title: How can I make a curve border using CSS3?
body: <p>I have added 2 pictures here. You can see that first curve is down curve and second one is up curve. </p>
  
  <p>Now, I have a rectangle box using CSS. I want to make the top and bottom border should be like the picture. </p>
  
  <p>I can use CSS <code>border-radius</code> property to make a border curve. But I don't understand how can I make this type of border curve using CSS3?</p>
  
  <p><a href="https://i.stack.imgur.com/NM9vO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NM9vO.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/dRfmO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dRfmO.png" alt="enter image description here"></a></p>
  
  <p><strong>Updated:</strong></p>
  
  <p>Here is the full output I desire:</p>
  
  <p><a href="https://i.stack.imgur.com/nw06b.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nw06b.png" alt="enter image description here"></a></p>