JSON formatting of list header part - two rows of text

I have the below json code added to the header section of a item list editing window. The code adds two links, one next to each other.

I'd like the second link to appear either in a new row (i.e. under the first link) or, should this be not feasible, I'd like the second link to be preceded by 1 or 2 tabs.

    {
    "elmType": "div",
    "attributes": {
        "class": "ms-borderColor-neutralTertiary"
    },
    "style": {
        "width": "99%",
        "border-top-width": "0px",
        "border-bottom-width": "1px",
        "border-left-width": "0px",
        "border-right-width": "0px",
        "border-style": "solid",
        "margin-bottom": "16px"
    },
    "children": [
        {
            "elmType": "div",
            "style": {
                "display": "flex",
                "box-sizing": "border-box",
                "align-items": "center"
            },
            "children": [
                {
                    "elmType": "div",
                    "attributes": {
                        "iconName": "link",
                        "class": "ms-fontSize-42 ms-fontWeight-regular ms-fontColor-themePrimary",
                        "title": "Details"
                    },
                    "style": {
                        "flex": "none",
                        "padding": "0px",
                        "padding-left": "0px",
                        "height": "32px"
                    }
                },
                {
                    "elmType": "div",
                    "attributes": {
                        "iconName": "link",
                        "class": "ms-fontSize-42 ms-fontWeight-regular ms-fontColor-themePrimary",
                        "title": "Details"
                    },
                    "style": {
                        "flex": "none",
                        "padding": "0px",
                        "padding-left": "0px",
                        "height": "32px"
                    }
                }
            ]
        },
        {
            "elmType": "div",
            "attributes": {
                "class": "ms-fontColor-neutralSecondary ms-fontWeight-bold ms-fontSize-24"
            },
            "style": {
                "box-sizing": "border-box",
                "width": "100%",
                "text-align": "left",
                "padding": "18px 12px",
                "overflow": "hidden"
            },
            "children": [
                {
                    "elmType": "a",
                    "txtContent": "Add new project",
                    "attributes": {
                        "href": "https://www.google.com",
                        "target": "_blank"
                    }
                },
                {
                    "elmType": "a",
                    "txtContent": "Add new customer",
                    "attributes": {
                        "href": "https://www.bing.com",
                        "target": "_blank"
                    }
                }
            ]
        }
    ]
}