/* ============================================
   Cosmic Documentary Theme
   2025 Shoemaker Lecture - AGU Conference
   ============================================ */

/* CSS Custom Properties - Color Palette */
:root {
    --space-black: #0D0D0D;
    --deep-rust: #6B2D1A;
    --mars-rust: #B54B2A;
    --orange-accent: #E86A33;
    --cream-white: #F5F5F0;
    --gold-emphasis: #D4A537;

    /* Derived colors */
    --space-black-transparent: rgba(13, 13, 13, 0.95);
    --mars-glow: rgba(181, 75, 42, 0.3);
    --gold-glow: rgba(212, 165, 55, 0.2);

    /* Typography */
    --font-display: 'Playfair Display', Georgia, serif;
    --font-body: 'Source Sans Pro', -apple-system, BlinkMacSystemFont, sans-serif;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 4rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-medium: 300ms ease;
    --transition-slow: 600ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Z-index layers */
    --z-slides: 1;
    --z-nav: 100;
    --z-progress: 200;
    --z-notes: 300;
    --z-overview: 400;
    --z-modal: 500;
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    background: var(--space-black);
    color: var(--cream-white);
    overflow: hidden;
    height: 100vh;
    width: 100vw;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 600;
    line-height: 1.2;
}

/* ============================================
   Progress Bar
   ============================================ */
.progress-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    z-index: var(--z-progress);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--mars-rust), var(--orange-accent), var(--gold-emphasis));
    width: 3.33%;
    transition: width var(--transition-medium);
    box-shadow: 0 0 10px var(--mars-glow);
}

.progress-text {
    position: fixed;
    top: 12px;
    right: var(--spacing-lg);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--cream-white);
    opacity: 0.7;
    z-index: var(--z-progress);
    font-variant-numeric: tabular-nums;
    transition: opacity var(--transition-fast);
}

body:hover .progress-text {
    opacity: 1;
}

/* ============================================
   Navigation Controls
   ============================================ */
.nav-controls {
    position: fixed;
    bottom: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    z-index: var(--z-nav);
    opacity: 0;
    transition: opacity var(--transition-medium);
}

body:hover .nav-controls,
.nav-controls:focus-within {
    opacity: 1;
}

.nav-btn {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.2);
    background: var(--space-black-transparent);
    color: var(--cream-white);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    backdrop-filter: blur(10px);
}

.nav-btn:hover {
    border-color: var(--mars-rust);
    background: var(--deep-rust);
    transform: scale(1.1);
}

.nav-btn:active {
    transform: scale(0.95);
}

.nav-btn svg {
    width: 24px;
    height: 24px;
}

.nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.nav-btn:disabled:hover {
    transform: none;
    background: var(--space-black-transparent);
    border-color: rgba(255, 255, 255, 0.2);
}

.nav-utility {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0 var(--spacing-sm);
    background: rgba(13, 13, 13, 0.65);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 999px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.35);
    backdrop-filter: blur(10px);
}

.home-btn {
    width: 44px;
    height: 44px;
}

.slide-select {
    appearance: none;
    background: rgba(255,255,255,0.06);
    color: var(--cream-white);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 999px;
    padding: 0.65rem 2.4rem 0.65rem 1rem;
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    min-width: 220px;
    cursor: pointer;
    transition: all var(--transition-fast);
    background-image: linear-gradient(45deg, transparent 50%, var(--gold-emphasis) 50%),
                      linear-gradient(135deg, var(--gold-emphasis) 50%, transparent 50%);
    background-position: calc(100% - 18px) calc(50% - 3px), calc(100% - 12px) calc(50% - 3px);
    background-size: 6px 6px, 6px 6px;
    background-repeat: no-repeat;
}

.slide-select:hover,
.slide-select:focus {
    border-color: var(--gold-emphasis);
    box-shadow: 0 0 0 3px rgba(212, 165, 55, 0.2);
    outline: none;
}

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

/* Help Button */
.help-btn {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.2);
    background: var(--space-black-transparent);
    color: var(--cream-white);
    font-size: 1.25rem;
    font-weight: 600;
    cursor: pointer;
    z-index: var(--z-nav);
    opacity: 0;
    transition: all var(--transition-medium);
    backdrop-filter: blur(10px);
}

body:hover .help-btn {
    opacity: 0.7;
}

.help-btn:hover {
    opacity: 1;
    border-color: var(--gold-emphasis);
    color: var(--gold-emphasis);
    transform: scale(1.1);
}

