Function encode_tier1 

pub fn encode_tier1(
    display: LayoutDisplay,
    position: LayoutPosition,
    float: LayoutFloat,
    overflow_x: LayoutOverflow,
    overflow_y: LayoutOverflow,
    box_sizing: LayoutBoxSizing,
    flex_direction: LayoutFlexDirection,
    flex_wrap: LayoutFlexWrap,
    justify_content: LayoutJustifyContent,
    align_items: LayoutAlignItems,
    align_content: LayoutAlignContent,
    writing_mode: LayoutWritingMode,
    clear: LayoutClear,
    font_weight: StyleFontWeight,
    font_style: StyleFontStyle,
    text_align: StyleTextAlign,
    visibility: StyleVisibility,
    white_space: StyleWhiteSpace,
    direction: StyleDirection,
    vertical_align: StyleVerticalAlign,
    border_collapse: StyleBorderCollapse,
) -> u64

Pack all 21 enum properties into a single u64.