Custom button scaling too small

Hi,

I have a issue with my custom buttons.

The button becomes too small on different widths:
Large monitor looks fine, button is full size


On a smaller monitor the image scales down too much, I want to keep it at 100% the whole time
(like how buttons in squarespace behave):

Is it how i've set it up? can i add css that keeps the button at a suitable size?

Web: https://ellipse-teal-dl5w.squarespace.com/
Pass: 04

Here is the button  code at the moment, the hover works and the animated scaling also:

/* GET IN TOUCH BUTTON*/
div#block-yui_3_17_2_1_1701485718961_2891 {
    overflow: hidden;
    position: relative;
}

div#block-yui_3_17_2_1_1701485718961_2891 img {
    transition: transform 0.5s ease, opacity 1s ease;

    display: block;
    width: 100%;
    height: auto;
}

div#block-yui_3_17_2_1_1701485718961_2891:hover img {
    transform: scale(1.05);
opacity: 1;
content: url(https://images.squarespace-cdn.com/content/64d0a4ef828d1802cb65112a/94faff05-9d93-477d-952d-4ac5f8579fa3/BUT_getintouch_ON.png);

}

Appreciate any support on this Cheers,

Mac