font size in custom css not working

hi
i wrote this in my cotum css:
.entry-content {color: #000066;}
h1 {font-weight: bold;color: #CC00FF;}
h6 {font-size: 26px;}

it did work till now. but when i tried today to add h6 and to change all content size it didn’t work

.entry-content {color: #000066;font-size: 20px;}
h1 {font-weight: bold;color: #CC00FF;}
h6 {font-size: 26px;}