certain web ui buttons move upon mouseclick

### Describe the bug
when deleting a file in the web ui, the "Cancel" and "OK" buttons in the confirmation modal shift several pixels to the right when the mouse button is depressed (but before the button is released)

### To Reproduce
1. be in a directory in which you have permissions to delete items
2. right-click an item that you wish to delete
3. set your cursor over either the "Cancel" or "OK" buttons
4. observe the second confirmation modal and repeat step 3
(note: you may also trigger the buttons to move by left-clicking in a blank white space in the modal)

### Expected behavior
the buttons should not attempt to escape from the user's cursor. if the user happens to depress their left mouse button far enough to the left side of the desired button, the button may even move far enough to the right that when the left mouse button is released, it will not activate the button.

### Screenshots
https://github.com/user-attachments/assets/00b15d1a-f8f1-4b14-89ea-a9c410f507fb

### Server details (if you are using docker/podman)
remove the ones that are not relevant:
* **server OS / version:** Unraid 7.2.4
* **how you're running copyparty:** Docker
* **docker image:** official, latest stable, from the Unraid Community Applications repository
* **copyparty arguments and/or config-file:**
```[global]
p: 3923 # listen on port 3923
ah-alg: argon2
e2dsa
xff-hdr: cf-connecting-ip
shr: /share
shr-who: a
shr-site: https://butt.tld

[accounts]
admin: 123

[/books]
/mnt/user/data/media/books
accs:
A: admin
flags:
fka
dks

[/links]
/w/links
accs:
# g: *
A: admin
flags:
fka
dks```

### Client details
if the issue is possibly on the client-side, then mention some of the following:
MacBook Pro M4, macOS 26.3.1(a), Safari 26.3.1 (21623.2.7.111.2)
i also tested with Vivaldi 7.8.3925.76 (Official Build) (arm64) and could not reproduce

### The rest of the stack
this occurs when connecting directly to the container's exposed port

### Server log

### Additional context