/* ==========================================================================
   N-QUEENS CONSTRAINT OPTIMIZATION & VISUALIZATION SYSTEM
   Aesthetic: Architectural Minimalist Monochrome / High-Contrast Black & White
   Designed for Clarity, High Information Density, and Elegance
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500;600;700&display=swap');

:root {
    /* Core Monochrome Palette */
    --bg-canvas: #09090b;
    --bg-surface: #121215;
    --bg-surface-elevated: #18181b;
    --bg-surface-hover: #222227;

    /* Borders */
    --border-subtle: #27272a;
    --border-medium: #3f3f46;
    --border-strong: #71717a;
    --border-white: rgba(255, 255, 255, 0.85);

    /* Text Hierarchy */
    --text-primary: #fafafa;
    --text-secondary: #a1a1aa;
    --text-muted: #71717a;
    --text-inverse: #09090b;

    /* Functional Accents */
    --accent-white: #ffffff;
    --accent-conflict: #f43f5e;
    --accent-safe: #e4e4e7;
    --accent-subtle-glow: rgba(255, 255, 255, 0.15);

    /* Chessboard Themes */
    /* Theme 1: Monochrome Minimal (Default) */
    --sq-light-mono: #f4f4f5;
    --sq-dark-mono: #27272a;

    /* Theme 2: Deep Obsidian */
    --sq-light-obsidian: #3f3f46;
    --sq-dark-obsidian: #18181b;

    /* Theme 3: Tournament Slate */
    --sq-light-classic: #e4e4e7;
    --sq-dark-classic: #52525b;

    /* UI Scale & Timing */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --transition: 0.18s cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
    background-color: var(--bg-canvas);
    color: var(--text-primary);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
    letter-spacing: -0.01em;
    -webkit-font-smoothing: antialiased;
}

/* ==========================================================================
   HEADER & TOP BAR
   ========================================================================== */

.app-header {
    background-color: rgba(9, 9, 11, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-subtle);
    padding: 16px 36px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 16px;
}

.brand-icon {
    width: 42px;
    height: 42px;
    overflow: hidden;
    background: #18181b;
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
}

.brand-icon img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
}

.brand-text h1 {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: -0.025em;
    color: var(--text-primary);
    line-height: 1.25;
}

.brand-text .tagline {
    display: flex;
    gap: 8px;
    margin-top: 4px;
}

.tagline-badge {
    background: #18181b;
    border: 1px solid var(--border-subtle);
    padding: 2px 7px;
    border-radius: 4px;
    font-size: 11px;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.btn-icon {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    font-size: 12px;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
}

.btn-icon:hover {
    background: var(--bg-surface-hover);
    border-color: var(--border-medium);
}

.btn-indicator {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: #52525b;
}

.btn-icon.active .btn-indicator {
    background: #ffffff;
    box-shadow: 0 0 6px rgba(255, 255, 255, 0.8);
}

/* ==========================================================================
   PRIMARY WORKSPACE LAYOUT
   ========================================================================== */

.app-main {
    flex: 1;
    display: grid;
    grid-template-columns: minmax(560px, 1.2fr) minmax(380px, 0.9fr);
    gap: 28px;
    padding: 28px 36px;
    max-width: 1680px;
    margin: 0 auto;
    width: 100%;
}

/* ==========================================================================
   LEFT COLUMN: CHESSBOARD, CONTROLS & STAGE
   ========================================================================== */

.board-stage-wrapper {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Configuration Ribbon */
.config-ribbon {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 14px 20px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.config-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.config-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.n-picker {
    display: flex;
    align-items: center;
    gap: 10px;
}

.n-slider {
    -webkit-appearance: none;
    appearance: none;
    width: 110px;
    height: 4px;
    border-radius: 2px;
    background: var(--border-subtle);
    outline: none;
}

.n-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: #ffffff;
    border: 2px solid #09090b;
    cursor: pointer;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.6);
}

.n-badge {
    background: #ffffff;
    color: #000000;
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
    font-size: 13px;
    padding: 2px 8px;
    border-radius: 4px;
    min-width: 28px;
    text-align: center;
}

.quick-n-btns {
    display: flex;
    gap: 4px;
}

.btn-quick-n {
    background: var(--bg-surface-elevated);
    border: 1px solid var(--border-subtle);
    color: var(--text-secondary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    font-weight: 600;
    padding: 3px 8px;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
}

.btn-quick-n:hover {
    color: var(--text-primary);
    background: var(--bg-surface-hover);
    border-color: var(--border-medium);
}

