<div class="entry">
  <div class="entry--input-container">
    <select id="type">
      <option value="info">info</option>
      <option value="help">help</option>
      <option value="alert">error</option>
    </select>
    <input type="text" id="content" name="content" />
    <button id="add">forward</button>
  </div>
</div>

$anim: .75s;
$moveEase: cubic-bezier(0.39, 0.575, 0.565, 1);
$circEase: cubic-bezier(0.61, 0.425, 0.565, 1);
$sizeEase: ease-out;

* { box-sizing: border-box; }
html {
  background: url(https://source.unsplash.com/ooJi3CJQRa8/1920x1200),
              url(https://source.unsplash.com/ooJi3CJQRa8/19x12);
  background-color: #ceb99a;
  background-size: cover;
  background-position: center;
  min-height: 100vh;
  
  font-family: Roboto, sans-serif;
  color: #212121;
  line-height: 24px;
}
body { margin: 0; }

.notifications {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  
  position: fixed;
  top: 16px;
  right: 16px;
  max-height: 100%;
}
.notifications--notification {
  max-width: 256px;
  width: 100%;
  
  overflow: hidden;
  flex-shrink: 0;
  
  background: #fff;
  padding: 16px 18px;
  margin-bottom: 8px;
  border-radius: 4px;
  box-shadow: 0 2px 4px rgba(0,0,0,.15);
  
  transition: width $anim*4/5 $circEase;
  animation: circle-reveal $anim*3/4 $circEase,
             transform-left $anim $moveEase;
  
  &::before {
    /* material icon */
    font-family: 'Material Icons';
    font-size: 24px;
    line-height: 1;
    -webkit-font-smoothing: antialiased;
    font-feature-settings: 'liga' 1;
    vertical-align: bottom;
    
    display: inline-block;
    margin: 0 6px 0 -4px;
  }
  
  &.info::before { content: "info"; }
  &.help::before { content: "help"; }
  &.alert::before { content: "error"; }
}

@keyframes transform-left {
  from { transform: translateX(8px); }
  to { transform: translateX(0); }
}
@keyframes circle-reveal {
  0% {
    opacity: 0;
    clip-path: circle(10px at 100% 50%);
  }
  75% { opacity: 1; }
  100% { clip-path: circle(250px at center); }
}




/* Input styling */
.entry {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%,-50%);
}
.entry--input-container {
  display: flex;
  font-size: 16px;
  border-radius: 4px;
  background: #fff;
  box-shadow: 0 2px 4px rgba(0,0,0,.15);
}
#content {
  appearance: none;
  font-size: inherit;
  border: none;
  outline: none;
  
  border: 2px dashed #ddd;
  border-top: none;
  border-bottom: none;
  height: 24px + 16px*2;
  border-radius: inherit;
  padding: 16px;
  transition: border .1s;
}
#type {
  border: none;
  outline: none;
  
  height: 24px + 16px*2;
  padding: 16px 0 16px 8px;
  margin-right: 8px;
  border-radius: inherit;
  text-align: center;
  
  font-family: 'Material Icons';
  font-size: 24px;
  line-height: 1;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: 'liga' 1;
  vertical-align: bottom;
}
#add {
  appearance: none;
  background: none;
  border: none;
  
  height: 24px + 16px*2;
  padding: 16px;
  text-align: center;
  
  font-family: 'Material Icons';
  font-size: 24px;
  line-height: 1;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: 'liga' 1;
  vertical-align: bottom;
  
  &:hover {
    background: #eee;
  }
  &:active {
    background: #ddd;
  }
}

function FLIP($elms, makeChange) {
  let $elm;
  for ($elm of $elms) { // set
    $elm.style.width = "";
  }
  for ($elm of $elms) { // get
    $elm._flipW = $elm.getBoundingClientRect();
  }
  makeChange();
  for ($elm of $elms) { // set
    $elm.style.transition = "width 0s linear";
    $elm.style.width = $elm._flipW.width+"px";
  }
  +$elms[0].offsetHeight; // reflow
  for ($elm of $elms) {
    $elm.style.transition = "";
    $elm.style.width = "100%";
    delete $elm._flipW;
  }
}

class Notification {
  static initted = false;
  static init() {
    if (Notification.initted) { return; }
    Notification.initted = true;
    
    let $container
          = Notification.$container 
          = document.createElement("div");
    $container.classList.add("notifications");
    document.body.appendChild($container);
  }

  static stagger = 2500;
  static add($elm) {
    let _add = ()=>{Notification.$container.appendChild($elm)};
    
    if (!Notification.$container.childNodes.length) {
      _add();
    } else {
      FLIP([].slice.call(Notification.$container.childNodes), _add);
    }
  }
  
  constructor(content, type) {
    Notification.init();
    let $elm = this.$elm 
             = document.createElement("div");
    $elm.classList.add("notifications--notification");
    $elm.classList.add(type);
    
    $elm.innerHTML = content;
    Notification.add($elm);
  }
}


setTimeout(()=>new Notification("Test.", "info"),0);
setTimeout(()=>new Notification("Another test notification", "help"), 2500);

let submit = ()=>{
  let type = document.getElementById("type").value;
  let content = document.getElementById("content").value;
  
  if (!content) { return; }
  new Notification(content, type);
};
document.getElementById("add").addEventListener("click", submit);
document.getElementById("content").addEventListener("keyup", e=>{
  if (e.keyCode === 13) { submit(); }
});