Added toggle button for issue #6

dark-mode.css

@@ -0,0 +1,6 @@
+
+.dark-mode {
+    background-color: black;
+    color: white;
+  }
+

index.html

@@ -4,6 +4,7 @@
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>Calculator</title>
+  <link href="dark-mode.css" rel="stylesheet" type="text/css" />
   <link href="styles.css" rel="stylesheet" type="text/css" />
   <link href="https://fonts.googleapis.com/css2?family=Nunito:wght@700&display=swap" rel="stylesheet">
   <script src="script.js"></script>
@@ -31,7 +32,20 @@
     <button>+</button>
     <button>0</button>
     <button>.</button>
+
     <button class="span-two">=</button>
+    <br/>
+    <br/>
+    <label class="switch">
+      <input onclick="toggleDark()"type="checkbox">
+      <span class="slider round"></span>
+    </label>
   </div>
+  <script>
+    function toggleDark() {
+       var element = document.body;
+       element.classList.toggle("dark-mode");
+    }
+    </script>
 </body>
 </html>

styles.css

@@ -1,58 +1,118 @@
-*, *::before , *::after {
- box-sizing: border-box;
- font-family: 'Nunito', sans-serif;
- font-weight: normal;
-}
-
-body {
-  padding: 0;
-  margin: 0;
-  background: linear-gradient(to right, #FDC830, #F37335);
-}
-
-.calculator-grid {
-  display: grid;
-  justify-content: center;
-  align-content: center;
-  min-height: 100vh;
-  grid-template-columns: repeat(4, 75px);
-  grid-template-rows: minmax(90px, auto)  repeat(5, 75px);
-}
-
-.calculator-grid > button {
-  cursor: pointer;
-  font-size: 1.5rem;
-  border: 1px solid white;
-  outline: none;
-  background-color: rgba(255, 255, 255, .75);
-}
-
-.calculator-grid > button:hover {
-  background-color: rgba(255, 255, 255, .90);
-}
-
-.span-two {
-  grid-column: span 2;
-}
-
-.output {
-  grid-column: 1 / -1;
-  background-color: rgba(0, 0, 0, .75);
-  display: flex;
-  align-items: flex-end;
-  justify-content: space-around;
-  flex-direction: column;
-  padding: 10px;
-  word-wrap: break-word;
-  word-break: break-all;
-}
-
-.output .previous-operand {
-  color: rgba(255, 255, 255, .75);
-  font-size: 1 rem;
-}
-
-.output .current-operand {
-  color: white;
-  font-size: 1.75rem;
+
+.switch {
+    position: relative;
+    display: inline-block;
+    width: 60px;
+    height: 34px;
+  }
+
+  .switch input { 
+    opacity: 0;
+    width: 0;
+    height: 0;
+  }
+
+  .slider {
+    position: absolute;
+    cursor: pointer;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    background-color: #ccc;
+    -webkit-transition: .4s;
+    transition: .4s;
+  }
+
+  .slider:before {
+    position: absolute;
+    content: "";
+    height: 26px;
+    width: 26px;
+    left: 4px;
+    bottom: 4px;
+    background-color: white;
+    -webkit-transition: .4s;
+    transition: .4s;
+  }
+
+  input:checked + .slider {
+    background-color: #2196F3;
+  }
+
+  input:focus + .slider {
+    box-shadow: 0 0 1px #2196F3;
+  }
+
+  input:checked + .slider:before {
+    -webkit-transform: translateX(26px);
+    -ms-transform: translateX(26px);
+    transform: translateX(26px);
+  }
+
+  /* Rounded sliders */
+  .slider.round {
+    border-radius: 34px;
+  }
+
+  .slider.round:before {
+    border-radius: 50%;
+  }
+*, *::before , *::after {
+ box-sizing: border-box;
+ font-family: 'Nunito', sans-serif;
+ font-weight: normal;
+}
+
+body {
+  padding: 0;
+  margin: 0;
+  background: linear-gradient(to right, #FDC830, #F37335);
+}
+
+.calculator-grid {
+  display: grid;
+  justify-content: center;
+  align-content: center;
+  min-height: 100vh;
+  grid-template-columns: repeat(4, 75px);
+  grid-template-rows: minmax(90px, auto)  repeat(5, 75px);
+}
+
+.calculator-grid > button {
+  cursor: pointer;
+  font-size: 1.5rem;
+  border: 1px solid white;
+  outline: none;
+  background-color: rgba(255, 255, 255, .75);
+}
+
+.calculator-grid > button:hover {
+  background-color: rgba(255, 255, 255, .90);
+}
+
+.span-two {
+  grid-column: span 2;
+}
+
+.output {
+  grid-column: 1 / -1;
+  background-color: rgba(0, 0, 0, .75);
+  display: flex;
+  align-items: flex-end;
+  justify-content: space-around;
+  flex-direction: column;
+  padding: 10px;
+  word-wrap: break-word;
+  word-break: break-all;
+}
+
+.output .previous-operand {
+  color: rgba(255, 255, 255, .75);
+  font-size: 1 rem;
+}
+
+.output .current-operand {
+  color: white;
+  font-size: 1.75rem;
 }