HTML5 & CSS3

A card can appear in a wide main column on one page and a narrow sidebar on another. A media query sees the viewport; a container query lets the compo...

HTML can catch several common form mistakes before a request is sent. The browser can tell a user that a required field is empty or that a value does ...

A small HTML table does not need a search library. Read the search field, compare it with the loaded rows and hide rows that do not match. The importa...

Tabs let related sections share the same area of a page. They work well for short alternatives such as an overview, installation notes and examples. T...

A modal is useful when a short task needs the reader's attention without leaving the page. A dark overlay alone does not make a component modal: keybo...

Do not choose a form control only by its appearance. Decide whether the user should send one value, a longer explanation, or one of a fixed set of opt...

Choose between Flexbox and Grid by asking how items should align, not which feature is newer. Content widths often drive a button group; a card list m...

If a page looks fine on a desktop but shows tiny text or horizontal scrolling on a phone, separate two problems: the browser's viewport and the CSS la...

A sharp icon and an interactive graphic solve different problems. SVG supplies scalable geometry; interaction also needs an appropriate control, a cle...

Dark mode is becoming increasingly popular in modern web and mobile applications. It helps reduce eye strain and save battery life, which is why many ...