/* Modern App Styles */
:root {
    --primary-color: #2563eb;
    --primary-light: #3b82f6;
    --primary-dark: #1d4ed8;
    --primary-50: #eef2ff;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    --surface: #ffffff;
    --surface-secondary: #f8fafc;
    --border-color: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
}

/* PIN Authentication Styles */
.pin-backdrop {
    position: fixed;
    inset: 0;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(168, 85, 247, 0.1)), radial-gradient(circle at 30% 20%, rgba(59, 130, 246, 0.15), transparent 50%), radial-gradient(circle at 70% 80%, rgba(168, 85, 247, 0.15), transparent 50%), var(--gray-50);
    backdrop-filter: blur(20px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing);
}

.pin-modal {
    background: var(--surface);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 420px;
    overflow: hidden;
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px) scale(0.95);
    }

    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.pin-header {
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
}

.pin-home {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing);
    font-size: 1.75rem;
    backdrop-filter: blur(10px);
}

.pin-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin: 0 0 var(--spacing-xs) 0;
    line-height: 1.2;
}

.pin-subtitle {
    font-size: 1rem;
    margin: 0;
    opacity: 0.9;
    line-height: 1.4;
}

.pin-form {
    padding: var(--spacing-lg);
}

.pin-input-group {
    position: relative;
    margin-bottom: var(--spacing-md);
}

.pin-input {
    width: 100%;
    padding: var(--spacing) var(--spacing-xl) var(--spacing) var(--spacing);
    font-size: 1.125rem;
    font-weight: 600;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--surface);
    color: var(--text-primary);
    transition: all 0.2s ease;
    letter-spacing: 0.1em;
}

    .pin-input:focus {
        outline: none;
        border-color: var(--primary-color);
        box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
    }

.pin-input-icon {
    position: absolute;
    right: var(--spacing);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 1.125rem;
    pointer-events: none;
}

.pin-error {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--error-color);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: var(--spacing);
    padding: var(--spacing-sm) var(--spacing);
    background: rgba(239, 68, 68, 0.1);
    border-radius: var(--radius);
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.pin-submit-btn {
    width: 100%;
    padding: var(--spacing) var(--spacing-md);
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    box-shadow: var(--shadow);
}

    .pin-submit-btn:hover:not(:disabled) {
        background: var(--primary-dark);
        transform: translateY(-1px);
        box-shadow: var(--shadow-md);
    }

    .pin-submit-btn:disabled {
        opacity: 0.7;
        cursor: not-allowed;
        transform: none;
    }

.btn-spinner {
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top: 2px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Home Page Styles */
.home-container {
    min-height: 0;
    overflow-y: auto;
    overflow-x: clip;
    display: grid;
    align-content: start;
    background: linear-gradient(135deg, var(--gray-50) 0%, var(--gray-100) 100%);
}

.home-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    padding: var(--spacing-lg) 0;
}

.app-title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--text-primary);
    margin: 0 0 var(--spacing-xs) 0;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    -webkit-text-fill-color: transparent;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.app-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin: 0;
    font-weight: 500;
}

.categories-section > *:last-child {
    margin-bottom: 0;
}

.category-card {
    display: block;
    text-decoration: none;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    position: relative;
    aspect-ratio: 16/10;
    min-height: 200px;
    z-index: 0;
    min-width: 0;
}

.category-card .card-title {
    display: block;
    overflow-wrap: anywhere;
    word-break: break-word;
}

.category-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    text-decoration: none;
    z-index: 2;
}

.card-background {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.card-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.3), rgba(0, 0, 0, 0.1));
    transition: all 0.3s ease;
}

.category-card:hover .card-overlay {
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.2), rgba(0, 0, 0, 0.05));
}

.card-content-home {
    position: relative;
    z-index: 2;
    height: 100%;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    color: white;
}

.card-icon {
    width: 56px;
    height: 56px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    margin-bottom: auto;
}

