/* Aphantasia Creative Tools - Style Sheet (SEO Version) */
/* System fonts, zero external CSS dependencies, responsive, light/dark mode */

:root {
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    --font-mono: SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
    
    /* Light Theme Palette (Calm, Warm Paper & Deep Slate) */
    --bg-page: #f9f8f6;
    --bg-surface: #ffffff;
    --bg-surface-subtle: #f2f0ec;
    --bg-surface-elevated: #ffffff;
    
    --text-primary: #1c2024;
    --text-secondary: #525860;
    --text-muted: #707880;
    
    --border-color: #e2ded8;
    --border-strong: #c8c2b9;
    
    --brand-primary: #2d5be3;
    --brand-primary-hover: #1e44b8;
    --brand-accent: #027a73;
    
    --focus-ring: #2d5be3;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.07), 0 1px 3px rgba(0,0,0,0.04);
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-full: 9999px;

    --transition: 0.18s ease-in-out;
}

@media (prefers-color-scheme: dark) {
    :root {
        /* Dark Theme Palette (Deep Graphite & Soft Muted Slate) */
        --bg-page: #121417;
        --bg-surface: #1c2026;
        --bg-surface-subtle: #252a32;
        --bg-surface-elevated: #21262e;
        
        --text-primary: #f0f2f5;
        --text-secondary: #a0a8b4;
        --text-muted: #788290;
        
        --border-color: #2e3440;
        --border-strong: #404856;
        
        --brand-primary: #4f7df9;
        --brand-primary-hover: #7096fb;
        --brand-accent: #14b8a6;
        
        --focus-ring: #4f7df9;
        --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
        --shadow-md: 0 4px 14px rgba(0,0,0,0.5);
    }
}

/* Reset & Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-page);
    -webkit-font-smoothing: antialiased;
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
h1, h2, h3, h4 {
    color: var(--text-primary);
    font-weight: 700;
    line-height: 1.25;
}

h1 { font-size: clamp(1.8rem, 4vw, 2.75rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.4rem, 3vw, 1.85rem); letter-spacing: -0.01em; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.05rem; }

p {
    margin-bottom: 1rem;
}
p:last-child {
    margin-bottom: 0;
}

a {
    color: var(--brand-primary);
    text-decoration: underline;
    text-underline-offset: 3px;
    transition: color var(--transition);
}
a:hover {
    color: var(--brand-primary-hover);
}

/* Accessibility Focus States */
:focus-visible {
    outline: 3px solid var(--focus-ring);
    outline-offset: 2px;
}

.skip-link {
    position: absolute;
    top: -100px;
    left: 20px;
    background: var(--brand-primary);
    color: #ffffff;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    z-index: 1000;
    text-decoration: none;
    font-weight: 600;
}
.skip-link:focus {
    top: 20px;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}

/* Layout Container */
.container {
    width: 100%;
    max-width: 860px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Site Header & Header Nav */
.site-header {
    padding: 16px 0;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-surface);
}
.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}
.site-brand {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-primary);
    letter-spacing: -0.01em;
    text-decoration: none;
}
.site-brand:hover {
    color: var(--brand-primary);
}
.site-nav {
    display: flex;
    gap: 16px;
}
.site-nav a {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-decoration: none;
}
.site-nav a:hover {
    color: var(--brand-primary);
}

/* Breadcrumbs Navigation */
.breadcrumbs {
    background-color: var(--bg-surface-subtle);
    padding: 10px 0;
    font-size: 0.88rem;
    border-bottom: 1px solid var(--border-color);
}
.breadcrumb-item {
    color: var(--text-secondary);
    text-decoration: none;
}
.breadcrumb-item:hover {
    text-decoration: underline;
}
.breadcrumb-item.active {
    color: var(--text-muted);
    font-weight: 500;
}
.breadcrumb-divider {
    color: var(--text-muted);
}

