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HTML

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About the <head>

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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

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

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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 

              
                <link rel="preconnect" href="https://fonts.google.com">
<link href="https://fonts.googleapis.com/css2?family=Raleway:wght@400;500;600&display=swap" rel="stylesheet">

<div class="dropdown">
  <div class="dropdown-item">
    <div class="title">
      <h3>Поверхность планет-гигантов</h3>
      <button type="button" class="close-js">
        <svg width="31" height="30" viewBox="0 0 31 30" fill="none" xmlns="http://www.w3.org/2000/svg">
          <path d="M3 15H28.4558" stroke="black" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />
          <path d="M15.7279 27.7279V2.27208" stroke="black" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />
        </svg>
      </button>
    </div>
    <div class="content close">
      <div class="img-container">
        <img src="https://images.unsplash.com/photo-1545156521-77bd85671d30?ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&ixlib=rb-1.2.1&auto=format&fit=crop&w=1100&q=80" alt="планета">
      </div>
      <div class="col">
        <p>У&nbsp;планет-гигантов нет твёрдой поверхности, таким образом нулевой меридиан оценивает экваториальный секстант. Перигей, несмотря на&nbsp;внешние воздействия, интуитивно понятен. Возмущающий фактор, это удалось установить по&nbsp;характеру спектра, выслеживает первоначальный терминатор.</p>
      </div>
    </div>
  </div>
  <div class="dropdown-item">
    <div class="title">
      <h3>Атомное время</h3>
      <button type="button" class="close-js">
        <svg width="31" height="30" viewBox="0 0 31 30" fill="none" xmlns="http://www.w3.org/2000/svg">
          <path d="M3 15H28.4558" stroke="black" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />
          <path d="M15.7279 27.7279V2.27208" stroke="black" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />
        </svg>
      </button>
    </div>
    <div class="content close">
      <div class="img-container">
        <img src="https://images.unsplash.com/photo-1560507063-5ea26eec6f53?ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&ixlib=rb-1.2.1&auto=format&fit=crop&w=1650&q=80" alt="планета">
      </div>
      <div class="col">
        <p>У&nbsp;планет-гигантов нет твёрдой поверхности, таким образом нулевой меридиан оценивает экваториальный секстант. Перигей, несмотря на&nbsp;внешние воздействия, интуитивно понятен. Возмущающий фактор, это удалось установить по&nbsp;характеру спектра, выслеживает первоначальный терминатор.</p>
      </div>
    </div>
  </div>
  <div class="dropdown-item">
    <div class="title">
      <h3>Космический лимб глазами современников</h3>
      <button type="button" class="close-js">
        <svg width="31" height="30" viewBox="0 0 31 30" fill="none" xmlns="http://www.w3.org/2000/svg">
          <path d="M3 15H28.4558" stroke="black" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />
          <path d="M15.7279 27.7279V2.27208" stroke="black" stroke-width="3" stroke-linecap="round" stroke-linejoin="round" />
        </svg>
      </button>
    </div>
    <div class="content close">
      <div class="img-container">
        <img src="https://images.unsplash.com/photo-1537989036885-80b4d200958d?ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&ixlib=rb-1.2.1&auto=format&fit=crop&w=1000&q=80" alt="планета">
      </div>
      <div class="col">
        <p>У&nbsp;планет-гигантов нет твёрдой поверхности, таким образом нулевой меридиан оценивает экваториальный секстант. Перигей, несмотря на&nbsp;внешние воздействия, интуитивно понятен. Возмущающий фактор, это удалось установить по&nbsp;характеру спектра, выслеживает первоначальный терминатор.</p>
      </div>
    </div>
  </div>
!

CSS 

              
                body {
  background-color: #000000;
  padding-left: 10%;
  padding-right: 10%;
  width: 80%;
  padding-top: 30px;
  padding-bottom: 50px;
  position: relative;
  margin: 0 auto;
  font-family: "Raleway";
}
* {
  box-sizing: border-box;
}
h3 {
  font-weight: medium;
  font-size: 24px;
  line-height: 26px;
}
p {
  margin: 0;
  font-size: 16px;
  line-height: 24px;
}
.dropdown-item {
  max-width: 1000px;
  border-radius: 30px;
  background: #f6f8f9;
  padding: 30px 40px;
  margin-bottom: 20px;
}
.title {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
button {
  border: none;
  background-color: transparent;
  cursor: pointer;
  transition: all 0.6s ease;
}
.content {
  display: grid;
  grid-template-columns: 210px 1fr;
  grid-template-rows: 210px auto;
  grid-gap: 40px;
  width: 940px;
  padding-top: 14px;
  transition: all 0.6s ease;
}
img {
  object-fit: cover;
  width: 100%;
  height: 100%;
  border-radius: 20px;
}

.close {
  display: none;
}

.btn-active {
  transform: rotate(135deg);
  transition: all 0.5s ease;
}
!

JS 

              
                let dropitem = document.querySelectorAll(".dropdown-item");
let content = document.querySelectorAll(".content");

if (dropitem.lenght != 0) {
  dropitem.forEach(function (item) {
    let btn = item.querySelector(".close-js");
    let content = item.querySelector(".content");
    btn.addEventListener("click", function (event) {
      content.classList.toggle("close");
      btn.classList.toggle("btn-active")
       })
    
    });
  };
!
999px

Console