/* ============================================================================
 * 深色主题样式表 —— qt_calculator_mainwindow_qss（Day3 下午）
 * 整体深底浅字，功能分色保留但调暗，便于和浅色对照验证「切换生效」。
 * 资源路径 :/themes/dark.qss（themes.qrc 嵌入）。
 * ============================================================================ */
QMainWindow { background: #2b2b2b; color: #eee; }
QLineEdit#display, QTextEdit#expressionEdit {
    background: #3a3a2a; color: #fffbe6;
    border: 1px solid #6b6b4a; border-radius: 4px;
    font-size: 18px; padding: 4px;
}
QPushButton {
    border: 1px solid #555; border-radius: 4px;
    padding: 8px; font-size: 15px; min-height: 28px; color: #eee;
}
QPushButton#btn0,  QPushButton#btn1,  QPushButton#btn2,  QPushButton#btn3,
QPushButton#btn4,  QPushButton#btn5,  QPushButton#btn6,  QPushButton#btn7,
QPushButton#btn8,  QPushButton#btn9,  QPushButton#btnDot {
    background: #1565c0; border-color: #42a5f5; color: #e3f2fd;
}
QPushButton#btnPlus, QPushButton#btnMinus, QPushButton#btnMul, QPushButton#btnDiv {
    background: #d84315; border-color: #ff7043; color: #ffe0b2;
}
QPushButton#btnEquals {
    background: #2e7d32; border-color: #66bb6a; color: #c8e6c9; font-weight: bold;
}
QPushButton#btnLeftParen, QPushButton#btnRightParen {
    background: #455a64; border-color: #78909c; color: #eceff1;
}
QPushButton#btnClear, QPushButton#btnBackspace {
    background: #c62828; border-color: #ef5350; color: #ffcdd2;
}
QPushButton:hover    { background: #666; }
QPushButton:pressed  { background: #888; }
QListWidget { background: #333; alternate-background-color: #3d3d3d; color: #eee; }
QStatusBar { background: #1f1f1f; color: #eee; }
QMenuBar { background: #37474f; color: #eee; }
QDockWidget { color: #eee; }