Email Client
Operating System
- Webmail & App
- Operating systems: Windows, macOS, iOS, Android
Expected Result
The <style> tag placed in the <head> section should remain active and functional, allowing:
- Media queries to work for responsive mobile layouts
:hover pseudo-selectors to apply CSS property changes- Interactive email features to function properly
Actual Result
The <style> tag is automatically commented out by the email client, rendering it completely inactive:
<!--<style>
/* CSS rules */
</style>-->
This breaks:
- Responsive design (mobile versions don't render correctly)
:hover pseudo-selector interactions- Any interactive email features
Steps to reproduce
- Create an HTML email with a
<style> tag in the <head> section containing media queries or :hover rules
- Send the email to a Laposte.net or SFR email address
- Open the email in the respective webmail interface or mobile app
- Inspect the HTML source code
- Observe that the
<style> tag has been commented out
Additional context
This is intentional behavior, not a bug. According to discussions with the Laposte team, this filtering is implemented as a security measure to prevent phishing attacks that could exploit kobold letters.
Multiple workaround techniques have been tested without success:
- Duplicating the
<style> tag
- Adding HTML comments before the
<style> tag
- Various other encoding/obfuscation techniques
None of these workarounds bypass the email client's style tag filtering.
This issue significantly impacts the French market, forcing fallback to less optimal email layouts or alternative responsive techniques (Spongy code approaches).
Email Client
Operating System
Expected Result
The
<style>tag placed in the<head>section should remain active and functional, allowing::hoverpseudo-selectors to apply CSS property changesActual Result
The
<style>tag is automatically commented out by the email client, rendering it completely inactive:This breaks:
:hoverpseudo-selector interactionsSteps to reproduce
<style>tag in the<head>section containing media queries or:hoverrules<style>tag has been commented outAdditional context
This is intentional behavior, not a bug. According to discussions with the Laposte team, this filtering is implemented as a security measure to prevent phishing attacks that could exploit kobold letters.
Multiple workaround techniques have been tested without success:
<style>tag<style>tagNone of these workarounds bypass the email client's style tag filtering.
This issue significantly impacts the French market, forcing fallback to less optimal email layouts or alternative responsive techniques (Spongy code approaches).