/* ============================================================
   Chemical Functional Groups Encyclopedia — Stylesheet
   Version: 2.0.0 — Bilingual (EN/AR) with RTL Support
   ============================================================ */

/* ---------- CSS Custom Properties (Dark Theme Default) ---------- */
:root {
    --cfg-font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --cfg-font-ar: 'Noto Sans Arabic', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --cfg-transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --cfg-radius: 12px;
    --cfg-radius-sm: 8px;
    --cfg-radius-xs: 6px;
}

.cfg-theme-dark {
    --cfg-bg: #0a0e1a;
    --cfg-bg-secondary: #111827;
    --cfg-bg-card: #1a1f35;
    --cfg-bg-card-hover: #222845;
    --cfg-bg-controls: #111827;
    --cfg-bg-panel: #111827;
    --cfg-bg-tooltip: #1e2340;
    --cfg-bg-input: #1a1f35;
    --cfg-border: #2a3050;
    --cfg-border-light: #1e2540;
    --cfg-text: #f1f5f9;
    --cfg-text-secondary: #94a3b8;
    --cfg-text-muted: #64748b;
    --cfg-accent: #06b6d4;
    --cfg-accent-glow: rgba(6, 182, 212, 0.15);
    --cfg-accent-glow-strong: rgba(6, 182, 212, 0.3);
    --cfg-shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
    --cfg-shadow-card: 0 2px 12px rgba(0, 0, 0, 0.3);
    --cfg-shadow-hover: 0 8px 32px rgba(0, 0, 0, 0.5);
    --cfg-glass-bg: rgba(17, 24, 39, 0.92);
    --cfg-glass-border: rgba(255, 255, 255, 0.08);
    --cfg-tag-bg: rgba(255, 255, 255, 0.06);
    --cfg-tag-text: #94a3b8;
    --cfg-scrollbar-track: #111827;
    --cfg-scrollbar-thumb: #2a3050;
    --cfg-filter-btn-bg: rgba(255, 255, 255, 0.05);
    --cfg-filter-btn-hover: rgba(255, 255, 255, 0.1);
    --cfg-filter-btn-active-bg: var(--cfg-accent);
    --cfg-filter-btn-active-text: #0a0e1a;
}

.cfg-theme-light {
    --cfg-bg: #f0f4f8;
    --cfg-bg-secondary: #ffffff;
    --cfg-bg-card: #ffffff;
    --cfg-bg-card-hover: #f8fafc;
    --cfg-bg-controls: #ffffff;
    --cfg-bg-panel: #ffffff;
    --cfg-bg-tooltip: #ffffff;
    --cfg-bg-input: #f1f5f9;
    --cfg-border: #e2e8f0;
    --cfg-border-light: #f1f5f9;
    --cfg-text: #0f172a;
    --cfg-text-secondary: #475569;
    --cfg-text-muted: #94a3b8;
    --cfg-accent: #0891b2;
    --cfg-accent-glow: rgba(8, 145, 178, 0.1);
    --cfg-accent-glow-strong: rgba(8, 145, 178, 0.2);
    --cfg-shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
    --cfg-shadow-card: 0 1px 4px rgba(0, 0, 0, 0.06);
    --cfg-shadow-hover: 0 8px 32px rgba(0, 0, 0, 0.12);
    --cfg-glass-bg: rgba(255, 255, 255, 0.95);
    --cfg-glass-border: rgba(0, 0, 0, 0.06);
    --cfg-tag-bg: #f1f5f9;
    --cfg-tag-text: #475569;
    --cfg-scrollbar-track: #f1f5f9;
    --cfg-scrollbar-thumb: #cbd5e1;
    --cfg-filter-btn-bg: #f1f5f9;
    --cfg-filter-btn-hover: #e2e8f0;
    --cfg-filter-btn-active-bg: var(--cfg-accent);
    --cfg-filter-btn-active-text: #ffffff;
}

