/* ============================================
   GIF to Sprite Sheet - Green Theme
   gss- prefixed to avoid custom_styles.css conflicts
   ============================================ */

:root {
    --gss-primary:        #339966;
    --gss-primary-light:  #e6f5ee;
    --gss-primary-dark:   #267a52;
    --gss-success:        #339966;
    --gss-success-light:  #e6f5ee;
    --gss-warning:        #f59e0b;
    --gss-danger:         #e64e4e;
    --gss-danger-light:   #fee2e2;
    --gss-bg:             #f4faf7;
    --gss-bg-elevated:    #ffffff;
    --gss-bg-secondary:   #edf7f2;
    --gss-bg-tertiary:    #ddf0e8;
    --gss-text:           #0f2e1e;
    --gss-text-secondary: #2d5a40;
    --gss-text-muted:     #6b8f7a;
    --gss-border:         #c3e2d2;
    --gss-border-light:   #ddf0e8;
    --gss-shadow-sm:   0 1px 3px rgba(0,0,0,0.07);
    --gss-shadow-md:   0 4px 6px -1px rgba(0,0,0,0.09);
    --gss-shadow-lg:   0 10px 15px -3px rgba(0,0,0,0.1);
    --gss-shadow-xl:   0 20px 25px -5px rgba(0,0,0,0.1);
    --gss-shadow-primary:       0 4px 14px rgba(51,153,102,0.25);
    --gss-shadow-primary-hover: 0 6px 20px rgba(51,153,102,0.35);
    --gss-radius-sm:   6px;
    --gss-radius-md:   12px;
    --gss-radius-lg:   16px;
    --gss-radius-xl:   24px;
    --gss-radius-full: 9999px;
    --gss-checker-light: #d4ece1;
    --gss-checker-dark:  #c3e2d2;
    --gss-input-bg:      #ffffff;
    --gss-input-border:  #c3e2d2;

    /* layout mode badge colors */
    --gss-horizontal: #3399cc;
    --gss-vertical:   #8b5cf6;
    --gss-grid:       #339966;
    --gss-auto:       #f59e0b;
}

[data-theme="dark"] {
    --gss-primary:        #4ade9a;
    --gss-primary-light:  rgba(74,222,154,0.15);
    --gss-primary-dark:   #339966;
    --gss-success:        #4ade9a;
    --gss-success-light:  rgba(74,222,154,0.15);
    --gss-danger:         #f87171;
    --gss-danger-light:   rgba(248,113,113,0.15);
    --gss-bg:             #090f0c;
    --gss-bg-elevated:    #101a13;
    --gss-bg-secondary:   #182219;
    --gss-bg-tertiary:    #1f2e22;
    --gss-text:           #e0f5ea;
    --gss-text-secondary: #a3d4b5;
    --gss-text-muted:     #6b9e7e;
    --gss-border:         #1f2e22;
    --gss-border-light:   #182219;
    --gss-shadow-sm:   0 1px 3px rgba(0,0,0,0.3);
    --gss-shadow-md:   0 4px 6px -1px rgba(0,0,0,0.4);
    --gss-shadow-lg:   0 10px 15px -3px rgba(0,0,0,0.4);
    --gss-shadow-xl:   0 20px 25px -5px rgba(0,0,0,0.5);
    --gss-shadow-primary:       0 4px 14px rgba(74,222,154,0.15);
    --gss-shadow-primary-hover: 0 6px 20px rgba(74,222,154,0.25);
    --gss-checker-light: #1f2e22;
    --gss-checker-dark:  #182219;
    --gss-input-bg:      #182219;
    --gss-input-border:  #1f2e22;
}

* { box-sizing: border-box; }

/* ── Header ──────────────────────────────────────── */
.gss-header {
    text-align: center;
    margin-bottom: 2rem;
}

.gss-title-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.75rem;
}

.gss-icon-wrap {
    width: 56px;
    height: 56px;
    background: var(--gss-primary);
    border-radius: var(--gss-radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    flex-shrink: 0;
}

.gss-icon-wrap svg,
.gss-icon-wrap i {
    width: 28px;
    height: 28px;
}

.gss-title {
    font-size: clamp(1.75rem, 4vw, 2.4rem);
    font-weight: 700;
    color: var(--gss-primary);
    margin: 0;
    letter-spacing: -0.02em;
}

.gss-description {
    font-size: 1.05rem;
    color: var(--gss-text-secondary);
    max-width: 800px;
    margin: 0 auto;
    line-height: 1.7;
}

.gss-description a {
    color: var(--gss-primary);
    text-decoration: none;
}

.gss-description a:hover { text-decoration: underline; }

/* ── Main wrapper ────────────────────────────────── */
.gss-main {
    background: var(--gss-bg-elevated);
    border-radius: var(--gss-radius-xl);
    box-shadow: var(--gss-shadow-xl);
    border: 1px solid var(--gss-border);
    overflow: hidden;
    margin-bottom: 1.5rem;
}

