add preloader block

web/app/components/preloader/__bounce/preloader__bounce.scss

@@ -0,0 +1,35 @@
+.preloader__bounce {
+  display: inline-block;
+  width: 10px;
+  height: 10px;
+  margin-right: 3px;
+  background-color: #333;
+  border-radius: 100%;
+  animation: preloaderBounce 1.4s infinite ease-in-out both;
+
+  &:first-child {
+    animation-delay: -.32s;
+  }
+
+  &:nth-child(2) {
+    animation-delay: -.16s;
+  }
+
+  &:last-child {
+    margin-right: 0;
+  }
+
+  @keyframes preloaderBounce {
+    0% {
+      transform: scale(0);
+    }
+
+    40% {
+      transform: scale(1);
+    }
+
+    80%, 100% {
+      transform: scale(0);
+    }
+  }
+}

web/app/components/preloader/index.js

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+export { default } from './preloader';
+
+require('./preloader.scss');
+
+require('./__bounce/preloader__bounce.scss');

web/app/components/preloader/preloader.jsx

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+import { h, Component } from 'preact';
+
+export default class Preloader extends Component {
+  render(props, state) {
+    return (
+      <div className={b('preloader', props)}>
+        <div className="preloader__bounce"/>
+        <div className="preloader__bounce"/>
+        <div className="preloader__bounce"/>
+      </div>
+    );
+  }
+}

web/app/components/preloader/preloader.scss

@@ -0,0 +1,5 @@
+.preloader {
+  width: 60px;
+  text-align: center;
+  font-size: 0;
+}