CSS

wave css

<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>

waves css

@import url(//fonts.googleapis.com/css?family=Lato:300:400);

body {
  margin:0;
  padding-top:10px ;
}

p.ims-tagline{

  font-size: large;
  color: rgb(255, 255, 255);
}


h1 {
  font-family: 'Lato', sans-serif;
  font-weight:300;
  letter-spacing: 2px;
  font-size:48px;
}
p {
  font-family: 'Lato', sans-serif;
  letter-spacing: 1px;
  font-size:14px;
  color: #333333;
}

.header {
  position:relative;
  text-align:center;
  background: linear-gradient(60deg, rgba(84,58,183,1) 0%, rgba(0,172,193,1) 100%);
  color:white;
}
.logo {
  width:50px;
  fill:white;
  padding-right:15px;
  display:inline-block;
  vertical-align: middle;
}

.inner-header {
  height:65vh;
  width:100%;
  margin: 0;
  padding: 0;
}

.flex { /*Flexbox for containers*/
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
}

.waves {
  position:relative;
  width: 100%;
  height:15vh;
  margin-bottom:-7px; /*Fix for safari gap*/
  min-height:100px;
  max-height:150px;
}

.content {
  position:relative;
  height:20vh;
  text-align:center;
  background-color: white;
}

/* Animation */

.parallax > use {
  animation: move-forever 25s cubic-bezier(.55,.5,.45,.5)     infinite;
}
.parallax > use:nth-child(1) {
  animation-delay: -2s;
  animation-duration: 7s;
}
.parallax > use:nth-child(2) {
  animation-delay: -3s;
  animation-duration: 10s;
}
.parallax > use:nth-child(3) {
  animation-delay: -4s;
  animation-duration: 13s;
}
.parallax > use:nth-child(4) {
  animation-delay: -5s;
  animation-duration: 20s;
}
@keyframes move-forever {
  0% {
   transform: translate3d(-90px,0,0);
  }
  100% { 
    transform: translate3d(85px,0,0);
  }
}
/*Shrinking for mobile*/
@media (max-width: 768px) {
  .waves {
    height:40px;
    min-height:40px;
  }
  .content {
    height:30vh;
  }
  h1 {
    font-size:24px;
  }
}

html {
  height: 100%;
}
body {
  margin:0;
  padding:0;
  font-family: sans-serif;
  background: linear-gradient(#141e30, #243b55);

css waves background

section {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 400px;
    padding-top: 100px;
    background: #3c31dd;
}

.curve {
    position: absolute;
    height: 250px;
    width: 100%;
    bottom: 0;
    text-align: center;
}

.curve::before {
    content: '';
    display: block;
    position: absolute;
    border-radius: 100% 50%;
    width: 55%;
    height: 100%;
    transform: translate(85%, 60%);
    background-color: hsl(216, 21%, 16%);
}

.curve::after {
    content: '';
    display: block;
    position: absolute;
    border-radius: 100% 50%;
    width: 55%;
    height: 100%;
    background-color: #3c31dd;
    transform: translate(-4%, 40%);
    z-index: -1;
}