.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin: var(--spacing) 0;
    line-height: 1.3;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.card-arrow {
    position: absolute;
    right: 16px;
    bottom: 16px;
    width: 40px;
    height: 40px;
    border-radius: 9999px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,.22);
    border: 1px solid rgba(255,255,255,.35);
    box-shadow: var(--shadow);
    transition: transform .2s ease, background .2s ease;
    z-index: 3;
}

.card-arrow i {
    color: #fff;
    font-size: 1.125rem;
}

/* Loading Container */
.loading-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--gray-50) 0%, var(--gray-100) 100%);
}

.loading-content {
    text-align: center;
    padding: var(--spacing-xl);
}

.loading-spinner {
    margin-bottom: var(--spacing-lg);
}

.loading-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0 0 var(--spacing-sm) 0;
}

.loading-description {
    font-size: 1rem;
    color: var(--text-secondary);
    margin: 0;
}

/* Base Styles */
* {
    box-sizing: border-box;
}

html, body {
    height: 100%;
    margin: 0;
    overflow: clip;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--gray-50) 0%, var(--gray-100) 100%);
}

html, body, .modern-app {
    overflow-x: hidden;
}

.modern-app {
    position: fixed; 
    inset: 0;
    display: grid;
    grid-template-rows: 1fr;
    min-height: 0;
    overflow: clip;
}

.hidden {
    display: none !important;
}

/* Header Styles */
.app-header .header-content {
    position: relative;
    min-height: 120px;
    padding: var(--spacing) var(--spacing-md);
}

.app-header {
    border: 0;
    position: relative;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing);
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing) var(--spacing-md);
    position: relative;
    flex-wrap: wrap;
    min-height: 80px;
}

.nav-button-centered {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: var(--radius-xl);
    font-weight: 600;
    font-size: 1.25rem;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
    white-space: nowrap;
    transform-origin: center;
    will-change: transform;
    -webkit-tap-highlight-color: transparent;
}

.nav-button-centered i {
    font-size: 1.5rem;
}

.nav-button-centered:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.brand-chip-center {
    position: absolute;
    left: 50%;
    top: 10px;
    transform: translateX(-50%);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    border-radius: 999px;
    background: rgba(255,255,255,.85);
    backdrop-filter: blur(6px);
    box-shadow: 0 6px 16px rgba(0,0,0,.06);
    font-weight: 600;
    color: #334155;
}

.brand-chip-center img {
    height: 55px;
    display: block;
}

.brand-chip-center span {
    font-size: .9rem;
    line-height: 1;
    white-space: nowrap;
}

.brand-chip-sm {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    border-radius: 999px;
    background: rgba(255,255,255,.85);
    backdrop-filter: blur(6px);
    box-shadow: 0 6px 16px rgba(0,0,0,.06);
    font-weight: 600;
    color: #334155;
    z-index: 1;
}

.brand-chip-sm img {
    height: 28px;
    display: block;
}

.brand-chip-sm span {
    font-size: .9rem;
    line-height: 1;
    white-space: nowrap;
}

/* Main Content */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
    overflow-y: visible;
}

/* Items Grid */
.items-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing);
}

.item-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    cursor: pointer;
    border: 1px solid var(--border-color);
    overflow: hidden;
}

    .item-card:hover {
        transform: translateY(-4px);
        box-shadow: var(--shadow-xl);
        border-color: var(--primary-light);
    }

.card-content {
    padding: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing);
}

.icon-container {
    flex-shrink: 0;
}

.icon-wrapper {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    box-shadow: var(--shadow-md);
}

.icon-image {
    background: linear-gradient(135deg, #10b981, #059669) !important;
}

.icon-pdf {
    background: linear-gradient(135deg, #ef4444, #dc2626) !important;
}

.icon-video {
    background: linear-gradient(135deg, #8b5cf6, #7c3aed) !important;
}

.icon-default {
    background: linear-gradient(135deg, var(--gray-500), var(--gray-600));
}

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

.item-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 var(--spacing-xs) 0;
    line-height: 1.4;
}

