/* ============================================================
   apps_tool.css — Calc84 Mini Apps & Tools UI/UX
   Version: 2.0.0
   Purpose: Dedicated styling for all interactive mini-app
            cards, workspaces, inputs, buttons, results,
            and embedded tools on the /apps page.
   Excludes: Header, sidebar, footer, SEO content sections,
             breadcrumbs, and general page layout.
   ============================================================ */

/* ==================== CSS Custom Properties (Fallbacks) ==================== */
:root {
    /* If parent theme vars are missing, these kick in */
    --app-card-bg: #ffffff;
    --app-card-border: #e2e8f0;
    --app-card-radius: 1rem;
    --app-card-shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
    --app-card-shadow-hover: 0 10px 25px rgba(0, 0, 0, 0.08), 0 4px 10px rgba(0, 0, 0, 0.05);
    --app-card-shadow-active: 0 4px 15px rgba(0, 0, 0, 0.1);
    --app-icon-bg: #f1f5f9;
    --app-icon-color: #475569;
    --app-input-bg: #f8fafc;
    --app-input-border: #e2e8f0;
    --app-input-focus-border: #3b82f6;
    --app-input-focus-ring: rgba(59, 130, 246, 0.15);
    --app-btn-primary-bg: #3b82f6;
    --app-btn-primary-hover: #2563eb;
    --app-btn-primary-text: #ffffff;
    --app-btn-secondary-bg: #f1f5f9;
    --app-btn-secondary-hover: #e2e8f0;
    --app-btn-secondary-text: #334155;
    --app-result-bg: #f8fafc;
    --app-result-border: #e2e8f0;
    --app-workspace-bg: #fafbfc;
    --app-text-primary: #0f172a;
    --app-text-secondary: #64748b;
    --app-text-tertiary: #94a3b8;
    --app-text-info: #3b82f6;
    --app-text-success: #22c55e;
    --app-text-warning: #f59e0b;
    --app-text-error: #ef4444;
    --app-transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --app-transition-smooth: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --app-transition-bounce: 300ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* Dark theme overrides for app-specific variables */
[data-theme="dark"] {
    --app-card-bg: #1a1d2e;
    --app-card-border: #2a2d3e;
    --app-card-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.2);
    --app-card-shadow-hover: 0 10px 25px rgba(0, 0, 0, 0.4), 0 4px 10px rgba(0, 0, 0, 0.3);
    --app-card-shadow-active: 0 4px 15px rgba(0, 0, 0, 0.35);
    --app-icon-bg: #252840;
    --app-icon-color: #8b9dc3;
    --app-input-bg: #1e2135;
    --app-input-border: #2e3148;
    --app-input-focus-border: #60a5fa;
    --app-input-focus-ring: rgba(96, 165, 250, 0.2);
    --app-btn-primary-bg: #3b82f6;
    --app-btn-primary-hover: #60a5fa;
    --app-btn-primary-text: #ffffff;
    --app-btn-secondary-bg: #252840;
    --app-btn-secondary-hover: #2e3148;
    --app-btn-secondary-text: #cbd5e1;
    --app-result-bg: #1e2135;
    --app-result-border: #2e3148;
    --app-workspace-bg: #151823;
    --app-text-primary: #e2e8f0;
    --app-text-secondary: #94a3b8;
    --app-text-tertiary: #64748b;
    --app-text-info: #60a5fa;
    --app-text-success: #4ade80;
    --app-text-warning: #fbbf24;
    --app-text-error: #f87171;
}

