diff --git a/tools/lammps-gui/highlighter.cpp b/tools/lammps-gui/highlighter.cpp
index 9846011836..ec196438d9 100644
--- a/tools/lammps-gui/highlighter.cpp
+++ b/tools/lammps-gui/highlighter.cpp
@@ -13,6 +13,27 @@
 
 #include "highlighter.h"
 #include "helpers.h"
+#include <QColor>
+
+// workaround for Qt-5.12
+#if QT_VERSION < QT_VERSION_CHECK(5, 14, 0)
+namespace QColorConstants {
+const QColor Red     = QColor::fromRgb(0xff, 0x00, 0x00);
+const QColor Green   = QColor::fromRgb(0x00, 0xff, 0x00);
+const QColor Blue    = QColor::fromRgb(0x00, 0x00, 0xff);
+const QColor Cyan    = QColor::fromRgb(0x00, 0xff, 0xff);
+const QColor Magenta = QColor::fromRgb(0xff, 0x00, 0xff);
+const QColor Yellow  = QColor::fromRgb(0xff, 0xff, 0x00);
+namespace Svg {
+const QColor dodgerblue   = QColor::fromRgb(0x1e, 0x90, 0xff);
+const QColor indianred    = QColor::fromRgb(0xcd, 0x5c, 0x5c);
+const QColor lightcoral   = QColor::fromRgb(0xf0, 0x80, 0x80);
+const QColor lightgray    = QColor::fromRgb(0xd3, 0xd3, 0xd3);
+const QColor lightgreen   = QColor::fromRgb(0x90, 0xee, 0x90);
+const QColor lightskyblue = QColor::fromRgb(0x87, 0xce, 0xfa);
+} // namespace Svg
+} // namespace QColorConstants
+#endif
 
 Highlighter::Highlighter(QTextDocument *parent) :
     QSyntaxHighlighter(parent),