:root {
    --nav-width: clamp(60px, 6vw, 80px);
    --content-padding: clamp(1rem, 5vw, 6rem);
    --quiz-mobile-nav-height: 3rem;
    --quiz-mobile-footer-height: 4.5rem;
}

html {
    scroll-behavior: auto;
}

body {
    min-height: 100vh;
    overflow-x: hidden;
    overflow-y: auto;
}

.quiz-layout {
    min-height: 100vh;
    width: 100%;
}

.quiz-workspace {
    flex: 1;
    display: flex;
    align-items: flex-start;
}

.quiz-body {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
}

.question-nav {
    width: var(--nav-width);
    flex-shrink: 0;
    background-color: var(--color-surface);
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: clamp(1rem, 2vw, 1.5rem) 0;
    gap: 0.5rem;
    overflow-x: hidden;
    overflow-y: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
    align-self: flex-start;
    position: sticky;
    top: 0;
    max-height: 100vh;
}
.question-nav::-webkit-scrollbar {
    display: none;
}

.nav-node {
    width: clamp(2rem, 3vw, 2.5rem);
    height: clamp(2rem, 3vw, 2.5rem);
    border-radius: 0.375rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: clamp(0.7rem, 1vw, 0.75rem);
    font-family: monospace;
    font-weight: 500;
    color: var(--color-text-muted);
    transition: background-color 0.2s ease, color 0.2s ease;
    flex-shrink: 0;
    border: none;
    background: none;
    cursor: pointer;
    padding: 0;
}

.nav-node-check {
    display: none;
    width: 0.875rem;
    height: 0.875rem;
}

.nav-node:hover {
    background-color: var(--color-primary-hover-bg);
    color: var(--color-primary);
}

.nav-node.active {
    background-color: var(--color-primary);
    color: var(--color-surface);
    font-weight: 700;
}

.nav-node.answered:not(.active) {
    background-color: var(--color-primary-hover-bg);
    color: var(--color-text-main);
}

.nav-node.answered:not(.active) .nav-node-label {
    display: none;
}

.nav-node.answered:not(.active) .nav-node-check {
    display: block;
}

.quiz-main {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.quiz-brand-bar {
    flex-shrink: 0;
    padding: clamp(0.875rem, 2vw, 1.25rem) clamp(1rem, 3vw, 2.5rem);
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
}

.quiz-brand {
    display: inline-flex;
    align-items: center;
    gap: 0.625rem;
    text-decoration: none;
    color: var(--color-text-main);
    transition: color var(--transition-fast);
}

.quiz-brand:hover {
    color: var(--color-primary);
}

.quiz-brand__logo {
    display: block;
    width: auto;
    height: clamp(2rem, 5vw, 2.5rem);
    object-fit: contain;
    flex-shrink: 0;
}

.quiz-brand__text {
    font-size: clamp(1.05rem, 1.75vw, 1.35rem);
    font-weight: 700;
    letter-spacing: -0.025em;
    line-height: 1.2;
    white-space: nowrap;
}

.quiz-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: clamp(0.75rem, 2vw, 1.25rem);
    padding: clamp(0.75rem, 1.5vw, 1rem) clamp(1rem, 3vw, 2.5rem);
    padding-left: clamp(1rem, 2.5vw, 1.5rem);
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    flex-shrink: 0;
    min-height: 3.25rem;
}

.quiz-toolbar__start {
    display: flex;
    align-items: center;
    gap: clamp(0.75rem, 1.5vw, 1rem);
    min-width: 0;
    flex: 1 1 auto;
}

.quiz-toolbar__end {
    display: flex;
    align-items: center;
    gap: clamp(0.625rem, 1.5vw, 1rem);
    flex-shrink: 0;
    margin-left: auto;
}

.quiz-current-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: clamp(2rem, 3vw, 2.5rem);
    height: clamp(2rem, 3vw, 2.5rem);
    border-radius: 0.375rem;
    background-color: var(--color-primary);
    color: var(--color-surface);
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: clamp(0.7rem, 1vw, 0.75rem);
    font-weight: 700;
    flex-shrink: 0;
}

.quiz-breadcrumbs {
    margin-bottom: 0;
    min-width: 0;
    flex: 1 1 auto;
}

.quiz-breadcrumbs .breadcrumb-current {
    max-width: min(16rem, 32vw);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.quiz-breadcrumbs h1.breadcrumb-current {
    margin: 0;
    font-size: inherit;
    line-height: inherit;
}

.quiz-progress-pct {
    font-size: clamp(0.75rem, 1.1vw, 0.8125rem);
    font-weight: 700;
    color: var(--color-text-main);
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    flex-shrink: 0;
}