[data-theme="solar"] {
    --app-card-bg: #fefce8;
    --app-card-border: #fde68a;
    --app-card-shadow: 0 1px 3px rgba(180, 83, 9, 0.08), 0 1px 2px rgba(180, 83, 9, 0.04);
    --app-card-shadow-hover: 0 10px 25px rgba(180, 83, 9, 0.12), 0 4px 10px rgba(180, 83, 9, 0.06);
    --app-icon-bg: #fef3c7;
    --app-icon-color: #b45309;
    --app-input-bg: #fffbeb;
    --app-input-border: #fde68a;
    --app-input-focus-border: #d97706;
    --app-input-focus-ring: rgba(217, 119, 6, 0.2);
    --app-btn-primary-bg: #d97706;
    --app-btn-primary-hover: #b45309;
    --app-btn-primary-text: #ffffff;
    --app-btn-secondary-bg: #fef3c7;
    --app-btn-secondary-hover: #fde68a;
    --app-btn-secondary-text: #78350f;
    --app-result-bg: #fffbeb;
    --app-result-border: #fde68a;
    --app-workspace-bg: #fffbeb;
    --app-text-primary: #451a03;
    --app-text-secondary: #78350f;
    --app-text-tertiary: #a16207;
    --app-text-info: #d97706;
    --app-text-success: #16a34a;
    --app-text-warning: #ea580c;
    --app-text-error: #dc2626;
}

/* ==================== Search Wrapper ==================== */
.search-wrapper {
    position: relative;
    max-width: 640px;
    margin: 0 auto 2rem auto;
    display: flex;
    align-items: center;
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--app-text-tertiary, #94a3b8);
    pointer-events: none;
    transition: color var(--app-transition-fast, 150ms ease);
    z-index: 2;
}

.search-input {
    width: 100%;
    padding: 0.875rem 1rem 0.875rem 2.75rem;
    font-size: 0.95rem;
    font-family: inherit;
    color: var(--app-text-primary, #0f172a);
    background: var(--app-card-bg, #ffffff);
    border: 2px solid var(--app-card-border, #e2e8f0);
    border-radius: 3rem;
    outline: none;
    transition: all var(--app-transition-smooth, 250ms ease);
    box-shadow: var(--app-card-shadow, 0 1px 3px rgba(0,0,0,0.06));
    letter-spacing: 0.01em;
}

.search-input::placeholder {
    color: var(--app-text-tertiary, #94a3b8);
    font-weight: 400;
}

.search-input:focus {
    border-color: var(--app-input-focus-border, #3b82f6);
    box-shadow: 0 0 0 4px var(--app-input-focus-ring, rgba(59,130,246,0.15)),
                0 4px 15px rgba(0,0,0,0.06);
}

.search-input:focus ~ .search-icon {
    color: var(--app-input-focus-border, #3b82f6);
}

/* Clear button for search (if added via JS) */
.search-input::-webkit-search-cancel-button {
    cursor: pointer;
    opacity: 0.6;
    transition: opacity var(--app-transition-fast, 150ms ease);
}

.search-input::-webkit-search-cancel-button:hover {
    opacity: 1;
}

/* ==================== Apps Grid Layout ==================== */
.apps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.25rem;
    padding: 0;
    width: 100%;
}

@media (min-width: 768px) {
    .apps-grid {
        grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
        gap: 1.5rem;
    }
}

@media (min-width: 1200px) {
    .apps-grid {
        grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
        gap: 1.75rem;
    }
}

@media (min-width: 1440px) {
    .apps-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 2rem;
    }
}

/* ==================== App Card ==================== */
.app-card {
    display: flex;
    flex-direction: column;
    background: var(--app-card-bg, #ffffff);
    border: 1px solid var(--app-card-border, #e2e8f0);
    border-radius: var(--app-card-radius, 1rem);
    padding: 1.25rem;
    transition: all var(--app-transition-smooth, 250ms ease);
    box-shadow: var(--app-card-shadow, 0 1px 3px rgba(0,0,0,0.06));
    position: relative;
    overflow: hidden;
    animation: appCardFadeIn 0.4s ease both;
    will-change: transform, box-shadow;
}

