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/* 1. Define the default state on the component container */
/* This applies when there is NO image */
.article-card {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 1.5rem;
  border: 1px solid #ccc;
  border-radius: 8px;
}

/* 2. Apply styles when a specific child element is present */
/* MANDATORY: Target the container and use :has() to check for the descendant */
.article-card:has(img) {
  /* Change the layout to a row if an image exists */
  flex-direction: row;
  align-items: center;
}

/* Optional: Style the image itself (no :has() needed here) */
.article-card img {
  width: 150px;
  height: auto;
  border-radius: 4px;
}

/* You can also combine :has() and :not() to explicitly target the ABSENCE of content */
/* This selects a card that DOES NOT have an image */
.article-card:not(:has(img)) {
  /* E.g., apply a different background color for text-only cards */
  background-color: #f9f9f9;
}

<!-- Assume an <h1> precedes these components in the document layout -->
<!-- A card WITH an image (will use row layout) -->
<article class="article-card">
  <img src="thumbnail.jpg" alt="Article thumbnail" />
  <div class="content">
    <h2>Card With Image</h2>
    <p>This card lays out its content horizontally.</p>
  </div>
</article>

<!-- A card WITHOUT an image (will use default column layout) -->
<article class="article-card">
  <div class="content">
    <h2>Text-Only Card</h2>
    <p>This card lays out its content vertically, and gets its background color from the :not(:has()) rule.</p>
  </div>
</article>

/* Fallback CSS for older browsers */
/* We check if the browser DOES NOT support the :has() selector */
@supports not selector(:has(*)) {
  /* Define a traditional modifier class that applies the exact same layout overrides */
  .article-card.has-image {
    flex-direction: row;
    align-items: center;
  }
  
  .article-card:not(.has-image) {
    background-color: #f9f9f9;
  }
}

/* Fallback JavaScript for older browsers (if not using SSR to add the class) */
/* Check for support before running the script to avoid unnecessary work in modern browsers */
if (!CSS.supports('selector(:has(*))')) {
  // Find all components that need checking
  const cards = document.querySelectorAll('.article-card');
  
  cards.forEach(card => {
    // If the critical content exists, manually add the fallback class
    if (card.querySelector('img')) {
      card.classList.add('has-image');
    }
  });
}