lightning:input


Base Lightning components are the building blocks that make up the modern Lightning Experience, Salesforce1, and Lightning Communities user interfaces.
Beyond being equipped with the Lightning Design System styling, they handle accessibility, real-time interaction, and enhanced error messages.

https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/lightning_overview.htm

ui:input


Lightning Design System styling is not applied by default.