<div class="registration-form">
    <form>
        <h3 class="text-center">Create your account</h3>
        <div class="form-group">
            <input class="form-control item" type="text" name="username" maxlength="15" minlength="4" pattern="^[a-zA-Z0-9_.-]*$" id="username" placeholder="Username" required>
        </div>
        <div class="form-group">
            <input class="form-control item" type="password" name="password" minlength="6" id="password" placeholder="Password" required>
        </div>
        <div class="form-group">
            <input class="form-control item" type="email" name="email" id="email" placeholder="Email" required>
        </div>
        <div class="form-group">
            <button class="btn btn-primary btn-block create-account" type="submit">Create Account</button>
        </div>
    </form>
</div>

html {
  background-color:#214c84;
  background-blend-mode:overlay;
  display:flex;
  align-items:center;
  justify-content:center;
  background-image:url(../../assets/img/image4.jpg);
  background-repeat:no-repeat;
  background-size:cover;
  height:100%;
}

body {
  background-color:transparent;
}

.registration-form {
  padding:50px 0;
}

.registration-form form {
  max-width:800px;
  padding:50px 70px;
  border-radius:10px;
  box-shadow:4px 4px 15px rgba(0, 0, 0, 0.2);
  background-color:#fff;
}

.registration-form form h3 {
  font-weight:bold;
  margin-bottom:30px;
}

.registration-form .item {
  border-radius:10px;
  margin-bottom:25px;
  padding:10px 20px;
}

.registration-form .create-account {
  border-radius:30px;
  padding:10px 20px;
  font-size:18px;
  font-weight:bold;
  background-color:#3f93ff;
  border:none;
  color:white;
  margin-top:20px;
}

@media (max-width: 576px) {
  .registration-form form {
    padding:50px 20px;
  }
}