btcpayserver/BTCPayServer/Views/Shared/LayoutHeadTheme.cshtml

@using BTCPayServer.Abstractions.Extensions
@using BTCPayServer.Services
@inject ThemeSettings Theme
@addTagHelper *, BundlerMinifier.TagHelpers

@if (Theme.CustomTheme)
{
    <link href="@Context.Request.GetRelativePathOrAbsolute(Theme.CssUri)" rel="stylesheet" asp-append-version="true" />
}
else
{
    <link href="~/main/themes/default.css" asp-append-version="true" rel="stylesheet" />
    <link href="~/main/themes/default-dark.css" asp-append-version="true" rel="stylesheet" id="DarkThemeLinkTag" />
    <script src="~/js/theme-switch.js" asp-append-version="true"></script>
    <noscript><style>.btcpay-theme-switch { display: none !important; }</style></noscript>
}