*{margin:0;padding:0;box-sizing:border-box}:root[data-theme=light]{--bg-gradient-start: #f5f7fa;--bg-gradient-end: #e8ecf1;--text-primary: #1f2937;--text-secondary: rgba(31, 41, 55, .8);--text-tertiary: rgba(31, 41, 55, .6);--white: #ffffff;--button-bg: rgba(255, 255, 255, .1);--button-bg-hover: rgba(255, 255, 255, .15);--button-border: rgba(31, 41, 55, .2);--button-border-hover: rgba(31, 41, 55, .4);--primary-color: #667eea;--answer-color: #059669;--keyboard-hint-bg: rgba(102, 126, 234, .1)}:root[data-theme=dark]{--bg-gradient-start: #1a1a2e;--bg-gradient-end: #16213e;--text-primary: #f3f4f6;--text-secondary: rgba(243, 244, 246, .9);--text-tertiary: rgba(243, 244, 246, .6);--white: #ffffff;--button-bg: rgba(255, 255, 255, .1);--button-bg-hover: rgba(255, 255, 255, .15);--button-border: rgba(255, 255, 255, .2);--button-border-hover: rgba(255, 255, 255, .4);--primary-color: #667eea;--answer-color: #10b981;--keyboard-hint-bg: rgba(255, 255, 255, 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