.select-modern {
    background: var(--bg-surface-elevated);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 13px;
    font-weight: 500;
    padding: 7px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    outline: none;
    transition: var(--transition);
}

.select-modern:focus {
    border-color: var(--border-strong);
}

/* Board Container Frame */
.board-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.board-viewport {
    position: relative;
    width: 100%;
    max-width: 580px;
    aspect-ratio: 1 / 1;
    border-radius: 8px;
    padding: 10px;
    background: #09090b;
    border: 1px solid var(--border-medium);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.6);
}

/* Chessboard Grid */
.chessboard {
    display: grid;
    grid-template-columns: repeat(var(--grid-size, 8), 1fr);
    grid-template-rows: repeat(var(--grid-size, 8), 1fr);
    width: 100%;
    height: 100%;
    position: relative;
    border-radius: 4px;
    overflow: hidden;
    user-select: none;
}

.attack-overlay-svg {
    position: absolute;
    top: 10px;
    left: 10px;
    width: calc(100% - 20px);
    height: calc(100% - 20px);
    pointer-events: none;
    z-index: 20;
}

.board-cell {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.15s ease;
}

/* Board Theme: Monochrome Minimal */
.theme-monochrome .light-cell { background-color: var(--sq-light-mono); }
.theme-monochrome .dark-cell  { background-color: var(--sq-dark-mono); }

/* Board Theme: Deep Obsidian */
.theme-obsidian .light-cell { background-color: var(--sq-light-obsidian); }
.theme-obsidian .dark-cell  { background-color: var(--sq-dark-obsidian); }

/* Board Theme: Tournament Slate */
.theme-classic .light-cell { background-color: var(--sq-light-classic); }
.theme-classic .dark-cell  { background-color: var(--sq-dark-classic); }

/* Coordinate Labels */
.coord-label {
    position: absolute;
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    font-weight: 700;
    pointer-events: none;
    opacity: 0.6;
}

.rank-label { top: 3px; left: 4px; }
.file-label { bottom: 3px; right: 4px; }

.light-cell .coord-label { color: #52525b; }
.dark-cell .coord-label  { color: #a1a1aa; }

/* Threat Heatmap */
.board-cell.has-threat {
    background-image: radial-gradient(circle, rgba(244, 63, 94, calc(var(--threat-intensity, 0.3) * 0.5)) 0%, transparent 80%);
}

.threat-badge {
    position: absolute;
    top: 3px;
    right: 4px;
    font-size: 9px;
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
    color: #f43f5e;
    background: rgba(0, 0, 0, 0.7);
    padding: 1px 4px;
    border-radius: 3px;
    display: none;
    z-index: 5;
}

/* Cell States */
.cell-candidate {
    box-shadow: inset 0 0 0 2px #ffffff;
    background-color: rgba(255, 255, 255, 0.18) !important;
}

.cell-conflict {
    box-shadow: inset 0 0 0 2px var(--accent-conflict);
    background-color: rgba(244, 63, 94, 0.25) !important;
    animation: shake 0.2s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
}

.cell-placed {
    box-shadow: inset 0 0 10px rgba(255, 255, 255, 0.1);
}

.victory-pulse {
    animation: flashMono 0.8s ease-out;
}

@keyframes shake {
    10%, 90% { transform: translate3d(-1px, 0, 0); }
    20%, 80% { transform: translate3d(2px, 0, 0); }
    30%, 50%, 70% { transform: translate3d(-2px, 0, 0); }
    40%, 60% { transform: translate3d(2px, 0, 0); }
}

@keyframes flashMono {
    0% { background-color: #ffffff !important; }
    100% { background-color: inherit; }
}

/* Piece Slot & 3D Vector Queen */
.piece-slot {
    width: 82%;
    height: 82%;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10;
}

.chess-queen-svg {
    width: 100%;
    height: 100%;
    filter: drop-shadow(0 3px 5px rgba(0, 0, 0, 0.6));
    transition: transform 0.18s ease;
}

.piece-drop .chess-queen-svg {
    animation: pieceSlam 0.2s cubic-bezier(0.2, 0.8, 0.2, 1);
}

@keyframes pieceSlam {
    0% { transform: translateY(-25%) scale(1.15); opacity: 0.7; }
    100% { transform: translateY(0) scale(1); opacity: 1; }
}

.chess-queen-svg.state-conflict {
    filter: drop-shadow(0 0 8px rgba(244, 63, 94, 0.9));
}

