Answers for "text field with only bottom border"

input text field with only bottom border

input {
  outline: 0;
  border-width: 0 0 2px;
  border-color: blue
}
input:focus {
  border-color: green
}

border bottom under text only

li {
	a {
		    width: auto;
			display: block;
			height: auto;
            &:hover {
            	border-bottom: 3px solid red;
            }
    }
}