<div class="grid">
  <div class="sub-grid sub-grid-1">
    <article class="card">
      <figure>
        <img width="1600" height="900" src="https://assets.codepen.io/162656/beach2.jpg" alt="">
        <figcaption>
          <div>
            Santorini, Greece
            <span>by <a href="https://unsplash.com/photos/white-sun-lounger-lot-KrGbdPfIYD4" target="_blank">Khamkéo</a>
            </span>
          </div>
        </figcaption>
      </figure>
    </article>
    <article class="card">
      <figure>
        <img width="1600" height="1067" src="https://assets.codepen.io/162656/beach6.jpg" alt="">
        <figcaption>
          <div>
            Kvalvika Beach, Moskenes, Norway
            <span>by <a href="https://unsplash.com/photos/beach-near-mountain-range-wnRvXXzZK7w" target="_blank"></a>Martine Jacobsen
            </span>
          </div>
        </figcaption>
      </figure>
    </article>
    <article class="card">
      <figure>
        <img width="1600" height="1036" src="https://assets.codepen.io/162656/beach3.jpg" alt="">
        <figcaption>
          <div>
            San Lorenzo, Italy
            <span>by <a href="https://unsplash.com/photos/photo-of-seashore-d7M5Xramf8g" target="_blank">Camille Minouflet</a>
            </span>
          </div>
        </figcaption>
      </figure>
    </article>
  </div>
  <article class="card">
    <figure>
      <img width="1600" height="900" src="https://assets.codepen.io/162656/beach4.jpg" alt="">
      <figcaption>
        <div>
          McWay Falls, California, USA
          <span>by <a href="https://unsplash.com/photos/aerial-photography-of-boulders-on-body-of-water-07mSKrzKiRw" target="_blank">Chor Tsang</a>
          </span>
        </div>
      </figcaption>
    </figure>
  </article>
  <div class="sub-grid sub-grid-2">
    <article class="card">
      <figure>
        <img width="1600" height="1064" src="https://assets.codepen.io/162656/beach5.jpg" alt="">
        <figcaption>
          <div>
            Inisheer, County Galway, Ireland
            <span>by <a href="https://unsplash.com/photos/a-beach-with-a-boat-on-it-and-people-walking-on-it-Il4WLGeMsUk" target="_blank">Ulrike R. Donohue</a>
            </span>
          </div>
        </figcaption>
      </figure>
    </article>
    <article class="card">
      <figure>
        <img width="1600" height="898" src="https://assets.codepen.io/162656/beach1.jpg" alt="">
        <figcaption>
          <div>
            Beaches, Jacksonville Beach, Florida, United States
            <span>by <a href="https://unsplash.com/photos/man-surfing-on-waves-L5aI2jU0i50" target="_blank">Lance Asper</a>
            </span>
          </div>
        </figcaption>
      </figure>
    </article>
  </div>
</div>
<p class="notification">Hover over a card</p>
<footer class="page-footer">
  <span>made by </span>
  <a href="https://georgemartsoukos.com/" target="_blank">
    <img width="24" height="24" src="https://assets.codepen.io/162656/george-martsoukos-small-logo.svg" alt="George Martsoukos logo">
  </a>
</footer>

/* RESET STYLES
–––––––––––––––––––––––––––––––––––––––––––––––––– */
@import url("https://fonts.googleapis.com/css2?family=Bitter:ital,wght@0,100..900;1,100..900&display=swap");

:root {
  --height: 80vh;
  --half-height: calc(var(--height) / 2);
  --transition: all 1s;
}

* {
  box-sizing: border-box;
}

body {
  font-family: "Bitter", serif;
  margin: 20px 0;
  padding: 0 15px;
  background: #cae9ff;
}

a {
  color: inherit;
}

.notification {
  display: none;
  position: absolute;
  top: 0;
  right: 0;
  padding: 10px;
  font-size: 0.85em;
  background: #e9c46a;
}

/* MAIN STYLES
–––––––––––––––––––––––––––––––––––––––––––––––––– */
.grid,
.sub-grid,
.grid .card {
  transition: var(--transition);
}

.grid {
  max-width: 1600px;
  margin: 0 auto;
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.35);
}

.card {
  cursor: pointer;

  figure,
  img {
    width: 100%;
    height: 100%;
  }

  figure {
    position: relative;
    margin: 0;
    overflow: hidden;
  }

  img {
    object-fit: cover;
    background: #333;
  }

  figcaption {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: grid;
    place-items: center;
    font-size: 1.5em;
    line-height: 1.3;
    text-align: center;
    padding: 10px;
    color: white;
    background: rgba(0, 0, 0, 0.5);

    span {
      display: block;
      font-size: 0.75em;
    }
  }
}

@media (max-width: 899px) {
  .card {
    height: var(--half-height);
  }
}

@media (min-width: 900px) {
  .grid,
  .sub-grid {
    display: grid;
  }

  .grid {
    grid-template-columns: 2fr 1fr 1fr;
  }

  .sub-grid {
    grid-template-rows: var(--half-height) var(--half-height);
  }

  .sub-grid-1 {
    grid-template-columns: 1fr 1fr auto;
  }

  .sub-grid-1 .card:last-child {
    grid-column: 1/-1;
  }

  /*.sub-grid-2 {
    grid-template-columns: 1fr;
  }*/

  .grid > .card {
    height: var(--height);
  }
}

@media (hover: hover) and (min-width: 900px) {
  .notification {
    display: block;
  }

  .grid:has(.sub-grid-1 .card:first-of-type:hover) .sub-grid-1 {
    grid-template-columns: 1fr 0fr auto;
  }

  .grid:has(.sub-grid-1 .card:nth-of-type(2):hover) .sub-grid-1 {
    grid-template-columns: 0fr 1fr auto;
  }

  .grid:has(.sub-grid-1 .card:last-of-type:hover) .sub-grid-1 {
    grid-template-rows: 0 var(--height);
  }

  .grid:has(> .card:hover) {
    grid-template-columns: 0fr 1fr 0fr;
  }

  .grid:has(.sub-grid-2 .card:first-of-type:hover) .sub-grid-2 {
    grid-template-rows: var(--height) 0;
  }

  .grid:has(.sub-grid-2 .card:last-of-type:hover) .sub-grid-2 {
    grid-template-rows: 0 var(--height);
  }

  .card {
    filter: grayscale(1);

    figcaption {
      opacity: 0;
    }

    &:hover {
      filter: grayscale(0);

      figcaption {
        opacity: 1;
        transition: opacity 0.5s 0.5s;
      }
    }
  }
}

/* FOOTER STYLES
–––––––––––––––––––––––––––––––––––––––––––––––––– */
.page-footer {
  position: fixed;
  right: 0;
  bottom: 50px;
  display: flex;
  align-items: center;
  padding: 5px;
  font-size: 0.9em;
  background: white;
}

.page-footer a {
  display: flex;
  margin-left: 4px;
}