table-cell-color-example.css

/*
Set background color for table cell in selected row.
*/
.table-row-cell:selected .table-cell {
	/*
	We set the background color to the looked-up color -fx-background. The
	reason for this is that the default text fill for the cell depends on -fx-background,
	in a way that ensures it always contrasts that value. 
	*/
	-fx-background-color: -fx-background ;
	
	/*
	Now set the value of -fx-background to the looked-up color cell-selection-color, which
	is set in the Java code.
	*/
	-fx-background: cell-selection-color ;
}

TableCellColorExample.java

import java.util.Random;
import java.util.function.Function;

import javafx.application.Application;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.value.ObservableValue;
import javafx.scene.Scene;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.TextFieldTableCell;
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Callback;
import javafx.util.converter.IntegerStringConverter;

public class TableCellColorExample extends Application {

    private final Random RNG = new Random();

    @Override
    public void start(Stage primaryStage) {
        
        // Table. Item is defined below: just has three integer properties, x, y, z.
        TableView<Item> table = new TableView<>();
        table.setEditable(true);

        // Columns for x, y, and z repspectively:
        TableColumn<Item, Integer> xCol = column("X", item -> item.xProperty().asObject());
        TableColumn<Item, Integer> yCol = column("Y", item -> item.yProperty().asObject());
        TableColumn<Item, Integer> zCol = column("Z", item -> item.zProperty().asObject());

        // Default cell factory provides text field for editing and converts text in text field to int.
        // Note in real life you might want a custom implementation that restricts input to valid values.
        Callback<TableColumn<Item, Integer>, TableCell<Item, Integer>> defaultCellFactory = 
                TextFieldTableCell.forTableColumn(new IntegerStringConverter());

        // Cell factory implementation that uses default cell factory above, and augments the implementation
        // by updating the value of the looked-up color cell-selection-color for the cell when the item changes:
        Callback<TableColumn<Item, Integer>, TableCell<Item, Integer>> cellFactory = col -> {
            TableCell<Item, Integer> cell = defaultCellFactory.call(col);
            cell.itemProperty().addListener((obs, oldValue, newValue) -> {
                if (newValue == null) {
                    cell.setStyle("cell-selection-color: -fx-selection-bar ;");
                } else {
                    Color color = createColor(newValue.intValue());
                    String formattedColor = formatColor(color);
                    cell.setStyle("cell-selection-color: "+ formattedColor + " ;");
                }
            });
            return cell;
        };

        // attach cell factory defined above to each column:
        xCol.setCellFactory(cellFactory);
        yCol.setCellFactory(cellFactory);
        zCol.setCellFactory(cellFactory);

        // add each column to table:
        table.getColumns().add(xCol);
        table.getColumns().add(yCol);
        table.getColumns().add(zCol);

        // create 100 items for table with random values:
        for (int i = 0; i < 100; i++) {
            table.getItems().add(new Item(
                    RNG.nextInt(360), 
                    RNG.nextInt(360), 
                    RNG.nextInt(360)));
        }

        // simple layout:
        BorderPane root = new BorderPane(table);
        Scene scene = new Scene(root, 600, 600);
        
        // add stylesheet that applies looked-up color cell-selection-color to cells in selected row:
        scene.getStylesheets().add("table-cell-color-example.css");
        
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    // Create color based on int value. Just use value as hue, full saturation and brightness:
    private Color createColor(int x) {
        return Color.hsb(x, 1.0, 1.0);
    }

    // Format color as string for CSS (#rrggbb format, values in hex).
    private String formatColor(Color c) {
        int r = (int) (255 * c.getRed());
        int g = (int) (255 * c.getGreen());
        int b = (int) (255 * c.getBlue());
        return String.format("#%02x%02x%02x", r, g, b);
    }

    // Utility method to create table columns for title and property
    private <S, T> TableColumn<S, T> column(String title, Function<S, ObservableValue<T>> property) {
        TableColumn<S, T> col = new TableColumn<>(title);
        col.setCellValueFactory(cellData -> property.apply(cellData.getValue()));
        col.setPrefWidth(150);
        return col;
    }

    // Simple model class
    public static class Item {
        private IntegerProperty x = new SimpleIntegerProperty();
        private IntegerProperty y = new SimpleIntegerProperty();
        private IntegerProperty z = new SimpleIntegerProperty();

        public Item(int x, int y, int z) {
            setX(x);
            setY(y);
            setZ(z);
        }

        public final IntegerProperty xProperty() {
            return this.x;
        }

        public final int getX() {
            return this.xProperty().get();
        }

        public final void setX(final int x) {
            this.xProperty().set(x);
        }

        public final IntegerProperty yProperty() {
            return this.y;
        }

        public final int getY() {
            return this.yProperty().get();
        }

        public final void setY(final int y) {
            this.yProperty().set(y);
        }

        public final IntegerProperty zProperty() {
            return this.z;
        }

        public final int getZ() {
            return this.zProperty().get();
        }

        public final void setZ(final int z) {
            this.zProperty().set(z);
        }

    }

    public static void main(String[] args) {
        launch(args);
    }
}

it didn't work

it didn't work

It works, maybe you have the wrong css file location, which should be placed in "src\main\resources" directory for Maven project.