How to stack different divs on each other (should be responsive)-CodePudding

I have just started to deal with HTML and CSS. I would like to stack different divs (see picture).

The black div represents the container. The red div a header and the blue one a circle which is centered and has the center at the bottom edge of the red div.

The solution should finally also be responsive. What do I have to consider here?

enter image description here

.container {
  height: 300px;
  width: 600px;
  background-color: black;
  text-align: center;
}

.header {
  height: 40%;
  width: 100%;
  background-color: red;
}

.circle {
  background-color: blue;
  height: 100px;
  width: 100px;
  border-radius: 50%;
  display: inline-flex;
}

<div >
  <div >
    <div ></div>
  </div>
</div>

CodePudding user response：

you can use position and flexbox

.container {
  height: 300px;
  width: 80%;
  margin: 0 auto;
  background-color: black;
  text-align: center;
}

.header {
  height: 40%;
  width: 100%;
  background-color: red;
  position: relative;
  display: flex;
  justify-content: center;
}

.circle {
  background-color: blue;
  height: 100px;
  width: 100px;
  border-radius: 50%;
  display: inline-flex;
  position: absolute;
  bottom: 0;
  transform: translateY(50%);
}

<div >
  <div >
    <div ></div>
  </div>
</div>

CodePudding user response：

Make header relative, and align circle to bottom with translate.

.container {
  height: 300px;
  width: 600px;
  background-color: black;
  text-align: center;
}

.header {
  height: 40%;
  width: 100%;
  background-color: red;
  position: relative; /* make header container relative */
}

.circle {
  background-color: blue;
  height: 100px;
  width: 100px;
  border-radius: 50%;
  display: inline-flex;
  
  /* bottom position with centered circle */
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translate3d(-50%, 50%, 0);
}

<div >
  <div >
    <div ></div>
  </div>
</div>

<hr />

<!-- Option with bigger header -->
<div >
  <div  style="height: 70%;">
    <div ></div>
  </div>
</div>