Refactor print styles and enhance chart configuration for better visualization

- Adjusted chart grid color for improved contrast in visualizations.
- Implemented print-specific styles to ensure proper layout and formatting on A4 paper.
- Enhanced chart configuration in JavaScript to include grid line width and tick border dash for clearer data representation.
- Updated HTML to streamline print functionality, replacing the PDF export button with a direct print command.

static/js/dashboard.js

@@ -265,7 +265,21 @@
                     }
                 },
                 scales: {
-                    y: { beginAtZero: true, max: 100, grid: { drawBorder: false, color: gridColor }, ticks: { color: textColor, callback: function(value) { return value + '%'; } } },
+                    y: {
+                        beginAtZero: true,
+                        max: 100,
+                        grid: {
+                            drawBorder: false,
+                            color: gridColor,
+                            lineWidth: 0.5,
+                            tickBorderDash: [4, 4]
+                        },
+                        ticks: {
+                            stepSize: 25,
+                            color: textColor,
+                            callback: function(value) { return value + '%'; }
+                        }
+                    },
                     x: { grid: { display: false }, ticks: { display: false }, barPercentage: 1, categoryPercentage: 0.85 }
                 }
             }