Wavy shape with css

Question

I'm trying to recreate this image with CSS:

I would not need it to repeat. This is what I started but it just has a straight line:

#wave {
  position: absolute;
  height: 70px;
  width: 600px;
  background: #e0efe3;
}

<div id="wave"></div>

Answer 1

My pure CSS implementation based on above with 100% width. Hope it helps!

#wave-container {
  width: 100%;
  height: 100px;
  overflow: hidden;
}

#wave {
  display: block;
  position: relative;
  height: 40px;
  background: black;
}

#wave:before {
  content: "";
  display: block;
  position: absolute;
  border-radius: 100%;
  width: 100%;
  height: 300px;
  background-color: white;
  right: -25%;
  top: 20px
}

#wave:after {
  content: "";
  display: block;
  position: absolute;
  border-radius: 100%;
  width: 100%;
  height: 300px;
  background-color: black;
  left: -25%;
  top: -240px;
}

<div id="wave-container">
  <div id="wave">
  </div>
</div>

Answer 2

I think this is the right way to make a shape like you want. By using the SVG possibilities, and an container to keep the shape responsive.

svg {
  display: inline-block;
  position: absolute;
  top: 0;
  left: 0;
}
.container {
  display: inline-block;
  position: relative;
  width: 100%;
  padding-bottom: 100%;
  vertical-align: middle;
  overflow: hidden;
}

<div class="container">
  <svg viewBox="0 0 500 500" preserveAspectRatio="xMinYMin meet">
    <path d="M0,100 C150,200 350,0 500,100 L500,00 L0,0 Z" style="stroke: none; fill:red;"></path>
  </svg>
</div>

Answer 3

I'm not sure it's your shape but it's close - you can play with the values:

https://jsfiddle.net/7fjSc/9/

#wave {
  position: relative;
  height: 70px;
  width: 600px;
  background: #e0efe3;
}
#wave:before {
  content: "";
  display: block;
  position: absolute;
  border-radius: 100% 50%;
  width: 340px;
  height: 80px;
  background-color: white;
  right: -5px;
  top: 40px;
}
#wave:after {
  content: "";
  display: block;
  position: absolute;
  border-radius: 100% 50%;
  width: 300px;
  height: 70px;
  background-color: #e0efe3;
  left: 0;
  top: 27px;
}

<div id="wave"></div>

Answer 4

My implementation uses the svg element in html and I also made a generator for making the wave you want:

https://smooth.ie/blogs/news/svg-wavey-transitions-between-sections

<div style="height: 150px; overflow: hidden;">
  <svg viewBox="0 0 500 150" preserveAspectRatio="none" style="height: 100%; width: 100%;">
    <path d="M0.00,92.27 C216.83,192.92 304.30,8.39 500.00,109.03 L500.00,0.00 L0.00,0.00 Z" style="stroke: none;fill: #e1efe3;"></path>
  </svg>
</div>

https://jsfiddle.net/1b8L7nax/5/