<div class="border-custom border-red-900">hello world</div>

<div class="border-4 border-red-900 text-17">hello world</div>
<div class="border-4 border-red-900 text-[17px]">hello world</div>

const customBorder = {
  3: '3px',
  5: '5px',
  'custom': '10rem'
}

const customFont = {
  10: '10px',
  11: '11px',
  12: '12px',
  13: '13px',
  14: '14px',
  15: '15px',
  16: '16px',
  17: '17px',
  18: '18px',
  19: '19px',
  20: '20px',
  'custom': '100px'
}

const px100 = {...Array.from(Array(101)).map((_, i) => i + 'px')}

module.exports = {
  theme: {
    extend: {
      borderWidth: customBorder,
      fontSize: customFont
    },
  },
  plugins: [],
}