.content-width-minus-button,
.content-width-plus-button,
.line-height-minus-button,
.content-width-minus-button,
.content-width-plus-button,
.line-height-minus-button,
.content-width-minus-button {
background-size: 42px 16px;
background-image: url("chrome://global/skin/reader/RM-Content-Width-Minus-42x16.svg");
.content-width-minus-button {
background-size: 42px 16px;
background-image: url("chrome://global/skin/reader/RM-Content-Width-Minus-42x16.svg");