btcpayserver/BTCPayServer/Views/Shared/LayoutHeadTheme.cshtml

@using BTCPayServer.Abstractions.Extensions
@using BTCPayServer.Services
@using Microsoft.AspNetCore.Mvc.TagHelpers
@using BTCPayServer.Abstractions.Contracts
@inject ThemeSettings Theme
@inject IFileService FileService

<script>if (window.localStorage.getItem('btcpay-hide-sensitive-info') === 'true') { document.documentElement.setAttribute('data-hide-sensitive-info', 'true')}</script>
@if (Theme.CustomTheme && !string.IsNullOrEmpty(Theme.CssUri))
{   // legacy customization with CSS URI - keep it for backwards-compatibility
    <link href="@Context.Request.GetRelativePathOrAbsolute(Theme.CssUri)" rel="stylesheet" asp-append-version="true" />
}
else if (Theme.CustomTheme && !string.IsNullOrEmpty(Theme.CustomThemeFileId))
{   // new customization uses theme file id provided by upload
    @if (Theme.CustomThemeExtension != ThemeExtension.Custom)
    {   // needs to be added for light and dark, because dark extends light
        <link href="~/main/themes/default.css" rel="stylesheet" asp-append-version="true" />
    }
    @if (Theme.CustomThemeExtension == ThemeExtension.Dark)
    {
        <link href="~/main/themes/default-dark.css" rel="stylesheet" asp-append-version="true" />
    }
    <link href="@(await FileService.GetFileUrl(Context.Request.GetAbsoluteRootUri(), Theme.CustomThemeFileId))" 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>
}