durationSmtransition-duration / animation-duration..25sdurationMdtransition-duration / animation-duration..4sdurationLgtransition-duration / animation-duration..6sdurationXltransition-duration / animation-duration.1.2seaseIntransition-timing-function.cubic-bezier(0,0,.2,1)easeInOuttransition-timing-function.cubic-bezier(.25,.1,.25,1)easeOuttransition-timing-function.cubic-bezier(.4,0,.5,1)color-scheme property: light for light mode, dark for dark mode, or light dark to follow the user's system preference.dir global attribute in HTML changes the direction of text and other content within an element. It's most often used on the <html> tag to set the entire page's direction, which is crucial for supporting languages that are written from right to left (RTL), such as Arabic and Hebrew. For example, using <html dir="rtl"> makes the entire page display from right to left, adjusting the layout and text flow accordingly.rem is a best practice for achieving this, as they allow the text to scale uniformly based on the user's browser settings.