.item-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0 0 var(--spacing-sm) 0;
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.item-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.category-badge {
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 9999px;
    text-transform: uppercase;
    letter-spacing: 0.025em;
    display: inline-flex;
    place-items: center;
    white-space: nowrap;
    justify-content: center;
    line-height: 1;
    padding: 0.35rem 0.85rem;
}

.badge-primary {
    background: #dbeafe;
    color: #1d4ed8;
}

.badge-success {
    background: #d1fae5;
    color: #065f46;
}

.badge-warning {
    background: #fef3c7;
    color: #92400e;
}

.badge-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--spacing-2xl) var(--spacing);
}

.empty-icon {
    font-size: 4rem;
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
}

.empty-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 var(--spacing-sm) 0;
}

.empty-description {
    font-size: 1rem;
    color: var(--text-secondary);
    margin: 0;
}

/* Loading State */
.loading-state {
    text-align: center;
    padding: var(--spacing-2xl) var(--spacing);
}

.loading-spinner {
    margin-bottom: var(--spacing-md);
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--gray-200);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

.loading-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 var(--spacing-sm) 0;
}

.loading-description {
    font-size: 1rem;
    color: var(--text-secondary);
    margin: 0;
}

/* SubCategories */
.subcat-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 1rem 0 .5rem;
    padding: .5rem .75rem;
    background: #f8fafc;
    border: 1px solid #e6e9f2;
    border-radius: 12px;
    box-shadow: 0 1px 0 rgba(16,24,40,.04);
}

.subcat-title {
    display: flex;
    align-items: center;
    gap: .5rem;
    font-weight: 600;
    color: #0f172a;
}

.subcat-title .bi {
    color: #0D73E8;
    font-size: 1rem;
}

.subcat-count-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: .15rem .5rem;
    font-size: .8rem;
    line-height: 1;
    color: #0D73E8;
    background: #eef6ff;
    border: 1px solid #c7dbff;
    border-radius: 9999px;
}

@media (min-width: 640px) {
    .subcat-header.sticky {
        position: sticky;
        top: 64px; 
        z-index: 2;
        backdrop-filter: saturate(180%) blur(6px);
    }
}

.subcat-bar {
    display: flex;
    align-items: center;
    gap: .5rem;
    overflow-x: visible;
    overflow-y: hidden;
    margin-bottom: .25rem;
    white-space: nowrap;
    flex-wrap: wrap;
}

.subcat-chip {
    display: inline-flex;
    align-items: center;
    gap: .5rem;
    line-height: 1;
    vertical-align: middle; 
    margin: 0;
    -webkit-appearance: none;
    appearance: none;
    background: #f5f7fb;
    color: #0f172a;
    border: 1px solid #e6e9f2;
    border-radius: 9999px;
    padding: .35rem .7rem;
    font-weight: 500;
    transition: all .15s ease;
    position: relative;
}

.subcat-chip:hover {
    background: #eef6ff;
    border-color: #c7dbff;
}

.subcat-chip:focus {
    outline: 2px solid #98c7ff;
    outline-offset: 2px;
}

.subcat-chip.active {
    background: #0D73E8;
    color: #fff;
    border-color: #0D73E8;
    box-shadow: none;
}

.subcat-chip.active::after {
    content: "";
    position: absolute;
    inset: 0;
    border-radius: inherit;
    pointer-events: none;
}

.subcat-chip .subcat-count {
    opacity: .6;
}

.subcat-chip.active .subcat-count {
    opacity: .9;
}

/* Viewer Styles */
.viewer-container {
    position: fixed;
    inset: 0;
    background: var(--surface);
    z-index: 200;
    overflow: auto;
}

.viewer-content {
    height: 100dvh;
    display: flex;
    flex-direction: column;
    max-height: 100dvh;
}

.viewer-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing) var(--spacing-md);
    position: relative;
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
}

.viewer-info {
    grid-column: 2;
    text-align: center;
    pointer-events: none;
}

.back-button {
    grid-column: 1;
    justify-self: start;
    gap: var(--spacing-xs);
    padding: var(--spacing) var(--spacing-md);
    background: var(--gray-100);
    color: var(--text-primary);
    border: none;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
    flex-shrink: 0;
    z-index: 1;
}

