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

body {
    font-family: 'Arial', sans-serif;
    background-color: #f0f2f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background-color: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 500px;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 1.5rem;
}

.game-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2rem;
    font-size: 1.2rem;
}

.question {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 1.5rem;
    color: #2c3e50;
}

.answer-input {
    width: 100%;
    padding: 0.8rem;
    font-size: 1.2rem;
    border: 2px solid #ddd;
    border-radius: 5px;
    margin-bottom: 1rem;
}

.answer-input:focus {
    outline: none;
    border-color: #3498db;
}

button {
    width: 100%;
    padding: 1rem;
    font-size: 1.1rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
    margin-bottom: 0.5rem;
}

.submit-btn {
    background-color: #2ecc71;
    color: white;
}

.submit-btn:hover {
    background-color: #27ae60;
}

.start-btn {
    background-color: #3498db;
    color: white;
}

.start-btn:hover {
    background-color: #2980b9;
}

.result {
    text-align: center;
    margin-top: 1rem;
    font-size: 1.1rem;
    min-height: 1.5rem;
}

.correct {
    color: #2ecc71;
}

.wrong {
    color: #e74c3c;
}

.heart, .sad-face {
    position: fixed;
    font-size: 2rem;
    user-select: none;
    pointer-events: none;
    animation: float-heart 1.5s ease-out forwards;
}

.heart {
    color: #e74c3c;
}

.sad-face {
    color: #3498db;
}

@keyframes float-heart {
    0% {
        transform: scale(0) translate(0, 0) rotate(0deg);
        opacity: 0.8;
    }
    50% {
        transform: scale(1.4) translate(0, -40px) rotate(10deg);
        opacity: 0.9;
    }
    100% {
        transform: scale(1) translate(0, -80px) rotate(-10deg);
        opacity: 0;
    }
}

.history-table {
    width: 100%;
    margin-top: 20px;
    border-collapse: collapse;
    background-color: white;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.history-table th,
.history-table td {
    padding: 12px;
    text-align: center;
    border: 1px solid #ddd;
}

.history-table th {
    background-color: #f8f9fa;
    font-weight: bold;
    color: #2c3e50;
}

.history-table tr:nth-child(even) {
    background-color: #f8f9fa;
}

.history-table .correct-row {
    background-color: rgba(46, 204, 113, 0.1);
}

.history-table .wrong-row {
    background-color: rgba(231, 76, 60, 0.1);
}

.history-container {
    max-height: 300px;
    overflow-y: auto;
    margin-top: 20px;
    border-radius: 5px;
    border: 1px solid #ddd;
}