diff --git a/app/views/common/_calendar.html.erb b/app/views/common/_calendar.html.erb
index 704f865..393a09a 100644
--- a/app/views/common/_calendar.html.erb
+++ b/app/views/common/_calendar.html.erb
@@ -1,3 +1,5 @@
+<%= javascript_include_tag('dynamic_favicon', plugin: :redmine_qbo_calendar) %>
+
 <%
   # Check if toggles are active via query params
   only_appointments = params[:only_appointments] == '1'
diff --git a/app/views/customer_appointments/edit.html.erb b/app/views/customer_appointments/edit.html.erb
index 8db5cd9..0084ae4 100644
--- a/app/views/customer_appointments/edit.html.erb
+++ b/app/views/customer_appointments/edit.html.erb
@@ -1,3 +1,5 @@
+<%= javascript_include_tag('dynamic_favicon', plugin: :redmine_qbo_calendar) %>
+
 <h2>Edit Appointment</h2>
 
 <%= render "form" %>
\ No newline at end of file
diff --git a/app/views/customer_appointments/new.html.erb b/app/views/customer_appointments/new.html.erb
index 852510f..b440001 100644
--- a/app/views/customer_appointments/new.html.erb
+++ b/app/views/customer_appointments/new.html.erb
@@ -1,3 +1,5 @@
+<%= javascript_include_tag('dynamic_favicon', plugin: :redmine_qbo_calendar) %>
+
 <h2>New Appointment</h2>
 
 <%= render "form" %>
\ No newline at end of file
diff --git a/app/views/customer_appointments/show.html.erb b/app/views/customer_appointments/show.html.erb
index 6ad3250..57950a9 100644
--- a/app/views/customer_appointments/show.html.erb
+++ b/app/views/customer_appointments/show.html.erb
@@ -1,3 +1,5 @@
+<%= javascript_include_tag('dynamic_favicon', plugin: :redmine_qbo_calendar) %>
+
 <div class="contextual">
   <%= link_to issues_calendar_path do %>
     <i class="fa-regular fa-calendar-days"></i> <%= l(:button_calendar) %>
diff --git a/assets/javascripts/dynamic_favicon.js b/assets/javascripts/dynamic_favicon.js
new file mode 100644
index 0000000..ffb57b1
--- /dev/null
+++ b/assets/javascripts/dynamic_favicon.js
@@ -0,0 +1,140 @@
+(function() {
+  'use strict';
+
+  console.log('[Redmine QBO Calendar] dynamic_favicon.js loaded (Simplified Canvas PNG)');
+
+  const FAVICON_ID = 'redmine-qbo-calendar-favicon';
+
+  function generatePngFaviconUrl(day, callback) {
+    const svg = `
+      <svg xmlns="http://www.w3.org/2000/svg"
+           width="64" height="64" viewBox="0 0 64 64">
+
+        <rect
+          x="3"
+          y="4"
+          width="58"
+          height="57"
+          rx="7"
+          fill="#ffffff"
+          stroke="#888888"
+          stroke-width="2"/>
+
+        <rect
+          x="3"
+          y="4"
+          width="58"
+          height="18"
+          rx="7"
+          fill="#d92626"/>
+
+        <rect
+          x="3"
+          y="15"
+          width="58"
+          height="7"
+          fill="#d92626"/>
+
+        <rect
+          x="14"
+          y="1"
+          width="6"
+          height="12"
+          rx="3"
+          fill="#555555"/>
+
+        <rect
+          x="44"
+          y="1"
+          width="6"
+          height="12"
+          rx="3"
+          fill="#555555"/>
+
+        <text
+          x="32"
+          y="17"
+          text-anchor="middle"
+          font-family="Arial, sans-serif"
+          font-size="8"
+          font-weight="bold"
+          fill="#ffffff">
+          OSOR
+        </text>
+
+        <text
+          x="32"
+          y="50"
+          text-anchor="middle"
+          font-family="Arial, sans-serif"
+          font-size="36"
+          font-weight="bold"
+          fill="#222222">
+          ${day}
+        </text>
+
+      </svg>
+    `;
+
+    const cleanSvg = svg.replace(/\n/g, '').replace(/\s+/g, ' ').trim();
+    const svgDataUrl = 'data:image/svg+xml;base64,' + btoa(unescape(encodeURIComponent(cleanSvg)));
+
+    const canvas = document.createElement('canvas');
+    canvas.width = 64;
+    canvas.height = 64;
+    const ctx = canvas.getContext('2d');
+
+    const img = new Image();
+    
+    img.onload = function() {
+      ctx.drawImage(img, 0, 0, 64, 64);
+      const pngDataUrl = canvas.toDataURL('image/png');
+      callback(pngDataUrl);
+    };
+    
+    img.src = svgDataUrl;
+  }
+
+  function setFavicon() {
+    const day = new Date().getDate();
+
+    generatePngFaviconUrl(day, function(newFaviconUrl) {
+      const existingIcons = document.querySelectorAll('link[rel*="icon"]');
+
+      if (existingIcons.length > 0) {
+        existingIcons.forEach(function(icon) {
+          icon.type = 'image/png';
+          icon.rel = 'icon'; 
+          icon.href = newFaviconUrl;
+        });
+      } else {
+        const favicon = document.createElement('link');
+        favicon.id = FAVICON_ID;
+        favicon.rel = 'icon';
+        favicon.type = 'image/png';
+        favicon.href = newFaviconUrl;
+        document.head.appendChild(favicon);
+      }
+
+      console.log(
+        '[OSOR Calendar] favicon updated (Simplified PNG)',
+        { day: day }
+      );
+    });
+  }
+
+  function initialize() {
+    console.log('[OSOR Calendar] initializing favicon');
+    setTimeout(setFavicon, 150);
+  }
+
+  if (document.readyState === 'loading') {
+    document.addEventListener(
+      'DOMContentLoaded',
+      initialize
+    );
+  } else {
+    initialize();
+  }
+
+})();
\ No newline at end of file