/* ---------- Base Reset ---------- */
.cfg-encyclopedia {
    font-family: var(--cfg-font);
    background: var(--cfg-bg);
    color: var(--cfg-text);
    line-height: 1.6;
    padding: 32px 24px 48px;
    min-height: 100vh;
    box-sizing: border-box;
    position: relative;
    overflow-x: hidden;
    transition: background var(--cfg-transition), color var(--cfg-transition);
}

.cfg-encyclopedia *,
.cfg-encyclopedia *::before,
.cfg-encyclopedia *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* ---------- Controls Bottom Row ---------- */
.cfg-controls-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 14px;
}

.cfg-theme-toggle {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 1px solid var(--cfg-border);
    background: var(--cfg-bg-card);
    color: var(--cfg-text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--cfg-transition);
    flex-shrink: 0;
}

.cfg-theme-toggle:hover {
    background: var(--cfg-accent-glow);
    border-color: var(--cfg-accent);
    color: var(--cfg-accent);
}

.cfg-theme-dark .cfg-icon-sun { display: block; }
.cfg-theme-dark .cfg-icon-moon { display: none; }
.cfg-theme-light .cfg-icon-sun { display: none; }
.cfg-theme-light .cfg-icon-moon { display: block; }

/* ---------- Toggle Buttons Container ---------- */
.cfg-toggle-buttons {
    display: flex;
    align-items: center;
    gap: 8px;
}

/* ---------- Language Toggle ---------- */
.cfg-lang-toggle {
    height: 36px;
    padding: 0 14px;
    border-radius: 18px;
    border: 1px solid var(--cfg-border);
    background: var(--cfg-bg-card);
    color: var(--cfg-text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--cfg-transition);
    font-family: var(--cfg-font);
    font-size: 13px;
    font-weight: 600;
    white-space: nowrap;
    flex-shrink: 0;
}

.cfg-lang-toggle:hover {
    background: var(--cfg-accent-glow);
    border-color: var(--cfg-accent);
    color: var(--cfg-accent);
}

.cfg-lang-label-en,
.cfg-lang-label-ar {
    line-height: 1;
}

/* ---------- RTL / Arabic Support ---------- */
.cfg-lang-ar {
    direction: rtl;
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-search {
    padding: 12px 44px 12px 40px;
    font-family: var(--cfg-font-ar);
    text-align: right;
}

.cfg-lang-ar .cfg-search-icon {
    left: auto;
    right: 14px;
}

.cfg-lang-ar .cfg-search-clear {
    right: auto;
    left: 10px;
}

.cfg-lang-ar .cfg-filter-label {
    text-transform: none;
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-filter-btn {
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-card-name {
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-card-number {
    left: auto;
    right: 12px;
}

.cfg-lang-ar .cfg-panel {
    right: auto;
    left: 0;
    border-left: none;
    border-right: 1px solid var(--cfg-border);
    transform: translateX(-100%);
    box-shadow: 8px 0 40px rgba(0, 0, 0, 0.3);
}

.cfg-lang-ar .cfg-panel.active {
    transform: translateX(0);
}

.cfg-lang-ar .cfg-panel-header {
    justify-content: flex-start;
}

.cfg-lang-ar .cfg-panel-body {
    font-family: var(--cfg-font-ar);
    text-align: right;
}

.cfg-lang-ar .cfg-panel-section-title {
    font-family: var(--cfg-font-ar);
    text-transform: none;
}

.cfg-lang-ar .cfg-panel-section-title::before {
    order: 1;
}

.cfg-lang-ar .cfg-panel-description {
    font-family: var(--cfg-font-ar);
    text-align: right;
    direction: rtl;
}

.cfg-lang-ar .cfg-panel-hero {
    text-align: center;
}

.cfg-lang-ar .cfg-example-card {
    flex-direction: row-reverse;
}

.cfg-lang-ar .cfg-example-info {
    text-align: right;
}

.cfg-lang-ar .cfg-example-name,
.cfg-lang-ar .cfg-example-formula {
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-results-count,
.cfg-lang-ar .cfg-results-label {
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-no-results h3,
.cfg-lang-ar .cfg-no-results p {
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-tooltip-inner {
    direction: rtl;
    text-align: right;
    font-family: var(--cfg-font-ar);
}

