/* Hallmark · macrostructure: preserved app shell + continuous explanation disclosure · components: masthead + native dialog + explanation disclosure · genre: modern-minimal · tone: restrained utilitarian · theme: existing teal · anchor hue: teal · motion: restrained · contrast: pass (40–41) · nav/footer: n/a · honest: pass (46) · chrome: pass (47) · tokens: pass (48) · responsive: pass (49) · icons: pass (30) · mobile: pass (34, 49, 50–57) · slop: pass · pre-emit critique: P5 H5 E5 S5 R5 V4 */
@import url('./tokens.css');

html,
body {
    overflow-x: clip;
}

body {
    transition: none;
}

h1,
h2,
h3 {
    min-width: 0;
    overflow-wrap: anywhere;
}

/* The page wrapper is layout, not another card. */
.container {
    background: transparent;
    border-radius: 0;
    box-shadow: none;
    backdrop-filter: none;
    transition: none;
}

/* The masthead identifies the tool; it is not a dashboard or a marketing hero. */
header.app-header {
    position: relative;
    overflow: visible;
    margin-bottom: var(--spacing-xl);
    padding: 0 0 var(--spacing-lg);
    color: var(--text-color);
    background: transparent;
    border-bottom: 1px solid var(--refine-rule);
    border-radius: 0;
    box-shadow: none;
    animation: none;
}

header.app-header::before {
    content: none;
}

.app-header .header-content {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: var(--spacing-lg);
    margin: 0;
}

.app-header .title-section h1 {
    gap: 0;
    margin: 0;
    color: var(--text-color);
    font-size: clamp(1.5rem, 3vw, 1.85rem);
    font-weight: var(--font-weight-bold);
    line-height: 1.2;
    letter-spacing: -0.035em;
    text-shadow: none;
}

.header-question-count {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-xs);
    margin: 0;
    color: var(--refine-muted-text);
    font-size: 0.9rem;
    font-weight: var(--font-weight-medium);
    white-space: nowrap;
}

#total-questions-header {
    color: var(--text-color);
    font-size: 1rem;
    font-variant-numeric: tabular-nums;
}

/* Section headings provide grouping; an extra section card is unnecessary. */
.study-modes-section {
    background: transparent;
    border: 0;
    border-radius: 0;
    padding: 0;
    box-shadow: none;
}

.section-header {
    border-bottom: 1px solid var(--refine-rule);
}

/* Cards remain only where each surface represents a distinct study action. */
.card {
    border: 1px solid var(--refine-rule);
    border-radius: var(--refine-radius-panel);
    box-shadow: none;
    transition-property: background-color, border-color;
    transition-duration: var(--refine-duration-fast);
    transition-timing-function: var(--refine-ease-out);
}

.card::before,
.card:hover::before {
    height: 3px;
    transition: none;
}

.card:hover {
    transform: none;
    box-shadow: none;
    border-color: var(--refine-rule);
}

.card-icon {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    box-shadow: none;
    text-shadow: none;
}

.card p {
    color: var(--refine-muted-text);
}

.primary-card .card-icon {
    background: var(--refine-primary-control);
}

.secondary-card .card-icon,
.warning-card .card-icon {
    background: var(--refine-warning-control);
}

.settings-card .card-icon {
    background: var(--refine-neutral-control);
}

.progress-info,
.wrong-count-display {
    border-radius: var(--refine-radius-sm);
    box-shadow: none;
}

.progress-info {
    background: var(--refine-surface-muted);
    border: 0;
    border-left: 2px solid var(--primary-color);
}

.wrong-count-display {
    background: var(--refine-warning-surface);
    color: var(--refine-warning-control);
}

/* Common app dialog · states: default, hover, focus-visible, active, disabled. */
body.app-dialog-open {
    overflow: hidden;
}

.app-dialog {
    width: min(calc(100% - (var(--spacing-lg) * 2)), 30rem);
    max-height: min(80dvh, 40rem);
    margin: auto;
    padding: 0;
    color: var(--text-color);
    background: var(--refine-surface);
    border: 1px solid var(--refine-rule);
    border-radius: var(--refine-radius-panel);
    box-shadow: var(--refine-dialog-shadow);
    opacity: 0;
    transform: translateY(var(--spacing-sm));
}