/* Staggered animation for cards */
.app-card:nth-child(1) { animation-delay: 0.05s; }
.app-card:nth-child(2) { animation-delay: 0.10s; }
.app-card:nth-child(3) { animation-delay: 0.15s; }
.app-card:nth-child(4) { animation-delay: 0.20s; }
.app-card:nth-child(5) { animation-delay: 0.25s; }
.app-card:nth-child(6) { animation-delay: 0.30s; }
.app-card:nth-child(7) { animation-delay: 0.35s; }
.app-card:nth-child(8) { animation-delay: 0.40s; }
.app-card:nth-child(9) { animation-delay: 0.45s; }
.app-card:nth-child(10) { animation-delay: 0.50s; }
.app-card:nth-child(11) { animation-delay: 0.55s; }

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

/* Subtle top accent line */
.app-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg,
        var(--app-input-focus-border, #3b82f6) 0%,
        var(--app-text-info, #3b82f6) 50%,
        transparent 100%);
    opacity: 0;
    transition: opacity var(--app-transition-smooth, 250ms ease);
    border-radius: var(--app-card-radius, 1rem) var(--app-card-radius, 1rem) 0 0;
}

.app-card:hover::before {
    opacity: 1;
}

.app-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--app-card-shadow-hover, 0 10px 25px rgba(0,0,0,0.08));
    border-color: var(--app-input-focus-border, #3b82f6);
}

.app-card:focus-within {
    box-shadow: 0 0 0 3px var(--app-input-focus-ring, rgba(59,130,246,0.15)),
                var(--app-card-shadow-hover, 0 10px 25px rgba(0,0,0,0.08));
    border-color: var(--app-input-focus-border, #3b82f6);
}

/* Card with custom border-color (like AI Math Tutor) */
.app-card[style*="border-color"] {
    border-left-width: 3px;
}

/* ==================== App Header (Icon + Meta) ==================== */
.app-header {
    display: flex;
    align-items: flex-start;
    gap: 0.875rem;
    margin-bottom: 1rem;
    flex: 0 0 auto;
}

.app-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.35rem;
    background: var(--app-icon-bg, #f1f5f9);
    color: var(--app-icon-color, #475569);
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.04);
    transition: transform var(--app-transition-bounce, 300ms ease),
                box-shadow var(--app-transition-smooth, 250ms ease);
    flex-shrink: 0;
    line-height: 1;
}

.app-card:hover .app-icon {
    transform: scale(1.08);
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.04),
                0 4px 12px rgba(0,0,0,0.08);
}

.app-meta {
    flex: 1;
    min-width: 0;
}

.app-meta h3 {
    margin: 0 0 0.25rem 0;
    font-size: 1rem;
    font-weight: 700;
    color: var(--app-text-primary, #0f172a);
    letter-spacing: -0.01em;
    line-height: 1.3;
}

.app-meta p {
    margin: 0;
    font-size: 0.8125rem;
    color: var(--app-text-secondary, #64748b);
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* ==================== Action Buttons ==================== */
.action-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.7rem 1rem;
    font-size: 0.875rem;
    font-weight: 600;
    font-family: inherit;
    letter-spacing: 0.01em;
    color: var(--app-btn-secondary-text, #334155);
    background: var(--app-btn-secondary-bg, #f1f5f9);
    border: 1.5px solid var(--app-card-border, #e2e8f0);
    border-radius: 0.625rem;
    cursor: pointer;
    transition: all var(--app-transition-fast, 150ms ease);
    text-align: center;
    white-space: nowrap;
    user-select: none;
    position: relative;
    overflow: hidden;
    flex: 0 0 auto;
    margin-top: 0.25rem;
}

.action-btn:hover {
    background: var(--app-btn-secondary-hover, #e2e8f0);
    border-color: var(--app-input-focus-border, #3b82f6);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.action-btn:active {
    transform: translateY(0);
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.1);
    transition: all 50ms ease;
}

.action-btn:focus-visible {
    outline: 2px solid var(--app-input-focus-border, #3b82f6);
    outline-offset: 2px;
}

/* Ripple effect on click */
.action-btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at center,
        var(--app-input-focus-ring, rgba(59,130,246,0.3)) 0%,
        transparent 70%);
    opacity: 0;
    transition: opacity var(--app-transition-fast, 150ms ease);
    pointer-events: none;
}

