added background and landing page

sass/index.sass

@@ -9,11 +9,31 @@ body
   padding: 0
   display: flex
   flex-direction: column
+  background-color: $background-color
+
+a
+    color: $text-color
+    text-decoration: none
+    font-weight: bold
+    letter-spacing: 1px
+
+.greeting
+  color: $secondary-text-color
+  font-size: 30px
+  font-weight: 900
+  display: flex
+  justify-content: center
+  align-items: center
+  height: 50vh
+  background-image: url("https://i1.wp.com/sirus.be/sirus_afbeeldingen/2020/04/Smartcities.png?fit=2560%2C1594&ssl=1")
+  background-position: center center
+  background-size: cover
+  background-clip: border-box
 
 .header
-  background-color: $background-color
+  background-color: $secondary-color
   width: 100%
-  height: 100px
+  height: 50px
   display: flex
   align-items: center
   justify-content: flex-end
@@ -31,3 +51,9 @@ ol
   display: flex
   flex-direction: column
   list-style: georgian
+
+.content
+  display: flex
+  flex-direction: row
+
+  .navigation