.cfg-lang-ar .cfg-tooltip-header {
    flex-direction: row-reverse;
}

.cfg-lang-ar .cfg-tooltip-name,
.cfg-lang-ar .cfg-tooltip-desc {
    font-family: var(--cfg-font-ar);
}

/* ---------- Controls (Search & Filters) ---------- */
.cfg-controls {
    max-width: 1400px;
    margin: 0 auto 28px;
    background: var(--cfg-bg-controls);
    border: 1px solid var(--cfg-border);
    border-radius: var(--cfg-radius);
    padding: 20px 24px;
    transition: background var(--cfg-transition), border-color var(--cfg-transition);
}

.cfg-search-wrapper {
    position: relative;
    margin-bottom: 16px;
}

.cfg-search-icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--cfg-text-muted);
    pointer-events: none;
}

.cfg-search {
    width: 100%;
    padding: 12px 40px 12px 44px;
    border: 1px solid var(--cfg-border);
    border-radius: var(--cfg-radius-sm);
    background: var(--cfg-bg-input);
    color: var(--cfg-text);
    font-family: var(--cfg-font);
    font-size: 15px;
    outline: none;
    transition: all var(--cfg-transition);
}

.cfg-search:focus {
    border-color: var(--cfg-accent);
    box-shadow: 0 0 0 3px var(--cfg-accent-glow);
}

.cfg-search::placeholder {
    color: var(--cfg-text-muted);
}

.cfg-search-clear {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--cfg-text-muted);
    font-size: 20px;
    cursor: pointer;
    padding: 4px 8px;
    line-height: 1;
    display: none;
    transition: color var(--cfg-transition);
}

.cfg-search-clear.visible {
    display: block;
}

.cfg-search-clear:hover {
    color: var(--cfg-text);
}

.cfg-filters {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.cfg-filter-group {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.cfg-filter-label {
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--cfg-text-muted);
    white-space: nowrap;
}

.cfg-filter-buttons {
    display: flex;
    gap: 4px;
    flex-wrap: wrap;
}

.cfg-filter-btn {
    padding: 5px 12px;
    border: 1px solid transparent;
    border-radius: 20px;
    background: var(--cfg-filter-btn-bg);
    color: var(--cfg-text-secondary);
    font-family: var(--cfg-font);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--cfg-transition);
    white-space: nowrap;
}

.cfg-filter-btn:hover {
    background: var(--cfg-filter-btn-hover);
    color: var(--cfg-text);
}

.cfg-filter-btn.active {
    background: var(--cfg-filter-btn-active-bg);
    color: var(--cfg-filter-btn-active-text);
    font-weight: 600;
}

.cfg-results-count {
    font-size: 13px;
    color: var(--cfg-text-muted);
    margin: 0;
}

.cfg-results-count span {
    font-weight: 700;
    color: var(--cfg-accent);
}

/* ---------- Card Grid ---------- */
.cfg-grid {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
}

/* ---------- Card ---------- */
.cfg-card {
    position: relative;
    background: var(--cfg-bg-card);
    border: 1px solid var(--cfg-border);
    border-radius: var(--cfg-radius);
    padding: 16px 14px 14px;
    cursor: pointer;
    transition: all var(--cfg-transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 4px;
    overflow: hidden;
    animation: cfgCardFadeIn 0.5s ease both;
}

.cfg-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--card-accent);
    opacity: 0.7;
    transition: opacity var(--cfg-transition);
}

.cfg-card:hover {
    background: var(--cfg-bg-card-hover);
    border-color: var(--card-accent);
    box-shadow: var(--cfg-shadow-hover), 0 0 20px color-mix(in srgb, var(--card-accent) 20%, transparent);
    transform: translateY(-3px);
}