/* ── Upload Section ──────────────────────────────── */
.gss-upload-section { padding: 2rem; }

.gss-upload-area {
    border: 2px dashed var(--gss-border);
    border-radius: var(--gss-radius-lg);
    padding: 3.5rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.25s;
    background: var(--gss-bg-secondary);
}

.gss-upload-area:hover,
.gss-upload-area.dragover {
    border-color: var(--gss-primary);
    background: var(--gss-primary-light);
    transform: translateY(-2px);
    box-shadow: var(--gss-shadow-md);
}

.gss-upload-icon {
    color: var(--gss-primary);
    margin-bottom: 1.25rem;
    transition: transform 0.25s;
}

.gss-upload-area:hover .gss-upload-icon { transform: translateY(-4px); }

.gss-upload-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--gss-text);
    margin: 0 0 0.4rem;
}

.gss-upload-subtitle {
    color: var(--gss-text-muted);
    margin: 0 0 1rem;
}

.gss-file-badge {
    display: inline-block;
    padding: 0.2rem 0.65rem;
    background: var(--gss-bg-tertiary);
    color: var(--gss-primary);
    border-radius: var(--gss-radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    margin: 0 0.2rem 0.75rem;
    letter-spacing: 0.05em;
}

.gss-upload-hint {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    background: var(--gss-bg-elevated);
    color: var(--gss-text-muted);
    padding: 0.4rem 0.9rem;
    border-radius: var(--gss-radius-full);
    font-size: 0.8rem;
}

/* ── Error ───────────────────────────────────────── */
.gss-error {
    margin: 0 2rem 1.5rem;
    padding: 1rem 1.25rem;
    background: var(--gss-danger-light);
    border-radius: var(--gss-radius-md);
    border: 1px solid rgba(230,78,78,0.3);
}

.gss-error-content {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--gss-danger);
    font-weight: 500;
    margin-bottom: 0.4rem;
}

.gss-error-help {
    font-size: 0.85rem;
    color: var(--gss-text-muted);
    margin: 0;
}

.gss-error-help a {
    color: var(--gss-primary);
    text-decoration: none;
}

.gss-error-help a:hover { text-decoration: underline; }

/* ── File Info Bar ───────────────────────────────── */
.gss-file-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    align-items: center;
    padding: 1rem 2rem;
    background: var(--gss-bg-secondary);
    border-bottom: 1px solid var(--gss-border);
}

.gss-file-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.875rem;
    color: var(--gss-text-secondary);
}

.gss-file-item i,
.gss-file-item svg {
    color: var(--gss-primary);
    flex-shrink: 0;
}

.gss-file-item strong {
    color: var(--gss-text);
}

.gss-change-btn {
    margin-left: auto;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.85rem;
    background: var(--gss-bg-elevated);
    border: 1px solid var(--gss-border);
    border-radius: var(--gss-radius-full);
    font-size: 0.8rem;
    color: var(--gss-text-secondary);
    cursor: pointer;
    transition: all 0.2s;
}

.gss-change-btn:hover {
    border-color: var(--gss-primary);
    color: var(--gss-primary);
}

/* ══════════════════════════════════════════════════
   LAYOUT B - sidebar + wide main
   ══════════════════════════════════════════════════ */

/* Outer wrapper: sidebar left, main right, both full height */
.gss-lb-wrap {
    display: grid;
    grid-template-columns: 300px 1fr;
    min-height: 600px;
    border-top: 1px solid var(--gss-border);
}

/* ── Sidebar ─────────────────────────────────────── */
.gss-lb-sidebar {
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--gss-border);
    background: var(--gss-bg-secondary);
    overflow-y: auto;
}

.gss-lb-sidebar-section {
    padding: 1.1rem 1.25rem;
    border-bottom: 1px solid var(--gss-border);
}

.gss-lb-divider {
    height: 1px;
    background: var(--gss-border);
    margin: 0;
}

.gss-lb-sec-label {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.72rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--gss-text-muted);
    margin-bottom: 0.75rem;
}

.gss-lb-sec-label i,
.gss-lb-sec-label svg { color: var(--gss-primary); flex-shrink: 0; }

/* Action buttons pinned at bottom of sidebar */
.gss-lb-actions {
    display: flex;
    gap: 0.6rem;
    padding: 1rem 1.25rem;
    margin-top: auto;
    border-top: 1px solid var(--gss-border);
    background: var(--gss-bg-secondary);
    position: sticky;
    bottom: 0;
}

.gss-lb-actions .gss-btn { flex: 1; justify-content: center; }

/* ── Main area ───────────────────────────────────── */
.gss-lb-main {
    display: flex;
    flex-direction: column;
    min-height: 0;
    overflow: hidden;
}

/* Frame selection panel - fixed height, scrollable grid */
.gss-lb-frames-panel {
    flex: 0 0 auto;
    border-bottom: 1px solid var(--gss-border);
    background: var(--gss-bg-elevated);
}

