" add="fa-2x fa-flash m-4 rounded-circle" remove="fa-3x fa-photo m-3 rounded" separator=" "/>
    </xpath>
    <xpath expr="(//i)[3]" position="attributes">
        <attribute name="class" add="fa-2x fa-tint m-4 rounded-circle" remove="fa-3x fa-leaf m-3 rounded" separator=" "/>
    </xpath>
</template>

</odoo>