.cfg-card:hover::before {
    opacity: 1;
    height: 4px;
}

.cfg-card.cfg-card-hidden {
    display: none;
}

@keyframes cfgCardFadeIn {
    from {
        opacity: 0;
        transform: translateY(12px) scale(0.97);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.cfg-card-number {
    position: absolute;
    top: 10px;
    left: 12px;
    font-size: 11px;
    font-weight: 700;
    color: var(--cfg-text-muted);
    opacity: 0.6;
}

.cfg-card-abbr {
    font-size: 22px;
    font-weight: 800;
    color: var(--card-accent);
    line-height: 1.2;
    margin-top: 8px;
    word-break: break-word;
    letter-spacing: -0.5px;
}

.cfg-card-name {
    font-size: 13px;
    font-weight: 600;
    color: var(--cfg-text);
    margin-top: 2px;
    line-height: 1.3;
}

.cfg-card-formula {
    display: none;
    font-size: 11px;
    color: var(--cfg-text-muted);
    font-family: 'Inter', monospace;
    margin-top: 2px;
    word-break: break-all;
}

.cfg-card-tags {
    display: flex;
    gap: 4px;
    margin-top: 8px;
    flex-wrap: wrap;
    justify-content: center;
}

.cfg-tag {
    font-size: 10px;
    padding: 2px 7px;
    border-radius: 10px;
    background: var(--cfg-tag-bg);
    color: var(--cfg-tag-text);
    font-weight: 500;
    white-space: nowrap;
}

/* ---------- No Results ---------- */
.cfg-no-results {
    max-width: 1400px;
    margin: 60px auto;
    text-align: center;
    color: var(--cfg-text-muted);
}

.cfg-no-results svg {
    margin-bottom: 16px;
    opacity: 0.4;
}

.cfg-no-results h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--cfg-text-secondary);
    margin-bottom: 8px;
}

.cfg-no-results p {
    font-size: 14px;
}

/* ---------- Side Panel (Off-canvas) ---------- */
.cfg-panel-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 99998;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.35s ease, visibility 0.35s ease;
}

.cfg-panel-overlay.active {
    opacity: 1;
    visibility: visible;
}

.cfg-panel {
    position: fixed;
    top: 0;
    right: 0;
    width: 520px;
    max-width: 92vw;
    height: 100vh;
    background: var(--cfg-bg-panel);
    border-left: 1px solid var(--cfg-border);
    z-index: 99999;
    transform: translateX(100%);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    box-shadow: -8px 0 40px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

.cfg-panel.active {
    transform: translateX(0);
}

.cfg-panel-header {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding: 16px 20px;
    border-bottom: 1px solid var(--cfg-border);
    flex-shrink: 0;
}

.cfg-panel-close {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 1px solid var(--cfg-border);
    background: var(--cfg-bg-card);
    color: var(--cfg-text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--cfg-transition);
}

.cfg-panel-close:hover {
    background: #ef4444;
    border-color: #ef4444;
    color: #fff;
}

.cfg-panel-body {
    flex: 1;
    overflow-y: auto;
    padding: 28px 24px 40px;
    scrollbar-width: thin;
    scrollbar-color: var(--cfg-scrollbar-thumb) var(--cfg-scrollbar-track);
}

.cfg-panel-body::-webkit-scrollbar {
    width: 6px;
}

.cfg-panel-body::-webkit-scrollbar-track {
    background: var(--cfg-scrollbar-track);
}

.cfg-panel-body::-webkit-scrollbar-thumb {
    background: var(--cfg-scrollbar-thumb);
    border-radius: 3px;
}

/* Panel Content Styles */
.cfg-panel-hero {
    text-align: center;
    margin-bottom: 28px;
    padding: 32px 20px;
    border-radius: var(--cfg-radius);
    background: var(--cfg-accent-glow);
    border: 1px solid var(--cfg-border);
    position: relative;
    overflow: hidden;
}

.cfg-panel-hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--panel-accent, var(--cfg-accent));
}

/* SVG Structure Image in Panel */
.cfg-panel-structure {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 16px;
    padding: 12px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: var(--cfg-radius-sm);
    border: 1px solid var(--cfg-border);
    min-height: 120px;
    max-height: 180px;
    transition: var(--cfg-transition);
}

