color-contrast

Color & Contrast

CONTRAST RATIO REQUIREMENTS (WCAG 2.1 / Apple HIG):

• Normal text (<20pt): minimum 4.5:1 contrast ratio.
• Large text (20pt+ regular or 14pt+ bold): minimum 3:1 contrast ratio.
• Preferred: 7:1 for maximum readability.
• UI components (icons, borders, controls): minimum 3:1 against background.

SEMANTIC COLOR USAGE:

• Red (.red / destructive): delete, remove, error, critical alert.
• Green (.green): success, complete, enabled, positive.
• Orange (.orange): warning, caution, attention needed.
• Blue (.blue): informational, links, primary actions.
• NEVER use red for positive actions or green for destructive actions.

NEVER RELY ON COLOR ALONE:

• Status indicators: color + icon + text label (e.g. green circle + checkmark + "Complete").
• Error fields: red border + error icon + error message text.
• Charts/graphs: use patterns, shapes, or labels alongside color coding.
• Colorblindness: avoid red/green as the sole differentiator — use red/blue or add shapes.

SYSTEM ADAPTIVE COLORS:

• .primary: adapts to light/dark automatically — use for main text.
• .secondary: lighter text for subtitles, metadata.
• Color(.systemBackground): adapts to system appearance.
• These work well for structural elements; use AppTheme for brand colors.

DARK MODE COLOR PAIRING:

• Every custom color must have both light and dark variants.
• Light mode: dark text on light backgrounds.
• Dark mode: light text on dark backgrounds.
• Both variants must independently meet contrast requirements.
• Test both modes — a color that works in light may fail in dark.

APPTHEME COLOR PATTERNS:

• Use Color(light:dark:) extension when app has appearance switching.
• Use plain Color(hex:) when no dark mode support.
• Define semantic tokens: AppTheme.Colors.primary, .surface, .error, .success.
• NEVER use raw hex strings in views — always reference AppTheme tokens.

TEXT ON IMAGES/GRADIENTS:

• Add a dark overlay (.black.opacity(0.4)) before placing white text on images.
• Or use .shadow(color: .black.opacity(0.3), radius: 2) on text.
• Never place light text on light images without contrast treatment.

OPACITY GUIDELINES:

• Avoid text below .opacity(0.6) — fails contrast requirements.
• Disabled state: use .disabled() modifier (auto-handles opacity correctly).
• Placeholder text: use .foregroundStyle(.secondary) instead of manual opacity.