테두리 (border)
border-flat
border-radius-xs
border-radius-sm
border-radius-md
border-rounded
<div class="border-flat ex-border">
border-flat
</div>
<div class="border-radius-xs ex-border">
border-radius-xs
</div>
<div class="border-radius-sm ex-border">
border-radius-sm
</div>
<div class="border-radius-md ex-border">
border-radius-md
</div>
<div class="border-rounded ex-border">
border-rounded
</div>