add check boxes

src/App.css

@@ -93,6 +93,9 @@
   color: #5a5a5a;
   flex-grow: 1;
   position: relative;
+  z-index: 2;
+  margin-left: 40px;
+  width: 470px;
 }
 .todo-list-title:hover span[contenteditable="false"]:before {
   content: 'click to edit';
@@ -123,7 +126,7 @@
     font-size: 14px;
   }
   .todo-list {
-    padding: 20px;
+    padding: 15px;
     padding-top: 10px;
     width: auto;
   }
@@ -154,7 +157,109 @@
     /* Disable Auto Zoom in Input “Text” tag - Safari on iPhone */
     font-size: 16px;
   }
+  .todo-item button {
+    padding: 4px 12px;
+    font-size: 14px;
+  }
   .view-src {
     display: none;
   }
 }
+
+/** todo css via https://codepen.io/shshaw/pen/WXMdwE 😻 */
+.todo {
+  display: inline-block;
+  position: relative;
+  padding: 0;
+  margin: 0;
+  min-height: 40px;
+  min-width: 40px;
+  cursor: pointer;
+  padding-right: 5px;
+}
+.todo__state {
+  position: absolute;
+  top: 0;
+  left: 0;
+  opacity: 0;
+}
+.todo__text {
+  color: #135156;
+  transition: all 0.4s linear 0.4s;
+}
+.todo__icon {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  left: 0;
+  width: 280px;
+  height: 100%;
+  margin: auto;
+  fill: none;
+  stroke: #27FDC7;
+  stroke-width: 2;
+  stroke-linejoin: round;
+  stroke-linecap: round;
+}
+
+.todo__box,
+.todo__check {
+  transition: stroke-dashoffset 0.5s cubic-bezier(0.9, 0, 0.5, 1);
+}
+.todo__state:checked ~ .todo-list-title {
+  text-decoration: line-through;
+}
+.todo__circle {
+  stroke: #27FDC7;
+  stroke-dasharray: 1 6;
+  stroke-width: 0;
+  transform-origin: 13.5px 12.5px;
+  transform: scale(0.4) rotate(0deg);
+  animation: none 0.5s linear;
+}
+
+@keyframes explode {
+  30% {
+    stroke-width: 3;
+    stroke-opacity: 1;
+    transform: scale(0.8) rotate(40deg);
+  }
+  100% {
+    stroke-width: 0;
+    stroke-opacity: 0;
+    transform: scale(1.1) rotate(60deg);
+  }
+}
+.todo__box {
+  stroke-dasharray: 56.1053, 56.1053;
+  stroke-dashoffset: 0;
+  transition-delay: 0.16s;
+}
+.todo__check {
+  stroke: #27FDC7;
+  stroke-dasharray: 9.8995, 9.8995;
+  stroke-dashoffset: 9.8995;
+  transition-duration: 0.32s;
+}
+
+.todo__circle {
+  animation-delay: 0.56s;
+  animation-duration: 0.56s;
+}
+.todo__state:checked + .todo__text {
+  transition-delay: 0s;
+  color: #5EBEC1;
+  opacity: 0.6;
+}
+.todo__state:checked ~ .todo__icon .todo__box {
+  stroke-dashoffset: 56.1053;
+  transition-delay: 0s;
+}
+
+.todo__state:checked ~ .todo__icon .todo__check {
+  stroke-dashoffset: 0;
+  transition-delay: 0.48s;
+}
+.todo__state:checked ~ .todo__icon .todo__circle {
+  animation-name: explode;
+}