How to change Blog Page to 1 Column

#1. All Blog Pages

You can use this code to Website Tools > Custom CSS

@media screen and (min-width:768px) {
.tweak-blog-basic-grid-width-full .blog-basic-grid {
    grid-template-columns: repeat(1,minmax(0,1fr));
}
}

#2. Specific Blog Page

First, you need to find Blog Page ID.

Next, use CSS code like this

@media screen and (min-width:768px) {
#collection-6677756d03a4f15ba27ce9d8 .blog-basic-grid {
    grid-template-columns: repeat(1,minmax(0,1fr));
}
}

#3. If you want to make blog items smaller, you can add max-width, something like this

@media screen and (min-width:768px) {
#collection-6677756d03a4f15ba27ce9d8 .blog-basic-grid {
    grid-template-columns: repeat(1,minmax(0,1fr));
max-width: 1000px;
}
}