t_wの輪郭

出力したいHTML。
data-theme="dark"が入っていればダークモードでtweetを埋め込める。

<blockquote class="twitter-tweet" data-theme="dark"><p lang="en" dir="ltr">Arrowleaf balsamroot, a plant of the sunflower family, is found throughout the Rocky Mountain region and is sure to brighten your hikes and mood. <br><br>Photo at <a href="https://twitter.com/GrandTetonNPS?ref_src=twsrc%5Etfw">@GrandTetonNPS</a> by Anand Soundarajan <a href="https://t.co/eMjTFcEIJm">pic.twitter.com/eMjTFcEIJm</a></p>&mdash; US Department of the Interior (@Interior) <a href="https://twitter.com/Interior/status/1522698987115057154?ref_src=twsrc%5Etfw">May 6, 2022</a></blockquote>

JavaScript

if(window.matchMedia('(prefers-color-scheme: dark)').matches == true){
    for(const elem of document.querySelectorAll("blockquote.twitter-tweet")) {
        elem.dataset.theme = 'dark';
    }
}

表示例