.quiz-progress-count {
    margin: 0;
    font-size: clamp(0.8rem, 1.2vw, 0.875rem);
    color: var(--color-text-muted);
    white-space: nowrap;
    flex-shrink: 0;
}

.quiz-progress-count span {
    color: var(--color-text-main);
    font-weight: 600;
}

.quiz-toolbar__timer {
    margin: 0;
    font-family: monospace;
    font-size: clamp(0.7rem, 1vw, 0.75rem);
    color: var(--color-text-muted);
    white-space: nowrap;
}

.quiz-toolbar__timer:not([hidden]) {
    display: block;
}

.quiz-mode-bar {
    flex-shrink: 0;
    padding: 0.5rem clamp(1rem, 3vw, 2.5rem);
    padding-left: clamp(1rem, 2.5vw, 1.5rem);
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
}

.quiz-mode-bar .mode-switcher {
    display: inline-flex;
}


.mode-switcher {
    display: flex;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 0.5rem;
    overflow: hidden;
    padding: 0.25rem;
}
.mode-btn {
    padding: 0.5rem 1rem;
    font-size: clamp(0.75rem, 1vw, 0.875rem);
    font-weight: 600;
    color: var(--color-text-muted);
    border-radius: 0.375rem;
    transition: all 0.2s;
}
.mode-btn.active {
    background: var(--color-primary);
    color: var(--color-surface);
}

.close-btn {
    width: 2rem;
    height: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: 0.375rem;
    color: var(--color-text-muted);
    transition: all 0.2s ease;
}
.close-btn:hover {
    background-color: var(--color-surface);
    color: var(--color-text-main);
}
.quiz-scroll-area {
    flex: 1;
    min-width: 0;
    padding: var(--content-padding);
    overflow-x: clip;
}
.quiz-container {
    width: 100%;
    max-width: 48rem;
    margin: 0 auto;
    padding-bottom: 1rem;
}

.question-block {
    width: 100%;
    max-width: 100%;
    min-width: 0;
}

.question-extract {
    background-color: var(--color-primary-alpha-10);
    border-left: 4px solid var(--color-primary);
    padding: clamp(1rem, 2vw, 1.5rem);
    margin-bottom: 1.5rem;
    border-radius: 0 0.5rem 0.5rem 0;
    font-size: 0.9rem;
    color: var(--color-text-main);
    line-height: 1.6;
}
.question-image-container {
    width: 100%;
    max-width: 600px;
    margin: 0 0 1.5rem 0;
    border-radius: 0.5rem;
    overflow: hidden;
    border: 1px solid var(--color-border);
}
.question-image {
    width: 100%;
    height: auto;
    display: block;
    object-fit: contain;
}
.question-text {
    font-size: 1.05rem;
    line-height: 1.6;
    color: var(--color-text-main);
    margin-bottom: clamp(1.5rem, 4vw, 2rem);
    font-weight: 500;
    overflow-wrap: anywhere;
    word-break: break-word;
}

.question-interaction-area {
    width: 100%;
    max-width: 100%;
    min-width: 0;
}

.options-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    width: 100%;
    max-width: 100%;
    min-width: 0;
}
.option-card {
    display: flex;
    align-items: flex-start;
    gap: clamp(0.75rem, 2vw, 1rem);
    width: 100%;
    max-width: 100%;
    min-width: 0;
    text-align: left;
    padding: clamp(1rem, 2.5vw, 1.5rem);
    border: 2px solid var(--color-border);
    border-radius: 0.75rem;
    background-color: var(--color-surface);
    transition: all var(--transition-fast);
    user-select: none;
}
.option-card:hover {
    border-color: var(--color-accent-border);
    background-color: var(--color-primary-hover-bg);
}
.option-card.selected {
    border-color: var(--color-primary);
    background-color: var(--color-primary-hover-bg);
}

.option-letter {
    width: clamp(1.75rem, 3vw, 2rem);
    height: clamp(1.75rem, 3vw, 2rem);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    border: 2px solid var(--color-border);
    border-radius: 50%;
    font-family: monospace;
    font-size: clamp(0.75rem, 1.2vw, 0.875rem);
    color: var(--color-text-main);
    transition: all 0.2s ease;
    background: var(--color-surface);
}
.option-card.selected .option-letter {
    background-color: var(--color-primary);
    color: var(--color-surface);
    border-color: var(--color-primary);
}
.option-text {
    font-size: 0.95rem;
    line-height: 1.5;
    padding-top: 0.125rem;
    flex: 1 1 auto;
    min-width: 0;
    overflow-wrap: anywhere;
    word-break: break-word;
}