.app-dialog[open] {
    opacity: 1;
    transform: translateY(0);
    animation: app-dialog-in var(--refine-duration-dialog) var(--refine-ease-out);
}

.app-dialog::backdrop {
    background: var(--refine-dialog-backdrop);
    animation: app-dialog-backdrop-in var(--refine-duration-dialog) var(--refine-ease-out);
}

.app-dialog-panel {
    display: grid;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
}

.app-dialog-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.app-dialog-header h3 {
    margin: 0;
    font-size: 1.2rem;
    line-height: 1.3;
}

.app-dialog[data-tone="danger"] .app-dialog-header h3 {
    color: var(--refine-danger-control);
}

.app-dialog-message {
    max-width: 65ch;
    margin: 0;
    color: var(--refine-muted-text);
    line-height: 1.65;
    overflow-wrap: anywhere;
    white-space: pre-line;
}

.app-dialog-close {
    flex: 0 0 auto;
    display: inline-grid;
    place-items: center;
    width: 44px;
    min-width: 44px;
    height: 44px;
    padding: 0;
    color: var(--refine-muted-text);
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--refine-radius-control);
}

.app-dialog-close:hover:not(:disabled) {
    color: var(--text-color);
    background: var(--refine-surface-muted);
    border-color: var(--refine-rule);
}

.app-dialog-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--spacing-sm);
}

.app-dialog-actions .primary-btn,
.app-dialog-actions .secondary-btn {
    width: auto;
    min-width: 6rem;
    min-height: 44px;
    padding: var(--spacing-sm) var(--spacing-md);
    border-width: 1px;
    text-shadow: none;
}

.app-dialog[data-tone="danger"] .app-dialog-actions .primary-btn {
    color: var(--refine-control-ink);
    background: var(--refine-danger-control);
    border-color: var(--refine-danger-control);
}

.app-dialog :is(button):disabled {
    cursor: not-allowed;
    opacity: 0.55;
}

@keyframes app-dialog-in {
    from {
        opacity: 0;
        transform: translateY(var(--spacing-sm));
    }
}

@keyframes app-dialog-backdrop-in {
    from {
        opacity: 0;
    }
}

/* Controls get one clear surface and one restrained state change. */
button,
.primary-btn,
.secondary-btn,
.icon-btn,
.setting-btn,
.option-btn,
.backup-btn,
.tree-toggle,
.toggle-icon,
.category-item,
.guide-item {
    transition-property: background-color, border-color, color, filter;
    transition-duration: var(--refine-duration-fast);
    transition-timing-function: var(--refine-ease-out);
}

button {
    box-shadow: none !important;
    white-space: nowrap;
}

.option-btn {
    white-space: normal;
    overflow-wrap: anywhere;
    text-align: left;
}

.primary-btn,
.icon-btn,
.setting-btn,
.option-btn,
.backup-btn {
    box-shadow: none;
}

.icon-btn,
.setting-btn {
    border-width: 1px;
}

.setting-btn {
    background: var(--refine-surface-muted);
}

.primary-btn,
#start-sequential-btn,
#undo-wrong-btn,
#undo-from-quiz-btn,
#prev-btn,
#next-btn,
#explanation-btn,
.modal-btn.primary {
    background: var(--refine-primary-control);
    color: var(--refine-control-ink);
}

#start-quiz-btn,
#restart-btn,
#study-wrong-btn,
#add-to-wrong-btn {
    background: var(--refine-warning-control);
    color: var(--refine-control-ink);
}

#new-random-quiz-btn {
    background: var(--refine-purple-control);
    color: var(--refine-control-ink);
}

#stop-btn,
.remove-btn {
    background: var(--refine-danger-control);
    color: var(--refine-control-ink);
}

button:hover:not(:disabled),
.primary-btn:hover:not(:disabled),
.icon-btn:hover:not(:disabled),
.setting-btn:hover,
.option-btn:not(:disabled):hover,
#add-to-wrong-btn:hover:not(:disabled),
#undo-from-quiz-btn:hover:not(:disabled),
.backup-btn:hover,
.category-item:hover,
.guide-item:hover {
    transform: none;
    box-shadow: none;
    filter: none;
}