/* ============================================
   Presentation Container & Slides
   ============================================ */
.presentation {
    position: relative;
    width: 100vw;
    height: 100vh;
    z-index: var(--z-slides);
}

.slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-slow), visibility var(--transition-slow), transform var(--transition-slow);
    transform: scale(0.98);
}

.slide.active {
    opacity: 1;
    visibility: visible;
    transform: scale(1);
}

.slide.prev {
    transform: translateX(-5%) scale(0.95);
}

.slide.next {
    transform: translateX(5%) scale(0.95);
}

.slide-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
}

.slide-background img {
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
    object-fit: contain;
    border-radius: 4px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5), 0 0 100px var(--mars-glow);
}

/* Hidden notes data element */
.slide-notes {
    display: none;
}

/* ============================================
   Slide Content Overlay
   ============================================ */
.slide-content {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    padding: var(--spacing-xl) 5%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    z-index: 10;
    background: linear-gradient(
        90deg,
        rgba(13, 13, 13, 0.92) 0%,
        rgba(13, 13, 13, 0.85) 35%,
        rgba(13, 13, 13, 0.4) 60%,
        transparent 80%
    );
    max-width: 55%;
}

/* Keep text off in-image labels on graphic-heavy slides */
.slide[data-slide="2"] .slide-content,
.slide[data-slide="4"] .slide-content,
.slide[data-slide="7"] .slide-content,
.slide[data-slide="8"] .slide-content,
.slide[data-slide="5"] .slide-content,
.slide[data-slide="9"] .slide-content,
.slide[data-slide="10"] .slide-content,
.slide[data-slide="12"] .slide-content,
.slide[data-slide="13"] .slide-content,
.slide[data-slide="14"] .slide-content,
.slide[data-slide="17"] .slide-content,
.slide[data-slide="23"] .slide-content,
.slide[data-slide="26"] .slide-content,
.slide[data-slide="15"] .slide-content,
.slide[data-slide="18"] .slide-content,
.slide[data-slide="19"] .slide-content,
.slide[data-slide="20"] .slide-content,
.slide[data-slide="21"] .slide-content,
.slide[data-slide="22"] .slide-content,
.slide[data-slide="24"] .slide-content,
.slide[data-slide="25"] .slide-content,
.slide[data-slide="27"] .slide-content,
.slide[data-slide="28"] .slide-content,
.slide[data-slide="29"] .slide-content,
.slide[data-slide="30"] .slide-content,
.slide[data-slide="6"] .slide-content {
    height: auto;
    justify-content: flex-start;
    align-items: flex-start;
    padding-top: calc(var(--spacing-xl) * 0.75);
    padding-bottom: var(--spacing-xl);
    max-width: 48%;
    background: linear-gradient(
        105deg,
        rgba(13, 13, 13, 0.9) 0%,
        rgba(13, 13, 13, 0.82) 32%,
        rgba(13, 13, 13, 0.35) 55%,
        transparent 72%
    );
}

/* Title Slide */
.title-slide {
    max-width: 60%;
    justify-content: center;
    padding-left: 8%;
}

.main-title {
    font-size: clamp(2rem, 5vw, 4rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-lg);
    color: var(--cream-white);
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.8);
}

.title-accent {
    color: var(--gold-emphasis);
}

.title-meta {
    margin-top: var(--spacing-lg);
}

.title-meta .presenter {
    font-size: clamp(1.25rem, 2vw, 1.75rem);
    font-weight: 600;
    color: var(--cream-white);
    margin-bottom: var(--spacing-xs);
}

.title-meta .affiliation {
    font-size: clamp(1rem, 1.5vw, 1.25rem);
    color: var(--mars-rust);
    margin-bottom: var(--spacing-lg);
}

.event-badge {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: var(--spacing-md);
    background: rgba(181, 75, 42, 0.15);
    border-left: 3px solid var(--mars-rust);
    border-radius: 0 8px 8px 0;
}

