color palette table style tweaks

docs/color-system.js

@@ -200,7 +200,7 @@ export const Var = styled(Text).attrs({
 `
 
 export const PaletteHeading = ({indicatorColor, children, ...rest}) => (
-  <Text as="th" fontWeight="bold" {...rest} style={{borderBottom: `2px solid ${colors.black} !important`}}>
+  <Text as="th" fontWeight="bold" {...rest}>
     <Box pt={3}>{children}</Box>
   </Text>
 )

pages/css/utilities/borders.md

@@ -231,4 +231,4 @@ You can adjust border widths on all sides or each side individually with respons
     'variable',
     'value'
   ]}
-  borderSpacing="0 4px" />
+  style={{borderSpacing: '0 4px'}} />