.tree-toggle,
.tree-toggle:hover {
    transform: none;
    box-shadow: none;
    transition-property: background-color;
    transition-duration: var(--refine-duration-fast);
    transition-timing-function: var(--refine-ease-out);
}

.toggle-icon {
    transition: none;
}

button:active:not(:disabled) {
    filter: brightness(0.88);
}

:where(button, select, textarea, input, [tabindex]):focus-visible {
    outline: 2px solid var(--refine-focus-inner) !important;
    outline-offset: 2px;
    box-shadow: 0 0 0 5px var(--refine-focus-outer) !important;
}

@media (hover: hover) and (pointer: fine) {
    .card:hover {
        border-color: var(--refine-rule-strong);
    }

    .primary-btn:hover:not(:disabled) {
        background: var(--refine-primary-control);
        filter: brightness(0.95);
    }

    #undo-wrong-btn:hover:not(:disabled),
    #undo-from-quiz-btn:hover:not(:disabled),
    .modal-btn.primary:hover {
        background: var(--refine-primary-control);
    }

    .remove-btn:hover:not(:disabled) {
        background: var(--refine-danger-control);
    }

    .secondary-btn:hover:not(:disabled),
    .icon-btn:hover:not(:disabled) {
        background: var(--refine-primary-control);
        color: var(--refine-control-ink);
    }

    .icon-btn.danger:hover:not(:disabled) {
        background: var(--refine-danger-control);
        border-color: var(--refine-danger-control);
    }

    .secondary-btn:hover:not(:disabled),
    .icon-btn:hover:not(:disabled),
    .setting-btn:hover {
        border-color: var(--primary-color);
    }

    .setting-btn:hover {
        background: var(--refine-surface);
        color: var(--text-color);
    }
}

/* Explanation is a disclosure followed by one continuous reading document. */
.quiz-actions-container {
    margin: var(--spacing-lg) 0 var(--spacing-sm);
    text-align: left;
}

#explanation-btn {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    width: 100%;
    min-height: 48px;
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--text-color);
    background: var(--refine-surface);
    border: 1px solid var(--refine-control-rule);
    border-radius: var(--refine-radius-control);
    box-shadow: none;
    font-size: 1rem;
    font-weight: var(--font-weight-semibold);
    text-align: left;
    transition-property: background-color, border-color, color;
}

.explanation-trigger-label {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    min-width: 0;
}

.explanation-trigger-label .fa-book-open {
    color: var(--primary-color);
}

.explanation-trigger-chevron {
    flex: 0 0 auto;
    color: var(--refine-muted-text);
    transition: transform var(--refine-duration-fast) var(--refine-ease-out);
}

#explanation-btn[aria-expanded="true"] {
    background: var(--refine-surface-muted);
    border-color: var(--refine-control-rule);
}

#explanation-btn[aria-expanded="true"] .explanation-trigger-chevron {
    transform: rotate(180deg);
}

#explanation-btn:active:not(:disabled) {
    filter: none;
    transform: translateY(1px);
}

#explanation-btn:disabled {
    color: var(--refine-muted-text);
    background: var(--refine-surface-muted);
    cursor: not-allowed;
    opacity: 0.55;
}

#explanation-btn:focus-visible {
    outline: 2px solid var(--refine-focus-outer) !important;
    outline-offset: 2px;
    box-shadow: none !important;
}

#explanation-container {
    margin: var(--spacing-md) 0 0;
    padding: var(--spacing-xl) 0 0;
    color: var(--text-color);
    background: transparent;
    border: 0;
    border-top: 1px solid var(--refine-rule);
    border-radius: 0;
    box-shadow: none;
    font-size: 1rem;
    line-height: 1.75;
    overflow-wrap: anywhere;
}

#explanation-container > * {
    width: min(100%, 72ch);
    margin-inline: auto;
}