.action-btn:active::after {
    opacity: 1;
    transition: opacity 0ms;
}

/* Primary Action Button */
.action-btn.primary {
    color: var(--app-btn-primary-text, #ffffff);
    background: var(--app-btn-primary-bg, #3b82f6);
    border-color: transparent;
    font-weight: 700;
    box-shadow: 0 2px 8px rgba(59,130,246,0.25);
}

.action-btn.primary:hover {
    background: var(--app-btn-primary-hover, #2563eb);
    border-color: transparent;
    box-shadow: 0 4px 16px rgba(59,130,246,0.35);
    transform: translateY(-2px);
}

.action-btn.primary:active {
    box-shadow: 0 1px 4px rgba(59,130,246,0.2);
    transform: translateY(0);
}

.action-btn.primary::after {
    background: radial-gradient(circle at center,
        rgba(255,255,255,0.3) 0%,
        transparent 70%);
}

/* Disabled state */
.action-btn:disabled,
.action-btn.primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
    filter: grayscale(20%);
}

/* Button with aria-expanded */
.action-btn[aria-expanded="true"] {
    background: var(--app-btn-primary-bg, #3b82f6);
    color: var(--app-btn-primary-text, #ffffff);
    border-color: transparent;
    font-weight: 700;
    box-shadow: 0 2px 8px rgba(59,130,246,0.25);
}

.action-btn[aria-expanded="true"]:hover {
    background: var(--app-btn-primary-hover, #2563eb);
}

/* ==================== App Workspace (Expandable Panel) ==================== */
.app-workspace {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transform: translateY(-8px);
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1),
                opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1),
                transform 0.3s cubic-bezier(0.4, 0, 0.2, 1),
                margin 0.3s cubic-bezier(0.4, 0, 0.2, 1),
                padding 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    margin-top: 0;
    padding: 0 0.125rem;
    background: var(--app-workspace-bg, #fafbfc);
    border-radius: 0 0 0.75rem 0.75rem;
    border: 1px solid transparent;
    flex: 0 0 auto;
}

.app-workspace.active {
    max-height: 800px;
    opacity: 1;
    transform: translateY(0);
    margin-top: 0.875rem;
    padding: 1rem 0.125rem 0.125rem 0.125rem;
    border-color: var(--app-card-border, #e2e8f0);
    overflow-y: auto;
}

/* Custom scrollbar for workspace */
.app-workspace.active::-webkit-scrollbar {
    width: 5px;
}

.app-workspace.active::-webkit-scrollbar-track {
    background: transparent;
    border-radius: 10px;
}

.app-workspace.active::-webkit-scrollbar-thumb {
    background: var(--app-text-tertiary, #94a3b8);
    border-radius: 10px;
    opacity: 0.5;
}

.app-workspace.active::-webkit-scrollbar-thumb:hover {
    background: var(--app-text-secondary, #64748b);
}

/* ==================== Input Groups ==================== */
.input-group {
    margin-bottom: 0.875rem;
}

.input-group:last-child {
    margin-bottom: 0;
}

.input-group label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--app-text-secondary, #64748b);
    margin-bottom: 0.375rem;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

/* ==================== App Inputs ==================== */
.app-input {
    width: 100%;
    padding: 0.65rem 0.75rem;
    font-size: 0.875rem;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', 'Monaco', monospace;
    color: var(--app-text-primary, #0f172a);
    background: var(--app-input-bg, #f8fafc);
    border: 1.5px solid var(--app-input-border, #e2e8f0);
    border-radius: 0.5rem;
    outline: none;
    transition: all var(--app-transition-fast, 150ms ease);
    box-sizing: border-box;
    letter-spacing: 0.01em;
}

.app-input::placeholder {
    color: var(--app-text-tertiary, #94a3b8);
    font-weight: 400;
    font-family: inherit;
}

