Burger button styling

css/knacss-unminified.css

@@ -1811,7 +1811,8 @@ label {
 [type="text"],
 [type="time"],
 [type="url"],
-[type="week"] select,
+[type="week"],
+select,
 textarea {
   white-space: nowrap;
   font-family: inherit;
@@ -1834,6 +1835,7 @@ textarea {
 [type="submit"] {
   background-color: #777;
   color: #fff;
+  cursor: pointer;
 }
 
 input[disabled] {
@@ -2067,6 +2069,74 @@ button:focus {
   outline: none;
 }
 
+.button-burger {
+  position: relative;
+  height: 2.4rem;
+  width: 2.8rem;
+  background-color: transparent;
+  background-image: -webkit-linear-gradient(left, currentColor, currentColor);
+  background-image: linear-gradient(to right, currentColor, currentColor);
+  background-position: center;
+  background-repeat: no-repeat;
+  background-size: 100% 5px;
+  padding: 0;
+  outline: 0;
+  border: 0;
+  color: #333;
+  cursor: pointer;
+  -webkit-tap-highlight-color: transparent;
+  -webkit-transition: 0.25s cubic-bezier(0.17, 0.67, 0.89, 1.4);
+  transition: 0.25s cubic-bezier(0.17, 0.67, 0.89, 1.4);
+  -webkit-transition-property: -webkit-transform;
+  transition-property: -webkit-transform;
+  transition-property: transform;
+  transition-property: transform, -webkit-transform;
+  will-change: transform;
+}
+
+.button-burger::before, .button-burger::after {
+  content: "";
+  position: absolute;
+  left: 0;
+  right: 0;
+  display: block;
+  height: 5px;
+  background: currentColor;
+  -webkit-transition: .25s;
+  transition: .25s;
+  -webkit-transition-property: top, -webkit-transform;
+  transition-property: top, -webkit-transform;
+  transition-property: transform, top;
+  transition-property: transform, top, -webkit-transform;
+  will-change: transform, top;
+}
+
+.button-burger::before {
+  top: 0;
+}
+
+.button-burger:after {
+  top: calc(100% - 4px);
+}
+
+.button-burger:focus, .button-burger.is-active, .button-burger.js-active {
+  background-image: none;
+}
+
+.button-burger:focus::before, .button-burger:focus::after, .button-burger.is-active::before, .button-burger.is-active::after, .button-burger.js-active::before, .button-burger.js-active::after {
+  top: 50%;
+}
+
+.button-burger:focus::before, .button-burger.is-active::before, .button-burger.js-active::before {
+  -webkit-transform: translate3d(0, -50%, 0) rotate3d(0, 0, 1, 45deg);
+          transform: translate3d(0, -50%, 0) rotate3d(0, 0, 1, 45deg);
+}
+
+.button-burger:focus::after, .button-burger.is-active::after, .button-burger.js-active::after {
+  -webkit-transform: translate3d(0, -50%, 0) rotate3d(0, 0, 1, -45deg);
+          transform: translate3d(0, -50%, 0) rotate3d(0, 0, 1, -45deg);
+}
+
 /* ----------------------------- */
 /* ==Badges                      */
 /* ----------------------------- */

sass/components/buttons.scss

@@ -93,3 +93,62 @@ button {
     }
   }
 }
+
+// burger button
+.button-burger {
+  position: relative;
+  height: 2.4rem;
+  width: 2.8rem;
+  background-color: transparent;
+  background-image: linear-gradient(to right, currentColor, currentColor);
+  background-position: center;
+  background-repeat: no-repeat;
+  background-size: 100% 5px;
+  padding: 0;
+  outline: 0;
+  border: 0;
+  color: #333;
+  cursor: pointer;
+  -webkit-tap-highlight-color: transparent;
+  transition: .25s cubic-bezier(.17,.67,.89,1.4);
+  transition-property: transform;
+  will-change: transform;
+
+  &::before,
+  &::after {
+    content: "";
+    position: absolute;
+    left: 0; right: 0;
+    display: block;
+    height: 5px;
+    background: currentColor;
+    transition: .25s;
+    transition-property: transform, top;
+    will-change: transform, top;
+  }
+
+  &::before {
+    top: 0;
+  }
+
+  &:after {
+    top: calc(100% - 4px);
+  }
+
+  &:focus,
+  &.is-active,
+  &.js-active {
+    background-image: none;
+
+    &::before,
+    &::after {
+       top: 50%;
+    }
+    &::before {
+      transform: translate3d(0,-50%,0) rotate3d(0,0,1,45deg);
+    }
+    &::after {
+      transform: translate3d(0,-50%,0) rotate3d(0,0,1,-45deg);
+    }
+  }
+}

sass/components/forms.scss

@@ -38,7 +38,7 @@ label {
 [type="text"],
 [type="time"],
 [type="url"],
-[type="week"]
+[type="week"],
 select,
 textarea {
   white-space: nowrap;
@@ -60,6 +60,7 @@ textarea {
 [type="submit"] {
   background-color: $color-border;
   color: $color-light;
+  cursor: pointer;
 }
 
 input[disabled] {