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HTML/CSSBeginner#css#transitions
+ selects only the immediately following sibling, while ~ selects all following siblings matching the selector, regardless of how far apart they are, as long as they share the same parent.
h2 + p { font-weight: bold; } /* only the paragraph right after an h2 */
h2 ~ p { color: gray; } /* every paragraph after an h2 at the same level */