.app-input:hover {
    border-color: var(--app-text-tertiary, #94a3b8);
}

.app-input:focus {
    border-color: var(--app-input-focus-border, #3b82f6);
    box-shadow: 0 0 0 3px var(--app-input-focus-ring, rgba(59,130,246,0.15));
    background: var(--app-card-bg, #ffffff);
}

.app-input:focus::placeholder {
    opacity: 0.5;
}

/* Number input - hide spinners for cleaner look */
.app-input[type="number"] {
    -moz-appearance: textfield;
    appearance: textfield;
}

.app-input[type="number"]::-webkit-inner-spin-button,
.app-input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

/* Select input */
select.app-input {
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M6 9l6 6 6-6'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    padding-right: 2.25rem;
}

select.app-input option {
    background: var(--app-card-bg, #ffffff);
    color: var(--app-text-primary, #0f172a);
}

/* ==================== Result Boxes ==================== */
.result-box {
    display: none;
    margin-top: 0.75rem;
    padding: 0.875rem 1rem;
    font-size: 0.8125rem;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', 'Monaco', monospace;
    color: var(--app-text-primary, #0f172a);
    background: var(--app-result-bg, #f8fafc);
    border: 1px solid var(--app-result-border, #e2e8f0);
    border-radius: 0.5rem;
    white-space: pre-line;
    word-break: break-word;
    min-height: 2.5rem;
    line-height: 1.6;
    transition: all var(--app-transition-smooth, 250ms ease);
    animation: resultPopIn 0.25s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.result-box[style*="display:block"],
.result-box[style*="display: block"] {
    display: block !important;
}

@keyframes resultPopIn {
    from {
        opacity: 0;
        transform: scale(0.96) translateY(-4px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.result-box strong {
    color: var(--app-text-info, #3b82f6);
    font-weight: 700;
}

/* ==================== Store Button ==================== */
.store-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.4rem 0.75rem;
    margin-top: 0.5rem;
    font-size: 0.75rem;
    font-weight: 600;
    font-family: inherit;
    color: var(--app-text-info, #3b82f6);
    background: transparent;
    border: 1.5px dashed var(--app-text-info, #3b82f6);
    border-radius: 0.4rem;
    cursor: pointer;
    transition: all var(--app-transition-fast, 150ms ease);
    letter-spacing: 0.01em;
}

.store-btn:hover {
    background: var(--app-input-focus-ring, rgba(59,130,246,0.08));
    border-style: solid;
    transform: translateY(-1px);
}

.store-btn:active {
    transform: scale(0.97);
    transition: transform 80ms ease;
}

.store-btn:focus-visible {
    outline: 2px solid var(--app-input-focus-border, #3b82f6);
    outline-offset: 2px;
}

/* Success flash for store button */
.store-btn[style*="text-success"],
.store-btn[style*="Saved"] {
    animation: storeSuccessPulse 0.5s ease;
}

@keyframes storeSuccessPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

/* ==================== Element Search ==================== */
.element-search {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 0.875rem;
    align-items: center;
}

.element-search .app-input {
    flex: 1;
    min-width: 0;
}

.element-search .action-btn {
    width: auto;
    flex-shrink: 0;
    white-space: nowrap;
}

/* ==================== Fractal Container ==================== */
.fractal-container {
    position: relative;
    width: 100%;
    aspect-ratio: 16 / 10;
    min-height: 180px;
    max-height: 350px;
    border-radius: 0.625rem;
    overflow: hidden;
    border: 2px solid var(--app-card-border, #e2e8f0);
    background: #000;
    cursor: crosshair;
    transition: border-color var(--app-transition-smooth, 250ms ease);
}

.fractal-container:hover {
    border-color: var(--app-input-focus-border, #3b82f6);
}

.fractal-container canvas {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.fractal-container div {
    position: absolute;
    bottom: 0.375rem;
    left: 0.5rem;
    color: rgba(255, 255, 255, 0.75);
    opacity: 0.85;
    font-size: 0.625rem;
    font-weight: 500;
    background: rgba(0, 0, 0, 0.5);
    padding: 0.2rem 0.5rem;
    border-radius: 0.25rem;
    pointer-events: none;
    letter-spacing: 0.02em;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

