One pixel borders are done with:
border-t border-top-width: 1px; border-r border-right-width: 1px; border-b border-bottom-width: 1px; border-l border-left-width: 1px;
Colors
border-transparent border-current border-black border-white border-gray-### border-red-### border-yellow-### border-green-### border-blue-### border-indigo-### border-purple-### border-pink-###
The other options are:
border-0 border-width: 0px; border-2 border-width: 2px; border-4 border-width: 4px; border-8 border-width: 8px; border border-width: 1px; border-t-0 border-top-width: 0px; border-r-0 border-right-width: 0px; border-b-0 border-bottom-width: 0px; border-l-0 border-left-width: 0px; border-t-2 border-top-width: 2px; border-r-2 border-right-width: 2px; border-b-2 border-bottom-width: 2px; border-l-2 border-left-width: 2px; border-t-4 border-top-width: 4px; border-r-4 border-right-width: 4px; border-b-4 border-bottom-width: 4px; border-l-4 border-left-width: 4px; border-t-8 border-top-width: 8px; border-r-8 border-right-width: 8px; border-b-8 border-bottom-width: 8px; border-l-8 border-left-width: 8px;