：not（：empty）CSSセレクターが機能していませんか？

input:not([value=""]):not(:focus):invalid{
  background-color: tomato;
}

<input 
  type="email" 
  value="" 
  placeholder="valid mail" 
  onchange="this.setAttribute('value', this.value);" />

input {
  padding: 10px 15px;
  font-size: 16px;
  border-radius: 5px;
  border: 2px solid lightblue;
  outline: 0;
  font-weight:bold;
  transition: border-color 200ms;
  font-family: sans-serif;
}

.validation {
  opacity: 0;
  font-size: 12px;
  font-family: sans-serif;
  color: crimson;
  transition: opacity;
}

input:required:valid {
  border-color: forestgreen;
}

input:required:invalid:not(:placeholder-shown) {
  border-color: crimson;
}

input:required:invalid:not(:placeholder-shown) + .validation {
  opacity: 1;
}

  

<input type="email" placeholder="e-mail" required>
<div class="validation">Not valid</span>

.floating-label-input {
  position: relative;
  height:60px;
}
.floating-label-input input {
  width: 100%;
  height: 100%;
  position: relative;
  background: transparent;
  border: 0 none;
  outline: none;
  vertical-align: middle;
  font-size: 20px;
  font-weight: bold;
  padding-top: 10px;
}
.floating-label-input label {
  position: absolute;
  top: calc(50% - 5px);
  font-size: 22px;
  left: 0;
  color: #000;
  transition: all 0.3s;
}
.floating-label-input input:focus ~ label, .floating-label-input input:focus ~ label, .floating-label-input input:valid ~ label {
  top: 0;
  font-size: 15px;
  color: #33bb55;
}
.floating-label-input .line {
  position: absolute;
  height: 1px;
  width: 100%;
  bottom: 0;
  background: #000;
  left: 0;
}
.floating-label-input .line:after {
  content: "";
  display: block;
  width: 0;
  background: #33bb55;
  height: 1px;
  transition: all 0.5s;
}
.floating-label-input input:focus ~ .line:after, .floating-label-input input:focus ~ .line:after, .floating-label-input input:valid ~ .line:after {
  width: 100%;
}

<div class="floating-label-input">
      <input type="text" id="id" required/>
      <label for="id" >User ID</label>
      <span class="line"></span>
</div>

var inputs = document.getElementsByTagName('input');

for (var i = 0; i < inputs.length; i++) {
  var input = inputs[i];
  input.addEventListener('input', function() {
    var bg = this.value ? 'green' : 'red';
    this.style.backgroundColor = bg;
  });
}

body {
  padding: 40px;
}
#inputList li {
  list-style-type: none;
  padding-bottom: 1.5em;
}
#inputList li input,
#inputList li label {
  float: left;
  width: 10em;
}
#inputList li input {
  color: white;
  background-color: red;
}
#inputList li label {
  text-align: right;
  padding-right: 1em;
}

<ul id="inputList">
  <li>
    <label for="username">Enter User Name:</label>
    <input type="text" id="username" />
  </li>
  <li>
    <label for="password">Enter Password:</label>
    <input type="password" id="password" />
  </li>
</ul>

.form{
  position:relative;
  display:inline-block;
}
.form input{
  margin-top:10px;
}
.form label{
    position:absolute;
    left:0;
    top:0;
    opacity:0;
    transition:all 1s ease;
}
input:not(:placeholder-shown) + label{
    top:-10px;
    opacity:1;
}

<div class="form">
    <input type="text" id="inputFName" placeholder="Firstname">
    <label class="label" for="inputFName">Firstname</label>
</div>
<div class="form">
    <input type="text" id="inputLName" placeholder="Lastname">
    <label class="label" for="inputLName">Lastname</label>
</div>