Border Width

Use border or border-{0,2,4,8} to set the border width on all sides:

Style('border border-indigo-600 ...')
Style('border-2 border-indigo-600 ...')
Style('border-4 border-indigo-600 ...')
Style('border-8 border-indigo-600 ...')

Individual sides

Use border-{t,r,b,l}-{N} to set the width on a single side:

Style('border-t-4 border-indigo-500 ...')
Style('border-r-4 border-indigo-500 ...')
Style('border-b-4 border-indigo-500 ...')
Style('border-l-4 border-indigo-500 ...')

Horizontal and vertical sides

Use border-x-{N} (left + right) and border-y-{N} (top + bottom):

Style('border-x-4 border-indigo-500 ...')
Style('border-y-4 border-indigo-500 ...')

Using logical properties

Use border-s-{N} and border-e-{N} for inline-start / inline-end widths. They flip with Directionality:

Directionality(
  textDirection: TextDirection.ltr,
  child: Style('border-s-4 ...'),
)
Directionality(
  textDirection: TextDirection.rtl,
  child: Style('border-s-4 ...'),
)

Block-axis variants border-bs-{N} (block-start) and border-be-{N} (block-end) map to top / bottom in horizontal writing mode.

Class reference

Class	Value
border	1px on all sides
border-{0,2,4,8}	All sides
border-{t,r,b,l}	Single side, 1px
border-{t,r,b,l}-{N}	Single side, explicit width
border-{x,y} / border-{x,y}-{N}	Axis pair
border-{s,e} / border-{s,e}-{N}	Logical inline-start / inline-end
border-{bs,be} / border-{bs,be}-{N}	Logical block-start / block-end