.explanation-panel-header {
    margin-bottom: var(--spacing-lg);
    padding: 0;
    color: var(--text-color);
    background: transparent;
    border: 0;
    border-radius: 0;
    box-shadow: none;
    animation: none;
    position: static;
    overflow: visible;
}

.explanation-panel-header::before,
#explanation-title::before {
    content: none;
}

#explanation-title {
    margin: 0;
    padding: 0;
    color: var(--text-color);
    border: 0;
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    letter-spacing: -0.02em;
    line-height: 1.35;
}

#explanation-content {
    min-width: 0;
}

.explanation-answer {
    display: flex;
    align-items: baseline;
    flex-wrap: wrap;
    gap: var(--spacing-xs) var(--spacing-sm);
    margin: 0 0 var(--spacing-xl);
    padding: var(--spacing-md);
    color: var(--refine-success-text);
    background: var(--refine-success-surface);
    border: 0;
    border-top: 2px solid var(--refine-success-rule);
    border-radius: 0;
    box-shadow: none;
}

.explanation-answer-label {
    font-size: 0.85rem;
    font-weight: var(--font-weight-semibold);
    letter-spacing: 0.04em;
}

.explanation-answer-number {
    color: var(--refine-success-text) !important;
    font-size: 1.125rem;
    font-variant-numeric: tabular-nums;
}

.explanation-answer-text {
    color: var(--text-color);
    font-weight: var(--font-weight-medium);
}

.explanation-section {
    position: static;
    margin: 0 0 var(--spacing-xl);
    padding: 0 0 var(--spacing-xl);
    color: var(--text-color);
    background: transparent;
    border: 0;
    border-bottom: 1px solid var(--refine-rule);
    border-radius: 0;
    box-shadow: none;
}

.explanation-analysis {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: 0;
}

.explanation-reason::before,
.explanation-concept::before {
    content: none;
}

#explanation-container .explanation-section-title,
#explanation-container h1,
#explanation-container h2,
#explanation-container h3 {
    margin: 0 0 var(--spacing-md);
    padding: 0;
    color: var(--text-color) !important;
    border: 0;
    font-size: 1.05rem;
    font-weight: var(--font-weight-bold);
    letter-spacing: -0.01em;
    line-height: 1.45;
}

.explanation-section-body,
.explanation-prose,
.choice-explanation {
    color: var(--text-color);
    font-size: 1rem;
    line-height: 1.75;
}

#explanation-container p {
    margin: 0 0 var(--spacing-md);
    line-height: inherit;
}

#explanation-container p:last-child {
    margin-bottom: 0;
}

#explanation-container strong,
#explanation-container b {
    color: inherit !important;
    font-weight: var(--font-weight-bold) !important;
}

#explanation-container ul,
#explanation-container ol {
    margin: 0 0 var(--spacing-md);
    padding-left: var(--spacing-lg);
}

#explanation-container li {
    margin-bottom: var(--spacing-xs);
}

#explanation-container blockquote {
    margin: var(--spacing-md) 0;
    padding: 0 0 0 var(--spacing-md);
    color: var(--refine-muted-text);
    border-left: 2px solid var(--refine-rule-strong);
    font-style: normal;
}

#explanation-container code {
    padding: var(--spacing-xs);
    color: var(--refine-code-text);
    background: var(--refine-code-surface);
    border-radius: 4px;
    font-family: var(--refine-font-mono);
    font-size: 0.9em;
}

#explanation-container pre {
    max-width: 100%;
    margin: var(--spacing-md) 0;
    padding: var(--spacing-md);
    color: var(--refine-code-text);
    background: var(--refine-code-surface);
    border-radius: var(--refine-radius-sm);
    overflow-x: auto;
}

#explanation-container pre code {
    padding: 0;
    color: inherit;
    background: transparent;
}

#explanation-container :is(a, td, th) {
    overflow-wrap: anywhere;
}

#explanation-container :is(img, video) {
    max-width: 100%;
    height: auto;
}

#explanation-container table {
    display: block;
    max-width: 100%;
    overflow-x: auto;
    border-collapse: collapse;
}