.cfg-theme-light .cfg-panel-structure {
    background: #ffffff;
    border-color: #e2e8f0;
    box-shadow: 0 1px 4px rgba(0,0,0,0.06);
}

.cfg-structure-img {
    max-width: 100%;
    max-height: 150px;
    width: auto;
    height: auto;
    object-fit: contain;
    filter: none;
}

.cfg-panel-hero-abbr {
    font-size: 64px;
    font-weight: 900;
    color: var(--panel-accent, var(--cfg-accent));
    line-height: 1;
    margin-bottom: 8px;
}

.cfg-panel-hero-name {
    font-size: 24px;
    font-weight: 700;
    color: var(--cfg-text);
    margin-bottom: 4px;
}

.cfg-panel-hero-formula {
    font-size: 16px;
    color: var(--cfg-text-secondary);
    font-family: 'Inter', monospace;
}

.cfg-panel-meta {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
    margin-top: 16px;
}

.cfg-panel-meta-tag {
    padding: 5px 14px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    background: var(--cfg-tag-bg);
    color: var(--cfg-text-secondary);
    border: 1px solid var(--cfg-border);
}

.cfg-panel-section {
    margin-bottom: 24px;
}

.cfg-panel-section-title {
    font-size: 14px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: var(--cfg-text-muted);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    border: none;
    background: none;
    padding: 0;
}

.cfg-panel-section-title::before {
    content: '';
    width: 3px;
    height: 16px;
    background: var(--panel-accent, var(--cfg-accent));
    border-radius: 2px;
}

.cfg-panel-description {
    font-size: 15px;
    line-height: 1.75;
    color: var(--cfg-text-secondary);
}

/* Glossary keyword links in description */
.cfg-glossary-link {
    color: var(--cfg-accent);
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    border-bottom: 1px dashed var(--cfg-accent);
    transition: all var(--cfg-transition);
    position: relative;
}

.cfg-glossary-link:hover {
    color: var(--cfg-text);
    border-bottom-color: var(--cfg-text);
}

/* Examples Grid */
.cfg-examples-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
}

.cfg-example-card {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 16px;
    background: var(--cfg-bg-card);
    border: 1px solid var(--cfg-border);
    border-radius: var(--cfg-radius-sm);
    transition: all var(--cfg-transition);
}

.cfg-example-card:hover {
    border-color: var(--panel-accent, var(--cfg-accent));
    background: var(--cfg-bg-card-hover);
}

.cfg-example-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--cfg-radius-xs);
    background: var(--cfg-accent-glow);
    border: 1px solid var(--cfg-border);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: var(--panel-accent, var(--cfg-accent));
    font-weight: 800;
    font-size: 14px;
}

.cfg-example-info {
    flex: 1;
    min-width: 0;
}

.cfg-example-name {
    font-size: 14px;
    font-weight: 600;
    color: var(--cfg-text);
    margin-bottom: 2px;
}

.cfg-example-formula {
    font-size: 12px;
    color: var(--cfg-text-muted);
    font-family: 'Inter', monospace;
}

/* ---------- Tooltip ---------- */
.cfg-tooltip {
    position: fixed;
    z-index: 100000;
    pointer-events: none;
    max-width: 300px;
    animation: cfgTooltipIn 0.2s ease;
}

.cfg-tooltip-inner {
    background: var(--cfg-bg-tooltip);
    border: 1px solid var(--cfg-border);
    border-radius: var(--cfg-radius-sm);
    padding: 14px 16px;
    box-shadow: var(--cfg-shadow);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.cfg-tooltip-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 8px;
}

.cfg-tooltip-abbr {
    width: 36px;
    height: 36px;
    border-radius: var(--cfg-radius-xs);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 14px;
    background: var(--cfg-accent-glow);
    flex-shrink: 0;
}