/* Sprite preview panel - fills all remaining height */
.gss-lb-sprite-panel {
    flex: 1;
    min-height: 0;
    display: flex;
    flex-direction: column;
    background: var(--gss-bg-secondary);
}

/* Sprite wrap fills the whole sprite panel */
.gss-lb-sprite-panel .gss-sprite-wrap {
    flex: 1;
    min-height: 240px;
    max-height: none;
    border-radius: 0;
    border: none;
    border-top: 1px solid var(--gss-border);
    overflow: auto;      /* both axes controlled by zoom JS */
    padding: 12px;
    position: relative;
}

/* Scroll hint for very wide sprite sheets */
.gss-wide-tip {
    position: absolute;
    bottom: 0.6rem;
    left: 50%;
    transform: translateX(-50%);
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    background: rgba(0,0,0,0.65);
    color: #fff;
    font-size: 0.7rem;
    font-weight: 600;
    padding: 0.3rem 0.75rem;
    border-radius: var(--gss-radius-full);
    white-space: nowrap;
    pointer-events: none;
    z-index: 10;
}

/* Shared panel header */
.gss-lb-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.25rem;
    flex-wrap: wrap;
    gap: 0.5rem;
    border-bottom: 1px solid var(--gss-border);
    background: var(--gss-bg-elevated);
}

.gss-lb-panel-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.88rem;
    color: var(--gss-text);
}

.gss-lb-panel-title i,
.gss-lb-panel-title svg { color: var(--gss-primary); flex-shrink: 0; }

.gss-lb-panel-tools {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

/* panel header keeps the same legacy name too */
.gss-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
}

.gss-panel-header h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--gss-text);
    margin: 0;
}

.gss-panel-header h3 i,
.gss-panel-header h3 svg {
    color: var(--gss-primary);
}

/* ── Preview Wrapper ─────────────────────────────── */
.gss-preview-wrap {
    background:
        linear-gradient(45deg, var(--gss-checker-light) 25%, transparent 25%),
        linear-gradient(-45deg, var(--gss-checker-light) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--gss-checker-light) 75%),
        linear-gradient(-45deg, transparent 75%, var(--gss-checker-light) 75%);
    background-size: 16px 16px;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0;
    background-color: var(--gss-checker-dark);
    border-radius: var(--gss-radius-md);
    padding: 1.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    border: 1px solid var(--gss-border);
}

.gss-preview-wrap img {
    max-width: 100%;
    max-height: 220px;
    border-radius: var(--gss-radius-sm);
    box-shadow: var(--gss-shadow-md);
}

/* ── Animation Controls ──────────────────────────── */
.gss-anim-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    margin-top: 0.9rem;
    padding: 0.6rem 1rem;
    background: var(--gss-bg-elevated);
    border-radius: var(--gss-radius-md);
    border: 1px solid var(--gss-border);
    flex-wrap: wrap;
}

.gss-ctrl-btn {
    width: 38px;
    height: 38px;
    border: 1.5px solid var(--gss-border);
    border-radius: var(--gss-radius-md);
    background: var(--gss-bg);
    color: var(--gss-text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    padding: 0;
}

.gss-ctrl-btn:hover {
    border-color: var(--gss-primary);
    color: var(--gss-primary);
}

.gss-ctrl-btn.primary {
    background: var(--gss-primary);
    border-color: var(--gss-primary);
    color: #fff;
    width: 44px;
    height: 44px;
}

.gss-ctrl-btn.primary:hover {
    background: var(--gss-primary-dark);
    transform: scale(1.05);
}

.gss-speed-row {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-left: 0.75rem;
    padding-left: 0.75rem;
    border-left: 1px solid var(--gss-border);
}

.gss-speed-slider {
    width: 80px;
    height: 5px;
    border-radius: var(--gss-radius-full);
    background: var(--gss-border);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
}

.gss-speed-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--gss-primary);
    cursor: pointer;
}

.gss-speed-label {
    font-size: 0.78rem;
    color: var(--gss-text-muted);
    font-weight: 600;
    min-width: 32px;
}

.gss-frame-indicator {
    text-align: center;
    margin-top: 0.6rem;
    font-size: 0.82rem;
    color: var(--gss-text-muted);
}

.gss-frame-indicator strong { color: var(--gss-primary); }

/* ── Sprite Preview ──────────────────────────────── */
.gss-sprite-preview-section {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--gss-border);
}

.gss-sprite-wrap {
    background:
        linear-gradient(45deg, var(--gss-checker-light) 25%, transparent 25%),
        linear-gradient(-45deg, var(--gss-checker-light) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--gss-checker-light) 75%),
        linear-gradient(-45deg, transparent 75%, var(--gss-checker-light) 75%);
    background-size: 12px 12px;
    background-position: 0 0, 0 6px, 6px -6px, -6px 0;
    background-color: var(--gss-checker-dark);
    border-radius: var(--gss-radius-md);
    padding: 12px;
    min-height: 140px;
    overflow: auto;
    border: 1px solid var(--gss-border);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.gss-sprite-wrap canvas,
.gss-sprite-wrap img {
    display: block;
    max-width: none;  /* zoom JS sets explicit px sizes */
    flex-shrink: 0;
    box-shadow: 0 2px 12px rgba(0,0,0,0.2);
    image-rendering: auto;
}

