Edit in JSFiddle

<div class="wrapper">
  <div class="color-picker" name="color">
     <div class="color-indicator" name="color"></div> 
  </div>
  <div class="preview"></div>
  <div class="hue palette" name="hue">
    <div class="slider" name="hue"></div>
  </div>
  <div class="alpha palette" name="alpha">
     <div class="slider" name="alpha"></div> 
  </div>
  <h5 class="hex result">#fff</h5>
  <h5 class="rgb result">rgba(255, 255, 255, 1)</h5>
  <h5 class="hsl result">hsla(0, 0%, 100%, 1)</h5>
</div>
<div class="target">Change my color pls!</div>

@import url(https://fonts.googleapis.com/css?family=Quicksand);

html, body {
  margin: 0;
  box-sizing: border-box;
}
body {
  background-color: #333;
  font-family: 'Quicksand', sans-serif;
  padding-top: 20px;
}

.wrapper {
  position: relative;
  background: white;
  margin: 0 auto;
  width: 200px;
  height: 265px;
  border-radius: 3px;
  border: 1px solid #666;
}

.wrapper::after {
  content: '';
  position: absolute;
  width: 10px;
  height: 10px;
  top: 260px;
  left: 94px;
  background: linear-gradient(135deg, transparent 50%, white 50%);
  border-width: 1px 1px 0 0 inherit solid;
  transform: rotate(45deg);
}

.color-picker {
  width: 200px;
  height: 120px;
  margin-bottom: 15px;
  border-radius: inherit;
  background: linear-gradient(to bottom, rgba(0, 0, 0, 0), rgba(0, 0, 0, 1)), linear-gradient(to left, rgba(0, 0, 0, 0), rgba(255, 255, 255, 1));
  background-color: red;
  overflow: hidden;
}

.color-indicator {
  width: 12px;
  height: 12px;
  transform: translate(-12px, -12px);
  border-radius: 50%;
  border: 1px solid white;
}

.preview {
  background:
     linear-gradient(45deg, rgba(0,0,0,.25) 25%, transparent 0, transparent 75%, rgba(0,0,0,.25) 0) 0 0 / 12px 12px,
     linear-gradient(45deg, rgba(0,0,0,.25) 25%, transparent 0, transparent 75%, rgba(0,0,0,.25) 0) 6px 6px / 12px 12px;
  background-color: rgba(255,0,0,0.5);
  float: left;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  margin-left: 12px;
  border: 1px solid #eee;
}
.palette {
  background: darkblue;
  width: 120px;
  height: 12px;
  margin-left: 60px;
  position: relative;
  border-radius: 1px;
  margin-bottom: 10px;
}

.hue {
  background: linear-gradient(to left,
    hsl(0, 100%, 50%) 0%,
    hsl(30, 100%, 50%) 8.33%,
    hsl(60, 100%, 50%) 16.67%,
    hsl(90, 100%, 50%) 25%,
    hsl(120, 100%, 50%) 33.33%,
    hsl(150, 100%, 50%) 41.67%,
    hsl(180, 100%, 50%) 50%,
    hsl(210, 100%, 50%) 58.33%,
    hsl(240, 100%, 50%) 66.67%,
    hsl(270, 100%, 50%) 75%,
    hsl(300, 100%, 50%) 83.33%,
    hsl(330, 100%, 50%) 91.67%,
    hsl(0, 100%, 50%) 100%);
}

.alpha {
   background:
     linear-gradient(to right, rgba(0,0,0,0), rgba(0,0,255,1)) 0 0 / cover,
     linear-gradient(45deg, rgba(0,0,0,.25) 25%, transparent 0, transparent 75%, rgba(0,0,0,.25) 0) 0 0 / 12px 12px,
     linear-gradient(45deg, rgba(0,0,0,.25) 25%, transparent 0, transparent 75%, rgba(0,0,0,.25) 0) 6px 6px / 12px 12px;
}

.slider {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  transform: translateX(120px);
  background: rgb(248, 248, 248);
  position: relative;
  left: -8px;
  top: -2px;
  filter: drop-shadow(2px 2px 3px rgba(0,0,0,.2));
}

.result {
  color: #aaa;
  margin: 0;
  line-height: 2;
  text-align: center;
  user-select: auto;
}

.target {
  width: max-content;
  margin: 0 auto;
  padding-top: 10px;
  color: white;
  font-size: 24px;
  cursor: pointer;
}