.multi-select .option-letter {
    border-radius: 0.375rem;
}

.image-options-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 180px), 1fr));
    gap: 1rem;
    width: 100%;
    max-width: 100%;
    min-width: 0;
}
.option-card.image-card {
    flex-direction: column;
    align-items: center;
    padding: 0.75rem;
}
.option-card.image-card .option-image {
    display: block;
    width: 100%;
    max-width: 100%;
    height: auto;
    max-height: min(240px, 45vw);
    object-fit: contain;
    object-position: center;
    border-radius: 0.5rem;
    margin-top: 0.5rem;
}

.calc-input-wrapper {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-width: 300px;
}
.calc-input {
    width: 100%;
    padding: 1rem 1.25rem;
    font-size: 1.1rem;
    border: 2px solid var(--color-border);
    border-radius: 0.75rem;
    outline: none;
    transition: all 0.2s;
    font-family: monospace;
    background: var(--color-surface);
}
.calc-input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px var(--color-primary-hover-bg);
}

.dnd-interface {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}
.dnd-zone-title {
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}
.dnd-zone {
    min-height: 80px;
    border: 2px dashed var(--color-border);
    border-radius: 0.75rem;
    padding: 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    background: var(--color-primary-hover-bg);
}
.dnd-zone.target-zone {
    background: var(--color-surface);
    border-style: solid;
}
.dnd-item {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
    transition: transform 0.1s;
}
.dnd-item:active {
    transform: scale(0.98);
}
.dnd-item .drag-handle {
    color: var(--color-text-muted);
    cursor: grab;
}

.rationale-container {
    margin-top: 2rem;
    padding: 1.5rem;
    border-radius: 0.75rem;
    display: none;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
}
.rationale-container.visible {
    display: block;
}
.feedback-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-weight: 700;
    font-size: 0.875rem;
    margin-bottom: 1rem;
}
.feedback-correct {
    background: var(--color-success-bg);
    color: var(--color-success);
    border: 1px solid var(--color-success);
}
.feedback-incorrect {
    background: var(--color-danger-bg);
    color: var(--color-danger);
    border: 1px solid var(--color-danger);
}
.rationale-text {
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--color-text-main);
    white-space: pre-line;
}

.rationale-text em {
    font-style: italic;
}
.rationale-title {
    font-weight: 700;
    margin-bottom: 0.5rem;
    display: block;
    color: var(--color-primary);
}

.option-card.is-correct {
    border-color: var(--color-success);
    background-color: var(--color-success-bg);
}
.option-card.is-correct .option-letter {
    background-color: var(--color-success);
    border-color: var(--color-success);
    color: white;
}
.option-card.is-wrong {
    border-color: var(--color-danger);
    background-color: var(--color-danger-bg);
}
.option-card.is-wrong .option-letter {
    background-color: var(--color-danger);
    border-color: var(--color-danger);
    color: white;
}

.quiz-actions {
    margin-top: clamp(1.5rem, 4vw, 2rem);
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    flex-wrap: wrap;
}

.quiz-actions.is-hidden {
    display: none;
}
.action-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: clamp(0.875rem, 1vw, 1rem);
    font-weight: 600;
    border-radius: 0.5rem;
    transition: all 0.2s ease;
}

@media (max-width: 768px) {
    .quiz-workspace {
        display: block;
    }

    .quiz-body {
        width: 100%;
        max-width: 100%;
    }

    .question-nav {
        position: fixed;
        top: auto;
        bottom: 0;
        left: 0;
        right: 0;
        width: 100%;
        height: var(--quiz-mobile-nav-height);
        max-height: var(--quiz-mobile-nav-height);
        flex-direction: row;
        align-items: center;
        padding: 0.5rem var(--page-padding, 0.75rem);
        gap: 0.375rem;
        overflow-x: auto;
        overflow-y: hidden;
        border-right: none;
        border-top: 1px solid var(--color-border);
        background-color: var(--color-surface);
        z-index: 15;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        align-self: auto;
    }

    .question-nav::-webkit-scrollbar {
        display: none;
    }

    .nav-node {
        flex-shrink: 0;
        width: 2.125rem;
        height: 2.125rem;
        font-size: 0.6875rem;
    }

    .quiz-current-badge {
        display: none;
    }

    .quiz-brand-bar {
        padding: 0.625rem var(--page-padding, 0.75rem);
    }

    .quiz-toolbar {
        flex-wrap: nowrap;
        align-items: center;
        padding: 0.625rem var(--page-padding, 0.75rem);
        gap: 0.5rem;
    }

    .quiz-toolbar__start {
        flex: 1 1 auto;
        min-width: 0;
        gap: 0.375rem;
    }

    .quiz-toolbar__end {
        flex: 0 0 auto;
        justify-content: flex-end;
        gap: 0.5rem;
        min-width: 0;
    }

