/* ============================================
   EGF Studio - Premium Design System
   ============================================ */

/* CSS Custom Properties */

:root
{
    /* Browser native UI */
    color-scheme: dark light;

    /* Colors - brand */
    --primary-hue: 260;
    --primary-sat: 85%;
    --primary-light: 60%;
    
    --primary-100: hsl(var(--primary-hue), var(--primary-sat), 95%);
    --primary-200: hsl(var(--primary-hue), var(--primary-sat), 85%);
    --primary-300: hsl(var(--primary-hue), var(--primary-sat), 75%);
    --primary-400: hsl(var(--primary-hue), var(--primary-sat), 65%);
    --primary-500: hsl(var(--primary-hue), var(--primary-sat), var(--primary-light));
    --primary-600: hsl(var(--primary-hue), var(--primary-sat), 50%);
    --primary-700: hsl(var(--primary-hue), var(--primary-sat), 40%);
    
    --accent-hue: 320;
    --accent-500: hsl(var(--accent-hue), 80%, 60%);
    --accent-600: hsl(var(--accent-hue), 80%, 50%);
    
    --success: hsl(140, 70%, 55%);
    --warning: hsl(40, 95%, 60%);
    --error: hsl(0, 80%, 60%);
    --info: hsl(200, 85%, 60%);

    /* Layout */
    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;

    /* Shared semantic aliases */
    --primary-color: var(--primary-500);

    /* Fixed header sizes */
    --desktop-header-height: 92px;
    --tablet-header-height: 82px;
    --mobile-header-height: 112px;

    /* Fixed bottom nav height */
    --bottom-nav-height: 72px;

    /* Layering */
    --z-top-header: 1200;
    --z-bottom-nav: 1100;
    --z-modal: 2000;

    /* Default theme = dark */
    --bg-primary: hsl(240, 15%, 10%);
    --bg-secondary: hsl(240, 15%, 14%);
    --bg-tertiary: hsl(240, 15%, 18%);
    --bg-elevated: hsl(240, 15%, 22%);
    
    --text-primary: hsl(0, 0%, 98%);
    --text-secondary: hsl(0, 0%, 75%);
    --text-tertiary: hsl(0, 0%, 55%);
    
    --border-color: hsl(240, 15%, 25%);
    --border-focus: var(--primary-500);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px hsla(var(--primary-hue), var(--primary-sat), var(--primary-light), 0.35);

    --bg-gradient-1: hsla(var(--primary-hue), 85%, 30%, 0.15);
    --bg-gradient-2: hsla(var(--accent-hue), 80%, 30%, 0.15);
}

html[data-theme="light"]
{
    color-scheme: light;

    --bg-primary: hsl(0, 0%, 98%);
    --bg-secondary: hsl(0, 0%, 100%);
    --bg-tertiary: hsl(220, 20%, 96%);
    --bg-elevated: hsl(220, 18%, 93%);
    
    --text-primary: hsl(240, 20%, 12%);
    --text-secondary: hsl(240, 12%, 32%);
    --text-tertiary: hsl(240, 10%, 46%);
    
    --border-color: hsl(220, 16%, 84%);
    --border-focus: var(--primary-500);

    --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
    --shadow-md: 0 8px 20px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 18px 35px rgba(15, 23, 42, 0.12);
    --shadow-glow: 0 0 18px hsla(var(--primary-hue), var(--primary-sat), var(--primary-light), 0.18);

    --bg-gradient-1: hsla(var(--primary-hue), 85%, 55%, 0.10);
    --bg-gradient-2: hsla(var(--accent-hue), 80%, 55%, 0.10);

    --warning-bg: hsl(38, 100%, 92%);
    --warning-border: hsl(38, 90%, 55%);
    --warning-text: hsl(32, 85%, 25%);

    --info-bg: hsl(210, 100%, 94%);
    --info-border: hsl(210, 90%, 55%);
    --info-text: hsl(210, 85%, 28%);