/* Hero Section */
.hero-section {
    padding: 40px 0 32px;
    text-align: center;
    background: linear-gradient(180deg, var(--bg-surface) 0%, var(--bg-page) 100%);
    border-bottom: 1px solid var(--border-color);
}
.hero-section h1 {
    max-width: 720px;
    margin: 0 auto 14px;
}
.hero-subline {
    font-size: clamp(1.05rem, 2vw, 1.2rem);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Section Layout */
.section {
    padding: 40px 0;
    border-bottom: 1px solid var(--border-color);
}
.section-header {
    margin-bottom: 28px;
}
.section-intro {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-top: 6px;
}

/* Selector Group & Pills */
.controls-wrapper {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin-bottom: 32px;
    background: var(--bg-surface);
    padding: 24px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.selector-group {
    border: none;
}
.selector-label {
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 10px;
    display: block;
}

.pills-container {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.pill-btn {
    appearance: none;
    background-color: var(--bg-surface-subtle);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    border-radius: var(--radius-full);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
}
.pill-btn:hover {
    border-color: var(--border-strong);
    background-color: var(--border-color);
}
.pill-btn.active {
    background-color: var(--brand-primary);
    color: #ffffff;
    border-color: var(--brand-primary);
    font-weight: 600;
}

/* Exercise Cards */
.exercise-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.exercise-card[hidden] {
    display: none !important;
}

.exercise-tag {
    display: inline-block;
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--brand-accent);
    margin-bottom: 6px;
}

.exercise-title {
    font-size: clamp(1.3rem, 2.5vw, 1.6rem);
}
.exercise-title a {
    color: var(--text-primary);
    text-decoration: none;
}
.exercise-title a:hover {
    color: var(--brand-primary);
}

.exercise-intro-text {
    font-size: 1.05rem;
    color: var(--text-secondary);
    font-style: italic;
    border-left: 3px solid var(--brand-accent);
    padding-left: 14px;
}

.exercise-steps-wrapper h4,
.exercise-steps-wrapper h2 {
    margin-bottom: 12px;
    color: var(--text-primary);
    font-size: 1.1rem;
}

.exercise-steps-list {
    padding-left: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.exercise-steps-list li {
    font-size: 1.05rem;
    color: var(--text-primary);
}

.exercise-closing-text {
    margin-top: 8px;
    padding: 12px 16px;
    background-color: var(--bg-surface-subtle);
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.exercise-card-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
    margin-top: 10px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}
.btn-link {
    font-size: 0.9rem;
    color: var(--brand-primary);
    text-decoration: none;
    margin-left: auto;
}
.btn-link:hover {
    text-decoration: underline;
}

/* Standalone Single Exercise & Question Cards */
.standalone-card,
.question-single-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow-md);

    margin-bottom: 32px;
}
.question-single-card h1 {
    font-size: clamp(1.5rem, 3vw, 2.2rem);
    margin-bottom: 20px;
}
.question-answer-body {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--text-primary);
}

/* Grids for Index Pages */
.medium-groups-grid,
.exercises-grid,
.questions-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.medium-group-card,
.exercise-summary-card,
.question-summary-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 24px;
    box-shadow: var(--shadow-sm);
}
.medium-group-card h3,
.exercise-summary-card h3,
.question-summary-card h3 {
    margin-bottom: 8px;
}
.medium-group-card h3 a,
.exercise-summary-card h3 a,
.question-summary-card h3 a {
    color: var(--text-primary);
    text-decoration: none;
}
.medium-group-card h3 a:hover,
.exercise-summary-card h3 a:hover,
.question-summary-card h3 a:hover {
    color: var(--brand-primary);
}

.medium-desc {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.exercise-links-list {
    padding-left: 20px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

/* Related Blocks Grid */
.related-blocks-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    margin-top: 32px;
}
@media (min-width: 600px) {
    .related-blocks-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.related-block {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 20px;
}
.related-block h3 {
    font-size: 1.05rem;
    margin-bottom: 12px;
    color: var(--text-secondary);
}
.related-block ul {
    padding-left: 18px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 0.95rem;
}

