GUIDE深度 · Deep dive
HTML Email Compatibility
Email clients are not browsers: Outlook uses Word rendering, Gmail filters some CSS and images are often blocked by default. Use table layout, inline styles, system fonts and alt text, then send a test.
Tables and inline styles, width at most 600px.
System fonts; do not rely on webfonts.
Use alt text and never put key info only in images.
Send to Gmail/Outlook/Apple Mail.
Check wrapping and tap targets on mobile.
FAQ
Why does it break in Outlook?
It lacks much modern CSS; tables and inline styles are safest.
Can I use external CSS?
Many clients strip it; inline styles for signatures.