Search Handbook Cards

Dark mode is not simple inversion

Dark mode requires rebuilding the luminance hierarchy in reverse

Contrast in dark mode must be recalculated, not reused from the light palette

High-contrast mode serves low vision; it is not dark mode

In dark mode, height is surface lightness, not shadow

Semantic colours need lightness remapped in dark mode

Cursor colour and contrast must remain discernible on light and dark backgrounds

Images and icons need variants prepared for dark backgrounds

The five states must be checked per theme, not inverted from light

Night interfaces need an independently set peak brightness

Shadows are almost invisible on dark grounds

The focus indicator must be discernible on every background

High-contrast mode usually wants a more extreme figure/ground split and stronger borders

Higher layers are lighter surfaces

Hierarchy that depends on shadow or gradient needs a substitute in high-contrast mode

Pure black grounds with pure white type contrast too hard

Luminance difference ranks hierarchy more reliably than hue difference

Text on photos and gradients needs a guaranteed floor

Semi-transparent text must be measured on the composited color

Screen reflections turn the environment into superimposed noise

Checking a chart in greyscale belongs in design review, since fixing it after launch costs far more

Theme switching retargets the semantic layer, not raw values

Saturated colours need chroma reduced on dark grounds

How many layers you can have is limited by discriminable lightness gaps

Each hue needs a full lightness range

Consistency is gained by using system controls, not by mimicking their appearance

Inherit OS accessibility settings rather than shipping a parallel stack

A focus ring must retain contrast on every background

Elevation levels need a consistent light-source assumption

Theme is not only light and dark; it includes contrast and density

Day–night lighting requires automatic brightness and color adaptation

System-forced high contrast can override custom colours and distort the design

How many stops a scale has trades fine control against upkeep

Brand occupies the content layer; convention occupies the frame

A reference line should sit visually between the data, which is heaviest, and the gridlines, lightest

The adaptation time constant determines how long to wait for perception to stabilize after an interface switch

Low-vision users and anyone in bright sunlight lose a data mark the instant its contrast falls short

Visual information that changes on hover or focus must keep the same contrast

Contrast cannot be signed off on mockups; it must be verified on rendered pixels

Shadows express how elements stack

The key decline button can be blended into the background until unseen

Uneven visual weight between filled and outline icons in one row fakes a hierarchy

The skip link must become visible on focus

Contrast thresholds relax as type size and weight increase

Theme switches must not drop state or focus

High-saturation colour jumps the queue

Extra breakpoints multiply the cost of checking

A highlighted element stands out from its gap with the rest of the chart, not its own boldness

The intermediate state during adaptation produces brief perceptual distortions

Some low-vision users rely on color, not zoom — both paths must work