# Style Model
This document defines how `Style` is applied to cells.
## Style Fields
A cell style may include:
- Foreground color
- Background color
- Flags (bold, italic, underline, etc.)
Exact fields are defined by `Style`.
## Overlay Rules
When an operation applies a `Style` overlay:
- If a foreground value is present, it MUST override the destination foreground.
- If a background value is present, it MUST override the destination background.
- Flags MUST be additive (logical OR).
- The absence of a field MUST NOT be interpreted as reset.
Reset behavior MUST be explicit.
## Empty Cells
`Cell::Empty` has no inherent style. Backends MUST define a consistent rendering for empty cells.
Backends MUST treat styled spaces as styled glyphs; consequently, clear operations that aim to erase visible content SHOULD use explicit plain spaces rather than `Cell::Empty` when the goal is to remove style bleed.