Instagram.html

<body>
  <div class='dialog'>
    <div class='dialog-header'>
      <div class='dialog-logo'></div>
    </div>
    <div class='dialog-body'>
      <div class='login-block'>
        <div class='login-label'>
          Username:
        </div>
        <div class='login-input'>
          <input type='text' id='username'></input>
        </div>
    </div>
    <div class='login-block'>
        <div class='login-label'>
          Password:
      </div>
      <div class='login-input'>
          <input type='text' id='password'></input>
        </div>
      </div>
  <div class='login-footer'>
    <div class='forgot-link'>
      <a href="#">Forgot password?</a>
    </div>
  <div id='login'>
    <button id='login-btn' onClick='authenticate()'>Log in</button>
  </div>
  </div>
  </div>
  <style>body {
  background-color: #F5F5Fc;
  font-family: 'proxima-nova', 'Helvetica Neue', Arial, Helvetica, sans-serif;
  line-height: 20px;
  color: #222;
  font-size: 14px;
  font-weight: 700;
}
.dialog-header {
  background-image: -webkit-linear-gradient(top, #517fa4, #306088);
    background-image: -moz-linear-gradient(top, #517fa4, #306088);
    background-image: -o-linear-gradient(top, #517fa4, #306088);
    background-image: -ms-linear-gradient(top, #517fa4, #306088);
    background-image: -linear-gradient(top, #517fa4, #306088);
  box-shadow: 0 -1px 0 #06365f inset, 0 1px 0 rgba(255, 255, 255, 0.2) inset;
  background-color: #517fa4;
  height: 44px;
  border: 1px solid #1c5380;
  border-bottom-width: 0px;
  border-radius: 4px 4px 0 0; /* neat trick to round top corners only, integrating into larger dialog */
}
.dialog-logo {
  position: relative;
   background: url("//instagramstatic-a.akamaihd.net/h1/images/branding/new-logo@2x.png/a15d7e70bdbc.png") no-repeat 0 0;
  background-size: 100px 32px;
  background-position: 50% 50%;
  width: 96px;
  height: 33px;
  margin: 10px auto;
}
.dialog {
  width: 400px;
  margin: 0 auto;
}
.dialog-body {
  background: #fff;
  border: 1px solid #a4baca;
  border-top-width: 0px;
  border-radius: 0 0  4px 4px;
  padding-top: 30px;
  padding-right: 20px;
  padding-bottom: 40px;
}
.login-label {
  float: left;
  width: 35%;
  padding-top: 5px;
  padding-right: 10px;
  margin: 0 0px 5px;
  text-align: center;
}
.login-input {
  margin: 0 5px;
  display: inline;
}
input {
  border: 1px solid #ccc;
  line-height: 16px;
  border-radius: 3px;
  width: 55%;
  padding: 9px 8px 7px;
}
input:active {
  background: #000000;
}
.login-block {
  margin-bottom: 15px;
}
.login-footer {;
  margin-top: 25px;
}
.forgot-link {
  position: relative;
  margin-left: 30px;
  top: 5px;
  display: inline;
}
.forgot-link a {
  font-weight: 500;
  text-decoration: none;
}
a:hover {
  color: #1c5380;
  text-decoration: underline;
}
a, a:visited {
  color: #3f729b;
}
#login-btn {
  font-weight: bold;
  padding: 7px 10px 8px;
  color: #FFF;
  border-radius: 3px;
  display: inline;
  border: 1px solid #3d8b5f;
      background-color: #6bb38a;
    background-image: -webkit-gradient(linear, left top, left bottom, from(#6bb38a), to(#3d8b5f));
    background-image: -webkit-linear-gradient(top, #6bb38a, #3d8b5f);
    background-image: -moz-linear-gradient(top, #6bb38a, #3d8b5f);
    background-image: -o-linear-gradient(top, #6bb38a, #3d8b5f);
    background-image: -ms-linear-gradient(top, #6bb38a, #3d8b5f);
    background-image: linear-gradient(top, #6bb38a, #3d8b5f);
  text-shadow: 0 1px 1px #1e693f;
  cursor: pointer;
}
#login {
  display: inline;
  float: right;
  margin-right: 5px;
}</style>
<script>const credentials = {
  lance: 'secret',
  ahmad: 'super_secret'
};
function authenticate() {
  if (credentials[document.getElementById('username').value] && credentials[document.getElementById('username').value] === document.getElementById('password').value) {
    alert('ok!');
  } else {
    alert('no no no...');
  }
}</script>
</body>