What is the meaning of it?

Question

Specialy use of General Sibling Selector and Universal Selector together.

#expand-toggle:checked ~ * .expandable {
visibility: visible;
}

Answer 1

sibling selector target next sibling element
universal selector target any element

so (from right o left) the rule target all elements wich have 'expandable' as class, are child (from any level) of any element following element with id 'expand-toggle' if it is in 'checked' state...

Answer 2

অসাধারণ ব্যাখা।

Answer 3

visph a lot of thanks