Hi

You can use the below XML code to set the color of a kanban view.

<kanban>
    <!--                Other fileds-->
    <field name="color"/>
    <templates>
        <t t-name="kanban-box">
            <div t-attf-class="{{'oe_kanban_color_' + kanban_getcolor(record.color.raw_value) }} oe_kanban_card oe_kanban_global_click oe_semantic_html_override">
                <!--                        Define view-->
            </div>
        </t>
    </templates>
</kanban>

And inside your model define a color field and compute its value according to the expiration date.

color = fields.Integer('Color', compute='_get_color')

def _get_color(self):
    """Compute Color value according to the conditions"""
    for rec in self:
        if rec.expiry_date:
            rec.color = 1
        else:
            rec.color = 2

Hope it helps

try this

decoration-danger="condition"