Hi,
First you need to add a css file by following:
<template id="assets_frontend" inherit_id="website.assets_frontend">
<xpath expr="link[last()]" position="after">
<link rel="stylesheet" type="text/scss" href="Your module name/static/src/scss/yourcss file name.scss"/>
</xpath>
</template>
Then you can add your class and make sure that in class ksp you have added some css codes as well.
For example: In css code,
.ksp {
font-size: 12px;
font-weight: bold;
color: black;
text-transform: uppercase;
text-align: center;
line-height: 20px;
}
Then in XML Code,
<t t-if='website.warehouse_ids'>
<t t-set="product_variant" t-value="product.env ['product.product']. browse (combination_info ['product_id'])"/>
<span class='o_not_editable' style='color: # 239B56'>
<t t-esc='product_variant'/>
Unit (s) available
</span>
<t t-att-class="'top_left'">
<span>Your text Here</span>
</t>
'OR'
<div class="ksp">Your Text/Code/required field here</div>
</t>
For example:
<div class="ksp"> <t t-esc = 'product_variant' /> Unit (s) available</div>
Otherwise you can add css code directly into XML as,
<span t-att-style="'color: black;'
'font-size: 12px'
'font-weight: bold;'">
<t t-esc='product_variant'/>
Unit (s) available
</span>
Regards