    --warning-text-strong: hsl(32, 85%, 25%);
    --info-text-strong: hsl(210, 85%, 28%);
    --error-text-strong: hsl(0, 70%, 32%);
    --success-text-strong: hsl(145, 70%, 26%);

    --success-bg: hsl(145, 55%, 93%);
    --success-border: hsl(145, 60%, 45%);
    --success-text: hsl(145, 70%, 26%);

    --error-bg: hsl(0, 85%, 95%);
    --error-border: hsl(0, 75%, 58%);
    --error-text: hsl(0, 70%, 32%);
}

html[data-theme="dark"]
{
    color-scheme: dark;

    --bg-primary: hsl(240, 15%, 10%);
    --bg-secondary: hsl(240, 15%, 14%);
    --bg-tertiary: hsl(240, 15%, 18%);
    --bg-elevated: hsl(240, 15%, 22%);
    
    --text-primary: hsl(0, 0%, 98%);
    --text-secondary: hsl(0, 0%, 75%);
    --text-tertiary: hsl(0, 0%, 55%);
    
    --border-color: hsl(240, 15%, 25%);
    --border-focus: var(--primary-500);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px hsla(var(--primary-hue), var(--primary-sat), var(--primary-light), 0.35);

    --bg-gradient-1: hsla(var(--primary-hue), 85%, 30%, 0.15);
    --bg-gradient-2: hsla(var(--accent-hue), 80%, 30%, 0.15);

    --warning-bg: hsla(40, 95%, 60%, 0.12);
    --warning-border: var(--warning);
    --warning-text: hsl(40, 90%, 75%);

    --info-bg: hsla(200, 85%, 60%, 0.12);
    --info-border: var(--info);
    --info-text: hsl(200, 90%, 75%);

    --warning-text-strong: hsl(40, 90%, 75%);
    --info-text-strong: hsl(200, 90%, 75%);
    --error-text-strong: hsl(0, 90%, 75%);
    --success-text-strong: hsl(140, 70%, 70%);

    --success-bg: hsla(140, 70%, 55%, 0.12);
    --success-border: var(--success);
    --success-text: hsl(140, 70%, 70%);

    --error-bg: hsla(0, 80%, 60%, 0.12);
    --error-border: var(--error);
    --error-text: hsl(0, 90%, 75%);
}

/* ============================================
   Reset & Base Styles
   ============================================ */

*
{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html
{
    scroll-padding-top: calc(var(--desktop-header-height) + env(safe-area-inset-top));
}

body
{
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    padding-top: calc(var(--desktop-header-height) + env(safe-area-inset-top));
    transition:
        background-color var(--transition-normal),
        color var(--transition-normal);
}

/* Animated gradient background */

body::before
{
    content: '';
    position: fixed;
    inset: 0;
    background:
        radial-gradient(circle at 20% 30%, var(--bg-gradient-1) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, var(--bg-gradient-2) 0%, transparent 50%);
    z-index: -1;
    animation: gradientShift 15s ease infinite;
    transition: background var(--transition-normal);
}

@keyframes gradientShift
{
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

@keyframes shimmer
{
    0%, 100% { filter: brightness(1); }
    50% { filter: brightness(1.2); }
}

@keyframes fadeIn
{
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes slideUp
{
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ============================================
   Layout
   ============================================ */

.container
{
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
    padding: var(--space-xl);
}

.header
{
    text-align: center;
    margin-bottom: var(--space-2xl);
    padding: 0;
}

.header-top
{
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-top-header);

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-lg);

    min-height: var(--desktop-header-height);
    padding:
        calc(env(safe-area-inset-top) + 0.75rem)
        max(var(--space-xl), 24px)
        0.75rem;

    margin-bottom: 0;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    transition:
        background-color var(--transition-normal),
        border-color var(--transition-normal),
        box-shadow var(--transition-normal);
}

