Why it matters
One accent color gives the eye a single signal for 'act here'. Several saturated hues on buttons and highlights compete and cheapen the page.
How to fix it
Pick one brand hue for primary actions and highlights; use neutrals for everything else and reserve red/green/amber for status. Previews of other designs (theme pickers, swatches, mock pages) can be marked with a data-void-specimen attribute; design checks skip that subtree.
More design rules
void design reports 19 rules in this category. Measured design heuristics from computed styles: font families, type scale, line length, palette and accent sprawl, spacing grid, radius sprawl, dark mode and the tells of generated UI.
body-line-height-tightBody line-height is too tightheading-trackingLarge headings use default letter-spacingheading-no-balanceHeadings do not use text-wrap: balancepalette-sprawlToo many distinct colorsgradient-textGradient-filled heading textpurple-gradientPurple/indigo gradient backgroundemoji-iconsEmoji used as iconsspacing-off-gridSpacing values are off the 4px grid