    .back-button:hover {
        background: var(--gray-200);
        transform: translateY(-1px);
    }

    .back-button i {
        font-size: 1.125rem;
    }

.viewer-title {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    line-height: 1.3;
}

.viewer-type {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.viewer-actions {
    grid-column: 3;
    justify-self: end;
    display: flex;
    gap: var(--spacing-sm);
}

.qr-toggle-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 66px;
    height: 66px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1.125rem;
}

    .qr-toggle-btn:hover {
        background: var(--primary-dark);
        transform: translateY(-1px);
        box-shadow: var(--shadow-md);
    }

    .qr-toggle-btn i {
        font-size: 2.6rem;
    }


.media-container {
    flex: 1 1 auto;
    display: flex;
    position: relative;
    background: var(--gray-900);
    min-height: 0;
}

.media-wrapper {
    flex: 1 1 auto;
    min-height: 0;
    display: block;
    padding: 0;
    background: var(--gray-900);
}

.media-player {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: 0;
    box-shadow: none;
}

.pdf-frame {
    width: 100%;
    height: 100%;
    border: 0;
    background: transparent;
    border-radius: 0;
}

.powered-by {
    inset-block-end: calc(env(safe-area-inset-bottom, 0px) + 14px);
    inset-inline-start: 50%;
    position: fixed;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 12px;
    border-radius: 16px;
    background: rgba(255,255,255,.78);
    backdrop-filter: blur(8px);
    box-shadow: 0 8px 24px rgba(0,0,0,.08);
    font-weight: 600;
    color: #334155;
    z-index: 10;
}

.powered-by.vertical {
    flex-direction: column;
    gap: 6px;
    padding: 10px 14px 12px;
    border-radius: 18px;
}

.powered-by img {
    height: 46px;
    display: block;
}

.powered-by span {
    white-space: nowrap;
    line-height: 1;
    font-size: .95rem;
    letter-spacing: .1px;
}

.image-viewer {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #0f172a;
}

.qr-section {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    z-index: 10;
    transition: all 0.3s ease;
}

    .qr-section.hidden {
        opacity: 0;
        pointer-events: none;
        transform: translateY(-10px);
    }

.qr-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-xl);
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.2);
    min-width: 220px;
}

.qr-close-btn {
    position: absolute;
    top: 6px;
    right: 6px;
    background: transparent;
    border: none;
    font-size: 1.1rem;
    cursor: pointer;
    color: #444;
}

.qr-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 var(--spacing-sm) 0;
}

.qr-description {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: var(--spacing-sm) 0 0 0;
}


/* Responsive Design */
@media (max-width: 768px) {
    .header-content {
        padding: var(--spacing) var(--spacing);
    }

    .nav-button-centered {
        padding: var(--spacing) var(--spacing-md);
        font-size: 1rem;
        min-width: 160px;
    }

    .nav-button-centered i {
        font-size: 1.125rem;
    }

    .back-button {
        padding: var(--spacing-sm) var(--spacing);
        font-size: 0.875rem;
    }

    .back-button i {
        font-size: 1rem;
    }

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

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

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

    .icon-wrapper {
        width: 48px;
        height: 48px;
        font-size: 1.25rem;
    }

    .item-title {
        font-size: 1rem;
    }

    .viewer-header {
        padding: var(--spacing-sm) var(--spacing);
    }

    .viewer-title {
        font-size: 1.25rem;
    }

    .viewer-type {
        font-size: 0.75rem;
    }

    .media-wrapper {
        padding: var(--spacing);
    }

    .qr-section {
        position: fixed !important;
        top: 100px;
        right: var(--spacing-md);
        bottom: auto !important;
        left: auto !important;
        z-index: 2000;
        margin: 0;
        display: flex;
        justify-content: flex-end;
        pointer-events: none;
    }

    .qr-card {
        pointer-events: auto;
        max-width: 260px;
        margin: 0;
        box-shadow: var(--shadow-xl);
    }

    .image-viewer {
        max-height: calc(100vh - 120px);
        width: 100%;
        height: auto;
        object-fit: contain;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .items-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    }
}

