/usr/share/lxqt/themes/frost/lxqt-runner.qss is in lxqt-common 0.11.2-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104  | /*
 * Panel
 */
#panel {
    border: 1px solid palette(text);
    background: palette(text);
    padding: 2px;
    margin: 0px;
}
/*
 * Buttons
 */
QToolButton::menu-indicator {
   image: none;
}
QToolButton {
    margin: 0px;
    border: 0px solid transparent;
    padding: 0px;
    font-size: 10pt;
    color: palette(window);
    qproperty-iconSize: 20px;
}
QToolButton:hover {
    margin: 1px;
    padding: 1px;
}
#closeButton {
    qproperty-icon: url(lxqt-runner/close.svg);
}
#actionButton {
    qproperty-icon: url(lxqt-runner/down-arrow.svg);
}
/*
 *Search field
 */
#commandEd {
    border: 1px solid palette(text);
    padding: 0px;
    margin: 0px;
    background: white;
    color: palette(text);
    selection-background-color: palette(highlight);
    selection-color: palette(highlighted-text);
}
/*
 *Search results list
 */
#commandList {
    border: 1px solid #4C4C4C;
}
#commandList::item {
    margin: 2px;
    padding: 2px;
}
/*
 * Menus
 */
QMenu {
    background-color: palette(text);
}
QMenu::icon {
    background-color: transparent;
    border: 1px solid transparent;
    padding-left: 5px;
}
QMenu::item {
    color: palette(window);
    padding: 5px 13px 5px 30px;
}
QMenu::item:selected {
    background: palette(highlight);
    color: palette(highlighted-text);
}
QMenu::item:selected:disabled {
    background-color: palette(text);
}
QMenu::item:disabled {
    color: #6D6D6D;
}
QMenu::right-arrow {
    image: url(arrow-right.svg);
}
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