v1.5.40

• Bump Firefox strict_min_version to 57 to ensure compatibility with Android
• [installer] Allow adding custom sites and fix theme option
• [Editor] Fix active editor tab on Chrome startup
• [Editor] Fix live preview with adoptedStyleSheets
• [Editor] Increase undoDepth from 200 to 1000
• [CSSLint] New style-rule-nesting rule to warn about new CSS nesting syntax
• [Manager] Show descriptive age & full year in the tooltip for the age column
• [Options] New option for popup's max width to enable autofit-to-content

Full Changelog: v1.5.39...v1.5.40