404 when i create new product

i do it )
but

the product page setup does not work in terms of resizing – to the full length and displaying additional products – upsel, crossel, neither in the side nor in the standard.

it`s work
Say please how i can do blog post in elementor ?

Thank you very much, One more question, I hope it will be the last one)) ) and I will constantly buy only your theme.
I want to insert my own SON to change the display grid of products in the catalog. For example :

/* A grid of products in three columns */
.woocommerce ul.products {
display: flex;
flex-wrap: wrap;
}

/* Images in horizontal orientation – 2 in a row */
.woocommerce ul.products li.product.has-post-thumbnail img {
width: 48% !important;
margin-right: 4% !important;
}

/* Pictures in square orientation – 3 in a row */
.woocommerce ul.products li.product.has-post-thumbnail:nth-child(3n+1) img {
width: 100% !important;
margin-right: 0 !important;
}

/* Horizontal + Square + Square – 1 + 2 in a row */
.woocommerce ul.products li.product.has-post-thumbnail:nth-child(3n+2) img,
.woocommerce ul.products li.product.has-post-thumbnail:nth-child(3n+3) img {
width: 48% !important;
margin-right: 4% !important;
}

/* Horizontal + Square + Square – Clearing a new row */
.woocommerce ul.products li.product.has-post-thumbnail:nth-child(3n+1) {
clear: left;
}

I paste it into CSS styles, but it doesn’t work, probably the restrictions and theme settings don’t give, how do I do it?