* {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    text-align: center;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    padding-top: 100px;
}

#container {
    background: white;
    border-radius: 16px;
    border: 5px solid #ffffff00;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    padding: 40px;
    width: 100%;
    max-width: 400px;
    animation: slideIn 0.5s ease-out;
    transition: border-color 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#question {
    font-size: 48px;
    font-weight: bold;
    color: #667eea;
    margin-bottom: 30px;
    letter-spacing: 2px;
}

#answer {
    width: 100%;
    padding: 12px 16px;
    font-size: 18px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    margin-bottom: 20px;
    transition: all 0.3s ease;
}

#answer:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#submit {
    width: 100%;
    padding: 14px;
    font-size: 18px;
    font-weight: 600;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
}

#submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

#submit:active {
    transform: translateY(0);
}

#feedback {
    font-size: 18px;
    font-weight: 600;
    color: #667eea;
    margin-top: 20px;
    opacity: 0;
    transition: opacity 0.3s ease;
}

#history {
    margin-top: 40px;
    border-collapse: collapse;
    width: 100%;
    max-width: 400px;
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    animation: slideIn 0.5s ease-out 0.2s both;
}

#history th {
    background: #444;
    color: white;
    padding: 14px;
    font-weight: 600;
    letter-spacing: 0.5px;
}

#history td {
    padding: 12px 14px;
    border-bottom: 1px solid #444;
    color: #333;
    font-size: 16px;
}

#history tr:last-child td {
    border-bottom: none;
}

#history tbody tr:hover {
    background: #f8f9ff;
    transition: background-color 0.2s ease;
}

#history .correct {
    background-color: #62ff87;
    font-weight: 600;
}

#history .incorrect {
    background-color: #ff4a5c;
    font-weight: 600;
}

#history .slow {
    background-color: #ffb347;
    font-weight: 600;
}