diff --git a/static/app.js b/static/app.js
index 0116868..5c56db0 100644
--- a/static/app.js
+++ b/static/app.js
@@ -45,22 +45,21 @@ function enableEnterToSubmit(input, form) {
         if (e.key === 'Enter' && !e.shiftKey) {
             e.preventDefault();
             form.requestSubmit();
-            }
-        });
-    }
-    
-    // Optimistic UI for like/dislike buttons
-    document.querySelectorAll('form[action*="/like/"]').forEach(form => {
-        form.addEventListener('submit', (e) => {
-            const button = form.querySelector('button[type="submit"]');
-            if (button) {
-                button.style.opacity = '0.5';
-                button.textContent = button.textContent + ' ✓';
-            }
-        });
+        }
     });
 }
 
+// Optimistic UI for like/dislike buttons
+document.querySelectorAll('form[action*="/like/"]').forEach(form => {
+    form.addEventListener('submit', (e) => {
+        const button = form.querySelector('button[type="submit"]');
+        if (button) {
+            button.style.opacity = '0.5';
+            button.textContent = button.textContent + ' ✓';
+        }
+    });
+});
+
 // Initialize on DOM ready
 if (document.readyState === 'loading') {
     document.addEventListener('DOMContentLoaded', initRelativeTimestamps);
@@ -343,3 +342,88 @@ function showDraftIndicator(content, timestamp, onRestore, onDiscard) {
     
     return indicator;
 }
+
+// ============================================
+// Validation Functions
+// ============================================
+
+function validateRequired(value, fieldName) {
+    if (!value || value.trim() === '') {
+        return `${fieldName} is required`;
+    }
+    return null;
+}
+
+function validateUsername(username) {
+    if (!username || username.trim() === '') {
+        return 'Username is required';
+    }
+    if (username.length < 3) {
+        return 'Username must be at least 3 characters';
+    }
+    if (username.length > 50) {
+        return 'Username must be less than 50 characters';
+    }
+    if (!/^[a-zA-Z0-9_]+$/.test(username)) {
+        return 'Username can only contain letters, numbers, and underscores';
+    }
+    return null;
+}
+
+function validatePassword(password) {
+    if (!password || password.trim() === '') {
+        return 'Password is required';
+    }
+    if (password.length < 6) {
+        return 'Password must be at least 6 characters';
+    }
+    return null;
+}
+
+function showFieldError(field, error) {
+    field.classList.add('error');
+    let errorDiv = field.nextElementSibling;
+    if (!errorDiv || !errorDiv.classList.contains('field-error')) {
+        errorDiv = document.createElement('div');
+        errorDiv.className = 'field-error';
+        field.parentNode.insertBefore(errorDiv, field.nextSibling);
+    }
+    errorDiv.textContent = error;
+}
+
+function clearFieldError(field) {
+    field.classList.remove('error');
+    const errorDiv = field.nextElementSibling;
+    if (errorDiv && errorDiv.classList.contains('field-error')) {
+        errorDiv.remove();
+    }
+}
+
+function autoResizeTextarea(textarea) {
+    textarea.style.height = 'auto';
+    textarea.style.height = textarea.scrollHeight + 'px';
+}
+
+function addCharacterCounter(textarea, maxLength) {
+    const counter = document.createElement('div');
+    counter.className = 'char-counter';
+    textarea.parentNode.insertBefore(counter, textarea.nextSibling);
+    
+    const updateCounter = () => {
+        const length = textarea.value.length;
+        counter.textContent = `${length}/${maxLength}`;
+        if (length > maxLength * 0.9) {
+            counter.classList.add('warning');
+        } else {
+            counter.classList.remove('warning');
+        }
+    };
+    
+    textarea.addEventListener('input', updateCounter);
+    updateCounter();
+}
+
+function initRelativeTimestamps() {
+    // This function can be used to show relative timestamps
+    // For now, it's just a placeholder
+}
diff --git a/static/style.css b/static/style.css
index 7ccb3d7..3d1cf89 100644
--- a/static/style.css
+++ b/static/style.css
@@ -343,6 +343,13 @@ p.thread-info {
     background-color: #ffe0f0; /* Light pink background */
     animation: highlight-fade 2s ease-out;
 }
+/* Grouped messages (hide header for consecutive messages from same user) */
+.chat-message.grouped {
+    margin-top: -4px;
+}
+.chat-message.grouped .chat-message-header {
+    display: none;
+}
 @keyframes highlight-fade {
     from {
         background-color: #f582ae;
diff --git a/templates/pages/chat.html b/templates/pages/chat.html
index 2adba73..4d168db 100644
--- a/templates/pages/chat.html
+++ b/templates/pages/chat.html
@@ -437,7 +437,7 @@
                     <span id="typing-users"></span><span class="typing-dots"><span>.</span><span>.</span><span>.</span></span>
                 </div>
                 {{range .Messages}}
-                <div class="chat-message{{if .Mentions}}{{range .Mentions}}{{if eq . $.CurrentUsername}} chat-message-highlighted{{end}}{{end}}{{end}}" id="msg-{{.ID}}">
+                <div class="chat-message{{if .Mentions}}{{range .Mentions}}{{if eq . $.CurrentUsername}} chat-message-highlighted{{end}}{{end}}{{end}}" id="msg-{{.ID}}" data-user="{{.Username}}" data-reply="{{.ReplyTo}}">
                     <div class="chat-message-header">
                         {{if .PfpFileID.Valid}}
                         <img src="{{$.BasePath}}/file?id={{.PfpFileID.Int64}}" alt="PFP" class="chat-message-pfp">
@@ -627,6 +627,8 @@
             }
             msgDiv.className = 'chat-message' + highlightClass;
             msgDiv.id = 'msg-' + msg.id;
+            msgDiv.dataset.user = msg.username;
+            msgDiv.dataset.reply = msg.replyTo || 0;
             let pfpHTML = `<div class="chat-message-pfp" style="background-color: #001858;"></div>`;
             if (msg.pfpFileId && msg.pfpFileId.Valid) {
                 pfpHTML = `<img src="{{.BasePath}}/file?id=${msg.pfpFileId.Int64}&t=${new Date().getTime()}" alt="PFP" class="chat-message-pfp">`;
@@ -647,6 +649,9 @@
             `;
             messages.appendChild(msgDiv);
             
