body {
    background-color: #14181c;
}

.content {
    text-align: center;
    font: 1em Fira Sans;
    color: #abc
}

h1 {
    color: #fff;
    font: 900 3em Fira Sans
}

.form {
    display: inline-block;
    position: relative;
    padding: 15px 0;
    margin-top: 10px;
    width: 40%;
    font-family: "Source Code Pro";
}

input[type='text'] {
  font-family: inherit;
  width: 100%;
  border: 0;
  border-bottom: 2px solid #9b9b9b;
  outline: 0;
  font-size: 1.1rem;
  color: #fff;
  padding: 7px 0;
  background: transparent;
  transition: border-color 0.2s;

  &::placeholder {
    color: transparent;
  }

  &:placeholder-shown ~ .form__label {
    font-size: 1.1rem;
    cursor: text;
    top: 20px;
  }
}

.form__label {
  position: absolute;
  top: 0;
  display: block;
  transition: 0.2s;
  font-size: 1rem;
  color: #abc;
}

input[type='text']:focus {
  ~ .form__label {
    position: absolute;
    top: 0;
    display: block;
    transition: 0.2s;
    font-size: 1rem;
    color: #abc;
    font-weight:700;    
  }
  padding-bottom: 6px;  
  font-weight: 700;
  border-width: 3px;
  border-image: linear-gradient(to right, #005AFF, #db9f30);
  border-image-slice: 1;
}

/* reset input */
input[type='text'] {
  &:required,&:invalid { box-shadow:none; }
}

input[type='submit'] {
    font: 700 1.5em "Source Code Pro";
    letter-spacing: .02em;
    padding: 6px 26px;
    background: #00ac1c;
    box-shadow: inset 0 1px 0 hsla(0,0%,100%,.3);
    color: #f4fcf0;
    border: none;
    border-radius: 3px;
    cursor: pointer;
}

input[type='submit']:hover {
    background-color: #058f1c;
}