@supports ((backdrop-filter: blur(12px)) or (-webkit-backdrop-filter: blur(12px)))
{
    .header-top
    {
        background: color-mix(in srgb, var(--bg-secondary) 88%, transparent);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
    }
}

.header-controls
{
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: var(--space-sm);
    flex: 1;
    flex-wrap: wrap;
}

#install-pwa-btn[hidden]
{
    display: none !important;
}

.theme-switcher
{
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
    justify-content: flex-end;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 0.45rem 0.65rem;
    box-shadow: var(--shadow-sm);
    transition:
        background-color var(--transition-normal),
        border-color var(--transition-normal),
        box-shadow var(--transition-normal);
}

.control-group
{
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 0.25rem 0.5rem;
    min-width: 0;
}

.control-group + .control-group
{
    padding-inline-start: 0.75rem;
    border-inline-start: 1px solid var(--border-color);
}

.theme-label
{
    grid-column: 1 / -1;
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 600;
    line-height: 1.1;
}

.theme-select
{
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    padding: 0.45rem 1.9rem 0.45rem 0.7rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: linear-gradient(135deg, var(--bg-tertiary), var(--bg-elevated));
    color: var(--text-primary);
    font: inherit;
    font-size: 0.875rem;
    cursor: pointer;
    min-width: 110px;
    transition:
        border-color var(--transition-fast),
        background-color var(--transition-fast),
        box-shadow var(--transition-fast),
        color var(--transition-fast);
}

.theme-select:focus
{
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px hsla(var(--primary-hue), var(--primary-sat), var(--primary-light), 0.16);
}

.logo
{
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0;
}

.logo-image
{
    width: 46px;
    height: 46px;
    object-fit: contain;
    flex-shrink: 0;
    filter: drop-shadow(0 6px 14px rgba(0, 0, 0, 0.18));
}

.logo-text
{
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.logo h1
{
    font-size: 2.2rem;
    font-weight: 700;
    line-height: 1;
    background: linear-gradient(135deg, var(--primary-400), var(--accent-500));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: shimmer 3s ease infinite;
}

.version
{
    font-size: 0.72rem;
    padding: 0.2rem 0.55rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
}

.subtitle
{
    font-size: 1.125rem;
    color: var(--text-secondary);
    font-weight: 300;
    margin-top: var(--space-lg);
}

/* ============================================
   Tabs
   ============================================ */

.tab-nav
{
    display: flex;
    gap: var(--space-sm);
    margin-bottom: var(--space-xl);
    background: var(--bg-secondary);
    padding: var(--space-sm);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
}

.tab-btn
{
    flex: 1;
    padding: var(--space-md) var(--space-lg);
    background: transparent;
    border: none;
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    position: relative;
}

.tab-icon
{
    font-size: 1.25rem;
}

.tab-label
{
    display: inline;
}

.tab-btn:hover
{
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.tab-btn.active
{
    background: linear-gradient(135deg, var(--primary-600), var(--primary-700));
    color: white;
    box-shadow: var(--shadow-glow);
}

.tab-content
{
    display: none;
    animation: fadeIn var(--transition-normal);
}

.tab-content.active
{
    display: block;
}

.tab-content h2
{
    font-size: 2rem;
    margin-bottom: var(--space-sm);
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-description
{
    color: var(--text-secondary);
    margin-bottom: var(--space-xl);
    font-size: 1.0625rem;
}

/* Sub-tabs */

.sub-tab-nav
{
    display: flex;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
    border-bottom: 2px solid var(--border-color);
}

.sub-tab-btn
{
    padding: var(--space-md) var(--space-lg);
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    color: var(--text-secondary);
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-bottom: -2px;
}

.sub-tab-btn:hover
{
    color: var(--text-primary);
}

.sub-tab-btn.active
{
    color: var(--primary-400);
    border-bottom-color: var(--primary-500);
}

.sub-tab-content
{
    display: none;
}

.sub-tab-content.active
{
    display: block;
    animation: fadeIn var(--transition-normal);
}

