diff --git a/script.js b/script.js
index 4218ebc..4c39260 100644
--- a/script.js
+++ b/script.js
@@ -890,8 +890,34 @@ function navigatePeriod(evt, direction) {
         step = 16**1;
     }
 
-    currentOffset += direction * step;
-    updateCalendar();
+    animateSwipe(direction, () => {
+        currentOffset += direction * step;
+        updateCalendar();
+    });
+}
+
+function animateSwipe(direction, onDone) {
+    const grid = document.getElementById('eonstripGrid');
+    if (!grid) { onDone(); return; }
+
+    // slide out
+    grid.style.transition = 'transform 0.3s ease';
+    grid.style.transform = `translateX(${direction > 0 ? '-100%' : '100%'})`;
+
+    function afterOut() {
+        grid.removeEventListener('transitionend', afterOut);
+        // prepare new position off-screen on the other side
+        grid.style.transition = 'none';
+        grid.style.transform = `translateX(${direction > 0 ? '100%' : '-100%'})`;
+        onDone();
+        // force reflow to apply position instantly
+        void grid.offsetWidth;
+        // slide in with transition
+        grid.style.transition = 'transform 0.3s ease';
+        grid.style.transform = 'translateX(0)';
+    }
+
+    grid.addEventListener('transitionend', afterOut);
 }
 
 function goToNow() {
diff --git a/style.css b/style.css
index e650381..fdf8f5c 100644
--- a/style.css
+++ b/style.css
@@ -175,6 +175,7 @@
         padding: 20px;
         backdrop-filter: blur(10px);
         border: 1px solid rgba(255, 255, 255, 0.1);
+        overflow: hidden;
     }
 
     .calendar-header {
@@ -189,6 +190,9 @@
         grid-template-columns: repeat(4, 1fr);
         gap: 15px;
         margin-bottom: 20px;
+        transform: translateX(0);
+        transition: transform 0.3s ease;
+        will-change: transform;
     }
 
     .eonstrip-card {
@@ -353,4 +357,7 @@
 
     .eonstrip-grid {
       grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
+      transform: translateX(0);
+      transition: transform 0.3s ease;
+      will-change: transform;
     }