user1993
This part right here applies the image to the header.
.Hero{
margin-top: -1px;
background: url("https://i.imgur.com/OyRAJDJ.png") no-repeat center center fixed;
-webkit-background-size: cover !important;
-moz-background-size: cover !important;
-o-background-size: cover !important;
background-size: cover !important;
background-position: 0 0 !important;
text-align: center;
color: #FFFFFF;
text-shadow: 0 0 2px #000;
opacity: 0.68
}
This part right here adds the transparent background whatever behind the header text.
.DiscussionHero-title,.Hero-title,.Hero-subtitle,.PageHero-title > a{
background-color: rgba(0,0,0,0.3);
padding: 5px;
margin: 0px
}
.PageHero-title > a{
color: #FFFFFF;
border-radius: 2px
}
.PageHero-title > a:link{
text-decoration: none
}
.Hero-title{
border-radius: 2px 2px 0px 0px
}
.Hero-subtitle{
border-radius: 0px 0px 2px 2px
}
.DiscussionHero-title{
border-radius: 2px
}
This part right here hides the "X" that a user would be tempted to click to remove the header.
.Hero-close{
display: none !important
}
This part right here I felt necessary to include but am too inebriated to find the words to put meaning to it.
.UserCard--popover{
background-color: #E3E3E3 !important
}
.UserHero{
max-height: 394px
}
.UserBio-content{
max-height: 252px;
overflow: hidden
}
Flarums built in dark mode enabled + above code in pasted in Custom CSS demo results:
https://forum.freeflarum.com/
Hope this helps.