Background-gradient has outdated direction syntax

Hey

I noticed that the tiny-framework theme is using an out-of-date syntax for the background gradient. In the theme’s main /tiny-framework/style.css:1139 you can see the following rule:
{code}background-image: linear-gradient(top, #F4F4F4, #E6E6E6);{code}
I think this needs to change to become

{code}background-image: linear-gradient(to bottom, #F4F4F4, #E6E6E6);{code}

See the Mozilla guidelines https://developer.mozilla.org/en-US/docs/Web/CSS/linear-gradient
and the Autoprefixer discussion thread https://github.com/postcss/autoprefixer/issues/530

Thanks for keeping this theme alive and rocking