/* Zoom toolbar */
.gss-zoom-bar {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    margin-bottom: 0.6rem;
}

.gss-zoom-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.3rem;
    padding: 0.3rem 0.65rem;
    border: 1px solid var(--gss-border);
    border-radius: var(--gss-radius-full);
    background: var(--gss-bg-elevated);
    color: var(--gss-text-secondary);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s;
    white-space: nowrap;
}

.gss-zoom-btn:hover,
.gss-zoom-btn.active {
    border-color: var(--gss-primary);
    color: var(--gss-primary);
    background: var(--gss-primary-light);
}

.gss-zoom-level {
    font-size: 0.72rem;
    color: var(--gss-text-muted);
    font-weight: 600;
    min-width: 32px;
    text-align: center;
}

.gss-sprite-empty {
    text-align: center;
    color: var(--gss-text-muted);
}

.gss-sprite-empty i,
.gss-sprite-empty svg {
    color: var(--gss-border);
    margin-bottom: 0.5rem;
}

.gss-sprite-empty p { font-size: 0.85rem; margin: 0; }

/* ── Checks row (horizontal in settings) ────────── */
.gss-checks-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.1rem;
    margin-top: 0.5rem;
}

.gss-checks-row .gss-check-label {
    flex: 1;
    min-width: 120px;
    font-size: 0.8rem;
    padding: 0.35rem 0.5rem;
}

/* ── Frame grid (inside lb-frames-panel) ─────────── */
.gss-frames-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 0.5rem;
    max-height: 260px;
    overflow-y: auto;
    padding: 0.75rem 1.25rem;
    background: var(--gss-bg-elevated);
}

.gss-frames-grid.size-sm {
    grid-template-columns: repeat(auto-fill, minmax(54px, 1fr));
    max-height: 200px;
}
.gss-frames-grid.size-md {
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    max-height: 260px;
}
.gss-frames-grid.size-lg {
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    max-height: 360px;
}

/* Shared utility classes */
.gss-frames-count {
    font-size: 0.75rem;
    color: var(--gss-text-muted);
    background: var(--gss-bg-secondary);
    padding: 0.15rem 0.55rem;
    border-radius: var(--gss-radius-full);
    border: 1px solid var(--gss-border);
    font-weight: 600;
}

.gss-output-size-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.72rem;
    color: var(--gss-text-muted);
    background: var(--gss-bg-secondary);
    padding: 0.15rem 0.55rem;
    border-radius: var(--gss-radius-full);
    border: 1px solid var(--gss-border);
    font-weight: 600;
}

.gss-output-size-badge i,
.gss-output-size-badge svg { color: var(--gss-primary); }
.gss-controls-scroll {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.gss-settings-section {
    padding-bottom: 1.25rem;
    margin-bottom: 1.25rem;
    border-bottom: 1px solid var(--gss-border);
}

.gss-settings-section:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.gss-section-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--gss-text);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.gss-section-label i,
.gss-section-label svg { color: var(--gss-primary); }

.gss-section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.75rem;
}

/* ── Layout Options ──────────────────────────────── */
.gss-layout-options {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
}

.gss-layout-option { cursor: pointer; }

.gss-layout-option input[type="radio"] { display: none; }

.gss-layout-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
    padding: 0.65rem 0.4rem;
    border: 2px solid var(--gss-border);
    border-radius: var(--gss-radius-md);
    background: var(--gss-input-bg);
    transition: all 0.2s;
}

.gss-layout-card i,
.gss-layout-card svg { color: var(--gss-text-muted); transition: color 0.2s; }

.gss-layout-name {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--gss-text-muted);
}

.gss-layout-option input[type="radio"]:checked + .gss-layout-card {
    border-color: var(--gss-primary);
    background: var(--gss-primary-light);
}

.gss-layout-option input[type="radio"]:checked + .gss-layout-card i,
.gss-layout-option input[type="radio"]:checked + .gss-layout-card svg {
    color: var(--gss-primary);
}

.gss-layout-option input[type="radio"]:checked + .gss-layout-card .gss-layout-name {
    color: var(--gss-primary);
}

.gss-layout-option:hover .gss-layout-card { border-color: var(--gss-primary-light); }

/* ── Grid sub-options ────────────────────────────── */
.gss-grid-options {
    margin-top: 0.75rem;
    padding: 1rem;
    background: var(--gss-bg-secondary);
    border-radius: var(--gss-radius-md);
    border: 1px solid var(--gss-border);
}

/* ── Control Row / Group ─────────────────────────── */
.gss-ctrl-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.85rem;
}

.gss-ctrl-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.gss-ctrl-group label {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--gss-text-secondary);
}

