How to indent between submenus?

Question

css

There is a menu. codepen.io/anon/pen/MaNrBZ You need to make a 10 px left indent between the first submenu and the second one. I tried to make the left border transparent, but on the menu itself the shadow is around and this method does not work. How else can you step back? If you just step back, the submenu disappears from the focus and does not open.
And how can you make the guidance more convenient. If you hover over PORTFOLIO, then you need to hover exactly near the triangle and otherwise it will not hover. How to make it possible to hover over the entire length of the PORTFOLIO link?