.theme-viet { background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%); }
.theme-viet .game-header h1 { color: #2e7d32; }
.sentence-card { background: white; border-radius: 16px; padding: 25px; margin: 15px auto; max-width: 500px; box-shadow: 0 6px 20px rgba(0,0,0,0.08); font-size: 1.25rem; font-family: 'Nunito', sans-serif; font-weight: 600; color: #333; line-height: 1.8; text-align: center; }
.sentence-card .blank { display: inline-block; width: 30px; height: 30px; border-bottom: 3px solid #f44336; margin: 0 3px; font-size: 1.5rem; text-align: center; vertical-align: middle; color: #f44336; font-weight: 800; }
.punct-options { display: flex; gap: 12px; justify-content: center; margin: 20px auto; }
.punct-btn { width: 60px; height: 60px; border: 2px solid #c8e6c9; border-radius: 14px; background: white; font-size: 1.8rem; font-weight: 800; cursor: pointer; transition: all 0.2s; display: flex; align-items: center; justify-content: center; }
.punct-btn:hover { background: #e8f5e9; border-color: #66bb6a; transform: scale(1.1); }
.punct-btn.correct { background: #e8f5e9; border-color: #4caf50; }
.punct-btn.wrong { background: #ffebee; border-color: #f44336; }
.punct-btn.disabled { pointer-events: none; opacity: 0.6; }