/* ==================== Polynomial Input Flex Row ==================== */
#poly-inputs {
    display: flex;
    gap: 0.4rem;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
}

#poly-inputs .app-input {
    flex: 1;
    min-width: 0;
    text-align: center;
    padding-left: 0.4rem;
    padding-right: 0.4rem;
}

/* ==================== System Solver Row Inputs ==================== */
.app-workspace .input-group div[style*="display:flex"] {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.app-workspace .input-group div[style*="display:flex"] .app-input {
    flex: 1;
    min-width: 0;
    text-align: center;
}

/* ==================== Probability Section Dividers ==================== */
#app-prob > div {
    padding-bottom: 0.75rem;
    margin-bottom: 0.75rem;
}

#app-prob > div:last-child {
    padding-bottom: 0;
    margin-bottom: 0;
    border-bottom: none;
}

/* ==================== Molar Mass Section Divider ==================== */
#app-periodic > div[style*="border-top"] {
    border-top: 1px solid var(--app-card-border, #e2e8f0) !important;
    padding-top: 0.875rem !important;
    margin-top: 0.875rem !important;
}

/* ==================== Loading Skeleton (for async operations) ==================== */
.app-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    gap: 0.5rem;
}

.app-loading::before {
    content: '';
    width: 1.25rem;
    height: 1.25rem;
    border: 2px solid var(--app-card-border, #e2e8f0);
    border-top-color: var(--app-input-focus-border, #3b82f6);
    border-radius: 50%;
    animation: appSpin 0.6s linear infinite;
}

@keyframes appSpin {
    to { transform: rotate(360deg); }
}

/* ==================== Tooltip for inline help ==================== */
.app-tooltip {
    position: relative;
    cursor: help;
    border-bottom: 1px dotted var(--app-text-tertiary, #94a3b8);
}

.app-tooltip::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: calc(100% + 6px);
    left: 50%;
    transform: translateX(-50%) translateY(4px);
    padding: 0.4rem 0.7rem;
    font-size: 0.7rem;
    font-weight: 500;
    color: #fff;
    background: #1e293b;
    border-radius: 0.35rem;
    white-space: nowrap;
    pointer-events: none;
    opacity: 0;
    transition: all var(--app-transition-fast, 150ms ease);
    z-index: 100;
}

.app-tooltip:hover::after {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ==================== Badge for app status ==================== */
.app-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.2rem 0.5rem;
    font-size: 0.65rem;
    font-weight: 700;
    border-radius: 2rem;
    letter-spacing: 0.03em;
    text-transform: uppercase;
}

.app-badge--active {
    background: rgba(34, 197, 94, 0.12);
    color: var(--app-text-success, #22c55e);
}

.app-badge--info {
    background: rgba(59, 130, 246, 0.12);
    color: var(--app-text-info, #3b82f6);
}

/* ==================== Responsive Breakpoints ==================== */
@media (max-width: 640px) {
    .apps-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .app-card {
        padding: 1rem;
    }

    .app-icon {
        width: 40px;
        height: 40px;
        min-width: 40px;
        font-size: 1.15rem;
        border-radius: 10px;
    }

    .app-meta h3 {
        font-size: 0.9rem;
    }

    .app-meta p {
        font-size: 0.75rem;
    }

    .action-btn {
        padding: 0.6rem 0.875rem;
        font-size: 0.8rem;
    }

    .app-input {
        padding: 0.55rem 0.65rem;
        font-size: 0.8rem;
    }

    .search-input {
        padding: 0.75rem 0.875rem 0.75rem 2.5rem;
        font-size: 0.85rem;
    }

    .search-icon {
        left: 0.75rem;
        width: 18px;
        height: 18px;
    }

    .fractal-container {
        aspect-ratio: 4 / 3;
        min-height: 150px;
        max-height: 250px;
    }

