Normal Borders

w3-border

w3-border-left w3-border-top w3-border-right

w3-border-left w3-border-right

w3-border-left w3-border-bottom w3-border-right

Round Borders

w3-border

w3-border w3-round-small

w3-border w3-round

w3-border w3-round-large

w3-border w3-round-xlarge

w3-border w3-round-xxlarge

Thick Borders (bars)

w3-leftbar w3-topbar w3-rightbar

w3-leftbar w3-rightbar

w3-leftbar w3-bottombar w3-rightbar

Hoverable Borders

w3-pale-red w3-border-red w3-hover-border-black

w3-pale-red w3-border-red w3-hover-border-green

w3-white w3-border-white w3-hover-border-blue

w3-hover-border-green

w3-hover-border-blue