Question

In Django admin, how can I increase the width of the ManyToMany field’s widget when using filter_horizontal?

Answer 1

You could apply custom classes to the fields using ModelAdmin Fieldsets you wanted to change and add an extra stylesheet with:

class MyAdmin(admin.ModelAdmin):
    class Media:
        css = {
            "all": ("my_styles.css",)
        }

Otherwise you’ll have to write your own admin templates or widgets.