* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #333;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    padding: 30px;
    max-width: 1200px;
    width: 90%;
    text-align: center;
}

.game-header {
    margin-bottom: 30px;
}

.game-header h1 {
    color: #4a5568;
    margin-bottom: 20px;
    font-size: 3em;
    font-weight: bold;
}

.stats {
    display: flex;
    justify-content: space-around;
    background: #f7fafc;
    padding: 15px;
    border-radius: 10px;
    margin-top: 20px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.label {
    font-size: 0.9em;
    color: #718096;
    margin-bottom: 5px;
}

.value {
    font-size: 1.8em;
    font-weight: bold;
    color: #2d3748;
}

.game-area {
    margin-bottom: 30px;
    min-height: 600px;
    display: flex;
    flex-direction: column;
}

.question-container {
    background: #edf2f7;
    padding: 40px;
    border-radius: 15px;
    margin-bottom: 15px;
    position: relative;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    flex: 1;
}

.question {
    font-size: 3.5em;
    font-weight: bold;
    color: #2d3748;
    font-family: 'Courier New', monospace;
    text-align: center;
    line-height: 1.2;
}

.timer-container {
    background: #fed7d7;
    padding: 20px;
    border-radius: 15px;
    margin-bottom: 20px;
    border: 2px solid #feb2b2;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 80px;
}

.timer {
    font-size: 3em;
    color: #e53e3e;
    font-weight: bold;
    animation: pulse 1s infinite;
    text-align: center;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.answer-container {
    background: #f0fff4;
    padding: 35px;
    border-radius: 15px;
    border: 2px solid #68d391;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    flex: 1;
    opacity: 0.3;
    transition: opacity 0.3s ease;
}

.answer-container.active {
    opacity: 1;
}

.answer {
    font-size: 2.5em;
    font-weight: bold;
    color: #22543d;
    margin-bottom: 25px;
    font-family: 'Courier New', monospace;
    text-align: center;
}

.answer-input-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    width: 100%;
    max-width: 450px;
    margin-top: 15px;
}

.answer-input {
    flex-grow: 1;
    padding: 15px;
    font-size: 1.8em;
    font-family: 'Courier New', monospace;
    text-align: center;
    border: 2px solid #a0aec0;
    border-radius: 10px;
    outline: none;
    transition: border-color 0.3s ease;
}

.answer-input:focus {
    border-color: #4299e1;
}

#submit-btn {
    padding: 15px 30px;
    font-size: 1.2em;
    background-color: #4299e1;
    color: white;
}

#submit-btn:hover {
    background-color: #3182ce;
}

.buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.btn {
    padding: 18px 40px;
    font-size: 1.3em;
    font-weight: bold;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 160px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.btn-correct {
    background: #48bb78;
    color: white;
}

.btn-correct:hover {
    background: #38a169;
}

.btn-wrong {
    background: #f56565;
    color: white;
}

.btn-wrong:hover {
    background: #e53e3e;
}

.btn-restart {
    background: #4299e1;
    color: white;
    font-size: 1.2em;
    padding: 15px 40px;
}

.btn-restart:hover {
    background: #3182ce;
}

.game-over-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 20px;
}

#main-menu-btn {
    background-color: #a0aec0;
    color: white;
}

#main-menu-btn:hover {
    background-color: #718096;
}

.game-over {
    background: #fed7d7;
    padding: 30px;
    border-radius: 15px;
    border: 2px solid #feb2b2;
}

.result-message {
    font-size: 1.5em;
    font-weight: bold;
    margin-bottom: 20px;
    color: #742a2a;
}

.instructions {
    background: #f7fafc;
    padding: 20px;
    border-radius: 10px;
    text-align: left;
}

.instructions h3 {
    color: #4a5568;
    margin-bottom: 15px;
    text-align: center;
}

.instructions ul {
    list-style-type: none;
    padding-left: 0;
}

.instructions li {
    padding: 8px 0;
    color: #4a5568;
    position: relative;
    padding-left: 25px;
}

.instructions li:before {
    content: "•";
    color: #667eea;
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 20px;
        margin: 10px;
        max-width: 95%;
    }
    
    .game-header h1 {
        font-size: 2.2em;
    }
    
    .question {
        font-size: 2.5em;
    }
    
    .answer {
        font-size: 2em;
    }
    
    .timer {
        font-size: 2.2em;
    }
    
    .timer-container {
        padding: 15px;
        min-height: 60px;
    }
    
    .buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 220px;
    }
    
    .game-area {
        min-height: 500px;
    }
    
    .question-container {
        padding: 30px;
        min-height: 180px;
    }
    
    .answer-container {
        padding: 25px;
        min-height: 150px;
    }

    .answer-input-container {
        flex-direction: column;
        max-width: 100%;
    }

    .answer-input {
        font-size: 1.5em;
    }
    
    #submit-btn, .game-over-buttons .btn {
        width: 100%;
        padding: 15px;
        font-size: 1.1em;
    }

    .game-over-buttons {
        flex-direction: column;
    }

    /* Reorder for mobile view to keep question visible with keyboard */
    .question-container { order: 1; }
    .answer-container { order: 2; }
    .timer-container { order: 3; }
} 

.start-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    background: rgba(255,255,255,0.95);
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.08);
    padding: 32px 24px 24px 24px;
    margin: 40px auto;
    max-width: 420px;
}

.btn-start {
    background: #3182ce;
    color: #fff;
    font-size: 1.2em;
    padding: 12px 36px;
    border: none;
    border-radius: 8px;
    margin-top: 24px;
    cursor: pointer;
    transition: background 0.2s;
}
.btn-start:hover {
    background: #225ea8;
}

.timer-setting {
    margin: 18px 0 0 0;
    font-size: 1.1em;
    text-align: center;
}
.timer-setting label {
    margin-right: 16px;
    cursor: pointer;
}

#game-header, #game-area {
    transition: opacity 0.3s;
}