.event-badge .event-name {
    font-size: 1rem;
    font-weight: 600;
    color: var(--gold-emphasis);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.event-badge .event-org,
.event-badge .event-date {
    font-size: 0.9rem;
    color: rgba(245, 245, 240, 0.8);
}

/* Slide Titles */
.slide-title {
    font-size: clamp(1.5rem, 3.5vw, 2.5rem);
    font-weight: 700;
    color: var(--cream-white);
    margin-bottom: var(--spacing-lg);
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.8);
    line-height: 1.2;
}

.slide-title .subtitle {
    display: block;
    font-size: 0.6em;
    font-weight: 400;
    color: var(--gold-emphasis);
    margin-top: var(--spacing-sm);
}

/* Content Lists */
.content-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.content-list li {
    font-size: clamp(0.9rem, 1.5vw, 1.15rem);
    line-height: 1.5;
    color: rgba(245, 245, 240, 0.95);
    padding-left: 1.5rem;
    position: relative;
}

.content-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.6em;
    width: 8px;
    height: 8px;
    background: var(--mars-rust);
    border-radius: 50%;
}

.content-list li.list-header {
    padding-left: 0;
    margin-top: var(--spacing-sm);
    color: var(--cream-white);
    font-weight: 600;
}

.content-list li.list-header::before {
    display: none;
}

.content-list li.sub-item {
    padding-left: 2.5rem;
    font-size: clamp(0.85rem, 1.3vw, 1rem);
    color: rgba(245, 245, 240, 0.85);
}

.content-list li.sub-item::before {
    left: 1.25rem;
    width: 6px;
    height: 6px;
    background: var(--orange-accent);
}

.content-list.compact li {
    font-size: clamp(0.8rem, 1.2vw, 0.95rem);
    gap: var(--spacing-xs);
}

/* Timeline Lists */
.timeline-list li {
    padding-left: 0;
}

.timeline-list li::before {
    display: none;
}

.timeline-list .year {
    display: inline-block;
    min-width: 60px;
    font-weight: 700;
    color: var(--gold-emphasis);
    margin-right: var(--spacing-sm);
}

/* Two Column Layout */
.two-column {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-md);
}

.two-column .column h3 {
    font-size: clamp(0.9rem, 1.3vw, 1.1rem);
    color: var(--gold-emphasis);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.9);
}

/* Three Column Layout */
.three-column {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.three-column .column h3 {
    font-size: clamp(0.85rem, 1.2vw, 1rem);
    color: var(--gold-emphasis);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.9);
}

/* Conclusion/Highlight Text */
.conclusion {
    font-size: clamp(1rem, 1.5vw, 1.2rem);
    font-weight: 600;
    color: var(--gold-emphasis);
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background: rgba(212, 165, 55, 0.1);
    border-left: 3px solid var(--gold-emphasis);
    border-radius: 0 8px 8px 0;
    text-shadow: 0 1px 6px rgba(0, 0, 0, 0.7);
}

/* Quotes */
.slide-quote {
    font-family: var(--font-display);
    font-size: clamp(1rem, 1.5vw, 1.25rem);
    font-style: italic;
    color: rgba(245, 245, 240, 0.9);
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md) var(--spacing-lg);
    border-left: 3px solid var(--mars-rust);
    background: rgba(181, 75, 42, 0.1);
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.7);
}

/* Closing Slide */
.closing-slide .closing-quote {
    font-family: var(--font-display);
    font-size: clamp(1.1rem, 1.8vw, 1.5rem);
    font-style: italic;
    color: var(--cream-white);
    margin-top: var(--spacing-xl);
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, rgba(181, 75, 42, 0.2), rgba(212, 165, 55, 0.1));
    border-radius: 8px;
    text-align: center;
}

.closing-quote cite {
    display: block;
    font-size: 0.75em;
    font-style: normal;
    color: var(--gold-emphasis);
    margin-top: var(--spacing-sm);
}

/* Layer Markers (for climate history slide) */
.layer-marker {
    display: inline-block;
    width: 12px;
    height: 12px;
    border-radius: 2px;
    margin-right: var(--spacing-sm);
    vertical-align: middle;
}

.layer-marker.wet {
    background: #4a90d9;
}

.layer-marker.trans {
    background: #d4a537;
}

.layer-marker.dry {
    background: #b54b2a;
}

/* Bold/Strong text */
.content-list strong {
    color: var(--cream-white);
    font-weight: 600;
}

