can not see the copy button when hover

[loenvom]

Description

Can not see the copy button when hover.

I checked the CSS declaration and it looks like the copy button should appear on hover, but it doesn't. I don't know if it's just me having this issue.

Steps To Reproduce

1. open a page of hextra, like https://imfing.github.io/hextra/docs/guide/shortcodes/callout/#default.
2. check the code part.
3. move mouse cursor on the copy button.

Expected Behavior

display the copy button.

Actual Behavior

the copy button doesn't appear.

Screenshots

Environment

• Browser/OS: [e.g., Chrome, Windows]
• Theme Version: [e.g., v0.7.3]

[imfing]

I guess it's a bug introduced in #300

[loenvom]

I also spent some time try to find out why, But I failed. 😫
I tried to change the "hx-opacity-0" to "hx-opacity-5". It works well, I can see a copy-button with opacity, and when I hover it, it changes it's opacity.

[imfing]

Thanks for looking into it. #323 should address this issue