I have 12+ years of experiences with SharePoint, Office 365, HTML, CSS, JavaScript, and jQuery. For SharePoint default master page, I can complete a custom page layout within 2-4 hours, including 2 revisions, depending on the complexity. For custom master page, I can complete a custom page layout within 2-8 hours, including 2 revisions, depending on the complexity of the custom master page and custom page layout.