diff --git a/package-lock.json b/package-lock.json
index b15084556..8e15d45d4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -768,7 +768,8 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -789,12 +790,14 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -809,17 +812,20 @@
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "core-util-is": {
           "version": "1.0.2",
@@ -936,7 +942,8 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "ini": {
           "version": "1.3.5",
@@ -948,6 +955,7 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "number-is-nan": "^1.0.0"
           }
@@ -962,6 +970,7 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }
@@ -969,12 +978,14 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "minipass": {
           "version": "2.2.4",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "safe-buffer": "^5.1.1",
             "yallist": "^3.0.0"
@@ -993,6 +1004,7 @@
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -1073,7 +1085,8 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "object-assign": {
           "version": "4.1.1",
@@ -1085,6 +1098,7 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "wrappy": "1"
           }
@@ -1170,7 +1184,8 @@
         "safe-buffer": {
           "version": "5.1.1",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -1206,6 +1221,7 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "code-point-at": "^1.0.0",
             "is-fullwidth-code-point": "^1.0.0",
@@ -1225,6 +1241,7 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
+          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -1268,12 +1285,14 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         },
         "yallist": {
           "version": "3.0.2",
           "bundled": true,
-          "dev": true
+          "dev": true,
+          "optional": true
         }
       }
     },
diff --git a/week-1/1-parent-child/index.html b/week-1/1-parent-child/index.html
index 458a4cb21..9e9812283 100644
--- a/week-1/1-parent-child/index.html
+++ b/week-1/1-parent-child/index.html
@@ -27,6 +27,7 @@
           <p class="message__content">
             I can meet on Tuesday and Wednesday after 4.
           </p>
+          <span class="message__time">17:15pm</span>
         </div>
       </div>
     </div>
diff --git a/week-1/2-html-attributes/index.html b/week-1/2-html-attributes/index.html
index dc861fa4f..de8e7ffcc 100644
--- a/week-1/2-html-attributes/index.html
+++ b/week-1/2-html-attributes/index.html
@@ -23,14 +23,17 @@
         <div class="message">
           <div class="message__author">Luke</div>
           <p class="message__content">
-            Let's meet at the iCafe in Merchant City. https://goo.gl/maps/aza4h9nUBhn
+            Let's meet at the <a href=" https://goo.gl/maps/aza4h9nUBhn">icafe</a> in Merchant City.
+            https://goo.gl/maps/aza4h9nUBhn
           </p>
           <span class="message__time">7:35pm</span>
+          <img src="https://media.giphy.com/media/l41K4KlVE8dgozf8I/giphy.gif" />
         </div>
         <div class="message">
           <div class="message__author">Won</div>
           <p class="message__content">
             Ok! https://media.giphy.com/media/l41K4KlVE8dgozf8I/giphy.gif
+            <img src="https://media.giphy.com/media/l41K4KlVE8dgozf8I/giphy.gif" />
           </p>
           <span class="message__time">7:38pm</span>
         </div>
diff --git a/week-1/3-semantic-html/index.html b/week-1/3-semantic-html/index.html
index 3640deaff..2add9e97f 100644
--- a/week-1/3-semantic-html/index.html
+++ b/week-1/3-semantic-html/index.html
@@ -12,30 +12,30 @@
 
   <body>
     <div class="site-wrapper">
-      <div class="site-header">
+      <header class="site-header">
         <div class="site-header__title">Messages</div>
-      </div>
-      <div class="messages">
-        <div class="message">
+      </header>
+      <main class="messages" role="main">
+        <article class="message">