/* ── Inputs ──────────────────────────────────────── */
.gss-input {
    padding: 0.55rem 0.7rem;
    border: 1.5px solid var(--gss-input-border);
    border-radius: var(--gss-radius-md);
    font-size: 0.9rem;
    font-weight: 500;
    text-align: center;
    color: var(--gss-text);
    background: var(--gss-input-bg);
    transition: all 0.2s;
    width: 100%;
}

.gss-input:focus {
    outline: none;
    border-color: var(--gss-primary);
    box-shadow: 0 0 0 3px rgba(51,153,102,0.12);
}

.gss-select {
    padding: 0.55rem 0.7rem;
    border: 1.5px solid var(--gss-input-border);
    border-radius: var(--gss-radius-md);
    font-size: 0.85rem;
    color: var(--gss-text);
    background: var(--gss-input-bg);
    cursor: pointer;
    transition: all 0.2s;
    width: 100%;
}

.gss-select:focus {
    outline: none;
    border-color: var(--gss-primary);
}

/* ── Slider ──────────────────────────────────────── */
.gss-slider-wrap { margin-top: 0.4rem; }

.gss-slider {
    width: 100%;
    height: 6px;
    border-radius: var(--gss-radius-full);
    background: var(--gss-border);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
    accent-color: var(--gss-primary);
}

.gss-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #fff;
    border: 2.5px solid var(--gss-primary);
    cursor: pointer;
    box-shadow: var(--gss-shadow-sm);
    transition: transform 0.2s;
}

.gss-slider::-webkit-slider-thumb:hover { transform: scale(1.15); }

.gss-slider::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #fff;
    border: 2.5px solid var(--gss-primary);
    cursor: pointer;
}

.gss-slider-labels {
    display: flex;
    justify-content: space-between;
    margin-top: 0.35rem;
    font-size: 0.7rem;
    color: var(--gss-text-muted);
}

/* ── Color Input ─────────────────────────────────── */
.gss-color-row {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.gss-color-input {
    width: 46px;
    height: 36px;
    border: 1.5px solid var(--gss-input-border);
    border-radius: var(--gss-radius-md);
    cursor: pointer;
    padding: 2px;
    background: var(--gss-input-bg);
}

/* ── Checkboxes ──────────────────────────────────── */
.gss-check-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.875rem;
    color: var(--gss-text-secondary);
    padding: 0.45rem;
    border-radius: var(--gss-radius-sm);
    transition: background 0.2s;
    margin-top: 0.35rem;
}

.gss-check-label:hover { background: var(--gss-bg-secondary); }

.gss-check-label input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: var(--gss-primary);
    cursor: pointer;
    flex-shrink: 0;
}

.gss-check-label i,
.gss-check-label svg { color: var(--gss-text-muted); }

/* ── Frame Selection ─────────────────────────────── */
.gss-selection-btns {
    display: flex;
    gap: 0.3rem;
    flex-wrap: wrap;
}

.gss-sel-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.3rem 0.7rem;
    height: auto;
    border: 1.5px solid var(--gss-border);
    border-radius: var(--gss-radius-full);
    background: var(--gss-bg-elevated);
    color: var(--gss-text-secondary);
    font-size: 0.75rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.15s;
    white-space: nowrap;
}

.gss-sel-btn:hover {
    border-color: var(--gss-primary);
    color: var(--gss-primary);
    background: var(--gss-primary-light);
}

.gss-frames-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    gap: 0.4rem;
    max-height: 280px;
    overflow-y: auto;
    padding: 0.5rem;
    background: var(--gss-bg-secondary);
    border: 1px solid var(--gss-border);
    border-radius: var(--gss-radius-md);
}

/* Size variants toggled by JS */
.gss-frames-grid.size-sm { grid-template-columns: repeat(auto-fill, minmax(52px, 1fr)); }
.gss-frames-grid.size-md { grid-template-columns: repeat(auto-fill, minmax(72px, 1fr)); }
.gss-frames-grid.size-lg { grid-template-columns: repeat(auto-fill, minmax(110px, 1fr)); max-height: 360px; }

/* ── Frame thumbnails - class names created by sprite-sheet.js ── */
/* JS uses: thumbnail.className = 'frame-thumbnail selected' */
.frame-thumbnail {
    position: relative;
    border: 2px solid var(--gss-border);
    border-radius: var(--gss-radius-sm);
    overflow: hidden;
    cursor: pointer;
    transition: all 0.2s;
    opacity: 0.45;
    aspect-ratio: 1;
    background: var(--gss-checker-dark);
}

.frame-thumbnail:hover {
    border-color: var(--gss-primary);
    opacity: 0.85;
    transform: scale(1.05);
    z-index: 2;
    box-shadow: 0 4px 12px rgba(51,153,102,0.25);
}

.frame-thumbnail.selected {
    border-color: var(--gss-primary);
    opacity: 1;
    box-shadow: 0 0 0 2px rgba(51,153,102,0.3);
}

