CSS字体重量超过900？

I have a panel which can be expanded or minimised through a vertically centred link with a < or > symbol as the link text. At font-weight: 900 this does not stand out much, even with a large grey background around it. I do not want to use an image and, at the current font size, both symbols currently take up the maximum width of the panel.I have a panel which can be expanded or minimis