custom.qss

/* MISC */
QMenuBar, QToolBar, QFrame, QMenu {
    border: none;
}
QToolTip {
    background: palette(window);
}
QGroupBox {
    border: 1px solid palette(highlight);
    margin-top: 3ex;
}
QListView, QTableView, QTreeView, QTextEdit, QTextBrowser, QColumnView {
    background: palette(dark);
    border: 1px solid palette(highlight);
    padding: 1px;
}
QHeaderView::section {
    background-color: palette(window);
    border: 1px solid palette(dark);
    padding: 4px;
}

/* BUTTONS */
QPushButton, QComboBox {
    background: palette(window);
    border: 1px solid palette(light);
    border-radius: 3px;
    padding: 6px;
}
QPushButton:hover, QComboBox:hover {
    background: palette(light);
    border: 1px solid palette(dark);
    border-radius: 3px;
    padding: 6px;
}
QPushButton:pressed {
    background: palette(highlight);
    border: 1px solid palette(dark);
    border-radius: 3px;
    padding: 6px;
}

/* SCROLLBARS */
QScrollBar {
    background: palette(window);
}
QScrollBar:horizontal {
    height: 10px;
}
QScrollBar:vertical {
    width: 10px;
}
QScrollBar::handle {
    background: palette(light);
}
QScrollBar::handle:hover, QScrollBar::add-line:hover, QScrollBar::sub-line:hover {
    background: palette(highlight);
}
QScrollBar::add-line {
    subcontrol-origin: none;
}
QScrollBar::add-line, QScrollBar::sub-line {
    background: palette(window);
}
QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical {
    height: 0px;
}
QScrollBar::add-line:horizontal, QScrollBar::sub-line:horizontal {
    width: 0px;
}
QScrollBar::sub-line {
    subcontrol-origin: none;
}

/* TABS */
QTabBar::tab {
    background: palette(alternatebase);
    min-width: 8ex;
    padding: 8px;
    border: 1px solid palette(dark);
    border-bottom-color: palette(window);
    margin-bottom: 1px;
}
QTabBar::tab:selected {
    background: palette(light);
    border: 1px solid palette(highlight);
    border-bottom-color: palette(light);
    margin-bottom: -1px;
}
QTabWidget::pane {
    background: palette(light);
    border: 1px solid palette(highlight);
    margin-top: -1px;
}