           <div class="message__author">Won</div>
           <p class="message__content">Where should we meet later?</p>
-          <span class="message__time">Mar 25, 2018 7:25pm</span>
-        </div>
-        <div class="message">
+          <span class="message__time"><time datetime=" 2018-25 7:25">25, 2018 7:25pm</time></span>
+        </article>
+        <article class="message">
           <div class="message__author">Luke</div>
           <p class="message__content">
             Let's meet at the iCafe in Merchant City. https://goo.gl/maps/aza4h9nUBhn
           </p>
-          <span class="message__time">Mar 25, 2018 7:35pm</span>
-        </div>
-        <div class="message">
+          <span class="message__time"><time datetime="2018-25 7:35">25, 2018 7:35pm</time></span>
+        </article>
+        <article class="message">
           <div class="message__author">Won</div>
           <p class="message__content">
             Ok! https://media.giphy.com/media/l41K4KlVE8dgozf8I/giphy.gif
           </p>
-          <span class="message__time">Mar 25, 2018 7:38pm</span>
-        </div>
-      </div>
+          <span class="message__time"><time datetime="2018-25 7:38">25, 2018 7:38pm</time></span>
+        </article>
+      </main>
       <div id="result" class="result"></div>
     </div>
     <script defer src="/js/3-result.js"></script>
diff --git a/week-1/4-links-scripts/index.html b/week-1/4-links-scripts/index.html
index 303c7fbd2..7e6214e39 100644
--- a/week-1/4-links-scripts/index.html
+++ b/week-1/4-links-scripts/index.html
@@ -4,6 +4,7 @@
     <meta charset="utf-8" />
     <title>4. Adding Links and Scripts - HTML, CSS and Git Exercises</title>
     <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <link rel="stylesheet" href="missing-styles.css" />
   </head>
 
   <body>
@@ -33,5 +34,6 @@
         </div>
       </div>
     </div>
+    <script src="convertUrls.js"></script>
   </body>
 </html>
diff --git a/week-1/5-css-selectors/message-backgrounds.css b/week-1/5-css-selectors/message-backgrounds.css
index ffe483325..a8f3a711c 100644
--- a/week-1/5-css-selectors/message-backgrounds.css
+++ b/week-1/5-css-selectors/message-backgrounds.css
@@ -1 +1,10 @@
 /* Add your CSS code below */
+#first-message {
+  background-color: red;
+}
+article {
+  background-color: cadetblue;
+}
+.message--latest {
+  background-color: yellow;
+}
diff --git a/week-1/6-css-properties/index.html b/week-1/6-css-properties/index.html
index 8e2de7baa..cb1e12f8a 100644
--- a/week-1/6-css-properties/index.html
+++ b/week-1/6-css-properties/index.html
@@ -21,7 +21,7 @@
           <p class="message__content">
             Where should we meet tomorrrow?
           </p>
-          <time class="message__time message__time--old">Yesterday, 7:25pm</time>
+          <time class="message__time message__time--old"><span>yesterday</span>, 7:25pm</time>
         </div>
         <div class="message">
           <div class="message__author">Luke</div>
diff --git a/week-1/6-css-properties/styles.css b/week-1/6-css-properties/styles.css
index ffe483325..c592e695a 100644
--- a/week-1/6-css-properties/styles.css
+++ b/week-1/6-css-properties/styles.css
@@ -1 +1,19 @@
 /* Add your CSS code below */
+
+a {
+  color: red;
+  font-weight: bold;
+  text-decoration: none;
+}
+.message_time {
+  font-size: 0.9rem;
+}
+.message:last-child {
+  border-left: 2px solid blue;
+}
+time span {
+  opacity: 0.5;
+}
+.message {
+  line-height: 22px;
+}
diff --git a/week-1/7-css-box/styles.css b/week-1/7-css-box/styles.css
index 013b94f1e..f5df95813 100644
--- a/week-1/7-css-box/styles.css
+++ b/week-1/7-css-box/styles.css
@@ -3,4 +3,10 @@
   border: 1px solid #4491db;
   border-radius: 4px;
   background: #fff;
+  width: 2px;
+  height: 2px;
+  padding: 2px;
+}
+.country {
+  margin: 20px;
 }
diff --git a/week-1/8-advanced-selectors/index.html b/week-1/8-advanced-selectors/index.html
index 24f5ca00b..4d5e62c7b 100644
