Cannot see margin and padding options for my navigation

I am learning how to create block themes, however, I do not see the option to increase or decrease the margin and padding of my navigation.

this is my themes.json file:

{

"$schema": "https://schemas.wp.org/trunk/theme.json",

"version": 3,

"settings": {

"appearanceTools": true,

"useRootPaddingAwareAlignments": true,

"layout": {

"contentSize": "1200px",

"wideSize": "1200px"

},

"spacing": {

"units": ["px", "em", "rem", "vh", "vw", "%"]

},

"typography": {}

},

"styles": {},

"customTemplates": [

{

"name": "home",

"title": "Home",

"postTypes": ["page"]

},

{

"name": "archive",

"title": "Archive",

"postTypes": ["page", "post"]

},

{

"name": "blank",

"title": "Blank",

"postTypes": ["page", "post"]

}

]

}

I would also apppreciate if you can recommend a resource that deals with creating these block themes from scrach without having to rely on usin another theme as a starter so that it will help my undertanding.