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<html><head><style>h1 { margin: 0 0 50px 0;}h2 { margin: 20px 0 0 0;}</style></head><body><p>In this example the h1 element has a bottom margin of 50px and the h2 element has a top margin of 20px. So, the vertical margin between h1 and h2 should have been 70px (50px + 20px). However, due to margin collapse, the actual margin ends up being 50px.</p><h1>Heading 1</h1><h2>Heading 2</h2></body></html>