Need for wordpress dynamic menu

hi
tow week a go i want to create a wordpress theme … and this theme should supporting vertical drop-down menu for categories by child’s .
i need but not see any css or js or jquery cod special wordpress , i cant send a example theme for this because i’ve never seen …

for example ( non wordpress ) : https://www.dralexmarketing.com/articles/navigate/web_menu_preview.gif

please help me , (” you can introduction a theme , { just theme name} that supported vertical dropdown menu by child category “)