.frame-thumbnail.selected::after {
    content: '';
    position: absolute;
    top: 3px;
    right: 3px;
    width: 14px;
    height: 14px;
    background: var(--gss-primary);
    border-radius: 50%;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: center;
    background-size: 9px 9px;
    z-index: 2;
}

.frame-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: transparent;
    display: block;
}

/* JS creates: number.className = 'frame-number' */
.frame-number {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: rgba(0,0,0,0.6);
    color: #fff;
    font-size: 9px;
    text-align: center;
    padding: 2px 0;
    font-weight: 700;
    letter-spacing: 0.02em;
}

/* Frame size toggle buttons */
.gss-size-toggle {
    display: flex;
    gap: 0.25rem;
}

.gss-size-btn {
    padding: 0.28rem 0.6rem;
    border: 1px solid var(--gss-border);
    border-radius: var(--gss-radius-full);
    background: var(--gss-input-bg);
    color: var(--gss-text-muted);
    font-size: 0.72rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.15s;
}

.gss-size-btn:hover,
.gss-size-btn.active {
    border-color: var(--gss-primary);
    color: var(--gss-primary);
    background: var(--gss-primary-light);
}

/* ── Output Summary ──────────────────────────────── */
.gss-output-summary {
    display: flex;
    gap: 1.25rem;
    padding: 1rem;
    background: var(--gss-primary-light);
    border-radius: var(--gss-radius-md);
    border: 1px solid var(--gss-border);
    margin-top: 1.25rem;
    flex-wrap: wrap;
}

.gss-sum-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex: 1;
    min-width: 100px;
}

.gss-sum-item i,
.gss-sum-item svg { color: var(--gss-primary); flex-shrink: 0; }

.gss-sum-content { display: flex; flex-direction: column; }

.gss-sum-label {
    font-size: 0.68rem;
    color: var(--gss-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.gss-sum-value {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--gss-text);
}

/* ── Action Bar ──────────────────────────────────── */
.gss-action-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.25rem 2rem;
    background: var(--gss-bg-secondary);
    border-top: 1px solid var(--gss-border);
    gap: 1rem;
}

/* ── Buttons ─────────────────────────────────────── */
.gss-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    padding: 0.7rem 1.5rem;
    border: none;
    border-radius: var(--gss-radius-full);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.25s;
    text-decoration: none;
}

.gss-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.gss-btn-primary {
    background: var(--gss-primary);
    color: #fff;
    box-shadow: var(--gss-shadow-primary);
}

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

.gss-btn-success {
    background: var(--gss-success);
    color: #fff;
    box-shadow: var(--gss-shadow-primary);
}

.gss-btn-success:hover:not(:disabled) {
    background: var(--gss-primary-dark);
    transform: translateY(-1px);
}

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

.gss-btn-secondary:hover:not(:disabled) {
    border-color: var(--gss-primary);
    color: var(--gss-primary);
}

.gss-btn-outline {
    background: transparent;
    color: var(--gss-primary);
    border: 2px solid var(--gss-primary);
}

.gss-btn-outline:hover:not(:disabled) {
    background: var(--gss-primary);
    color: #fff;
}

.gss-btn-sm {
    padding: 0.4rem 0.9rem;
    font-size: 0.82rem;
}

/* ── Processing ──────────────────────────────────── */
.gss-processing {
    padding: 3rem 2rem;
    text-align: center;
}

.gss-processing-box {
    max-width: 360px;
    margin: 0 auto;
}

.gss-spinner {
    width: 52px;
    height: 52px;
    border: 4px solid var(--gss-border);
    border-top-color: var(--gss-primary);
    border-radius: 50%;
    animation: gss-spin 0.9s linear infinite;
    margin: 0 auto 1.25rem;
}

@keyframes gss-spin { to { transform: rotate(360deg); } }

.gss-proc-title {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--gss-text);
    margin: 0 0 0.4rem;
}

.gss-proc-sub {
    font-size: 0.88rem;
    color: var(--gss-text-muted);
    margin: 0 0 1rem;
}

.gss-progress-track {
    height: 8px;
    background: var(--gss-border);
    border-radius: var(--gss-radius-full);
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.gss-progress-bar {
    height: 100%;
    background: var(--gss-primary);
    border-radius: var(--gss-radius-full);
    width: 0%;
    transition: width 0.3s ease;
}

.gss-proc-pct {
    font-size: 0.85rem;
    color: var(--gss-text-muted);
    margin: 0;
}

/* ── Results ─────────────────────────────────────── */
.gss-results {
    padding: 2.5rem 2rem;
    text-align: center;
    animation: gss-fade 0.35s ease;
}

.gss-results-header { margin-bottom: 1.75rem; }

.gss-success-icon {
    width: 68px;
    height: 68px;
    margin: 0 auto 1rem;
    background: var(--gss-success-light);
    border-radius: var(--gss-radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--gss-success);
}

.gss-results-header h2 {
    font-size: 1.6rem;
    color: var(--gss-success);
    margin: 0 0 0.4rem;
}

