theme: refine styles

src/resources/themes/v_detorte/v_detorte.css

@@ -85,6 +85,11 @@ p, ul, ol {
     line-height: 24px;
 }
 
+mark {
+    color: #000000;
+    background-color: #D8D800;
+}
+
 pre {
     display: block;
     overflow-y: hidden;

src/resources/themes/v_moonlight/v_moonlight.css

@@ -81,6 +81,11 @@ p, ul, ol {
     line-height: 24px;
 }
 
+mark {
+    color: #000000;
+    background-color: #C4C400;
+}
+
 pre {
     display: block;
     overflow-y: hidden;

src/vfilelist.cpp

@@ -69,6 +69,7 @@ void VFileList::setupUI()
     QPushButton *viewBtn = new QPushButton(VIconUtils::buttonIcon(":/resources/icons/view.svg"), "", this);
     viewBtn->setToolTip(tr("View"));
     viewBtn->setProperty("CornerBtn", true);
+    viewBtn->setFocusPolicy(Qt::NoFocus);
 
     QMenu *viewMenu = new QMenu(this);
     connect(viewMenu, &QMenu::aboutToShow,