style.css

@import url("https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap");

* {
  box-sizing: border-box;
}

:root {
  --bg-color: rebeccapurple;
}

/* https://caniuse.com/css-media-range-syntax */
@media screen and (width >= 600px) {
  :root {
    --bg-color: orangered;
  }
}

body {
  font-family: "Roboto", sans-serif;
  margin: 0;
  padding-block: 2rem;
  /* background-color: rebeccapurple; */
  background-color: var(--bg-color);
}

/* @media screen and (min-width: 600px) {
  body {
    background-color: orangered;
  }
} */

/* https://caniuse.com/css-container-queries-style */
@container style(--theme: dark) {
  .card {
    background: black;
    color: white;
  }

  .card > * {
    color: white;
  }
}

.primary-content,
.cards {
  container-type: inline-size;
}

main {
  display: grid;
  gap: 1rem;
}

@media (min-width: 760px) {
  main {
    grid-template-columns: 1fr 300px;
  }
}

.cards {
  /* container-type: inline-size;
  container-name: card-grid; */
  container: card-grid / inline-size;
}

.card {
  display: grid;
  gap: 1rem;
}

.card h2 {
  font-size: clamp(1.5rem, 10cqi, 3rem);
  /* cqi = 10% of a query container's inline size */
  /* cqb is based on the block size */
  /* https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_container_queries */
  /* https://caniuse.com/css-container-queries */
}

@container card-grid (min-width: 45ch) {
  .card {
    /*     background: yellow; */
    grid-template-columns: auto minmax(25ch, 1fr);
  }

  .card h2 {
    grid-column: 1 / -1;
  }
}

@layer demo {
  h1,
  p {
    color: white;
  }

  img {
    max-width: 100%;
    border-radius: 0.25rem;
  }

  .wrapper {
    width: min(100% - 3rem, 1200px);
    margin-inline: auto;
  }

  .cards {
    display: grid;
    gap: 1.5rem;
    min-height: 100vh;
    align-content: start;
  }

  .card {
    background-color: #fff;
    border-radius: 4px;
    box-shadow: 0 15px 15px rgb(0 0 0 / 0.25);
    padding: 0.75rem;
  }

  .card > * {
    margin: 0;
    color: #000;
  }
}