@media (min-width: 1025px) {
    .items-grid {
        grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    }
}

/* Tablet-specific optimizations */
@media (min-width: 768px) and (max-width: 1024px) and (orientation: landscape) {
    .header-content {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .main-content {
        padding: var(--spacing-md);
    }

    .items-grid {
        grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
        gap: var(--spacing-md);
    }

    .card-content {
        padding: var(--spacing-md);
    }
}

/* Touch-friendly interactions */
@media (hover: none) and (pointer: coarse) {
    .item-card:active {
        transform: scale(0.98);
    }

    .nav-button:active,
    .back-button:active {
        transform: scale(0.95);
    }
}

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

/* Focus styles for keyboard navigation */
.nav-button:focus,
.back-button:focus,
.item-card:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.item-card {
    position: relative;
}

.item-card:focus {
    outline: none;
}

.item-card:focus::before {
    content: '';
    position: absolute;
    inset: -2px;
    border: 2px solid var(--primary-color);
    border-radius: calc(var(--radius-lg) + 2px);
    pointer-events: none;
}

.item-card .item-meta {
    display: flex;
    justify-content: center;
    width: 100%;
}

.brand-bar {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0px 0 0px;
}

.brand-logo {
    max-height: 90px;
    width: auto;
    height: auto;
    object-fit: contain;
}

.logout-bar {
    display: flex;
    justify-content: flex-end;
    padding: 15px 15px;
}

.filter-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 12px 0 8px;
}

.search-wrap {
    position: relative;
    display: flex;
    align-items: center;
    width: min(520px, 100%);
}

.search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1rem;
    opacity: .6;
}

.search-input {
    width: 100%;
    padding: 10px 40px 10px 36px;
    border: 1px solid var(--border-color);
    border-radius: 9999px;
    background: var(--surface);
    box-shadow: 0 1px 2px rgba(0,0,0,.03);
    outline: none;
    transition: border-color .15s ease, box-shadow .15s ease;
}

.search-input:focus {
    border-color: var(--primary-500, #2563eb);
    box-shadow: 0 0 0 3px rgba(37,99,235,.15);
}

.search-clear {
    position: absolute;
    right: 8px;
    top: 50%;
    transform: translateY(-50%);
    border: 0;
    background: transparent;
    padding: 6px;
    border-radius: 8px;
    cursor: pointer;
}

.search-clear:hover {
    background: rgba(0,0,0,.05);
}

.result-count {
    font-size: .9rem;
    color: var(--muted-600, #64748b);
}

.scroll-invisible {
    -ms-overflow-style: none; /* IE/old Edge */
    scrollbar-width: none; /* Firefox */
}

.scroll-invisible::-webkit-scrollbar {
    width: 0;
    height: 0;
    display: none; /* Chrome/Safari/Edge */
}

.pin-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 14px;
    background: var(--primary-50);
    box-shadow: 0 1px 2px rgba(0,0,0,.04);
}

.pin-image {
    max-width: 70px;
    max-height: 70px;
    object-fit: contain;
}

.category-card {
    margin: 0 !important;
    min-width: 0;
    flex: 1 1 0%;
}

/* Categories Base */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit,minmax(280px,1fr));
    gap: 1.25rem;
    align-items: stretch;
    isolation: isolate;
    margin-top: var(--spacing);
    padding-inline: .75rem;
    margin-bottom: 0;
}

.categories-grid > * {
    min-width: 0;
}

/* Categories mobile, tablet, desktop */

/* mobile: 1 col */
@media (max-width:680px) {
    .categories-section {
        padding: var(--spacing-lg) var(--spacing); 
    }

    .categories-grid {
        grid-template-columns: 1fr !important;
        gap: 1rem !important;
        padding-inline: 0 !important;
    }

    .category-card {
        aspect-ratio: 16/9;
        min-height: 160px;
        border-radius: var(--radius-lg);
    }

