how to adjust the button "add to cart" on mobile phone

[PeaceDoe]

hello, yesterday I asked question in the community about how to adjust position "add to cart" button on website

i got the answer like this :

add this code at the end of your CSS file (Themes -> Edit code -> Assets -> theme.css )

.grid__item {
position: relative;
min-height: 450px;
}

.grid__item form {
position: absolute;
bottom: 0px;
margin-bottom: 15px;
}

@media only screen and (max-width: 768px) {
.grid__item {
min-height: 350px;
}
}

on my computer website, i see the button is tidy 

but on my mobile phone ,my store change like this

There is a huge gap in the middle of the button

my shopify store theme is dubet

my shopify store url is :

https://8ebr5g11vrsdzpz9-56140005553.shopifypreview.com/

please tell me what should i do to adjust the add to cart button on mobile phone 

thank you very much and have a nice day : )

[AlexEffron · Accepted solution]

Hello,

Welcome to the shopify Community.

Please  remove old given code.

Please Go to Online Store -> Themes -> Edit code -> Assets -> theme.scss.liquid and paste this code at the end of this file.

#shopify-section-collection .page-width .grid .grid__item {
position: relative;
min-height: 450px;
}

#shopify-section-collection .page-width .grid .grid__item form {
position: absolute;
bottom: 0px;
margin-bottom: 15px;
}

@media only screen and (max-width: 768px) {
#shopify-section-collection .page-width .grid .grid__item {
min-height: 350px;
}

[PeaceDoe]

well, i got you answer and solve the problem : )

Thank you very much and have a nice day!

[AlexEffron]

@PeaceDoe  Thank you for the update.