/* ============================================
   Forms
   ============================================ */

.form
{
    background: var(--bg-secondary);
    padding: var(--space-xl);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
}

.form-row
{
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-lg);
}

.form-group
{
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
    margin-bottom: var(--space-md);
}

.form-group label
{
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9375rem;
}

.checkbox-label
{
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    cursor: pointer;
    user-select: none;
}

.form-group.required label::after
{
    content: ' *';
    color: var(--error);
}

.form-group input,
.form-group textarea,
.form-group select
{
    padding: var(--space-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.9375rem;
    transition: all var(--transition-fast);
    width: 100%;
    max-width: 100%;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus
{
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px hsla(var(--primary-hue), var(--primary-sat), var(--primary-light), 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder
{
    color: var(--text-tertiary);
}

.form-group input[type="checkbox"]
{
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.form-group label:hover
{
    color: var(--primary-color);
}

.form-group input[type="checkbox"]:focus
{
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.helper-text
{
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-inline-start: 26px;
    line-height: 1.4;
}

/* ============================================
   Buttons
   ============================================ */

.btn
{
    padding: var(--space-md) var(--space-xl);
    border: none;
    border-radius: var(--radius-lg);
    font-family: inherit;
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
}

.btn-primary
{
    background: linear-gradient(135deg, var(--primary-600), var(--primary-700));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover
{
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow), var(--shadow-lg);
}

.btn-primary:active
{
    transform: translateY(0);
}

.btn-secondary
{
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover
{
    background: var(--bg-elevated);
}

.btn-danger
{
    background: var(--error);
    color: white;
}

.btn-danger:hover
{
    filter: brightness(1.1);
}

.btn-large
{
    padding: var(--space-lg) var(--space-2xl);
    font-size: 1.125rem;
}

/* ============================================
   Alerts
   ============================================ */

.alert
{
    padding: var(--space-md);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    margin-bottom: var(--space-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.alert-warning
{
    background: var(--warning-bg);
    border-color: var(--warning-border);
    color: var(--warning-text);
    border-inline-start: 4px solid var(--warning-border);
}

.alert-info
{
    background: var(--info-bg);
    border-color: var(--info-border);
    color: var(--info-text);
    border-inline-start: 4px solid var(--info-border);
}

.alert-success
{
    background: var(--success-bg);
    border-color: var(--success-border);
    border-inline-start: 4px solid var(--success-border);
    color: var(--success-text);
}

.alert-error
{
    background: var(--error-bg);
    border-color: var(--error-border);
    border-inline-start: 4px solid var(--error-border);
    color: var(--error-text);
}

.alert ul
{
    margin-inline-start: var(--space-lg);
    margin-top: var(--space-xs);
}

/* ============================================
   Manifest Items
   ============================================ */

.manifest-items
{
    display: grid;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.manifest-item
{
    background: var(--bg-secondary);
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all var(--transition-normal);
}

.manifest-item:hover
{
    border-color: var(--primary-500);
    box-shadow: 0 0 15px hsla(var(--primary-hue), var(--primary-sat), var(--primary-light), 0.2);
}

.manifest-item-info
{
    flex: 1;
}

.manifest-item-title
{
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.manifest-item-meta
{
    font-size: 0.875rem;
    color: var(--text-secondary);
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.manifest-item-badge
{
    padding: 0.25rem 0.5rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

.manifest-item-actions
{
    display: flex;
    gap: var(--space-sm);
}

.icon-btn
{
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 1.125rem;
}

.icon-btn:hover
{
    background: var(--bg-elevated);
    border-color: var(--primary-500);
}

/* ============================================
   Sequence Editor
   ============================================ */

.sequence-list
{
    display: grid;
    gap: var(--space-sm);
}

.sequence-item
{
    background: var(--bg-secondary);
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--space-md);
    cursor: move;
    transition: all var(--transition-normal);
}

