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Implementing Media Queries section (importance of comma)

@media screen and (max-width: 480px) {

.grid_1, .grid_2, .grid_3, .grid_4, .grid_5, .grid_6, .grid_7, .grid_8, .grid_9, .grid_10, .grid_11, .grid_12 { width: 100%; }

In this section I noticed that leaving off the comma in .grid_12 gets everything properly in one column for the 480px width.

If i add a comma to .grid_12, and nothing is changed. What feature of CSS makes leaving the comma out so necessary for this code to work properly?

2 Answers

Andrew McCormick
Andrew McCormick
17,730 Points

the comma tells CSS that another selector is coming. Kind ok like saying ".grid_1 AND .grid_2, AND .grid_3, etc" . When you put a comma after .grid_12 you are telling it to select another element, but you don't tell it what element to select so the statement is invalid and is ignored.