BTW I got some problems with my custom logo and I have solved it
wp-admin.css, line 7821
code:
.login h1 a {
background-image: url(data:image/svg+xml;base64,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);
background-size: auto; /*fixed here*/
background-position: center top;
background-repeat: no-repeat;
color: #999;
height: auto; /*fixed here*/
font-size: 20px;
font-weight: normal;
line-height: 1.3em;
margin: 0 auto 25px;
padding: 0;
text-decoration: none;
width: auto; /*fixed here*/
text-indent: -9999px;
outline: none;
overflow: hidden;
display: block;
}
It can come in handy if the user has replaced the default WordPress logo with a custom image
