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<html><head><style>h1 { text-decoration: underline; text-decoration-thickness: auto; }h2 { text-decoration: underline; text-decoration-thickness: 5px; }h3 { text-decoration: underline; text-decoration-thickness: 50%; }/* Use shorthand property */h4 { text-decoration: underline solid red 50%; }</style></head><body><h1>This is heading 1</h1><h2>This is heading 2</h2><h3>This is heading 3</h3><h4>This is heading 4</h4></body></html>