.content-list em {
    color: var(--gold-emphasis);
    font-style: normal;
}

/* DESIGN REVIEW FIX: Add text shadows to body content for better legibility */
.content-list li {
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.8);
}

.content-list li.sub-item {
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.75);
}

/* ============================================
   Speaker Notes Panel
   ============================================ */
.notes-panel {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    max-height: 35vh;
    background: var(--space-black-transparent);
    backdrop-filter: blur(20px);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    z-index: var(--z-notes);
    transform: translateY(100%);
    transition: transform var(--transition-medium);
    display: flex;
    flex-direction: column;
}

.notes-panel.visible {
    transform: translateY(0);
}

.notes-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    flex-shrink: 0;
}

.notes-header h3 {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--gold-emphasis);
}

.notes-close {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: none;
    background: rgba(255, 255, 255, 0.1);
    color: var(--cream-white);
    font-size: 1.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.notes-close:hover {
    background: var(--mars-rust);
}

.notes-content {
    padding: var(--spacing-lg);
    overflow-y: auto;
    flex: 1;
}

.notes-content p {
    font-size: 1.125rem;
    line-height: 1.8;
    max-width: 80ch;
    margin: 0 auto;
}

/* ============================================
   Slide Overview Grid
   ============================================ */
.overview-grid {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--space-black-transparent);
    backdrop-filter: blur(20px);
    z-index: var(--z-overview);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-medium);
    display: flex;
    flex-direction: column;
    padding: var(--spacing-lg);
}

.overview-grid.visible {
    opacity: 1;
    visibility: visible;
}

.overview-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    flex-shrink: 0;
}

.overview-header h2 {
    font-size: 1.5rem;
    color: var(--cream-white);
}

.overview-close {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    background: rgba(255, 255, 255, 0.1);
    color: var(--cream-white);
    font-size: 1.75rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.overview-close:hover {
    background: var(--mars-rust);
}

.overview-slides {
    flex: 1;
    overflow-y: auto;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
    padding-top: var(--spacing-lg);
    align-content: start;
}

.overview-slide {
    aspect-ratio: 16 / 9;
    background: var(--space-black);
    border-radius: 8px;
    overflow: hidden;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 2px solid transparent;
    position: relative;
}

.overview-slide:hover {
    transform: scale(1.05);
    border-color: var(--mars-rust);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.overview-slide.current {
    border-color: var(--gold-emphasis);
    box-shadow: 0 0 20px var(--gold-glow);
}

.overview-slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.overview-slide-number {
    position: absolute;
    bottom: 8px;
    left: 8px;
    background: var(--space-black-transparent);
    color: var(--cream-white);
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
}

/* ============================================
   Help Modal
   ============================================ */
.help-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(10px);
    z-index: var(--z-modal);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-medium);
    padding: var(--spacing-lg);
}

.help-modal.visible {
    opacity: 1;
    visibility: visible;
}

.help-content {
    background: linear-gradient(180deg, #1a1a1a 0%, var(--space-black) 100%);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    padding: var(--spacing-xl);
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
}

.help-content h2 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-lg);
    color: var(--gold-emphasis);
}

.help-content h3 {
    font-size: 1.125rem;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    color: var(--mars-rust);
}

.shortcuts-grid {
    display: grid;
    gap: var(--spacing-md);
}

.shortcut {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.shortcut kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 32px;
    height: 32px;
    padding: 0 8px;
    background: linear-gradient(180deg, #2a2a2a 0%, #1a1a1a 100%);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--cream-white);
    box-shadow: 0 2px 0 rgba(0, 0, 0, 0.5);
}

.shortcut span {
    margin-left: auto;
    color: rgba(255, 255, 255, 0.7);
}

.help-content p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.help-close {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    margin-top: var(--spacing-lg);
    background: linear-gradient(135deg, var(--mars-rust), var(--orange-accent));
    border: none;
    border-radius: 8px;
    color: var(--cream-white);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.help-close:hover {
    transform: scale(1.02);
    box-shadow: 0 10px 30px rgba(181, 75, 42, 0.3);
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(100%);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

