Maintain vertically centered alignment of overlay text

I am using a large hero image that is absolutely positioned in order to place a text overlay on top of it. I have also ensured that the hero image is responsive no matter the dimensions of the screen. THe issue I am running into, is ensuring the overlay text is vertically centered within the background image no matter what the screen size.

The following link shows the effect I am trying to achieve with the overlay text: https://www.youtube.com/watch?v=gfzWLbAbcCw

My jsx code is as follows:

   <>
      <div className="container">
        <div className="container-background">
          <img
            src="https://i.imgur.com/iyFtMNA.jpg"
            alt="bg"
            className="container-background-img"
          />
        </div>
        <div className="content">
          <Navbar />
          <div className="page-outer">
            <div className="page-inner">
              <div className="wel-top-header">text</div>
              <div className="wel-top-middle">
                <div style={{ marginTop: -30 }}>text</div>
                <div style={{ marginTop: -48 }}>text</div>
              </div>
              <div className="wel-tagline">
                Pagerland offers a great, smooth looking and ultra-fast landing
                page templates build on Gatsby and React.
              </div>
            </div>
          </div>
        </div>
      </div>
    </>

my css code is as follows:

* {
  margin: 0;
  padding: 0;
}

.navbar {
  height: 80px;
  background-color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  border: solid black 1px;
}



.container {
  position: relative;
}
.container .container-background {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  opacity: 0.25;
}

the following link contains a code sandbox for debugging! https://codesandbox.io/s/charming-dijkstra-im7nb?file=/src/styles.scss:0-1101

any and all suggestions would be greatly appreciated