modificaciones:

responsivo
no permita ingresar escuelas inexistentes

encuesta.php

@@ -40,7 +40,7 @@ session_start();
 </div>
 
 
-<div class="container col-md-12">
+<div class="container col-md-12" style="margin-top: 10%">
 
     <div class="d-flex justify-content-center  col-md-12 col-sm-12 col-xs-12">
         <div class="user_card">
@@ -104,7 +104,7 @@ session_start();
 					</div>
 
 					<div class="form-group" style="color: white;">
-						<textarea required class="form-control" rows="8" cols="50" name="comentario" style="resize: none" maxlength="200" onKeyDown="valida_longitud()" onKeyUp="valida_longitud()"></textarea>
+						<textarea required class="form-control" rows="6" cols="50" name="comentario" style="resize: none" maxlength="200" onKeyDown="valida_longitud()" onKeyUp="valida_longitud()"></textarea>
 						<?php
 						if ($_POST['idioma']=='Maya')
 						{

index.php

@@ -61,7 +61,7 @@ $conn->close();*/
 </div>
 
 
-<div class="container col-md-12">
+<div class="container col-md-12" style="margin-top: 10%">
 
     <div class="d-flex justify-content-center  col-md-12 col-sm-12 col-xs-12">
         <div class="user_card">
@@ -140,7 +140,6 @@ $conn->close();*/
 				<?php
 				if (isset($_GET['err'])) {
 					echo "<div class=\"alert alert-danger alert-dismissible \">
-    <a href=\"#\" class=\"close\" data-dismiss=\"alert\" aria-label=\"close\">&times;</a>
     <strong>Danger!</strong> This alert box could indicate a dangerous or potentially negative action.
   </div>";
 				}
@@ -150,11 +149,11 @@ $conn->close();*/
 
     </div>
     <div class="text-center" style="margin:40px;">
-        <img class="img-fluid" src="images/Logo-Horizontal-V2-blanco.png" width="300px"><br>
+        <img class="img-fluid img-responsive" src="images/Logo-Horizontal-V2-blanco.png" width="300"><br>
         <div>
 
             <div class="text-center" style="margin:40px;">
-                <img class="img-fluid" src="images/g122.png" width="400px">
+                <img class="img-fluid img-responsive" src="images/g122.png" width="400">
             </div>
         </div>
         <script>

lenguaje.php

@@ -86,7 +86,7 @@ if ($result->num_rows > 0) {
 </div>
 
 
-<div class="container col-md-12">
+<div class="container col-md-12"  style="margin-top: 10%">
 
     <div class="d-flex justify-content-center  col-md-12 col-sm-12 col-xs-12">
         <div class="user_card">

ownStyle.css

@@ -70,6 +70,24 @@ html {
     }
 }
 
+@media (min-width: 400px) {
+    .element {
+        background-image: url("images/463980.jpg");
+    }
+}
+
+@media (min-width: 500px) {
+    .element {
+        background-image: url("images/463980.jpg");
+    }
+}
+
+@media (min-width: 600px) {
+    .element {
+        background-image: url("images/463980.jpg");
+    }
+}
+
 body {
     /* Location of the image */
     background-image: url("images/463980.jpg");
@@ -101,9 +119,9 @@ body {
 }
 
 .user_card {
-    height: 600px;
+    height: 500px;
     width: 550px;
-    margin-top: 200px;
+    margin-top: 5%;
     margin-bottom: auto;
     background: rgba(220, 105, 29, 0.3);
     position: relative;

salida.php

@@ -37,7 +37,7 @@
 </div>
 
 
-<div class="container col-md-12">
+<div class="container col-md-12" style="margin-top: 10%">
 
     <div class="d-flex justify-content-center  col-md-12 col-sm-12 col-xs-12">
         <div class="user_card">