Pass

**Very well done Marcus!**

One complaint(!): The window is tiny. Also, black text on a dark-blue background is not great design.

A note: if-let-statements and match-statements can scope your value extractions.

_Example 1: Your code_:
```rust
if self.game.board.contains_key(position) {
let piece = self.game.board.get(position).unwrap();

// Select piece to move
if /*...*/ {
//...
let moves = self.game.get_possible_moves(position.to_string());

if moves.is_none() {
//...
} else {
//...
for _move in moves.unwrap().iter() {/*...*/}
//...
}
} else {/*...*/}
} else {/*...*/}
```
_Example 1: With if-let and match_:
```rust
if let Some(_piece) = self.game.board.get(position) {

// Select piece to move
if /*...*/ {
//...
match self.game.get_possible_moves(position.to_string()) {
Some(_moves) => {
//...
for _move in _moves.iter() {/*...*/}
//...
},
None => //...
}
} else {/*...*/}
} else {/*...*/}
```

_Example 2: Your code_:
```rust
// Select promotion
let selected_piece = match x_tile {
8 => Some(PieceType::Queen(self.game.active_color)),
9 => Some(PieceType::Knight(self.game.active_color)),
10 => Some(PieceType::Rook(self.game.active_color)),
11 => Some(PieceType::Bishop(self.game.active_color)),
_ => None,
};

if selected_piece.is_some() {
self.game.promotion[match self.game.active_color {
Colour::White => 0,
Colour::Black => 1,
}] = selected_piece.unwrap();
}
```
_Example 2: With if-let_:
```rust
// Select promotion
if let Some(_selected_piece) = match x_tile {
8 => Some(PieceType::Queen(self.game.active_color)),
9 => Some(PieceType::Knight(self.game.active_color)),
10 => Some(PieceType::Rook(self.game.active_color)),
11 => Some(PieceType::Bishop(self.game.active_color)),
_ => None,
} {
self.game.promotion[match self.game.active_color {
Colour::White => 0,
Colour::Black => 1,
}] = _selected_piece;
}
```

However, observe how functional expressions complicates code, hence single-use variables can ease readability, which is one of the criterias for good code design. Additionally, one big readability fallgroup is uninformative comments.

_Example 2: With if-let_:
```rust
// Get selected active promotion piece type.
let selected_piece = match x_tile {
8 => Some(PieceType::Queen(self.game.active_color)),
9 => Some(PieceType::Knight(self.game.active_color)),
10 => Some(PieceType::Rook(self.game.active_color)),
11 => Some(PieceType::Bishop(self.game.active_color)),
_ => None,
};

// Save promotion piece type, if any piece type was selected.
if let Some(_selected_piece) = selected_piece {
let active_colour_code = match self.game.active_color {
Colour::White => 0,
Colour::Black => 1,
}
self.game.promotion[active_colour_code] = _selected_piece;
}
```

No files, tests, or entry points are named. Start by locating the window setup and the Rust code shown in the issue, then review the sizing, color contrast, value extraction, and comments; done means the reported design and readability concerns are addressed.

Written by the indexing model from the issue text.