Total embedded font data exceeds maximum of ${MAX_TOTAL_FONT

Error message

Total embedded font data exceeds maximum of ${MAX_TOTAL_FONT_SIZE / 1024 / 1024}MB.

What it means

validateFontFaceBlocks sums the estimated decoded size of all embedded base64 fonts in the theme and throws if the total exceeds MAX_TOTAL_FONT_SIZE (limit in MB shown in the message). This caps the overall payload a custom theme can carry.

Source

Thrown at packages/desktop-client/src/style/customThemes.ts:293

            'Font files are automatically embedded when installing from GitHub.',
        );
      }
      // Estimate decoded size from base64 content
      const base64Match = uri.match(/;base64,(.+)$/);
      if (base64Match) {
        const size = Math.ceil((base64Match[1].length * 3) / 4);
        if (size > MAX_FONT_FILE_SIZE) {
          throw new Error(
            `Font file exceeds maximum size of ${MAX_FONT_FILE_SIZE / 1024 / 1024}MB.`,
          );
        }
        totalSize += size;
      }
    }
  }

  if (totalSize > MAX_TOTAL_FONT_SIZE) {
    throw new Error(
      `Total embedded font data exceeds maximum of ${MAX_TOTAL_FONT_SIZE / 1024 / 1024}MB.`,
    );
  }
}

/**
 * Split CSS declarations by semicolons, but respect quoted strings and url() contents.
 * This is needed because data: URIs contain semicolons (e.g., "data:font/woff2;base64,...").
 */
function splitDeclarations(content: string): string[] {
  const declarations: string[] = [];
  let start = 0;
  let inSingleQuote = false;
  let inDoubleQuote = false;
  let parenDepth = 0;

  for (let i = 0; i < content.length; i++) {
    const ch = content[i];

View on GitHub (pinned to d4334cb6e6)

Solutions

Reduce the number of embedded weights/styles to only those actually used in the theme.
Subset and WOFF2-compress each embedded font to shrink the total.
Reference locally installed fonts via --font-* variables instead of embedding every family.

Example fix

// before: 6 @font-face blocks (4 weights x 2 families) embedded
// after: keep only 2 @font-face blocks (regular + bold of one family), subset to WOFF2

Defensive patterns

Strategy: validation

Validate before calling

function checkTotalFontSize(css, maxBytes) {
  let total = 0;
  for (const m of css.matchAll(/;base64,([A-Za-z0-9+/=]+)/g)) {
    total += Math.ceil(m[1].length * 3 / 4);
  }
  return total <= maxBytes;
}

Try / catch

try {
  await installTheme(css);
} catch (err) {
  if ((err as Error).message.includes('Total embedded font data exceeds')) {
    // reduce embedded font count/weights in the theme
  } else throw err;
}

Prevention

Limit themes to a handful of embedded weights (regular + bold).
Budget total font size across all families when designing a theme.
Automate a size check over all data URIs in the theme build.

When it happens

Trigger: Installing a theme whose actual.css embeds several @font-face data URIs whose combined decoded size exceeds MAX_TOTAL_FONT_SIZE — even if each individual font is under its own limit.

Common situations: Themes bundling many font weights/styles (regular, bold, italic, multiple families) all embedded as base64; combining several large CJK/variable fonts in one theme.

Related errors

AI-assisted analysis of actualbudget/actual@d4334cb6e6 (2026-08-29). Data as JSON: /api/errors/e500358649926277. Report an issue: GitHub.