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HTML

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Insecure Resource

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CSS

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CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

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JavaScript

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JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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HTML 

              
                <section class="modal hidden">
  <div class="flex">
    <img src="https://avatars.githubusercontent.com/u/62628408?s=96&v=4" width="50px" height="50px" alt="user" />
    <button class="btn-close">⨉</button>
  </div>
  <div>
    <h3>Stay in touch</h3>
    <p>
      This is a dummy newsletter form so don't bother trying to test it. Not
      that I expect you to, anyways. :)
    </p>
  </div>

  <input type="email" id="email" placeholder="brendaneich@js.com" />
  <button class="btn">Do Something</button>
</section>

<div class="overlay hidden"></div>
<button class="btn btn-open">Open Modal</button>
!

CSS 

              
                * {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Inter", sans-serif;
}

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: #222;
  position: relative;
  min-height: 100vh;
  background-color: #b3e6f4;
}

.modal {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.4rem;
  width: 450px;
  padding: 1.3rem;
  min-height: 250px;
  position: absolute;
  z-index: 2;
  top: 20%;
  background-color: white;
  border: 1px solid #ddd;
  border-radius: 15px;
}

.modal .flex {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal input {
  padding: 0.7rem 1rem;
  border: 1px solid #ddd;
  border-radius: 5px;
  font-size: 0.9em;
}

.modal p {
  font-size: 0.9rem;
  color: #777;
  margin: 0.4rem 0 0.2rem;
}

button {
  cursor: pointer;
  border: none;
  font-weight: 600;
}

.btn {
  display: inline-block;
  padding: 0.8rem 1.4rem;
  font-weight: 700;
  background-color: black;
  color: white;
  border-radius: 5px;
  text-align: center;
  font-size: 1em;
}

.btn-open {
  position: absolute;
  bottom: 150px;
}

.btn-close {
  transform: translate(10px, -20px);
  padding: 0.5rem 0.7rem;
  background: #eee;
  border-radius: 50%;
}

.overlay {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(3px);
  z-index: 1;
}

.hidden {
  display: none;
}
!

JS 

              
                const modal = document.querySelector(".modal");
const overlay = document.querySelector(".overlay");
const openModalBtn = document.querySelector(".btn-open");
const closeModalBtn = document.querySelector(".btn-close");

// close modal function
const closeModal = function () {
  modal.classList.add("hidden");
  overlay.classList.add("hidden");
};

// close the modal when the close button and overlay is clicked
closeModalBtn.addEventListener("click", closeModal);
overlay.addEventListener("click", closeModal);

// close modal when the Esc key is pressed
document.addEventListener("keydown", function (e) {
  if (e.key === "Escape" && !modal.classList.contains("hidden")) {
    closeModal();
  }
});

// open modal function
const openModal = function () {
  modal.classList.remove("hidden");
  overlay.classList.remove("hidden");
};
// open modal event
openModalBtn.addEventListener("click", openModal);
!
999px

Console