<div class="container">
  <a class="button" href="#popup">モーダルウィンドウ表示</a>
  <div class="popup" id="popup">
    <div class="popup-inner">
      <div class="popup__photo">
        <img src="https://picsum.photos/500/500" alt="">
      </div>
      <div class="popup__text">
        <h1>foo bar</h1>
        <p>hogehoge hogehoge hogehoge 

 </p>
      </div>
      <a class="popup__close" href="#">X</a>
    </div>
  </div>
</div>

* {
   box-sizing: border-box;
}

.container {
  background-color: #9191E9;
  display: flex;
  align-items: center;
 justify-content: center;
  width: 100vw;
  height: 100vh;
}

.button {
  text-decoration: none;
  font-size: .875rem;
  font-weight: 300;
  text-transform: uppercase;
  display: inline-block;
  border-radius: 1.5rem;
  background-color: #fff;
  color: #9191E9;
  padding: 1rem 2rem;
}

.popup {
  display: flex;
  align-items: center;
  justify-content: center;
  position: fixed;
  width: 100vw;
  height: 100vh;
  background-color: rgba(0, 0, 0, 0.8);
  bottom: -100vw;
  right: -100vh;
  z-index: 2;
  visibility: hidden;
  opacity: 0;
  transition: .64s ease-in-out;
  transform: rotate(32deg);
}
.popup:target {
  bottom: 0;
  right: 0;
  visibility: visible;
  opacity: 1;
  transform: rotate(0);
}
.popup-inner {
  position: relative;
  display: flex;
  align-items: center;
  max-width: 800px;
  max-height: 600px;
  width: 60%;
  height: 80%;
  background-color: #fff;
}
.popup__photo {
  display: flex;
  justify-content: flex-end;
   align-items: flex-end;
  width: 40%;
  height: 100%;
  overflow: hidden;
}
.popup__photo img {
  width: auto;
  height: 100%;
}
.popup__text {
  display: flex;
  flex-direction: column;
justify-content: center;
  width: 60%;
  height: 100%;
  padding: 4rem;
}
.popup__text h1 {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 2rem;
  text-transform: uppercase;
  color: #0A0A0A;
}
.popup__text p {
  font-size: .875rem;
  color: #686868;
  line-height: 1.5;
}
.popup__close {
  position: absolute;
  right: -1rem;
  top: -1rem;
  width: 3rem;
  height: 3rem;
  font-size: .875rem;
  font-weight: 300;
  border-radius: 100%;
  background-color: #0A0A0A;
  z-index: 4;
  color: #fff;
  line-height: 3rem;
  text-align: center;
  cursor: pointer;
  text-decoration: none;
}