<div class="main-container">
  <div class="fixed-container">Header:固定尺寸</div>
  <div class="content-wrapper">
    <div class="overflow-container">
      <div class="overflow-content">
          <p>内容</p>
      </div>
    </div>
  </div>
</div>

@import 'https://fonts.googleapis.com/css?family=Share+Tech+Mono';

@import 'https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css';

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
    width: 100vw;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/1376484/jess-harding-lqT6NAmTaiY-unsplash.jpg'),radial-gradient(#28a3dd, #0d7751);
    background-size: cover;
    background-position: center;
    font-family: "Share Tech Mono", monospace;
    font-size: 2rem;
    background-blend-mode: multiply,screen, overlay;
}

.main-container {
    position: fixed;
    background-size: cover;
    background-position: center;
    backdrop-filter: blur(20px);
    background-color: rgba(255, 255, 255, 0.5);
    border-radius: 5px;
    padding:2vw 2vw 0;
    box-sizing: border-box;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
    transition: .3s ease;

    right: 20vw;
    left: 20vw;
    bottom: 0;
    top: 10vh;
  
    display: flex;
    flex-direction: column;
}

.fixed-container {
  height: 100px;
  padding: 20px;
  background-color: #0B5AB0;
  color: white;
  border-radius: 5px;
  display: flex;
  align-items: center;
}

.content-wrapper {
  display: flex;
  flex: 1;
  min-height: 0; /* 这个很重要*/
}

.overflow-container {
  flex: 1;
  overflow-y: auto;
}

.overflow-content {
  height: 2000px;
  color: black;
  background-color: #ddd;
  padding: 20px;
}
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External CSS

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External JavaScript

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