/* About Page Article */
.about-article {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 36px;
    box-shadow: var(--shadow-sm);
}
.about-article h2 {
    margin-top: 24px;
    margin-bottom: 12px;
}
.about-article h2:first-child {
    margin-top: 0;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition);
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--brand-primary);
    color: #ffffff;
}
.btn-primary:hover {
    background-color: var(--brand-primary-hover);
    color: #ffffff;
}

.btn-secondary {
    background-color: var(--bg-surface-subtle);
    color: var(--text-primary);
    border-color: var(--border-color);
}
.btn-secondary:hover {
    background-color: var(--border-color);
    border-color: var(--border-strong);
}

.btn-outline {
    background-color: transparent;
    color: var(--text-primary);
    border-color: var(--border-strong);
}
.btn-outline:hover {
    background-color: var(--bg-surface-subtle);
}

.btn-lg {
    padding: 14px 24px;
    font-size: 1.05rem;
}

/* Search Box */
.search-box-wrapper {
    margin-bottom: 24px;
}
.search-input-container {
    position: relative;
    display: flex;
    align-items: center;
}
.search-icon {
    position: absolute;
    left: 14px;
    color: var(--text-muted);
    pointer-events: none;
}
.search-input {
    width: 100%;
    padding: 14px 16px 14px 44px;
    font-size: 1rem;
    font-family: inherit;
    color: var(--text-primary);
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: border-color var(--transition);
}
.search-input:focus {
    border-color: var(--brand-primary);
}

.search-status-text {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 8px;
}

/* Topics Accordion */
.topics-accordion {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.topic-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color var(--transition);
}
.topic-card:hover {
    border-color: var(--border-strong);
}

.topic-summary {
    padding: 18px 20px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.topic-summary::-webkit-details-marker {
    display: none;
}
.topic-summary::after {
    content: "+";
    font-size: 1.4rem;
    font-weight: 400;
    color: var(--text-muted);
    transition: transform var(--transition);
}
.topic-card[open] .topic-summary::after {
    content: "−";
}

.topic-content {
    padding: 0 20px 20px;
    border-top: 1px solid var(--bg-surface-subtle);
    color: var(--text-primary);
    font-size: 1.02rem;
}
.topic-content p {
    margin-top: 14px;
}

.topic-link-row {
    margin-top: 12px;
    font-size: 0.9rem;
}

.book-pointer {
    margin-top: 14px;
    padding: 10px 14px;
    background-color: var(--bg-surface-subtle);
    border-left: 3px solid var(--brand-primary);
    font-size: 0.95rem;
    color: var(--text-secondary);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* Book Section & Card */
.book-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 36px;
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    gap: 24px;
}
@media (min-width: 640px) {
    .book-card {
        flex-direction: row;
        align-items: center;
    }
}

.book-cover-container img {
    max-width: 160px;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
}

.book-content {
    flex: 1;
}

.book-badge {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--brand-primary);
    background-color: var(--bg-surface-subtle);
    padding: 4px 10px;
    border-radius: var(--radius-full);
    margin-bottom: 12px;
}

.book-title {
    font-size: 1.6rem;
    margin-bottom: 4px;
}

.book-author {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-bottom: 16px;
}

.book-blurb {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.book-actions {
    display: flex;
}

/* Site Footer */
.site-footer {
    margin-top: auto;
    padding: 40px 0;
    background-color: var(--bg-surface);
    border-top: 1px solid var(--border-color);
    font-size: 0.95rem;
    color: var(--text-secondary);
}
.footer-content {
    display: flex;
    flex-direction: column;
    gap: 10px;
    text-align: center;
}
.footer-meta {
    font-size: 0.85rem;
    color: var(--text-muted);
}
.footer-disclaimer {
    font-size: 0.88rem;
    color: var(--text-muted);
}
.footer-contact {
    font-size: 0.9rem;
}
.footer-nav {
    margin-top: 6px;
    font-size: 0.9rem;
}