Красочные кампании: руководство по использованию CSS фильтров в письмах
https://medium.com/email-marketing-development/captivatingly-colourful-campaigns-our-guide-to-using-css-filters-in-email-b90214f58b63
https://medium.com/email-marketing-development/captivatingly-colourful-campaigns-our-guide-to-using-css-filters-in-email-b90214f58b63