    .card-content-home {
        padding: var(--spacing);
    }

    .card-title {
        font-size: 1.25rem;
    }

    .card-arrow {
        right: 12px;
        bottom: 12px;
    }

    .category-card:hover {
        transform: none !important;
        box-shadow: var(--shadow-md);
    }

    .categories-grid .category-card:last-child {
        margin-bottom: 100px !important;
    }
}

/* tablet: 3 cols */
@media (min-width:681px) and (max-width:1024px) {
    .categories-grid {
        display: grid !important;
        grid-template-columns: repeat(3, 1fr) !important;
        gap: 1.25rem !important;
        padding: 0 1rem !important;
    }

    .category-card {
        width: 100% !important;
        max-width: 100% !important;
        min-width: 0 !important;
        flex: 1 1 auto !important;
    }

    .card-arrow {
        opacity: 1 !important;
        visibility: visible !important;
        transform: none !important;
        background: rgba(255, 255, 255, 0.30) !important;
    }

    .category-card:hover .card-arrow {
        transform: none !important;
    }

    .category-card .card-title {
        font-size: clamp(1.1rem, 1.6vw, 1.35rem);
    }
}

/* desktop: 3 cols */
@media (min-width:1025px) {
    .categories-grid {
        grid-template-columns: repeat(3,minmax(0,1fr)) !important;
        gap: 2rem !important;
    }
}

@media (max-width: 500px) {
    .nav-button-centered {
        position: static;
        transform: none;
        width: 100%;
        margin-bottom: 8px;
        text-align: center;
    }

    .brand-chip-sm {
        position: static;
        transform: none;
        justify-content: center;
        width: 100%;
    }

    .header-content {
        display: flex;
        flex-direction: column;
        align-items: center;
    }

    .categories-grid .category-card:last-child {
        margin-bottom: 100px !important;
    }
}

@media (max-height: 560px) {
    .categories-grid .category-card:last-child {
        margin-bottom: 100px !important;
    }

}

/* --- Smallest phones: 320 x 568 (and similar) --- */
@media (max-width: 360px) {
    .categories-section {
        padding: var(--spacing) var(--spacing);
    }

    .categories-grid {
        grid-template-columns: 1fr !important;
        gap: .875rem !important;
        padding-inline: 0 !important;
        margin: 0;
    }

    .category-card {
        width: 100% !important;
        height: 200px;
        aspect-ratio: auto;
        border-radius: var(--radius-lg);
        overflow: hidden;
    }

    .card-content-home {
        padding: .75rem;
    }

    .card-title {
        font-size: 1.05rem;
    }

    .card-icon {
        width: 40px;
        height: 40px;
        font-size: 1.1rem;
    }

    .card-arrow {
        width: 32px;
        height: 32px;
        right: 10px;
        bottom: 10px;
    }

    .category-card .powered-by,
    .category-card [class*="powered"] {
        transform: scale(.9);
        transform-origin: center;
    }
}

/* --- Phone landscape (covers 844x390, 852x393, 896x414, 926x428) --- */
@media (orientation: landscape) and (max-height: 430px) {
    .categories-section {
        padding: var(--spacing) var(--spacing);
    }

    .categories-grid {
        grid-template-columns: repeat(3, 1fr) !important;
        gap: 1rem !important;
        align-items: stretch;
    }

    .category-card {
        height: 240px;
        aspect-ratio: auto;
        overflow: hidden;
    }

    .card-content-home {
        padding: 1rem;
    }

    .card-title {
        font-size: clamp(1rem, 2.6vh, 1.25rem);
    }

    .card-icon {
        width: 44px;
        height: 44px;
        font-size: 1.25rem;
    }

    .card-arrow {
        width: 36px;
        height: 36px;
    }

    .categories-grid .category-card:last-child {
        margin-bottom: 100px !important;
    }
}

/* Safety for very short landscapes (older phones) */
@media (orientation: landscape) and (max-height: 375px) {
    .category-card {
        height: 220px;
    }
}

@media (orientation: landscape) and (max-height: 500px) {
    .image-viewer {
        max-height: calc(100vh - 80px);
        width: auto;
        height: 100%;
        object-fit: contain;
    }
}