.sequence-item:hover
{
    border-color: var(--primary-500);
    box-shadow: var(--shadow-md);
}

.sequence-item.dragging
{
    opacity: 0.5;
    transform: scale(0.98);
}

.sequence-number
{
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-600), var(--primary-700));
    border-radius: 50%;
    font-weight: 600;
    color: white;
    font-size: 0.875rem;
}

.sequence-info
{
    flex: 1;
}

.sequence-title
{
    font-weight: 600;
    color: var(--text-primary);
}

.sequence-role
{
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* ============================================
   Modal
   ============================================ */

.modal
{
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(8px);
    z-index: var(--z-modal);
    align-items: center;
    justify-content: center;
    padding:
        calc(env(safe-area-inset-top) + 1rem)
        1rem
        calc(env(safe-area-inset-bottom) + 1rem);
}

.modal.active
{
    display: flex;
    animation: fadeIn var(--transition-normal);
}

.modal-content
{
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    width: min(90%, 800px);
    max-height: min(90vh, 900px);
    overflow-y: auto;
    animation: slideUp var(--transition-normal);
}

.modal-header
{
    padding: var(--space-lg) var(--space-xl);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3
{
    font-size: 1.5rem;
    color: var(--text-primary);
}

.modal-close
{
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color var(--transition-fast);
    width: 2rem;
    height: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-close:hover
{
    color: var(--text-primary);
}

.modal-body
{
    padding: var(--space-xl);
}

/* ============================================
   Validation Panel
   ============================================ */

.validation-panel
{
    background: var(--bg-secondary);
    padding: var(--space-xl);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    margin-bottom: var(--space-xl);
}

.validation-panel h3
{
    margin-bottom: var(--space-lg);
    font-size: 1.5rem;
}

.validation-item
{
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    margin-bottom: var(--space-sm);
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
}

.validation-icon
{
    font-size: 1.5rem;
}

.validation-item.valid .validation-icon
{
    color: var(--success);
}

.validation-item.invalid .validation-icon
{
    color: var(--error);
}

.validation-item-warning
{
    color: var(--warning-text-strong);
}

.validation-item-info
{
    color: var(--info-text-strong);
}

.validation-item-error
{
    color: var(--error-text-strong);
}

.validation-item-success
{
    color: var(--success-text-strong);
}

.export-actions
{
    text-align: center;
}

/* ============================================
   Utilities
   ============================================ */

.empty-state
{
    text-align: center;
    padding: var(--space-2xl);
    color: var(--text-tertiary);
}

.empty-state-icon
{
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: 0.5;
}

.container,
.header,
.form,
.tab-nav,
.tab-btn,
.sub-tab-nav,
.sub-tab-btn,
.manifest-item,
.sequence-item,
.modal-content,
.validation-panel,
.alert,
.version,
.theme-current,
.theme-switcher
{
    transition:
        background-color var(--transition-normal),
        border-color var(--transition-normal),
        color var(--transition-normal),
        box-shadow var(--transition-normal);
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 1024px)
{
    html
    {
        scroll-padding-top: calc(var(--tablet-header-height) + env(safe-area-inset-top));
    }

    body
    {
        padding-top: calc(var(--tablet-header-height) + env(safe-area-inset-top));
    }

    .container
    {
        padding: var(--space-lg);
        padding-bottom: calc(var(--bottom-nav-height) + 1.5rem + env(safe-area-inset-bottom));
    }

    .header
    {
        margin-bottom: var(--space-lg);
        padding: 0;
    }

    .header-top
    {
        min-height: var(--tablet-header-height);
        padding:
            calc(env(safe-area-inset-top) + 0.45rem)
            0.9rem
            0.45rem;
        gap: 0.75rem;
    }

    .header-controls
    {
        flex: 0 0 auto;
        width: auto;
        max-width: 58%;
    }