.choice-analysis-list {
    display: grid;
    gap: 0;
}

#explanation-container .choice-analysis-item,
#explanation-container .choice-analysis-item.incorrect {
    margin: 0;
    padding: var(--spacing-md) 0;
    color: var(--text-color);
    background: transparent;
    border: 0;
    border-bottom: 1px solid var(--refine-rule);
    border-radius: 0;
    box-shadow: none;
    transition: none;
}

#explanation-container .choice-analysis-item:last-child {
    border-bottom: 0;
}

#explanation-container .choice-analysis-item.correct {
    margin: var(--spacing-xs) 0;
    padding: var(--spacing-md);
    background: var(--refine-success-surface);
    border: 0;
    border-radius: var(--refine-radius-sm);
    box-shadow: none;
}

.choice-text {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
    margin: 0 0 var(--spacing-xs);
    color: var(--text-color);
    font-size: 0.95rem;
    font-weight: var(--font-weight-semibold);
}

.choice-number {
    font-variant-numeric: tabular-nums;
}

.choice-result {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--refine-success-text);
    font-size: 0.85rem;
    font-weight: var(--font-weight-bold);
}

.choice-result i {
    font-style: normal !important;
}

.choice-explanation {
    margin-left: 0;
}

.explanation-empty {
    margin: 0;
    padding: var(--spacing-md);
    color: var(--refine-muted-text);
    background: var(--refine-surface-muted);
    border: 1px solid var(--refine-rule);
    border-radius: var(--refine-radius-sm);
    font-style: normal;
}

#explanation-container:not(.hidden) ~ #navigation-btns {
    position: static !important;
    inset: auto !important;
    width: auto !important;
    margin: var(--spacing-xl) 0 0 !important;
    transform: none !important;
}

#quiz-container:has(#explanation-container:not(.hidden)) {
    padding-bottom: 0;
}

@media (hover: hover) and (pointer: fine) {
    #explanation-btn:hover:not(:disabled) {
        color: var(--text-color);
        background: var(--refine-surface-muted);
        border-color: var(--refine-control-rule);
    }
}

@media (max-width: 768px) {
    header.app-header {
        margin-bottom: var(--spacing-lg);
        padding-bottom: var(--spacing-md);
    }

    .app-header .header-content {
        flex-direction: row;
        align-items: baseline;
        gap: var(--spacing-md);
        text-align: left;
    }

    .app-header .title-section h1 {
        font-size: 1.4rem;
    }

    .cards-container {
        gap: 0;
    }

    .card {
        background: transparent;
        border: 0;
        border-bottom: 1px solid var(--refine-rule);
        border-radius: 0;
        padding: var(--spacing-lg) var(--spacing-sm);
    }

    .card::before {
        display: none;
    }

    .card-icon {
        width: 44px;
        height: 44px;
        border-radius: 11px;
    }

    .app-dialog {
        width: min(calc(100% - (var(--spacing-md) * 2)), 30rem);
        max-height: calc(100dvh - (var(--spacing-md) * 2));
    }

    .app-dialog-panel {
        gap: var(--spacing-md);
        padding: var(--spacing-md);
    }

    .app-dialog-actions > button {
        flex: 1 1 0;
    }

    #explanation-btn {
        min-height: 48px;
        padding: var(--spacing-sm) var(--spacing-md);
    }

    #explanation-container {
        margin-top: var(--spacing-sm);
        padding-top: var(--spacing-lg);
        font-size: 1rem;
    }

    .explanation-panel-header,
    .explanation-answer,
    .explanation-section {
        margin-bottom: var(--spacing-lg);
    }

    .explanation-section {
        padding-bottom: var(--spacing-lg);
    }

    .explanation-analysis {
        margin-bottom: 0;
        padding-bottom: 0;
    }

    #explanation-container .choice-analysis-item,
    #explanation-container .choice-analysis-item.incorrect {
        padding: var(--spacing-md) 0;
    }

    #explanation-container .choice-analysis-item.correct {
        padding: var(--spacing-md);
    }

    .choice-text {
        font-size: 0.95rem;
    }

    .choice-explanation {
        font-size: 1rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}