/* SVG Structure in Tooltip */
.cfg-tooltip-structure {
    width: 56px;
    height: 44px;
    border-radius: var(--cfg-radius-xs);
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.95);
    border: 1px solid var(--cfg-border);
    flex-shrink: 0;
    overflow: hidden;
    padding: 4px;
}

.cfg-theme-light .cfg-tooltip-structure {
    background: #ffffff;
    border-color: #e2e8f0;
}

.cfg-tooltip-svg {
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
    object-fit: contain;
}

.cfg-tooltip-name {
    font-size: 14px;
    font-weight: 700;
    color: var(--cfg-text);
}

.cfg-tooltip-formula {
    font-size: 11px;
    color: var(--cfg-text-muted);
}

.cfg-tooltip-desc {
    font-size: 12px;
    line-height: 1.6;
    color: var(--cfg-text-secondary);
}

@keyframes cfgTooltipIn {
    from {
        opacity: 0;
        transform: translateY(4px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---------- Download Card Button ---------- */
.cfg-panel-download-section {
    padding: 8px 0 16px;
    text-align: center;
}

.cfg-panel-download-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: 30px;
    border: 1px solid var(--cfg-accent);
    background: var(--cfg-accent-glow);
    color: var(--cfg-accent);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--cfg-transition);
    font-family: inherit;
}

.cfg-panel-download-btn:hover {
    background: var(--cfg-accent);
    color: #ffffff;
    box-shadow: 0 4px 16px rgba(13, 115, 119, 0.35);
}

.cfg-panel-download-btn:disabled {
    opacity: 0.6;
    cursor: wait;
}

.cfg-panel-download-btn svg {
    flex-shrink: 0;
}

/* ---------- Responsive ---------- */
@media (max-width: 1200px) {
    .cfg-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    }
}

@media (max-width: 900px) {
    .cfg-encyclopedia {
        padding: 20px 16px 40px;
    }

    .cfg-title {
        font-size: 22px;
    }

    .cfg-grid {
        grid-template-columns: repeat(auto-fill, minmax(145px, 1fr));
        gap: 10px;
    }

    .cfg-panel {
        width: 100%;
        max-width: 100vw;
        padding-top: 80px; /* Space for fixed header on mobile */
    }

    .cfg-panel-header {
        position: sticky;
        top: 0;
        z-index: 2;
        background: var(--cfg-bg-panel);
    }

    .cfg-filters {
        flex-direction: column;
        gap: 12px;
    }
}

@media (max-width: 600px) {
    .cfg-encyclopedia {
        padding: 16px 10px 32px;
    }

    .cfg-header {
        margin-bottom: 20px;
    }

    .cfg-header-icon {
        width: 44px;
        height: 44px;
    }

    .cfg-header-icon svg {
        width: 28px;
        height: 28px;
    }

    .cfg-title {
        font-size: 18px;
    }

    .cfg-subtitle {
        font-size: 12px;
    }

    .cfg-controls {
        padding: 14px 14px;
    }

    .cfg-grid {
        grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
        gap: 8px;
    }

    .cfg-card {
        padding: 12px 10px 10px;
    }

    .cfg-card-abbr {
        font-size: 18px;
    }

    .cfg-card-name {
        font-size: 11px;
    }

    .cfg-card-formula {
        font-size: 10px;
    }

    .cfg-card-tags {
        display: none;
    }

    .cfg-panel-body {
        padding: 20px 16px 32px;
    }

    .cfg-panel-hero-abbr {
        font-size: 48px;
    }

    .cfg-panel-hero-name {
        font-size: 20px;
    }
}

@media (max-width: 400px) {
    .cfg-grid {
        grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
    }
}

/* ---------- Print Styles ---------- */
@media print {
    .cfg-panel-overlay,
    .cfg-panel,
    .cfg-tooltip,
    .cfg-controls,
    .cfg-theme-toggle {
        display: none !important;
    }

    .cfg-encyclopedia {
        background: #fff;
        color: #000;
    }

    .cfg-card {
        break-inside: avoid;
        border: 1px solid #ccc;
    }
}