gmailの本文のみで等幅フォントを利用
chrome/userContent.css に、以下を記載
@-moz-document url-prefix(http://mail.google.com/) { div[class="mb cb"] { font-family: monospace !important; } textarea { font-family: monospace !important; } }
chrome/userContent.css に、以下を記載
@-moz-document url-prefix(http://mail.google.com/) { div[class="mb cb"] { font-family: monospace !important; } textarea { font-family: monospace !important; } }