I'm not sure if anyone else encountered this, not only does it alter the "{" and "}" upon editing, but In my experience tonight, it also removed the style of the template.
My default mail themes had this style:
<style> @media only screen and (max-width: 300px){
body {
width:218px !important;
margin:auto !important;
}
.table {width:195px !important;margin:auto !important;}
.logo, .titleblock, .linkbelow, .box, .footer, .space_footer{width:auto !important;display: block !important;}
span.title{font-size:20px !important;line-height: 23px !important}
span.subtitle{font-size: 14px !important;line-height: 18px !important;padding-top:10px !important;display:block !important;}
td.box p{font-size: 12px !important;font-weight: bold !important;}
.table-recap table, .table-recap thead, .table-recap tbody, .table-recap th, .table-recap td, .table-recap tr {
display: block !important;
}
.table-recap{width: 200px!important;}
.table-recap tr td, .conf_body td{text-align:center !important;}
.address{display: block !important;margin-bottom: 10px !important;}
.space_address{display: none !important;}
}
@media only screen and (min-width: 301px) and (max-width: 500px) {
body {width:308px!important;margin:auto!important;}
.table {width:285px!important;margin:auto!important;}
.logo, .titleblock, .linkbelow, .box, .footer, .space_footer{width:auto!important;display: block!important;}
.table-recap table, .table-recap thead, .table-recap tbody, .table-recap th, .table-recap td, .table-recap tr {
display: block !important;
}
.table-recap{width: 295px !important;}
.table-recap tr td, .conf_body td{text-align:center !important;}
}
@media only screen and (min-width: 501px) and (max-width: 768px) {
body {width:478px!important;margin:auto!important;}
.table {width:450px!important;margin:auto!important;}
.logo, .titleblock, .linkbelow, .box, .footer, .space_footer{width:auto!important;display: block!important;}
}
@media only screen and (max-device-width: 480px) {
body {width:308px!important;margin:auto!important;}
.table {width:285px;margin:auto!important;}
.logo, .titleblock, .linkbelow, .box, .footer, .space_footer{width:auto!important;display: block!important;}
.table-recap{width: 295px!important;}
.table-recap tr td, .conf_body td{text-align:center!important;}
.address{display: block !important;margin-bottom: 10px !important;}
.space_address{display: none !important;}
}
</style>
After BO editing, this style was removed.
At the moment, In my (Greenhorn) opinion, stay away from back office editing of Email templates, editing the actual files in Notepad++ will guarentee you get the result your looking for.