    .quiz-breadcrumbs.breadcrumbs {
        flex-wrap: nowrap;
        overflow: hidden;
        gap: 0.375rem;
        margin-bottom: 0;
    }

    .quiz-progress-count {
        font-size: 0.75rem;
    }

    .quiz-mode-bar {
        padding: 0.5rem var(--page-padding, 0.75rem);
    }

    .mode-switcher {
        width: 100%;
        display: flex;
    }

    .mode-btn {
        flex: 1;
        text-align: center;
        padding: 0.4375rem 0.5rem;
        font-size: 0.75rem;
    }

    .quiz-scroll-area {
        width: 100%;
        max-width: 100%;
        padding: 1rem var(--page-padding, 0.75rem);
        padding-bottom: calc(var(--quiz-mobile-nav-height) + 0.75rem);
    }

    .quiz-container {
        width: 100%;
        max-width: 100%;
        padding-bottom: 0;
    }

    .image-options-group {
        grid-template-columns: 1fr;
    }

    .question-extract,
    .dnd-interface,
    .dnd-zone,
    .rationale-container,
    .rationale-text {
        max-width: 100%;
        min-width: 0;
        overflow-wrap: anywhere;
        word-break: break-word;
    }

    .option-card:hover {
        transform: none;
    }

    .quiz-actions {
        justify-content: stretch;
        gap: 0.625rem;
        width: 100%;
        max-width: 100%;
    }

    .action-btn {
        flex: 1;
        justify-content: center;
        padding: 0.75rem 1rem;
        font-size: 0.875rem;
    }
}

@media (max-width: 640px) {
    .quiz-breadcrumbs .breadcrumb-link,
    .quiz-breadcrumbs .breadcrumb-current,
    .quiz-breadcrumbs .breadcrumb-segment {
        max-width: 4.5rem;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
        display: inline-block;
        vertical-align: bottom;
    }

    .quiz-progress-pct {
        font-size: 0.6875rem;
    }

    .quiz-progress-count {
        font-size: 0.6875rem;
    }
}

@media (max-width: 400px) {
    .quiz-progress-pct {
        display: none;
    }

    .quiz-breadcrumbs .breadcrumb-link,
    .quiz-breadcrumbs .breadcrumb-current,
    .quiz-breadcrumbs .breadcrumb-segment {
        max-width: 3.25rem;
    }
}

@media (max-width: 480px) {
    :root {
        --quiz-mobile-nav-height: 2.75rem;
        --quiz-mobile-footer-height: 4.25rem;
    }

    .question-nav {
        padding: 0.4375rem var(--page-padding, 0.75rem);
    }

    .nav-node {
        width: 2rem;
        height: 2rem;
        font-size: 0.625rem;
    }

    .mode-btn {
        font-size: 0.6875rem;
        padding: 0.375rem 0.375rem;
    }
}

@media (max-width: 320px) {
    :root {
        --quiz-mobile-nav-height: 2.5rem;
        --quiz-mobile-footer-height: 4rem;
    }

    .quiz-toolbar {
        gap: 0.375rem 0.5rem;
        padding: 0.5rem var(--page-padding, 0.625rem);
    }

    .quiz-brand-bar {
        padding: 0.5rem var(--page-padding, 0.625rem);
    }

    .option-card {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .image-options-group {
        grid-template-columns: 1fr;
    }
}

#check-btn {
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
}

#check-btn:hover:not(:disabled) {
    background-color: var(--color-primary-hover-bg);
}

/* Keep quiz page hover behavior unchanged (exclude site-wide navy hover) */
.quiz-layout .btn-primary:hover:not(:disabled),
.quiz-layout .action-btn.btn-primary:hover:not(:disabled) {
    background-color: var(--color-primary-light) !important;
    color: #ffffff !important;
    border-color: transparent !important;
}

.quiz-layout .btn-secondary:hover:not(:disabled),
.quiz-layout .action-btn.btn-secondary:hover:not(:disabled),
.quiz-layout #check-btn:hover:not(:disabled) {
    background-color: var(--color-primary-hover-bg) !important;
    color: var(--color-primary) !important;
    border-color: var(--color-primary) !important;
}

.quiz-layout .close-btn:hover {
    background-color: var(--color-surface) !important;
    color: var(--color-text-main) !important;
    border-color: var(--color-border) !important;
}

.quiz-layout .option-card:hover {
    border-color: var(--color-accent-border, var(--color-accent)) !important;
    background-color: var(--color-primary-hover-bg) !important;
    color: inherit !important;
}

.quiz-layout .option-card:hover .option-text,
.quiz-layout .option-card:hover .option-letter {
    color: inherit !important;
}