In Roseta the icon blocks glyphs use the theme’s accent colors.
To customize separately, try the following CSS (prepend body if the identifiers are not specific enough for your usage):
/* glyph in normal state */
.lp-block i[class^="blicon"]::before {
color: ...;
}
/* glyph on hover */
.lp-blocks1 .lp-block:hover i[class^="blicon"]::before {
color: ...;
}
/* background on hover */
.lp-block i[class^="blicon"]::after {
background-color: ...;
}