.gss-results-header p {
    color: var(--gss-text-secondary);
    margin: 0;
}

.gss-sheet-preview-wrap {
    display: inline-block;
    background:
        linear-gradient(45deg, var(--gss-checker-light) 25%, transparent 25%),
        linear-gradient(-45deg, var(--gss-checker-light) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--gss-checker-light) 75%),
        linear-gradient(-45deg, transparent 75%, var(--gss-checker-light) 75%);
    background-size: 14px 14px;
    background-position: 0 0, 0 7px, 7px -7px, -7px 0;
    background-color: var(--gss-checker-dark);
    border-radius: var(--gss-radius-lg);
    padding: 1rem;
    max-width: 100%;
    max-height: 380px;
    overflow: auto;
    border: 1px solid var(--gss-border);
    margin-bottom: 1.5rem;
}

.gss-sheet-preview-wrap img {
    max-width: 100%;
    border-radius: var(--gss-radius-sm);
    box-shadow: var(--gss-shadow-md);
}

.gss-results-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 1.75rem;
    flex-wrap: wrap;
}

.gss-stat-item { text-align: center; }

.gss-stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--gss-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.2rem;
}

.gss-stat-value {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--gss-text);
}

.gss-results-actions {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.gss-secondary-actions {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

/* ── Related Tools ───────────────────────────────── */
.gss-related-box {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.1rem 1.4rem;
    background: var(--gss-bg-elevated);
    border-radius: var(--gss-radius-lg);
    box-shadow: var(--gss-shadow-sm);
    border: 1px solid var(--gss-border);
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.gss-related-label {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-weight: 600;
    color: var(--gss-text);
    font-size: 0.875rem;
    white-space: nowrap;
}

.gss-related-label i,
.gss-related-label svg { color: var(--gss-primary); }

.gss-related-links {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.gss-related-link {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.38rem 0.85rem;
    background: var(--gss-bg-secondary);
    color: var(--gss-text-secondary);
    text-decoration: none;
    border-radius: var(--gss-radius-full);
    font-size: 0.82rem;
    font-weight: 500;
    border: 1px solid var(--gss-border);
    transition: all 0.2s;
}

.gss-related-link:hover {
    background: var(--gss-primary);
    color: #fff;
    border-color: var(--gss-primary);
    transform: translateY(-1px);
}

/* ── Info Cards ──────────────────────────────────── */
.gss-info-sections { display: grid; gap: 1.75rem; }

.gss-info-card {
    background: var(--gss-bg-elevated);
    border-radius: var(--gss-radius-xl);
    padding: 1.75rem;
    box-shadow: var(--gss-shadow-md);
    border: 1px solid var(--gss-border);
}

.gss-info-card h2 {
    display: flex;
    align-items: center;
    gap: 0.65rem;
    font-size: 1.25rem;
    color: var(--gss-text);
    margin: 0 0 1.25rem;
}

.gss-info-card h2 i,
.gss-info-card h2 svg {
    color: var(--gss-primary);
    flex-shrink: 0;
}

/* Steps */
.gss-steps {
    list-style: none;
    padding: 0;
    margin: 0;
    counter-reset: gss-step;
}

.gss-steps li {
    position: relative;
    padding-left: 3rem;
    padding-bottom: 1.1rem;
    counter-increment: gss-step;
    color: var(--gss-text-secondary);
    line-height: 1.6;
}

.gss-steps li:not(:last-child)::after {
    content: '';
    position: absolute;
    left: 0.9rem;
    top: 2rem;
    bottom: 0;
    width: 2px;
    background: var(--gss-border);
}

.gss-steps li::before {
    content: counter(gss-step);
    position: absolute;
    left: 0;
    top: 0;
    width: 1.9rem;
    height: 1.9rem;
    background: var(--gss-primary);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.82rem;
    z-index: 1;
}

.gss-steps li a { color: var(--gss-primary); text-decoration: none; }
.gss-steps li a:hover { text-decoration: underline; }

/* Mode explanations */
.gss-mode-list { display: grid; gap: 0.85rem; }

.gss-mode-row {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.gss-mode-tag {
    flex-shrink: 0;
    padding: 0.3rem 0.75rem;
    border-radius: var(--gss-radius-full);
    font-size: 0.77rem;
    font-weight: 700;
    color: #fff;
    letter-spacing: 0.03em;
}

.gss-mode-tag.horizontal { background: var(--gss-horizontal); }
.gss-mode-tag.vertical   { background: var(--gss-vertical); }
.gss-mode-tag.grid       { background: var(--gss-grid); }
.gss-mode-tag.auto       { background: var(--gss-auto); }

.gss-mode-row p {
    margin: 0;
    color: var(--gss-text-secondary);
    font-size: 0.925rem;
    line-height: 1.6;
}

/* Features grid */
.gss-features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
    gap: 1rem;
}

.gss-feat-card {
    padding: 1rem;
    background: var(--gss-bg-secondary);
    border-radius: var(--gss-radius-md);
    border: 1px solid var(--gss-border);
}