    .theme-switcher
    {
        width: auto;
        justify-content: flex-end;
        padding: 0.35rem 0.5rem;
        gap: 0.5rem;
    }

    .logo
    {
        margin-bottom: 0;
        gap: 0.6rem;
    }

    .logo-image
    {
        width: 38px;
        height: 38px;
    }

    .logo h1
    {
        font-size: 1.65rem;
    }

    .version
    {
        display: none;
    }

    .subtitle
    {
        display: none;
    }

    .tab-nav
    {
        position: fixed;
        left: 0;
        right: 0;
        bottom: 0;
        z-index: var(--z-bottom-nav);
        display: grid;
        grid-template-columns: repeat(5, 1fr);
        gap: 0;
        margin-bottom: 0;
        padding: 0.5rem;
        border-radius: 1rem 1rem 0 0;
        border: 1px solid var(--border-color);
        border-bottom: none;
        background: var(--bg-secondary);
        box-shadow: 0 -8px 24px rgba(0, 0, 0, 0.18);
        backdrop-filter: blur(10px);
    }

    .tab-btn
    {
        min-height: 56px;
        padding: 0.5rem;
        border-radius: var(--radius-md);
        font-size: 0;
        gap: 0;
    }

    .tab-btn .tab-icon
    {
        font-size: 1.35rem;
        line-height: 1;
        margin: 0;
    }

    .tab-nav .tab-btn
    {
        overflow: hidden;
        white-space: nowrap;
    }

    .tab-label
    {
        display: none;
    }
}

@media (max-width: 768px)
{
    html
    {
        scroll-padding-top: calc(var(--mobile-header-height) + env(safe-area-inset-top));
    }

    body
    {
        padding-top: calc(var(--mobile-header-height) + env(safe-area-inset-top));
    }

    .container
    {
        padding: var(--space-md);
        padding-bottom: calc(var(--bottom-nav-height) + 1.5rem + env(safe-area-inset-bottom));
    }

    .header
    {
        margin-bottom: var(--space-md);
        padding: 0;
    }

    .header-top
    {
        flex-direction: column;
        align-items: stretch;
        justify-content: center;
        gap: 0.45rem;

        min-height: var(--mobile-header-height);
        padding:
            calc(env(safe-area-inset-top) + 0.45rem)
            0.75rem
            0.45rem;
    }

    .logo
    {
        flex-direction: row;
        justify-content: center;
        text-align: left;
        gap: 0.55rem;
        margin-bottom: 0;
    }

    .logo-text
    {
        justify-content: flex-start;
        gap: 0.45rem;
    }

    .logo-image
    {
        width: 34px;
        height: 34px;
    }

    .logo h1
    {
        font-size: 1.35rem;
    }

    .version
    {
        display: none;
    }

    .subtitle
    {
        display: none;
    }

    .header-controls
    {
        width: 100%;
        max-width: none;
    }

    #install-pwa-btn
    {
        width: 100%;
        justify-content: center;
    }

    .theme-switcher
    {
        width: 100%;
        justify-content: center;
        padding: 0.35rem 0.45rem;
        gap: 0.45rem;
    }

    .control-group
    {
        flex: 1 1 0;
        min-width: 0;
    }

    .control-group + .control-group
    {
        padding-inline-start: 0.45rem;
        border-inline-start: 1px solid var(--border-color);
        border-top: none;
        padding-top: 0;
    }

    .theme-label
    {
        font-size: 0.7rem;
    }

    .theme-select
    {
        min-width: 0;
        width: 100%;
        font-size: 0.82rem;
        padding: 0.42rem 1.7rem 0.42rem 0.6rem;
    }

    .theme-current
    {
        display: none;
    }

    .form-row
    {
        grid-template-columns: 1fr;
    }

    .modal-content
    {
        width: 95%;
    }
}

/* ============================================
   Scene Configuration Forms
   ============================================ */

.scene-config-container
{
    margin-top: var(--space-md);
    padding: var(--space-lg);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

