diff --git a/css/portfolio.css b/css/portfolio.css
index 7cd72de..d25df4b 100644
--- a/css/portfolio.css
+++ b/css/portfolio.css
@@ -9,6 +9,7 @@
         border-radius: var(--border-radius);
         transition: transform 0.3s, box-shadow 0.3s;
         position: relative;
+        cursor: pointer;
     }
 
     & > *:hover {
@@ -41,3 +42,68 @@
         grid-row: span 2;
     }
 }
+
+#lightbox {
+    position: fixed;
+    inset: 0;
+    z-index: 1000;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: rgba(0, 0, 0, 0.8);
+    backdrop-filter: blur(8px);
+    -webkit-backdrop-filter: blur(8px);
+    opacity: 0;
+    pointer-events: none;
+    transition: opacity 0.3s;
+
+    &.open {
+        opacity: 1;
+        pointer-events: all;
+    }
+
+    & > img {
+        max-width: min(90vw, 1200px);
+        max-height: 85vh;
+        border-radius: var(--small-radius);
+        box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
+        object-fit: contain;
+    }
+
+    & > button {
+        position: absolute;
+        background: rgba(0, 0, 0, 0.5);
+        border: none;
+        color: white;
+        cursor: pointer;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        width: 3rem;
+        height: 3rem;
+        border-radius: 50%;
+        transition: background 0.2s;
+
+        &:hover {
+            background: rgba(0, 0, 0, 0.8);
+        }
+
+        & svg {
+            width: 1.5rem;
+            height: 1.5rem;
+        }
+    }
+
+    & #lb-close {
+        top: 1.5rem;
+        right: 1.5rem;
+    }
+
+    & #lb-prev {
+        left: 1.5rem;
+    }
+
+    & #lb-next {
+        right: 1.5rem;
+    }
+}
diff --git a/html/portfolio.templ b/html/portfolio.templ
index 3d62e6c..b16717e 100644
--- a/html/portfolio.templ
+++ b/html/portfolio.templ
@@ -14,5 +14,6 @@ templ Portfolio(images []string) {
 				</div>
 			</section>
 		</main>
+		<script defer src="portfolio.js"></script>
 	}
 }
diff --git a/html/portfolio_templ.go b/html/portfolio_templ.go
index f8162e9..84b2ab1 100644
--- a/html/portfolio_templ.go
+++ b/html/portfolio_templ.go
@@ -67,7 +67,7 @@ func Portfolio(images []string) templ.Component {
 					return templ_7745c5c3_Err
 				}
 			}
-			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 5, "</div></section></main>")
+			templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 5, "</div></section></main><script defer src=\"portfolio.js\"></script>")
 			if templ_7745c5c3_Err != nil {
 				return templ_7745c5c3_Err
 			}
diff --git a/js/portfolio.js b/js/portfolio.js
new file mode 100644
index 0000000..c69ba3a
--- /dev/null
+++ b/js/portfolio.js
@@ -0,0 +1,61 @@
+(function () {
+  var grid = document.getElementById('portfolio-grid');
+  if (!grid) return;
+
+  var items = Array.from(grid.querySelectorAll(':scope > div'));
+  if (!items.length) return;
+
+  var lb = document.createElement('div');
+  lb.id = 'lightbox';
+  lb.innerHTML =
+    '<button id="lb-close" aria-label="Zamknij"><svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M18 6 6 18"/><path d="m6 6 12 12"/></svg></button>' +
+    '<button id="lb-prev" aria-label="Poprzednie"><svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="m15 18-6-6 6-6"/></svg></button>' +
+    '<img src="" alt="">' +
+    '<button id="lb-next" aria-label="Następne"><svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="m9 18 6-6-6-6"/></svg></button>';
+  document.body.appendChild(lb);
+
+  var lbImg = lb.querySelector('img');
+  var current = -1;
+
+  function open(idx) {
+    current = idx;
+    var img = items[current].querySelector('img');
+    lbImg.src = img.src;
+    lbImg.alt = img.alt;
+    lb.classList.add('open');
+  }
+
+  function close() {
+    lb.classList.remove('open');
+    current = -1;
+  }
+
+  function prev() {
+    if (current < 0) return;
+    open((current - 1 + items.length) % items.length);
+  }
+
+  function next() {
+    if (current < 0) return;
+    open((current + 1) % items.length);
+  }
+
+  items.forEach(function (item, i) {
+    item.addEventListener('click', function () { open(i); });
+  });
+
+  lb.querySelector('#lb-close').addEventListener('click', close);
+  lb.querySelector('#lb-prev').addEventListener('click', function (e) { e.stopPropagation(); prev(); });
+  lb.querySelector('#lb-next').addEventListener('click', function (e) { e.stopPropagation(); next(); });
+
+  document.addEventListener('keydown', function (e) {
+    if (!lb.classList.contains('open')) return;
+    if (e.key === 'Escape') { close(); e.preventDefault(); }
+    if (e.key === 'ArrowLeft') { prev(); e.preventDefault(); }
+    if (e.key === 'ArrowRight') { next(); e.preventDefault(); }
+  });
+
+  lb.addEventListener('click', function (e) {
+    if (e.target === lb) close();
+  });
+})();
diff --git a/main.go b/main.go
index 9b0b069..9310c89 100644
--- a/main.go
+++ b/main.go
@@ -105,6 +105,7 @@ func main() {
 	mergeStyles()
 	utils.CopyFile("img/favicon.avif", "www/images/favicon.avif")
 	utils.CopyFile("img/logo.svg", "www/images/logo.svg")
+	utils.CopyFile("js/portfolio.js", "www/portfolio.js")
 	log.Println("listening on :8000")
 	log.Fatal(http.ListenAndServe(":8000", http.FileServer(http.Dir("www"))))
 }