Hello,
You have set a wider page width in comparison with our demo and 25% on full-width is wider than 25% on the default width.
Please do the following:
1. Remove the first empty column.
2. Make the column with the slider as 12 columns
3. Remove custom margin-left
4. Add left padding 300px approximately to the column with the slider depending on what gap you need
5. Add this class to the column reset-paddings
6. Add this code to the Theme Settings > Custom CSS > Global:
.reset-paddings {
padding-left: 15px !important;
}
Best Regards