I need to update existing email header. There for I have to modify some styles.but doesn't define in specific style in app/design/frontend/{themename}/{namespace}/Magento_Email/email/header.html
app/design/frontend/{themename}/{namespace}/Magento_Email/email/header.html
<!--
/**
* Copyright © 2016 Magento. All rights reserved.
* See COPYING.txt for license details.
*/
-->
<!--@subject Header @-->
<!--@vars {
"var logo_height":"Email Logo Image Height",
"var logo_width":"Email Logo Image Width",
"var template_styles|raw":"Template CSS"
} @-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="initial-scale=1.0, width=device-width" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<style type="text/css">
{{var template_styles|raw}}
{{css file="css/email.css"}}
</style>
</head>
<body>
{{inlinecss file="css/email-inline.css"}}
<!-- Begin wrapper table -->
<table class="wrapper" width="100%">
<tr>
<td class="wrapper-inner" align="center">
<table class="main" align="center">
<tr>
<td class="header">
<a class="logo" href="{{store url=""}}">
<img
{{if logo_width}}
width="{{var logo_width}}"
{{else}}
width="180"
{{/if}}
{{if logo_height}}
height="{{var logo_height}}"
{{else}}
height="52"
{{/if}}
src="{{var logo_url}}"
alt="{{var logo_alt}}"
border="0"
/>
</a>
</td>
</tr>
<tr>
<td class="main-content">
<!-- Begin Content -->
but after preview the Email template in admin panel it show as below. Check below image
I need to change background color and padding and width of the highlighted element (<td>)
How change the style in element ?