    .element-search {
        flex-direction: column;
        gap: 0.5rem;
    }

    .element-search .action-btn {
        width: 100%;
    }

    #poly-inputs {
        gap: 0.3rem;
    }
}

@media (max-width: 380px) {
    .apps-grid {
        gap: 0.75rem;
    }

    .app-card {
        padding: 0.875rem;
        border-radius: 0.75rem;
    }

    .app-header {
        gap: 0.625rem;
    }

    .app-icon {
        width: 36px;
        height: 36px;
        min-width: 36px;
        font-size: 1rem;
        border-radius: 8px;
    }

    .app-meta h3 {
        font-size: 0.825rem;
    }

    .app-meta p {
        font-size: 0.7rem;
        -webkit-line-clamp: 2;
        line-clamp: 2;
    }

    .action-btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.75rem;
        border-radius: 0.5rem;
    }

    .app-input {
        padding: 0.5rem 0.55rem;
        font-size: 0.75rem;
        border-radius: 0.4rem;
    }

    .result-box {
        padding: 0.65rem 0.75rem;
        font-size: 0.7rem;
    }

    .store-btn {
        font-size: 0.675rem;
        padding: 0.3rem 0.6rem;
    }
}

/* ==================== Print Styles ==================== */
@media print {
    .app-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
        page-break-inside: avoid;
    }

    .app-workspace {
        max-height: none !important;
        opacity: 1 !important;
        display: block !important;
    }

    .action-btn,
    .store-btn,
    .search-wrapper {
        display: none !important;
    }

    .fractal-container {
        border: 1px solid #ccc;
    }
}

/* ==================== Reduced Motion ==================== */
@media (prefers-reduced-motion: reduce) {
    .app-card,
    .app-workspace,
    .action-btn,
    .app-input,
    .result-box,
    .store-btn,
    .app-icon {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ==================== High Contrast / Forced Colors ==================== */
@media (forced-colors: active) {
    .app-card {
        border: 2px solid CanvasText;
    }

    .action-btn {
        border: 2px solid ButtonText;
    }

    .app-input {
        border: 2px solid CanvasText;
    }

    .app-input:focus {
        outline: 3px solid Highlight;
    }

    .action-btn:focus-visible {
        outline: 3px solid Highlight;
    }
}

/* ==================== Focus Visible Polyfill ==================== */
.app-input:focus:not(:focus-visible),
.action-btn:focus:not(:focus-visible) {
    outline: none;
}

/* ==================== Inline Result Highlight ==================== */
.result-highlight {
    color: var(--app-text-info, #3b82f6);
    font-weight: 700;
    background: var(--app-input-focus-ring, rgba(59,130,246,0.08));
    padding: 0.1em 0.3em;
    border-radius: 0.2em;
}

/* ==================== App Card Featured Variant ==================== */
.app-card--featured {
    border-color: var(--app-input-focus-border, #3b82f6);
    background: linear-gradient(135deg,
        var(--app-card-bg, #ffffff) 0%,
        var(--app-input-focus-ring, rgba(59,130,246,0.03)) 100%);
}

.app-card--featured::before {
    opacity: 1;
    background: linear-gradient(90deg,
        var(--app-input-focus-border, #3b82f6) 0%,
        var(--app-text-info, #3b82f6) 100%);
}

/* ==================== Quick Action Row ==================== */
.app-quick-actions {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-top: 0.5rem;
}

.app-quick-actions .action-btn {
    flex: 1;
    min-width: fit-content;
    font-size: 0.75rem;
    padding: 0.45rem 0.7rem;
}

/* ==================== Empty State ==================== */
.app-empty-state {
    text-align: center;
    padding: 2rem 1rem;
    color: var(--app-text-tertiary, #94a3b8);
}

.app-empty-state .app-icon {
    margin: 0 auto 0.75rem;
    font-size: 2rem;
    width: 56px;
    height: 56px;
}

.app-empty-state p {
    font-size: 0.8rem;
    margin: 0;
}