.gss-feat-card i,
.gss-feat-card svg {
    color: var(--gss-primary);
    margin-bottom: 0.5rem;
}

.gss-feat-card h4 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--gss-text);
    margin: 0 0 0.35rem;
}

.gss-feat-card p {
    font-size: 0.83rem;
    color: var(--gss-text-secondary);
    margin: 0;
    line-height: 1.5;
}

.gss-feat-card a { color: var(--gss-primary); text-decoration: none; }
.gss-feat-card a:hover { text-decoration: underline; }

/* FAQ */
.gss-faq-list { display: grid; gap: 0.6rem; }

.gss-faq-item {
    border: 1px solid var(--gss-border);
    border-radius: var(--gss-radius-md);
    overflow: hidden;
}

.gss-faq-q {
    width: 100%;
    padding: 0.9rem 1.1rem;
    background: var(--gss-bg-secondary);
    border: none;
    text-align: left;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--gss-text);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.75rem;
    transition: background 0.2s;
}

.gss-faq-q:hover { background: var(--gss-bg-tertiary); }

.gss-faq-q i,
.gss-faq-q svg {
    color: var(--gss-primary);
    transition: transform 0.3s;
    flex-shrink: 0;
}

.gss-faq-item.active .gss-faq-q i,
.gss-faq-item.active .gss-faq-q svg { transform: rotate(180deg); }

.gss-faq-a {
    display: none;
    padding: 0.75rem 1.1rem 1rem;
    background: var(--gss-bg-elevated);
}

.gss-faq-item.active .gss-faq-a { display: block; }

.gss-faq-a p {
    margin: 0;
    color: var(--gss-text-secondary);
    line-height: 1.7;
    font-size: 0.9rem;
}

.gss-faq-a a { color: var(--gss-primary); text-decoration: none; }
.gss-faq-a a:hover { text-decoration: underline; }

/* ── Processing Overlay (fixed, modal) ───────────── */
.gss-processing-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.55);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(3px);
}

.gss-processing-overlay[style*="display: flex"],
.gss-processing-overlay.active {
    display: flex !important;
}

.gss-processing-overlay .gss-processing-box {
    background: var(--gss-bg-elevated);
    padding: 2.5rem 3rem;
    border-radius: var(--gss-radius-xl);
    text-align: center;
    box-shadow: var(--gss-shadow-xl);
    min-width: 300px;
    max-width: 90vw;
    border: 1px solid var(--gss-border);
}

/* ── FAQ open state (JS uses .open not .active) ──── */
/* Also support .active for any inline JS fallback */
.faq-item.open .faq-answer,
.gss-faq-item.open .gss-faq-a { display: block; }

.faq-item.open .faq-question i,
.faq-item.open .faq-question svg,
.gss-faq-item.open .gss-faq-q i,
.gss-faq-item.open .gss-faq-q svg { transform: rotate(180deg); }

/* Base aliases so .faq-item/.faq-question/.faq-answer inherit gss styles */
.faq-item { }
.faq-answer { display: none; }

/* ── Animations ──────────────────────────────────── */
@keyframes gss-fade {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ── Responsive ──────────────────────────────────── */
@media (max-width: 900px) {
    .gss-lb-wrap { grid-template-columns: 260px 1fr; }
    .gss-file-bar { justify-content: flex-start; }
}

@media (max-width: 768px) {
    /* Stack sidebar above main on tablet/mobile */
    .gss-lb-wrap {
        grid-template-columns: 1fr;
        min-height: auto;
    }
    .gss-lb-sidebar {
        border-right: none;
        border-bottom: 1px solid var(--gss-border);
        max-height: none;
        overflow-y: visible;
    }
    .gss-lb-actions { position: static; }
    .gss-lb-frames-panel,
    .gss-lb-sprite-panel { flex: none; }
    .gss-lb-sprite-panel .gss-sprite-wrap {
        min-height: 220px;
        max-height: 380px;
        border-radius: var(--gss-radius-md);
        border: 1px solid var(--gss-border);
    }
    .gss-upload-section,
    .gss-results { padding: 1.5rem; }
    .gss-layout-options { grid-template-columns: repeat(2, 1fr); }
    .gss-ctrl-row { grid-template-columns: 1fr; }
    .gss-btn { width: 100%; }
    .gss-related-box { flex-direction: column; }
    .gss-related-links { justify-content: flex-start; }
    .gss-speed-row { margin-left: 0; padding-left: 0; border-left: none; width: 100%; justify-content: center; }
    .gss-lb-panel-header { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 480px) {
    .gss-title-row { flex-direction: row; gap: 0.65rem; }
    .gss-icon-wrap { width: 44px; height: 44px; }
    .gss-file-bar { flex-direction: column; gap: 0.6rem; }
    .gss-results-actions,
    .gss-secondary-actions { flex-direction: column; }
    .gss-features-grid { grid-template-columns: 1fr; }
    .gss-lb-panel-tools { flex-direction: column; align-items: flex-start; }
}

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