diff --git a/404.html b/404.html
index cb4606758..7c4cb4363 100644
--- a/404.html
+++ b/404.html
@@ -5,6 +5,47 @@
 
 ---
 
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>404 - Not Found</title>
+  <style>
+    body {
+      font-family: sans-serif;
+      margin: 0;
+      padding: 1rem;
+    }
+    .container {
+      max-width: 800px;
+      margin: 0 auto;
+      padding: 1rem;
+      text-align: center;
+    }
+    img {
+      max-width: 100%;
+      height: auto;
+    }
+    h2 {
+      font-size: 1.5rem;
+    }
+    p {
+      font-size: 1rem;
+      line-height: 1.5;
+    }
+    @media (max-width: 600px) {
+      h2 {
+        font-size: 1.2rem;
+      }
+      p {
+        font-size: 0.95rem;
+      }
+    }
+  </style>
+</head>
+<body>
+
 <div class="container">
   <p><img src="/assets/images/web/404-old-owasp.png"></p>
   <h2>WHOA THAT PAGE CANNOT BE FOUND</h2>
@@ -13,3 +54,5 @@ <h2>WHOA THAT PAGE CANNOT BE FOUND</h2>
   <hr>
   <p><strong>If all else fails you can search our <a href="https://wiki.owasp.org/">historical site</a>.</strong></p>
 </div>
+</body>
+</html>
diff --git a/_includes/slack_invite.html b/_includes/slack_invite.html
index 0d46bd320..d9d0944c3 100644
--- a/_includes/slack_invite.html
+++ b/_includes/slack_invite.html
@@ -1,37 +1,93 @@
-<h4><i class="fa fa-lg fa-slack"></i>&nbsp;Enter your email to join our Slack community</h4>
-<div id='div-slack-join' style='text-align:left;align-controls:center;padding: 8px;'>
-    <label for='emailaddr'>Email Address</label><br>
-    <input style='line-height: 24px;margin-bottom:8px;' id='emailaddr' type='email'><br>
-    <button class="cta-button dark" id="btn-join-slack">Join</button>
-</div>
-<div id='div-slack-result' style="display:hidden;font-weight:bold;margin: 24px;">
-</div>
-
-<script type="text/javascript">
-    $(function(){
-        $('#btn-join-slack').click(function(){
-            var email = $('#emailaddr').val();
-            $.ajax({
-                type: "POST",
-                url: "https://owaspadmin.azurewebsites.net/api/owasp_slack_add_user?code=aaanp3ICdjlaVHHoAnmO06EiDh9dgrCZfkjdTeoOQLVvdesivNWUjA==&email=" + encodeURIComponent(email),
-                dataType: "json",
-                success: function (result, status, xhr) {
-                   if(result['ok']){
-                    $("#div-slack-join").hide();
-                    $("#div-slack-result").text("Thanks for joining!  Be on the lookout for an email with more information.");
-                    $("#div-slack-result").show();
-                   }else {
-                    $("#div-slack-join").hide();
-                    $("#div-slack-result").text("Oops!  Looks like something went wrong or you are already signed up.");
-                    $("#div-slack-result").show();    
-                   }
-                },
-                error: function (xhr, status, error) {
-                   $("#div-slack-join").hide();
-                   $("#div-slack-result").text("Oops!  Looks like something went wrong or you are already signed up.");
-                   $("#div-slack-result").show();
-                }
+<style>
+    /* General form styling */
+    #div-slack-join {
+        text-align: left;
+        padding: 12px;
+        max-width: 400px;
+        margin: auto;
+    }
+    
+    #div-slack-join label {
+        font-weight: bold;
+        display: block;
+        margin-bottom: 4px;
+    }
+    
+    #div-slack-join input[type="email"] {
+        width: 100%;
+        padding: 8px;
+        margin-bottom: 12px;
+        font-size: 16px;
+        box-sizing: border-box;
+    }
+    
+    #btn-join-slack {
+        width: 100%;
+        padding: 10px;
+        font-size: 16px;
+        cursor: pointer;
+    }
+    
+    #div-slack-result {
+        display: none; /* Fixed from "hidden" */
+        font-weight: bold;
+        margin: 24px auto;
+        max-width: 400px;
+        text-align: center;
+    }
+    
+    /* Mobile adjustments */
+    @media (max-width: 600px) {
+        #div-slack-join {
+            padding: 8px;
+        }
+    
+        #btn-join-slack {
+            font-size: 14px;
+            padding: 8px;
+        }
+    
+        #div-slack-join input[type="email"] {
+            font-size: 14px;
+        }
+    }
+    </style>
+    
+    <h4 style="text-align:center;">
+      <i class="fa fa-lg fa-slack"></i>&nbsp;Enter your email to join our Slack community
+    </h4>
+    
+    <div id="div-slack-join">
+        <label for="emailaddr">Email Address</label>
+        <input id="emailaddr" type="email" placeholder="you@example.com">
+        <button class="cta-button dark" id="btn-join-slack">Join</button>
+    </div>
+    
+    <div id="div-slack-result"></div>
+    
+    <script type="text/javascript">
+        $(function(){
+            $('#btn-join-slack').click(function(){
+                var email = $('#emailaddr').val();
+                $.ajax({
+                    type: "POST",
+                    url: "https://owaspadmin.azurewebsites.net/api/owasp_slack_add_user?code=aaanp3ICdjlaVHHoAnmO06EiDh9dgrCZfkjdTeoOQLVvdesivNWUjA==&email=" + encodeURIComponent(email),
+                    dataType: "json",
+                    success: function (result) {
+                       $("#div-slack-join").hide();
+                       if(result['ok']){
+                           $("#div-slack-result").text("Thanks for joining! Be on the lookout for an email with more information.");
+                       } else {
+                           $("#div-slack-result").text("Oops! Something went wrong or you are already signed up.");
+                       }
+                       $("#div-slack-result").show();
+                    },
+                    error: function () {
+                       $("#div-slack-join").hide();
+                       $("#div-slack-result").text("Oops! Something went wrong or you are already signed up.");
+                       $("#div-slack-result").show();
+                    }
+                });
             });
         });
-    });
-</script>
+    </script>
\ No newline at end of file
diff --git a/pages/careers.md b/pages/careers.md
index c1586008f..79fa6e77b 100644
--- a/pages/careers.md
+++ b/pages/careers.md
@@ -5,6 +5,30 @@ title: Careers
 permalink: /careers/
 
 ---
+<style>
+  .callout-mono {
+    font-family: monospace;
+    background: #f4f4f4;
+    padding: 1rem;
+    margin: 1rem 0;
+    display: block;
+    border-left: 4px solid #999;
+  }
+
+  .callout-mono.right {
+    float: right;
+    margin-left: 1rem;
+    max-width: 300px;
+  }
+
+  @media (max-width: 768px) {
+    .callout-mono.right {
+      float: none;
+      max-width: 100%;
+      margin-left: 0;
+    }
+  }
+</style>
 
 ## Working for the OWASP Foundation
 
