Why don't you use the dark theme in settings of Aard2?
I wrote myself some css styles for settings > userstyles but ended up with the dark theme of Aard2, because there are many styles to consider and in the end my theme created at some points unreadable parts etc.
My user style (CSS) was this, but as I said, I use the inline dark mode:
body {
background-color: black;
color: white;
}
h1, h2, h3, h4, h5, h6 {
color: white !important;
}
.mjx-svg-mrow {
fill: white;
stroke: white;
}
img {
background-color: lightgray;
}
table {
background-color: black !important;
color: white !important;
}
table tr td {
color: #888;
}
table tr td a {
color: #aad;
}
table tr th span a {
color: #99f;
}
table tbody tr th {
color: #888;
}
table.translations td {
background-color: #191919;
}
table.translations {
border-collapse: collapse;
}
.wikitable th {
background-color: #292929 !important;
}
div.thumbinner {
background-color: #191919 !important;
}
div.thumb {
border-color: black !important;
}
a {
/*color: #A3964E;*/
color: #CCF;
}
a:visited {
/*color: #735A0A;*/
color: #AAF;
}
a.new {
color: #E88;
}
.toc {
background-color: #443 !important;
}
code {
background-color: darkgreen;
}
By the way, Aard2 saves this css as xml in:
/data/data/itkach.aard2/shared_prefs/userStyles.xml
greetings, frank