A component based on the inpit provided in the Salesforce Lightning Design System: https://www.lightningdesignsystem.com/components/input
We have no control over the HTML, so all the styling is being overwritten in the slds-input-calendar
scope.
<div class="a-input s-slds-input-calendar">
<label class="a-input__label"><!-- label --></label>
<div class="a-input__container">
<lightning-input class="a-input__field slds-form-element">
</lightning-input>
</div>
</div>