diff --git a/CHANGELOG.md b/CHANGELOG.md
index 664cd95..761a365 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 * bug: Migrate an existing `plugin_slowlog_details_methods` table in place during upgrade - `api_plugin_db_table_create()` never retrofits a table that already exists, so on an existing install the de-normalization above would otherwise leave the old `methodid` column (and no `method` column), breaking every import/detail/stat/chart query with an unknown-column error. `slowlog_check_upgrade()` now runs an idempotent `slowlog_migrate_details_methods_to_method()` that adds the `method` column, backfills the names from the `plugin_slowlog_methods` dictionary, then swaps the primary key to `(logid, logentry, method)` and drops `methodid`. It runs on every page (self-gating on the `methodid` column) because this schema change ships without a version bump, so the version-drift upgrade branch would never fire for it
 * refactor: Move the slowlog_functions.php library file into includes/ and switch every file inclusion from include/include_once to require/require_once for fail-fast consistency (references updated across setup.php, slowlog.php, import_log.php, and the test suite)
 * refactor: Rename includes/slowlog_functions.php to includes/functions.php to match the Cacti plugin naming convention; every require/loadPluginSource reference and the Pest coverage source list were updated, and a manifest.json tombstone (includes/slowlog_functions.php) prunes the old filename from existing installs on upgrade
+* bug: Fix the By Method/By Table charts and the import upload donut still rendering a white plot surface under dark themes (e.g. deepness) - `slowlog_apex_theme()` skinned the text (`foreColor`), gridlines, and donut track from the active theme's rrdtheme but never set the ApexCharts `chart.background`, so ApexCharts painted its default white background over the dark theme regardless of `theme.mode`. The helper now also resolves the theme's own panel background (rrdtheme `back`, falling back to the plotting `canvas`, then white) and it is applied as `chart.background` on the bar, box, and donut charts
 * refactor: Move all schema management (table definitions, create, upgrade, and drop helpers) into includes/database.php (the thold model) with the Cacti copyright header; setup.php's install/uninstall/upgrade paths now require that file and delegate to it, keeping the api_plugin_db_table_create() create path and the db_update_table() upgrade refresh unchanged
 * dev: Enforce patch coverage of changed lines in CI and remove the inert COMPOSER_ROOT_VERSION env from the Pest step
 * bug: Fix the By Method/By Table chart scope filter rendering two overlapping widgets (a select2 multi-select and the jQuery multiselect) with an overlapping search box - `slowlog_charts_filter()` unconditionally applied `.multiselect()` to `#chart_scope` while Cacti core independently turned the same plain `<select>` into a select2. The control now carries the `select2-multi-count` class and prefers select2 when it is loaded (binding `select2:close` to re-apply the filter), only falling back to the jquery-multiselect widget when select2 is unavailable; its empty-selection state preserves the original `Select Method`/`Select Table` prompt rather than an inaccurate `All Selected`
diff --git a/includes/functions.php b/includes/functions.php
index 3afa621..e98c954 100644
--- a/includes/functions.php
+++ b/includes/functions.php
@@ -3112,8 +3112,9 @@ function slowlog_get_chart_scope_items(string $chart_type, int $id): array {
  * Called from slowlog_import() and slowlog_view_charts() to skin the upload
  * donut and the By Method/By Table charts.
  *
- * @return array{mode:string,foreColor:string,gridColor:string} ApexCharts theme
- *               mode ('light'|'dark') plus '#rrggbb' text and gridline colors.
+ * @return array{mode:string,foreColor:string,gridColor:string,background:string}
+ *               ApexCharts theme mode ('light'|'dark') plus '#rrggbb' text,
+ *               gridline, and chart-surface background colors.
  *
  * @global array $config Cacti global configuration array; used to locate the
  *                       active theme's rrdtheme.php.
@@ -3151,6 +3152,11 @@ function slowlog_apex_theme(): array {
 	$font = slowlog_normalize_hex_color($rrdcolors['font'] ?? '', '000000');
 	$grid = slowlog_normalize_hex_color($rrdcolors['grid'] ?? '', 'cccccc');
 
+	// The chart surface must follow the theme too, or ApexCharts paints its default
+	// white plot background over a dark theme. Prefer the theme's panel background
+	// ('back'), falling back to the plotting canvas, then white for light defaults.
+	$back = slowlog_normalize_hex_color($rrdcolors['back'] ?? ($rrdcolors['canvas'] ?? ''), 'ffffff');
+
 	// A light font implies a dark theme; ApexCharts' mode drives the tooltip surface.
 	$r = hexdec(substr($font, 0, 2));
 	$g = hexdec(substr($font, 2, 2));
@@ -3159,9 +3165,10 @@ function slowlog_apex_theme(): array {
 	$luminance = (0.299 * $r) + (0.587 * $g) + (0.114 * $b);
 
 	return [
-		'mode'      => ($luminance >= 128) ? 'dark' : 'light',
-		'foreColor' => '#' . $font,
-		'gridColor' => '#' . $grid
+		'mode'       => ($luminance >= 128) ? 'dark' : 'light',
+		'foreColor'  => '#' . $font,
+		'gridColor'  => '#' . $grid,
+		'background' => '#' . $back
 	];
 }
 
