pub fn main() -> Result<(), taffy::TaffyError> {

    use taffy::prelude::*;

    let mut taffy: TaffyTree<()> = TaffyTree::new();

    let flex = Style {
        justify_content: Some(AlignContent::Center),
        size: Size { width: percent(1.0), height: percent(1.0) },
        ..default()
    };

    let sub_style = Style {
        display: Display::Grid,
        size: Size { width: percent(0.5), height: length(600.0) },
        grid_template_columns: vec![fr(1.0), fr(1.0) ],
        grid_template_rows: vec![fr(1.0)] ,
        ..default()
    };

    let left = taffy.new_leaf(Style { grid_row: line(1), grid_column: line(1), ..default() })?;
    let right = taffy.new_leaf(Style { grid_row: line(1), grid_column: line(2), ..default() })?;

    let sub = taffy.new_with_children(sub_style, &[left, right])?;
    let root = taffy.new_with_children(flex, &[sub])?;

    taffy.compute_layout(root, Size { width: length(350.0), height: length(600.0) })?;
    taffy.print_tree(root);

    Ok(())
}