--- a/week-1/8-advanced-selectors/index.html
+++ b/week-1/8-advanced-selectors/index.html
@@ -14,7 +14,7 @@
   <body>
     <div class="site-wrapper">
       <div class="site-header">
-        <div class="site-header__title">Messages</div>
+        <h1 class="site-header__title">Messages</h1>
         <p>All of your messages with Won are shown below.</p>
       </div>
       <div class="messages">
diff --git a/week-1/8-advanced-selectors/styles.css b/week-1/8-advanced-selectors/styles.css
index d35c3c371..a0a798727 100644
--- a/week-1/8-advanced-selectors/styles.css
+++ b/week-1/8-advanced-selectors/styles.css
@@ -1 +1,16 @@
 /* Try different box model properties below */
+.site-header > p {
+  color: white;
+}
+
+.site-header > h1 {
+  margin-bottom: 2px;
+}
+.site-footer > p {
+  font-size: 12px;
+  text-align: center;
+}
+.message: last-child {
+  box-shadow: 4px 4px 0 #dba944;
+  border-radius: 20px;
+}
diff --git a/week-2/10-media-queries/columns.css b/week-2/10-media-queries/columns.css
index 43e80d23c..3e8625825 100644
--- a/week-2/10-media-queries/columns.css
+++ b/week-2/10-media-queries/columns.css
@@ -1 +1,11 @@
 /* Add your own CSS code below */
+@media screen and (min-width: 768px) {
+  .countries {
+    columns: 2;
+  }
+}
+@media screen and (min-width: 1200px) {
+  .countries {
+    columns: 3;
+  }
+}
diff --git a/week-2/11-flexbox/flexbox.css b/week-2/11-flexbox/flexbox.css
index 43e80d23c..d632388bf 100644
--- a/week-2/11-flexbox/flexbox.css
+++ b/week-2/11-flexbox/flexbox.css
@@ -1 +1,12 @@
 /* Add your own CSS code below */
+.countries--first {
+  display: flex;
+}
+.countries--second {
+  display: flex;
+  flex-direction: column;
+}
+.countries--third {
+  display: flex;
+  flex-direction: column;
+}
diff --git a/week-2/12-justify-content/flexbox.css b/week-2/12-justify-content/flexbox.css
index 3c4c7ff18..9765cddec 100644
--- a/week-2/12-justify-content/flexbox.css
+++ b/week-2/12-justify-content/flexbox.css
@@ -7,3 +7,18 @@
 }
 
 /* Add your own CSS code below */
+.countries--first {
+  justify-content: flex-end;
+}
+.countries--second {
+  justify-content: space-around;
+  flex-direction: row;
+}
+.countries--third {
+  justify-content: flex-end;
+  flex-direction: column;
+}
+.countries--fourth {
+  justify-content: space-around;
+  flex-direction: column-reverse;
+}
diff --git a/week-2/13-align-items/flexbox.css b/week-2/13-align-items/flexbox.css
index 3675a0df3..9ddcffc8e 100644
--- a/week-2/13-align-items/flexbox.css
+++ b/week-2/13-align-items/flexbox.css
@@ -2,3 +2,19 @@
   display: flex;
 }
 /* Add your own CSS code below */
+.countries--first {
+  align-items: center;
+  flex-direction: row;
+}
+.countries--second {
+  align-items: flex-end;
+  flex-direction: row-reverse;
+}
+.countries--third {
+  align-items: flex-end;
+  flex-direction: column;
+}
+.countries--fourth {
+  align-items: center;
+  flex-direction: column-reverse;
+}
diff --git a/week-2/14-order/flexbox.css b/week-2/14-order/flexbox.css
index ed621b793..6e5dbe6bd 100644
--- a/week-2/14-order/flexbox.css
+++ b/week-2/14-order/flexbox.css
@@ -3,3 +3,58 @@
 }
 
 /* Add your own CSS code below */
+
+/*the first list group of countries*/
+
+.countries--first .country--brazil {
+  order: 5;
+}
+.countries--first.country--croatia {
+  order: 1;
+}
+.countries--first.country--ethiopia {
+  order: 2;
+}
+.countries--first.country--loas {
+  order: 3;
+}
+.countries--first.country--uganda {
+  order: 4;
+}
+
+/*the second list group of countries*/
+
+.countries--second .country--brazil {
+  order: 4;
+}
+.countries--second.country--croatia {
+  order: 1;
+}
+.countries--second.country--ethiopia {
+  order: 2;
+}
+.countries--second.country--loas {
+  order: 3;
+}
+.countries--second .country--uganda {
+  order: 5;
+}
+
+/*the third list group of countries*/
+
+.countries--third .country--brazil {
+  order: 5;
+}
+.countries--third .country--croatia {
+  order: 4;
+}
+
+.countries--third .country--ethiopia {
+  order: 3;