/* Credits Scene */

.credits-list
{
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

.credit-entry
{
    display: flex;
    gap: var(--space-sm);
    align-items: flex-start;
    animation: fadeIn var(--transition-fast);
}

/* MCQ Scene */

.mcq-question-container
{
    display: flex;
    gap: var(--space-sm);
}

.mcq-q-type
{
    width: 80px !important;
    flex-shrink: 0;
    padding: 0.5rem !important;
    font-size: 0.8125rem !important;
}

.mcq-input-wrapper
{
    flex: 1;
}

.feedback-grid
{
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
}

.feedback-item
{
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.sub-label
{
    font-size: 0.8125rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.mcq-answers-list
{
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.mcq-answer-row
{
    display: flex;
    gap: var(--space-sm);
    align-items: center;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    background: var(--bg-elevated);
    border: 1px solid transparent;
    transition: all var(--transition-fast);
    overflow: hidden;
}

.mcq-answer-row:hover
{
    border-color: var(--border-focus);
}

.mcq-answer-row input[type="radio"]
{
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    cursor: pointer;
}

.mcq-type-select
{
    width: 80px !important;
    flex-shrink: 0;
    padding: 0.5rem !important;
    font-size: 0.8125rem !important;
}

.mcq-answer-row .mcq-input-wrapper
{
    flex: 1;
    min-width: 0;
    overflow: hidden;
}

.mcq-answer-row .mcq-input-wrapper input
{
    width: 100% !important;
    padding: 0.5rem !important;
    min-width: 0;
}

/* Hangman Scene */

.hangman-grid
{
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
}

.hangman-stage-item
{
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
    background: var(--bg-elevated);
    padding: var(--space-sm);
    border-radius: var(--radius-md);
}

.hangman-stage-item input[type='file']
{
    font-size: 0.8125rem;
    padding: var(--space-xs);
}

@media (max-width: 600px)
{
    .feedback-grid,
    .hangman-grid
    {
        grid-template-columns: 1fr;
    }
    
    .mcq-question-container
    {
        flex-direction: column;
    }
}

/* ============================================
   File source chooser
   ============================================ */

.required-mark
{
    color: var(--error);
}

.file-source-field
{
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.file-source-toggle
{
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.file-source-option
{
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.65rem 0.85rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
}

.file-source-option:hover
{
    border-color: var(--border-focus);
    box-shadow: var(--shadow-sm);
}

.file-source-option input[type="radio"]
{
    width: 16px;
    height: 16px;
    margin: 0;
    accent-color: var(--primary-color);
}

.file-source-option.is-disabled
{
    opacity: 0.5;
    cursor: not-allowed;
}

.file-source-panel[hidden]
{
    display: none !important;
}

.helper-text-inline
{
    margin-left: 0;
}

.file-source-field .helper-text
{
    margin-left: 0;
}

.feedback-item .file-source-field,
.hangman-stage-item .file-source-field,
.mcq-input-wrapper .file-source-field
{
    width: 100%;
}

html[dir="rtl"] body
{
    text-align: right;
}

html[dir="rtl"] .header,
html[dir="rtl"] .tab-content,
html[dir="rtl"] .section-description,
html[dir="rtl"] .form,
html[dir="rtl"] .modal-body,
html[dir="rtl"] .validation-panel,
html[dir="rtl"] .empty-state
{
    text-align: right;
}

html[dir="rtl"] .manifest-item-meta,
html[dir="rtl"] .sequence-info,
html[dir="rtl"] .manifest-item-info
{
    text-align: right;
}

html[dir="rtl"] .helper-text,
html[dir="rtl"] .sub-label,
html[dir="rtl"] .theme-label
{
    text-align: right;
}

/* Technical content remains readable in LTR */

html[dir="rtl"] .manifest-item-badge,
html[dir="rtl"] .version,
html[dir="rtl"] code
{
    direction: ltr;
    unicode-bidi: isolate;
}