fix black theme

lib/ui/pages/server_details/cpu_chart.dart

@@ -1,5 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:fl_chart/fl_chart.dart';
+import 'package:selfprivacy/config/brand_colors.dart';
+import 'package:selfprivacy/config/text_themes.dart';
 import 'package:selfprivacy/logic/common_enum/common_enum.dart';
 import 'package:selfprivacy/logic/models/hetzner_metrics.dart';
 import 'package:intl/intl.dart';
@@ -58,6 +60,11 @@ class CpuChart extends StatelessWidget {
                 return bottomTitle(value.toInt());
               }),
           leftTitles: SideTitles(
+            getTextStyles: (value) => progressTextStyleLight.copyWith(
+              color: Theme.of(context).brightness == Brightness.dark
+                  ? BrandColors.gray4
+                  : null,
+            ),
             margin: 15,
             interval: 25,
             showTitles: true,

lib/ui/pages/server_details/network_charts.dart

@@ -2,6 +2,8 @@ import 'dart:math';
 
 import 'package:flutter/material.dart';
 import 'package:fl_chart/fl_chart.dart';
+import 'package:selfprivacy/config/brand_colors.dart';
+import 'package:selfprivacy/config/text_themes.dart';
 import 'package:selfprivacy/logic/common_enum/common_enum.dart';
 import 'package:selfprivacy/logic/models/hetzner_metrics.dart';
 import 'package:intl/intl.dart';
@@ -85,6 +87,11 @@ class NetworkChart extends StatelessWidget {
                   ].reduce(max) *
                   1.2 /
                   10,
+              getTextStyles: (value) => progressTextStyleLight.copyWith(
+                color: Theme.of(context).brightness == Brightness.dark
+                    ? BrandColors.gray4
+                    : null,
+              ),
               showTitles: true,
             ),
           ),