High opacity and large blur that harms readability, when excessive shadow opacity (over 50%) or large blur radii create visual noise that reduces text legibility, especially on complex backgrounds or at small font sizes, causing readability issues that defeat the purpose of text shadows intended to improve visibility.
Forgetting to check accessibility contrast after adding shadows, when shadows alter effective contrast ratios between text and background, potentially reducing WCAG compliance or making text less accessible for users with visual impairments, requiring contrast verification after applying text shadows to ensure accessibility standards are maintained.
Using identical offsets on stacked shadows (results look flat), when multiple shadow layers with identical X/Y offsets create overlapping effects that don't provide depth or visual interest, causing shadow stacks to look flat instead of creating layered depth requiring varied offsets for each shadow layer to achieve realistic depth effects.
Ignoring performance when stacking dozens of layers, when excessive shadow layers (10+) create high paint complexity that degrades rendering performance, especially on mobile devices or low-end hardware, causing janky animations or slow page loads requiring shadow layer count optimization for acceptable performance.
Using fixed pixel units (px) for responsive designs that scale text dynamically, when px-based shadows don't scale proportionally with font size changes, causing shadow effects to appear too large or too small as text scales in responsive layouts, requiring relative units (em, rem) for shadows that scale with text size.
Applying text shadows without considering light source direction in UI design, when shadow direction doesn't match UI light source (top-left, top-right) used elsewhere in the design, causing inconsistent visual hierarchy and breaking design coherence, requiring shadow direction alignment with overall UI lighting scheme.
Not testing shadows on both light and dark backgrounds, when shadows optimized for one background type may become invisible or cause contrast issues on opposite backgrounds, causing visibility problems if shadow colors aren't tested across different background variations commonly used in modern UI designs.
Creating shadows that conflict with text color in low-contrast scenarios, when shadow colors blend with text colors reducing visibility, especially with colored text or gradients, causing text to become illegible requiring careful color selection and contrast management when combining shadows with colored text.
Using text-shadow for effects that should use filter: drop-shadow(), when drop-shadow provides better control for complex shapes, outlines, or element-level effects while text-shadow is optimized for glyph-level shadows, causing suboptimal results if wrong CSS property is chosen for specific visual effect requirements.
Not considering print media where shadows may not render correctly, when CSS shadows may be ignored or rendered differently in print media, causing text to appear without intended visual enhancement in printed materials, requiring print-specific CSS or alternative styling approaches for print layouts.
Overusing decorative shadows on body text or functional UI elements, when shadows are intended for display text or accents rather than body content, causing visual noise and reduced readability if shadows are applied too broadly across all text elements instead of strategically on headings or emphasis.
Ignoring browser compatibility for advanced shadow features (color spaces, blend modes), when newer CSS features may not work in older browsers, causing inconsistent rendering across browser versions, requiring feature detection or fallback styles to ensure consistent shadow appearance across supported browsers.