/* Loading animation for images */
.slide-background img {
    animation: fadeIn 0.6s ease-out;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
    .overview-slides {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }

    .notes-content p {
        font-size: 1rem;
    }

    .slide-content {
        max-width: 65%;
    }

    .two-column {
        gap: var(--spacing-md);
    }

    .three-column {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
}

@media (max-width: 768px) {
    :root {
        --spacing-lg: 1rem;
        --spacing-xl: 2rem;
    }

    .nav-controls {
        opacity: 1;
        bottom: var(--spacing-md);
    }

    /* DESIGN REVIEW FIX: Increase button size for better touch targets */
    .nav-btn {
        width: 48px;
        height: 48px;
    }

    .help-btn {
        opacity: 0.7;
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }

    /* DESIGN REVIEW FIX: Keep progress text visible on mobile, just smaller */
    .progress-text {
        font-size: 0.75rem;
        right: var(--spacing-md);
        top: 8px;
    }

    .notes-panel {
        max-height: 45vh;
    }

    .notes-content p {
        font-size: 0.9375rem;
        line-height: 1.7;
    }

    .overview-slides {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
        gap: var(--spacing-sm);
    }

    .help-content {
        padding: var(--spacing-lg);
    }

    .shortcuts-grid {
        gap: var(--spacing-sm);
    }

    .shortcut {
        font-size: 0.875rem;
    }

    .shortcut kbd {
        min-width: 28px;
        height: 28px;
        font-size: 0.75rem;
    }

    /* DESIGN REVIEW FIX: Adjust mobile gradient to show more background image */
    .slide-content {
        max-width: 100%;
        background: linear-gradient(
            180deg,
            rgba(13, 13, 13, 0.88) 0%,
            rgba(13, 13, 13, 0.75) 50%,
            rgba(13, 13, 13, 0.65) 100%
        );
        padding: var(--spacing-lg) var(--spacing-md);
        padding-bottom: 80px;
    }

    /* Enhance text shadows for legibility with lighter gradient */
    .slide-title {
        text-shadow:
            0 2px 10px rgba(0, 0, 0, 0.9),
            0 4px 20px rgba(0, 0, 0, 0.8);
    }

    .content-list li {
        text-shadow: 0 1px 8px rgba(0, 0, 0, 0.9);
    }

    .title-slide {
        max-width: 100%;
        padding-left: var(--spacing-md);
    }

    /* DESIGN REVIEW FIX: Preserve two-column layout on larger tablets */
    .two-column {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-md);
    }
}

@media (max-width: 599px) {
    .two-column {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .content-list li {
        padding-left: 1.25rem;
    }

    .content-list li.sub-item {
        padding-left: 2rem;
    }
}

@media (max-width: 480px) {
    .slide-background {
        padding: var(--spacing-sm);
    }

    .overview-slides {
        grid-template-columns: repeat(2, 1fr);
    }

    .help-content h2 {
        font-size: 1.25rem;
    }
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
    .progress-container,
    .nav-controls,
    .help-btn,
    .notes-panel,
    .overview-grid,
    .help-modal {
        display: none !important;
    }

    .slide {
        page-break-after: always;
        position: relative;
        opacity: 1;
        visibility: visible;
        height: auto;
        min-height: 100vh;
    }

    .slide-background img {
        max-height: 90vh;
        box-shadow: none;
    }
}

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

/* DESIGN REVIEW FIX: Enhanced focus indicators for better accessibility */
:focus-visible {
    outline: 3px solid var(--gold-emphasis);
    outline-offset: 3px;
}

button:focus:not(:focus-visible) {
    outline: none;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --space-black: #000000;
        --cream-white: #ffffff;
    }

    .nav-btn,
    .help-btn {
        border-width: 3px;
    }
}

/* ============================================
   Dark/Light mode (default is dark)
   ============================================ */
@media (prefers-color-scheme: light) {
    /* Keep dark theme for presentation consistency */
}

/* ============================================
   Touch device optimizations
   ============================================ */
@media (hover: none) and (pointer: coarse) {
    .nav-controls {
        opacity: 1;
    }

    .help-btn {
        opacity: 0.8;
    }

    .nav-btn:hover {
        transform: none;
    }

    .nav-btn:active {
        transform: scale(0.95);
        background: var(--deep-rust);
    }
}