.os-quiz {
    --os-navy: #465C85;
    --os-ice-blue: #AFDFE3;
    --os-apple-green: #D9EDAB;
    --os-peach-pink: #FCA6A2;
    --os-banana: #FFEA96;
    --os-polar: #F5EED3;

    margin: 2.5rem 0;
    padding: 2rem;
    border-radius: 8px;
    background: var(--os-polar);
    color: #222;
}

.os-quiz [hidden] {
    display: none !important;
}


/* Start screen */

.os-quiz-start {
    padding: 1rem 0;
    text-align: center;
}

.os-quiz-kicker,
.os-quiz-progress {
    margin-bottom: 0.5rem;
    color: var(--os-navy);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.os-quiz-start p {
    margin-bottom: 1rem;
}


/* Main action buttons */

.os-quiz-start-button,
.os-quiz-next,
.os-quiz-show-result,
.os-quiz-restart {
    display: inline-block;
    padding: 0.85rem 1.4rem;
    border: 2px solid var(--os-navy);
    border-radius: 4px;
    background: var(--os-navy);
    color: #fff;
    cursor: pointer;
    font: inherit;
    font-weight: 700;
    line-height: 1.2;
    transition:
        background-color 0.15s ease,
        color 0.15s ease,
        transform 0.15s ease;
}

.os-quiz-start-button:hover,
.os-quiz-next:hover,
.os-quiz-show-result:hover,
.os-quiz-restart:hover {
    background: #fff;
    color: var(--os-navy);
}

.os-quiz-start-button:active,
.os-quiz-next:active,
.os-quiz-show-result:active,
.os-quiz-restart:active {
    transform: translateY(1px);
}


/* Keyboard accessibility */

.os-quiz button:focus-visible {
    outline: 3px solid #111;
    outline-offset: 3px;
}


/* Questions */

.os-quiz-question {
    scroll-margin-top: 2rem;
}

.os-quiz-question-text {
    margin: 0 0 1.5rem;
    color: var(--os-navy);
    font-size: clamp(1.35rem, 3vw, 1.8rem);
    line-height: 1.3;
}


/* Question image */

.os-quiz-question-figure {
    margin: 1.5rem 0;
}

.os-quiz-question-image {
    display: block;
    width: 100%;
    height: auto;
    border-radius: 4px;
}

.os-quiz-image-credit {
    margin: 0.4rem 0 0;
    font-size: 0.8rem;
    line-height: 1.4;
}


/* Answer choices */

.os-quiz-answers {
    display: grid;
    gap: 0.75rem;
    margin: 1.5rem 0;
}

.os-quiz-answer {
    display: flex;
    align-items: center;
    gap: 0.9rem;
    width: 100%;
    min-height: 3.5rem;
    padding: 0.85rem 1rem;

    border: 2px solid var(--os-navy);
    border-radius: 4px;

    background: #fff;
    color: #222;

    text-align: left;
    cursor: pointer;
    font: inherit;

    transition:
        background-color 0.15s ease,
        border-color 0.15s ease,
        transform 0.15s ease;
}

.os-quiz-answer:hover:not(:disabled) {
    background: var(--os-ice-blue);
    transform: translateY(-1px);
}

.os-quiz-answer-letter {
    display: inline-flex;
    flex: 0 0 2rem;
    align-items: center;
    justify-content: center;

    width: 2rem;
    height: 2rem;

    border-radius: 50%;
    background: var(--os-navy);
    color: #fff;

    font-weight: 700;
}

.os-quiz-answer:disabled {
    cursor: default;
    opacity: 1;
}


/* Correct / incorrect */

.os-quiz-answer.is-correct {
    border-color: var(--os-navy);
    background: var(--os-apple-green);
}

.os-quiz-answer.is-incorrect {
    border-color: var(--os-navy);
    background: var(--os-peach-pink);
}


/* Feedback */

.os-quiz-feedback {
    margin-top: 1.75rem;
    padding-top: 1.25rem;
    border-top: 2px solid var(--os-navy);
}

.os-quiz-feedback-result {
    margin-bottom: 0.6rem;
    color: var(--os-navy);
    font-size: 1.3rem;
    font-weight: 700;
}

.os-quiz-explanation {
    margin-bottom: 1.25rem;
    line-height: 1.6;
}

.os-quiz-next,
.os-quiz-show-result {
    margin-top: 0.5rem;
}


/* Results */

.os-quiz-results {
    padding: 1rem 0;
    text-align: center;
}

.os-quiz-results-heading {
    margin-bottom: 0.5rem;
    color: var(--os-navy);
}

.os-quiz-score {
    margin: 0;
    color: var(--os-navy);
    font-size: clamp(2rem, 8vw, 3.5rem);
    font-weight: 700;
    line-height: 1.1;
}

.os-quiz-percentage {
    margin: 0.5rem 0 0;
    font-size: 1.25rem;
    font-weight: 700;
}

.os-quiz-result-message {
    max-width: 36rem;
    margin: 1.25rem auto 0;
    font-size: 1.1rem;
    line-height: 1.6;
}

.os-quiz-result-messages {
    display: none;
}

.os-quiz-restart {
    margin-top: 1.5rem;
}


/* Small screens */

@media (max-width: 600px) {

    .os-quiz {
        margin: 1.5rem 0;
        padding: 1.25rem;
    }

    .os-quiz-answer {
        padding: 0.8rem;
    }

    .os-quiz-answer-letter {
        flex-basis: 1.8rem;
        width: 1.8rem;
        height: 1.8rem;
    }

    .os-quiz-start-button,
    .os-quiz-next,
    .os-quiz-show-result,
    .os-quiz-restart {
        width: 100%;
    }
}


/* Respect reduced-motion preferences */

@media (prefers-reduced-motion: reduce) {

    .os-quiz *,
    .os-quiz *::before,
    .os-quiz *::after {
        scroll-behavior: auto !important;
        transition: none !important;
    }
}