diff --git a/Ex3_Box model and positioning/3-7/default.html b/Ex3_Box model and positioning/3-7/default.html
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+++ b/Ex3_Box model and positioning/3-7/default.html	
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+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8"/>
+    <meta name="viewport" content="width=device-width"/>
+    <title>3 Columns example</title>
+    <style>
+        * {
+            box-sizing: border-box;   
+        }
+
+        .row {
+            width: 100%;
+        }
+
+        .column {
+            display: inline-block;
+            width: 30%;
+            padding: 15px;
+        }
+
+        @media screen and (max-width:600px) {
+        .column {
+          width: 100%;
+        }
+      }
+    </style>
+</head>
+<body>
+    <h2>3 column example</h2>
+    <hr>
+
+    <div class="row">
+        <div class="column">
+            <h2>Title-1</h2>
+            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas sit amet pretium urna. Vivamus venenatis velit nec neque ultricies, eget elementum magna tristique. Quisque vehicula, risus eget aliquam placerat, purus leo tincidunt eros, eget luctus
+            quam orci in velit. Praesent scelerisque tortor sed accumsan convallis.
+        </div>
+
+        <div class="column">
+            <h2>Title-2</h2>
+            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas sit amet pretium urna. Vivamus venenatis velit nec neque ultricies, eget elementum magna tristique. Quisque vehicula, risus eget aliquam placerat, purus leo tincidunt eros, eget luctus
+            quam orci in velit. Praesent scelerisque tortor sed accumsan convallis.
+        </div>
+
+        <div class="column">
+            <h2>Title-3</h2>
+            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas sit amet pretium urna. Vivamus venenatis velit nec neque ultricies, eget elementum magna tristique. Quisque vehicula, risus eget aliquam placerat, purus leo tincidunt eros, eget luctus
+            quam orci in velit. Praesent scelerisque tortor sed accumsan convallis.
+        </div>
+    </div>
+</body>
+</html>
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diff --git a/Ex3_Box model and positioning/3-8/default.html b/Ex3_Box model and positioning/3-8/default.html
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index 0000000..a089702
--- /dev/null
+++ b/Ex3_Box model and positioning/3-8/default.html	
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+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8"/>
+    <meta name="viewport" content="width=device-width"/>
+    <title>Center alignment</title>
+    <style>
+        .box-center {
+            margin: auto;
+            width: 50%;
+            border: 3px solid green;
+            padding: 10px;
+            text-align: center;
+        }
+
+        .img-center {
+            display: block;
+            margin: auto;
+        }
+    </style>
+</head>
+<body>
+    <h2>Center alignment</h2>
+    <div class="box-center">
+        Hello World
+    </div>
+    <p></p>
+    <img class="img-center" src="https://images.unsplash.com/photo-1718795903419-2bc5bba08d2f?w=200&auto=format&fit=crop&q=60&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxlZGl0b3JpYWwtZmVlZHwxMXx8fGVufDB8fHx8fA%3D%3D">
+</body>
+</html>
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