+}
+.countries--third .country--laos {
+  order: 2;
+}
+.countries--third .country--uganda {
+  order: 1;
+}
diff --git a/week-2/15-align-self/flexbox.css b/week-2/15-align-self/flexbox.css
index ed621b793..81d945de4 100644
--- a/week-2/15-align-self/flexbox.css
+++ b/week-2/15-align-self/flexbox.css
@@ -3,3 +3,34 @@
 }
 
 /* Add your own CSS code below */
+
+.countries--first .country--ethiopia {
+  align-self: flex-end;
+}
+.countries--second .country--ethiopia {
+  align-self: flex-end;
+}
+.countries--second {
+  align-items: center;
+}
+.countries--third .country--croatia {
+  align-self: flex-end;
+}
+.countries--third .country--ethiopia {
+  align-self: flex-end;
+}
+.countries--third .country--laos {
+  align-self: flex-end;
+}
+.countries--third {
+  align-items: flex-start;
+}
+/* list of group number fourth */
+
+.countries--fourth {
+  align-items: flex-start;
+  flex-direction: column;
+}
+.countries--fourth .country--uganda {
+  align-self: center;
+}
diff --git a/week-2/16-more-flexbox/flexbox.css b/week-2/16-more-flexbox/flexbox.css
index ed621b793..2c7641a9e 100644
--- a/week-2/16-more-flexbox/flexbox.css
+++ b/week-2/16-more-flexbox/flexbox.css
@@ -3,3 +3,69 @@
 }
 
 /* Add your own CSS code below */
+
+.countries--first {
+  justify-content: flex-end;
+  align-items: flex-end;
+}
+
+.countries--second {
+  justify-content: center;
+  align-items: flex-end;
+  flex-direction: row-reverse;
+}
+/* the list of third group */
+
+.countries--third {
+  justify-content: center;
+  align-items: flex-start;
+}
+.countries--third .country--brazil {
+  align-self: flex-end;
+}
+
+/* the list of fourth group */
+
+.countries--fourth {
+  flex-direction: column;
+  justify-content: center;
+}
+.countries--fourth .country--ethiopia {
+  align-self: center;
+}
+.countries--fourth .country--laos {
+  align-self: center;
+}
+
+.countries--fourth .country--brazil {
+  align-self: flex-end;
+}
+.countries--fourth .country--croatia {
+  align-self: flex-end;
+}
+.countries--fourth .country--uganda {
+  align-self: flex-end;
+}
+
+/* the list of fifth group */
+.countries--fifth {
+  flex-direction: column;
+  justify-content: space-around;
+  align-items: flex-end;
+}
+.countries--fifth .country--laos {
+  order: 1;
+}
+.countries--fifth .country--uganda {
+  align-self: center;
+  order: 2;
+}
+.countries--fifth .country--ethiopia {
+  order: 3;
+}
+.countries--fifth .country--croatia {
+  order: 4;
+}
+.countries--fifth .country--brazil {
+  order: 5;
+}
diff --git a/week-2/17-nav-menu/styles.css b/week-2/17-nav-menu/styles.css
index f04f4c7ba..970009894 100644
--- a/week-2/17-nav-menu/styles.css
+++ b/week-2/17-nav-menu/styles.css
@@ -1 +1,23 @@
 /* Write your media queries and flexbox CSS below */
+@media screen and (min-width: 480px) {
+  .site-header__nav {
+    display: flex;
+  }
+}
+@media screen and (min-width: 700px) {
+  .site-header {
+    display: flex;
+    align-items: baseline;
+  }
+}
+@media screen and (min-width: 992px) {
+  .site-header {
+    justify-content: space-between;
+  }
+  .site-header__checkout {
+    align-self: flex-end;
+  }
+  .site-header__nav {
+    align-self: center;
+  }
+}
diff --git a/week-2/18-git-merge/styles.css b/week-2/18-git-merge/styles.css
index 0051cdbaf..b0988b252 100644
--- a/week-2/18-git-merge/styles.css
+++ b/week-2/18-git-merge/styles.css
@@ -1,6 +1,6 @@
 /* Add your own CSS code below */
 .link {
-  color: #4491db;
+  color: orange;
   font-weight: 700;
   text-decoration: none;
 }
diff --git a/week-3/19-search/index.html b/week-3/19-search/index.html
index d94ec98dd..fe2ce06b2 100644
--- a/week-3/19-search/index.html
+++ b/week-3/19-search/index.html
@@ -11,7 +11,9 @@
   <body>
     <div class="site-wrapper">
       <main>
-        <p>Delete this line and add your form.</p>
+        <form action="https://www.google.com/search" method="GET">
+          <input type="text" name="q" />
+        </form>
       </main>
     </div>
   </body>