* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f5f5f5;
    color: #212529;
}

.header {
    background: #212529;
    color: white;
    padding: 20px;
    text-align: center;
}

.container {
    width: 100%;
    max-width: 700px;
    margin: 0 auto;
    padding: 20px;
}

.screen {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
}

.hidden {
    display: none;
}

.button {
    width: 100%;
    padding: 15px;
    border: none;
    border-radius: 8px;
    background: #212529;
    color: white;
    font-size: 18px;
    cursor: pointer;
}

.button:hover {
    opacity: 0.9;
}

.progress {
    margin-bottom: 10px;
    font-weight: bold;
}

.progress-bar {
    height: 8px;
    background: #ddd;
    border-radius: 5px;
    overflow: hidden;
    margin-bottom: 25px;
}

#progress-value {
    height: 100%;
    width: 0;
    background: #212529;
    transition: width 0.3s;
}

#question {
    margin-bottom: 25px;
}

.answers {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.answer {
    padding: 16px;
    background: white;
    border: 2px solid #ddd;
    border-radius: 8px;
    text-align: left;
    font-size: 17px;
    cursor: pointer;
}

.answer:hover:not(:disabled) {
    border-color: #212529;
}

.answer.correct {
    background: #d4edda;
    border-color: #28a745;
}

.answer.wrong {
    background: #f8d7da;
    border-color: #dc3545;
}

.answer:disabled {
    cursor: default;
}

.feedback {
    margin-top: 20px;
    padding: 15px;
    border-radius: 8px;
    background: #eee;
}

#next-button {
    margin-top: 20px;
}

.result {
    font-size: 48px;
    font-weight: bold;
    text-align: center;
    margin: 30px 0;
}

#result-text {
    text-align: center;
    margin-bottom: 30px;
}

@media (max-width: 600px) {

    .container {
        padding: 10px;
    }

    .screen {
        padding: 18px;
    }

    #question {
        font-size: 21px;
    }

}