How to Inspect CSS font-feature-settings JIS04 Proportional Kana and Tabular Figures in Safari Web Inspector

Precision East Asian typography on the web demands strict alignment between Latin numerals, punctuation, and Japanese CJK glyphs. When rendering financial reports, multi-column tables, or structured accounting records in Japanese, setting OpenType jp04 (JIS2004 standard forms) alongside proportional kana and tabular figures ensures that narrative headers flow naturally while monetary figures align across vertical columns. Apple Safari’s Web Inspector provides native font analysis tools that simplify testing and validation of these advanced layout features.

Understanding the Synergy Between jp04, pkna, and tnum

The jp04 OpenType feature updates historical character representations to conform with contemporary Japanese publishing standards defined in JIS X 0213:2004. Concurrently, pairing jp04 with pkna (Proportional Kana) provides fluid horizontal rhythm for Japanese script, while tnum (Tabular Figures) enforces uniform character advance widths for digits. This ensures that column decimals align without jitter while maintaining elegant Japanese copy.

Declare these OpenType properties using modern high-level CSS properties with fallbacks:

.japanese-financial-table {
  font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  font-variant-east-asian: jis04;
  font-variant-numeric: tabular-nums;
  font-feature-settings: "jp04" 1, "pkna" 1, "tnum" 1;
  text-spacing-trim: space-first;
  line-break: strict;
}

Validating Glyphs in Safari Web Inspector

To inspect and audit OpenType glyph substitution inside Apple Safari:

1. Launch Safari and navigate to your target page.
2. Right-click on the Japanese financial table passage and click Inspect Element.
3. Navigate to the Elements tab and select the Font sub-panel located in the right-hand inspection drawer.
4. Expand the Font Features disclosure widget.
5. Verify that both JIS2004 Forms (jp04) and Tabular Figures (tnum) are enabled and highlighted in blue.
6. Use the live text editing input within the Font panel to confirm that numeric digits maintain constant em-widths across varying values.

Troubleshooting Glyphs and Fallback Rendering

When font features fail to apply as anticipated in Safari, verify the following configuration vectors:

• Subset Stripping: Ensure your web font distribution pipeline has not stripped the tnum or pkna feature tables during WOFF2 subsetting.
• CSS Shorthand Precedence: Be cautious when using the font: shorthand property on child selectors, as it resets font-variant and font-feature-settings to initial values.
• Column Alignment: Ensure table cells apply text-align: right for numbers alongside tabular glyph metrics.