Proton Mail
Engine: Proton·webmail·Dark mode: Yes
CSS coverage profile for Proton Mail
Proton Mail renders with the Proton engine and supports 192 of 255 tracked CSS and HTML features fully, with 13 partially supported and 49 unsupported. That places it in a broad coverage band.
Modern CSS works largely as expected. The cost of supporting this client is low. Most production templates need only minor adjustments.
192
Supported
13
Partial
49
Unsupported
255
Total
HTML Elements40
| Feature | Support |
|---|---|
| <abbr> | Supported |
| <acronym> | Supported |
| <address> | Supported |
| <audio> | Unsupported |
| <base> | Partial |
| <bdi> | Supported |
| <blockquote> | Supported |
| <body> | Unsupported |
| <code> | Supported |
| <del> | Supported |
| <dfn> | Supported |
| <dialog> | Unsupported |
| <div> | Supported |
| <form> | Unsupported |
| <h1> | Supported |
| <hr> | Supported |
| <img> | Supported |
| <link> | Unsupported |
| <marquee> | Partial |
| <meter> | Supported |
| <object> | Unsupported |
| <p> | Supported |
| <picture> | Unsupported |
| <pre> | Supported |
| <progress> | Supported |
| <rp> | Supported |
| <rt> | Supported |
| <ruby> | Supported |
| <select> | Supported |
| <small> | Supported |
| <span> | Supported |
| <strike> | Supported |
| <strong> | Supported |
| <style> | Supported |
| <svg> | Supported |
| <table> | Supported |
| <textarea> | Supported |
| <ul> | Supported |
| <video> | Unsupported |
| <wbr> | Supported |
CSS At-Rules5
| Feature | Support |
|---|---|
| @font-face | Unsupported |
| @import | Unsupported |
| @keyframes | Unsupported |
| @media | Unsupported |
| @supports | Unsupported |
Pseudo-Elements6
| Feature | Support |
|---|---|
| ::after | Unsupported |
| ::before | Unsupported |
| ::first-letter | Unsupported |
| ::first-line | Unsupported |
| ::marker | Supported |
| ::placeholder | Unsupported |
Pseudo-Classes & Selectors34
| Feature | Support |
|---|---|
| :adjacent-sibling | Unsupported |
| :attribute-selector | Unsupported |
| :chaining | Unsupported |
| :checked | Unsupported |
| :child-combinator | Unsupported |
| :class-selector | Unsupported |
| :descendant-combinator | Unsupported |
| :first-child | Unsupported |
| :first-of-type | Unsupported |
| :focus | Supported |
| :focus-visible | Supported |
| :focus-within | Supported |
| :general-sibling | Unsupported |
| :grouping | Unsupported |
| :has | Supported |
| :hover | Supported |
| :id-selector | Unsupported |
| :lang | Supported |
| :last-child | Unsupported |
| :last-of-type | Unsupported |
| :link | Unsupported |
| :not | Unsupported |
| :nth-child | Unsupported |
| :nth-last-child | Unsupported |
| :nth-of-type | Unsupported |
| :only-child | Unsupported |
| :only-of-type | Unsupported |
| :target | Unsupported |
| :type-selector | Unsupported |
| :universal-selector | Unsupported |
| :visited | Unsupported |
| pseudo-class-active | Supported |
| pseudo-class-default | Unsupported |
| pseudo-class-nth-last-of-type | Unsupported |
CSS Functions8
| Feature | Support |
|---|---|
| calc | Supported |
| clamp | Supported |
| conic-gradient | Supported |
| fit-content | Supported |
| linear-gradient | Supported |
| max | Supported |
| min | Supported |
| radial-gradient | Supported |
CSS Properties162
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Try Emailens FreeSupport data last updated Apr 27, 2026 · synced from caniemail.com via @emailens/engine.