diff --git a/slowlog.php b/slowlog.php
index 615fc9a..5282b19 100644
--- a/slowlog.php
+++ b/slowlog.php
@@ -510,6 +510,7 @@ function initDonut() {
 					type: 'radialBar',
 					height: 160,
 					width: 160,
+					background: slowlogThemeColors.background,
 					sparkline: { enabled: true }
 				},
 				series: [0],
@@ -1189,6 +1190,7 @@ function renderChart(chartid, title, yaxislabel, categories, data, mode, height,
 				type:    'bar',
 				height:  height,
 				width:   width,
+				background: slowlogThemeColors.background,
 				foreColor: slowlogThemeColors.foreColor,
 				redrawOnParentResize: true,
 				redrawOnWindowResize: true,
@@ -1301,6 +1303,7 @@ function renderBoxChart(chartid, title, yaxislabel, categories, boxData, p95Data
 				type:    'boxPlot',
 				height:  height,
 				width:   width,
+				background: slowlogThemeColors.background,
 				foreColor: slowlogThemeColors.foreColor,
 				redrawOnParentResize: true,
 				redrawOnWindowResize: true
diff --git a/tests/Unit/ApexThemeTest.php b/tests/Unit/ApexThemeTest.php
index 84a5148..69e6caf 100644
--- a/tests/Unit/ApexThemeTest.php
+++ b/tests/Unit/ApexThemeTest.php
@@ -33,14 +33,15 @@
 
 	$themes = $this->sandbox . '/include/themes';
 
-	foreach (array('lightx', 'darkx', 'alphax', 'variantx') as $theme) {
+	foreach (array('lightx', 'darkx', 'alphax', 'variantx', 'canvasx') as $theme) {
 		mkdir($themes . '/' . $theme, 0777, true);
 	}
 
 	file_put_contents($themes . '/lightx/rrdtheme.php', "<?php\n\$rrdcolors['font'] = '000000';\n\$rrdcolors['grid'] = 'cccccc';\n");
-	file_put_contents($themes . '/darkx/rrdtheme.php', "<?php\n\$rrdcolors['font'] = 'FFFFFF';\n\$rrdcolors['grid'] = '545454';\n");
+	file_put_contents($themes . '/darkx/rrdtheme.php', "<?php\n\$rrdcolors['font'] = 'FFFFFF';\n\$rrdcolors['grid'] = '545454';\n\$rrdcolors['back'] = '11161D';\n");
 	file_put_contents($themes . '/alphax/rrdtheme.php', "<?php\n\$rrdcolors['font'] = 'FFFFffaa';\n\$rrdcolors['grid'] = '21212400';\n");
 	file_put_contents($themes . '/variantx/rrdtheme.php', "<?php\n\$rrdcolors['font'] = '000000';\n\$rrdcolors_dark['font'] = 'FFFFFF';\n\$rrdcolors_light['font'] = '000000';\n");
+	file_put_contents($themes . '/canvasx/rrdtheme.php', "<?php\n\$rrdcolors['font'] = 'FFFFFF';\n\$rrdcolors['canvas'] = '0B0E13';\n");
 
 	$GLOBALS['config']['base_path'] = $this->sandbox;
 });
@@ -53,7 +54,7 @@
 
 	$themes = $this->sandbox . '/include/themes';
 
-	foreach (array('lightx', 'darkx', 'alphax', 'variantx') as $theme) {
+	foreach (array('lightx', 'darkx', 'alphax', 'variantx', 'canvasx') as $theme) {
 		@unlink($themes . '/' . $theme . '/rrdtheme.php');
 		@rmdir($themes . '/' . $theme);
 	}
@@ -85,6 +86,7 @@
 	expect($apex['mode'])->toBe('light');
 	expect($apex['foreColor'])->toBe('#000000');
 	expect($apex['gridColor'])->toBe('#cccccc');
+	expect($apex['background'])->toBe('#ffffff');
 });
 
 it('resolves a dark theme to dark mode from its light font luminance', function () {
@@ -95,6 +97,15 @@
 	expect($apex['mode'])->toBe('dark');
 	expect($apex['foreColor'])->toBe('#ffffff');
 	expect($apex['gridColor'])->toBe('#545454');
+	expect($apex['background'])->toBe('#11161d');
+});
+
+it('uses the plotting canvas color as the background when back is absent', function () {
+	$GLOBALS['__test_selected_theme'] = 'canvasx';
+
+	$apex = slowlog_apex_theme();
+
+	expect($apex['background'])->toBe('#0b0e13');
 });
 
 it('strips RRDtool alpha suffixes from the resolved theme colors', function () {
@@ -135,4 +146,5 @@
 	expect($apex['mode'])->toBe('light');
 	expect($apex['foreColor'])->toBe('#000000');
 	expect($apex['gridColor'])->toBe('#cccccc');
+	expect($apex['background'])->toBe('#ffffff');
 });