[html] Fixed header, footer with scrollable content

Now we've got CSS grid. Welcome to 2019.

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/* Required */_x000D_
body {_x000D_
   margin: 0;_x000D_
   height: 100%;_x000D_
}_x000D_
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#wrapper {_x000D_
   height: 100vh;_x000D_
   display: grid;_x000D_
   grid-template-rows: 30px 1fr 30px;_x000D_
}_x000D_
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#content {_x000D_
   overflow-y: scroll;_x000D_
}_x000D_
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/* Optional */_x000D_
#wrapper > * {_x000D_
   padding: 5px;_x000D_
}_x000D_
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#header {_x000D_
   background-color: #ff0000ff;_x000D_
}_x000D_
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#content {_x000D_
   background-color: #00ff00ff;_x000D_
}_x000D_
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#footer {_x000D_
   background-color: #0000ffff;_x000D_
}
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<body>_x000D_
   <div id="wrapper">_x000D_
      <div id="header">Header Content</div>_x000D_
      <div id="content">_x000D_
         Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum._x000D_
      </div>_x000D_
      <div id="footer">Footer Content</div>_x000D_
   </div>_x000D_
</body>
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