diff --git a/src/core/CalendarConfig.ts b/src/core/CalendarConfig.ts
index cb731fc..20d1b31 100644
--- a/src/core/CalendarConfig.ts
+++ b/src/core/CalendarConfig.ts
@@ -546,6 +546,13 @@ export class CalendarConfig {
     return this.timeFormatConfig.timezone;
   }
 
+  /**
+   * Get configured locale
+   */
+  getLocale(): string {
+    return this.timeFormatConfig.locale;
+  }
+
   /**
    * Check if using 24-hour format
    */
diff --git a/src/renderers/HeaderRenderer.ts b/src/renderers/HeaderRenderer.ts
index 77ba231..25a86fa 100644
--- a/src/renderers/HeaderRenderer.ts
+++ b/src/renderers/HeaderRenderer.ts
@@ -29,15 +29,16 @@ export class DateHeaderRenderer implements HeaderRenderer {
 
   render(calendarHeader: HTMLElement, context: HeaderRenderContext): void {
     const { currentWeek, config } = context;
-    
+
     // FIRST: Always create all-day container as part of standard header structure
     const allDayContainer = document.createElement('swp-allday-container');
     calendarHeader.appendChild(allDayContainer);
-    
-    // Initialize date service with config
+
+    // Initialize date service with timezone and locale from config
     const timezone = config.getTimezone?.() || 'Europe/Copenhagen';
+    const locale = config.getLocale?.() || 'da-DK';
     this.dateService = new DateService(timezone);
-    
+
     const workWeekSettings = config.getWorkWeekSettings();
     const dates = this.dateService.getWorkWeekDates(currentWeek, workWeekSettings.workDays);
     const weekDays = config.getDateViewSettings().weekDays;
@@ -48,15 +49,15 @@ export class DateHeaderRenderer implements HeaderRenderer {
       if (this.dateService.isSameDay(date, new Date())) {
         (header as any).dataset.today = 'true';
       }
-      
-      const dayName = this.dateService.getDayName(date, 'short');
-      
+
+      const dayName = this.dateService.getDayName(date, 'long', locale).toUpperCase();
+
       header.innerHTML = `
         <swp-day-name>${dayName}</swp-day-name>
         <swp-day-date>${date.getDate()}</swp-day-date>
       `;
       (header as any).dataset.date = this.dateService.formatISODate(date);
-      
+
       calendarHeader.appendChild(header);
     });
   }
diff --git a/src/utils/DateService.ts b/src/utils/DateService.ts
index 48c6e87..daf6a87 100644
--- a/src/utils/DateService.ts
+++ b/src/utils/DateService.ts
@@ -139,10 +139,11 @@ export class DateService {
    * Get day name for a date
    * @param date - Date to get day name for
    * @param format - 'short' (e.g., 'Mon') or 'long' (e.g., 'Monday')
+   * @param locale - Locale for day name (default: 'da-DK')
    * @returns Day name
    */
-  public getDayName(date: Date, format: 'short' | 'long' = 'short'): string {
-    const formatter = new Intl.DateTimeFormat('en-US', {
+  public getDayName(date: Date, format: 'short' | 'long' = 'short', locale: string = 'da-DK'): string {
+    const formatter = new Intl.DateTimeFormat(locale, {
       weekday: format
     });
     return formatter.format(date);
diff --git a/wwwroot/css/calendar-layout-css.css b/wwwroot/css/calendar-layout-css.css
index 755ca7b..c333e5d 100644
--- a/wwwroot/css/calendar-layout-css.css
+++ b/wwwroot/css/calendar-layout-css.css
@@ -246,7 +246,7 @@ swp-day-header {
   flex-direction: column;
   align-items: center;
   justify-content: center;
-  padding-top: 7px;
+  padding-top: 3px;
 }
 
 swp-day-header:last-child {
@@ -299,27 +299,27 @@ swp-day-name {
   font-weight: 500;
   font-size: 12px;
   color: var(--color-text-secondary);
+  letter-spacing: 0.1em;
 }
 
 swp-day-date {
   display: block;
-  font-size: 20px;
-  font-weight: 600;
+  font-size: 30px;
   margin-top: 4px;
-  height: 41px;
+}
 
+/* Highlight entire header for today */
+swp-day-header[data-today="true"] {
+  background: rgba(33, 150, 243, 0.1);
+}
+
+swp-day-header[data-today="true"] swp-day-name {
+  color: var(--color-primary);
+  font-weight: 600;
 }
 
 swp-day-header[data-today="true"] swp-day-date {
   color: var(--color-primary);
-  background: rgba(33, 150, 243, 0.1);
-  border-radius: 50%;
-  width: 41px;
-  height: 41px;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  margin: 4px auto 0;
 }
 
 /* Ghost columns for mouseenter events */