JSFiddle - React, Tailwind, and code Playground

HTML

<div class="page-1">
  <form action="#" class="main-form">
    <div class="login-form">
      <span>
        <input id="username" class="email-input" type="email" placeholder="Identifiant" required="">
      </span>
      <span>
        <input id="password" class="pass-input" type="password" placeholder="Mot de passe" required="">
      </span>
    </div>
  </form>
</div>

CSS

.email-input, .pass-input{
    width: 20rem;
    height: 24px;
    border-radius: 0.3rem;
    font-size: 17px;
    font-weight: 200;
    margin: auto;
    padding: 0.5rem;
    outline: 1px solid rgb(155, 154, 154);
    outline-offset: -1px; /* So the middle border doesn't change positions */
    border: none;
    position: relative;
    display: flex;
    justify-content: center;
    z-index: 1; /* Default z-index */
}

.email-input:active, .email-input:focus{
    border: none;
    outline: 2px solid #0070c9;
    z-index: 2; /* Render the active field on top */
}

.pass-input:active, .pass-input:focus{
    border: none;
    outline: 2px solid #0070c9;
  z-index: 2; /* Render the active field on top */
}

.email-input{
    border-bottom-left-radius: 0px;
    border-bottom-right-radius: 0px;
}

.pass-input{
    border-top-left-radius: 0px;
    border-top-right-radius: 0px;
}