+            // Apply grouping
+            applyGrouping();
+            
             // Scroll handling
             if (wasAtBottom) {
                 messages.scrollTop = messages.scrollHeight;
@@ -834,6 +839,9 @@
             const messagesContainer = document.getElementById('chat-messages');
             messagesContainer.scrollTop = messagesContainer.scrollHeight;
             
+            // Apply message grouping on load
+            applyGrouping();
+            
             // Add scroll event listener
             messagesContainer.addEventListener('scroll', checkScrollPosition);
             
@@ -909,6 +917,30 @@
             // Initial check for scroll position
             checkScrollPosition();
         };
+        
+        function applyGrouping() {
+            const container = document.getElementById('chat-messages');
+            const msgs = Array.from(container.querySelectorAll('.chat-message')).filter(el => el.id.startsWith('msg-'));
+            
+            for (let i = 0; i < msgs.length; i++) {
+                const curr = msgs[i];
+                
+                // Remove grouped class first
+                curr.classList.remove('grouped');
+                
+                if (i === 0) continue; // First message is never grouped
+                
+                const prev = msgs[i - 1];
+                const currUser = curr.dataset.user;
+                const prevUser = prev.dataset.user;
+                const currReply = parseInt(curr.dataset.reply) || -1;
+                
+                // Group if same user and not a reply (reply is -1 or 0 when there's no reply)
+                if (currUser === prevUser && (currReply <= 0)) {
+                    curr.classList.add('grouped');
+                }
+            }
+        }
     </script>
 </body>
 </html>