diff --git a/timesheetweek_card.php b/timesheetweek_card.php
index 3e46a1b..4e6dd91 100644
--- a/timesheetweek_card.php
+++ b/timesheetweek_card.php
@@ -1572,7 +1572,7 @@ function updateWeekRange(){var v=$('#weekyear').val();var p=parseYearWeek(v);if(
 		echo '<div class="div-table-responsive grille-saisie-temps-wrapper">';
 		// EN: Scope the vertical and horizontal centering helper to the specific cells that need alignment (days/zones/baskets/hours/totals).
 		echo '<style>';
-		echo ':root { --tw-grid-top-gap: 0px; }';
+		echo ':root { --tw-grid-top-gap: 0px; --tw-project-task-bg: #f5f5f5; }';
 		echo '.grille-saisie-temps-wrapper { max-height: 70vh; overflow-y: auto; overflow-x: auto; position: relative; }';
 		echo '.grille-saisie-temps-wrapper.sticky-active { max-height: calc(100vh - var(--tw-grid-top-gap, 0px)); position: sticky; top: var(--tw-grid-top-gap, 0px); z-index: 4; }';
 		echo '.grille-saisie-temps .cellule-jour,';
@@ -1580,6 +1580,10 @@ function updateWeekRange(){var v=$('#weekyear').val();var p=parseYearWeek(v);if(
 		echo '.grille-saisie-temps .cellule-temps,';
 		echo '.grille-saisie-temps .cellule-total { vertical-align: middle; text-align: center; }';
 		echo '.grille-saisie-temps .col-project-task { position: sticky; left: 0; z-index: 20; }';
+		echo '.grille-saisie-temps .col-project-task,';
+		echo '.grille-saisie-temps .col-summary-sticky,';
+		echo '.grille-saisie-temps .col-project-task-filler,';
+		echo '.grille-saisie-temps .trforbreak { background-color: var(--tw-project-task-bg); }';
 		echo '.grille-saisie-temps .col-summary-sticky { position: sticky; left: 0; z-index: 8; }';
 		echo '.grille-saisie-temps .liste_titre .col-project-task { z-index: 21; }';
 		echo '.grille-saisie-temps .liste_titre .col-summary-sticky { z-index: 9; }';
@@ -1594,6 +1598,24 @@ function updateWeekRange(){var v=$('#weekyear').val();var p=parseYearWeek(v);if(
 		echo '(function($){';
 		echo '$(function(){';
 		echo "\tvar \$wrapper = $('.grille-saisie-temps-wrapper');";
+		echo "\tvar projectTaskBgCache = null;";
+		echo "\tfunction applyProjectTaskBackground() {";
+		echo "\t\tvar bgColor = '';";
+		echo "\t\tvar \$localTitle = $('.grille-saisie-temps .liste_titre').first();";
+		echo "\t\tif (\$localTitle.length) {";
+		echo "\t\t\tbgColor = window.getComputedStyle(\$localTitle[0]).backgroundColor;";
+		echo "\t\t}";
+		echo "\t\tif (!bgColor || bgColor === 'rgba(0, 0, 0, 0)' || bgColor === 'transparent') {";
+		echo "\t\t\tvar \$globalTitle = $('.liste_titre').first();";
+		echo "\t\t\tif (\$globalTitle.length) {";
+		echo "\t\t\t\tbgColor = window.getComputedStyle(\$globalTitle[0]).backgroundColor;";
+		echo "\t\t\t}";
+		echo "\t\t}";
+		echo "\t\tif (bgColor && bgColor !== 'rgba(0, 0, 0, 0)' && bgColor !== 'transparent' && bgColor !== projectTaskBgCache) {";
+		echo "\t\t\tprojectTaskBgCache = bgColor;";
+		echo "\t\t\tdocument.documentElement.style.setProperty('--tw-project-task-bg', bgColor);";
+		echo "\t\t}";
+		echo "\t}";
 		echo "\tif (!\$wrapper.length) { return; }";
 		echo "\tvar currentTopGap = 0;";
 		echo "\tfunction updateGridTopGap() {";
@@ -1625,12 +1647,26 @@ function updateWeekRange(){var v=$('#weekyear').val();var p=parseYearWeek(v);if(
 		echo "\t\tvar bottomVisible = rect.bottom <= window.innerHeight;";
 		echo "\t\ttoggleStickyState(!bottomVisible);";
 		echo "\t}";
+		echo "\tvar htmlTarget = document.documentElement;";
+		echo "\tvar bodyTarget = document.body;";
 		echo "\tupdateGridTopGap();";
+		echo "\tapplyProjectTaskBackground();";
 		echo "\tupdateStickyPosition();";
 		echo "\t$(window).on('resize scroll', function(){";
 		echo "\t\tupdateGridTopGap();";
+		echo "\t\tapplyProjectTaskBackground();";
 		echo "\t\tupdateStickyPosition();";
 		echo "\t});";
+		echo "\tvar observerConfig = { attributes: true, attributeFilter: ['class'] };";
+		echo "\tvar themeObserver = new MutationObserver(function(){";
+		echo "\t\tapplyProjectTaskBackground();";
+		echo "\t});";
+		echo "\tif (htmlTarget) {";
+		echo "\t\tthemeObserver.observe(htmlTarget, observerConfig);";
+		echo "\t}";
+		echo "\tif (bodyTarget) {";
+		echo "\t\tthemeObserver.observe(bodyTarget, observerConfig);";
+		echo "\t}";
 		echo '});';
 		echo '})(jQuery);';
 		echo '</script>';