.chess-queen-svg.state-testing {
    opacity: 0.85;
}

/* Attack Rays */
.laser-beam {
    animation: beamDash 0.7s linear infinite;
}

@keyframes beamDash {
    to { stroke-dashoffset: -20; }
}

.threat-ripple {
    animation: ripple 0.8s ease-out infinite;
}

@keyframes ripple {
    0% { r: 8px; opacity: 1; }
    100% { r: 35px; opacity: 0; }
}

/* Sandbox Interaction */
.chessboard.sandbox-active .board-cell {
    cursor: pointer;
}

.chessboard.sandbox-active .board-cell:hover {
    box-shadow: inset 0 0 0 2px #ffffff;
}

/* Step Description HUD */
.step-hud {
    width: 100%;
    background: #09090b;
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    padding: 12px 18px;
    margin-top: 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 13px;
    min-height: 46px;
}

.hud-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #ffffff;
    box-shadow: 0 0 8px rgba(255, 255, 255, 0.5);
    flex-shrink: 0;
}

.hud-text {
    color: var(--text-primary);
    line-height: 1.4;
    font-weight: 500;
}

/* Playback Control Deck */
.control-deck {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 14px 20px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.playback-btns {
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-ctrl {
    background: var(--bg-surface-elevated);
    border: 1px solid var(--border-subtle);
    color: var(--text-primary);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: var(--transition);
}

.btn-ctrl:hover {
    background: var(--bg-surface-hover);
    border-color: var(--border-medium);
}

.btn-primary-action {
    background: #ffffff;
    color: #000000;
    border: 1px solid #ffffff;
    padding: 8px 18px;
    font-weight: 700;
}

.btn-primary-action:hover {
    background: #e4e4e7;
    border-color: #e4e4e7;
}

.btn-pause-action {
    background: var(--bg-surface-elevated);
    color: #ffffff;
    border: 1px solid var(--border-strong);
    padding: 8px 18px;
    font-weight: 700;
}

.speed-control {
    display: flex;
    align-items: center;
    gap: 10px;
}

.speed-slider {
    -webkit-appearance: none;
    appearance: none;
    width: 90px;
    height: 4px;
    border-radius: 2px;
    background: var(--border-subtle);
    outline: none;
}

.speed-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: #ffffff;
    cursor: pointer;
}

.speed-display {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 600;
    min-width: 85px;
}

.toggles-strip {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
    font-size: 12px;
    color: var(--text-secondary);
}

.toggle-label {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    user-select: none;
}

.toggle-label input[type="checkbox"] {
    accent-color: #ffffff;
    width: 15px;
    height: 15px;
    cursor: pointer;
}

/* Sandbox Toolbar */
.sandbox-toolbar {
    background: #141417;
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-sm);
    padding: 10px 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    font-size: 13px;
}

.sandbox-actions {
    display: flex;
    gap: 8px;
}

/* ==========================================================================
   RIGHT COLUMN: TELEMETRY, LOGS (BEFORE DEPTH), AND METRICS
   ========================================================================== */

.analytics-wrapper {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* 1. Live Telemetry Grid (6 Metrics) */
.telemetry-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.metric-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.metric-title {
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.metric-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

.metric-value.highlight-warning { color: #f43f5e; }
.metric-value.highlight-white { color: #ffffff; }

/* 2. Algorithm Activity Logs Card (Placed BEFORE Recursion Depth!) */
.logs-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    max-height: 290px;
    min-height: 220px;
}

.card-heading {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logs-heading-actions {
    display: flex;
    align-items: center;
    gap: 10px;
}

.btn-log-clear {
    background: transparent;
    border: 1px solid var(--border-medium);
    color: var(--text-secondary);
    font-size: 10.5px;
    font-weight: 600;
    padding: 2px 8px;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
}

.btn-log-clear:hover {
    color: var(--text-primary);
    border-color: var(--text-muted);
    background: var(--bg-surface-elevated);
}

.metric-sublabel {
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 500;
    font-family: 'JetBrains Mono', monospace;
}

.logs-stream {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 5px;
    margin-top: 10px;
    padding-right: 4px;
}

.log-entry {
    background: #09090b;
    border: 1px solid var(--border-subtle);
    border-left: 3px solid var(--border-medium);
    padding: 6px 10px;
    border-radius: 4px;
    font-size: 11.5px;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
}

.log-entry:hover {
    background: var(--bg-surface-elevated);
    border-color: var(--border-medium);
}

.log-entry.active {
    background: var(--bg-surface-elevated);
    border-left-color: #ffffff;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.05);
}

.log-tag {
    font-family: 'JetBrains Mono', monospace;
    font-size: 9.5px;
    font-weight: 700;
    padding: 2px 5px;
    border-radius: 3px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: #27272a;
    color: #e4e4e7;
}

.log-tag.tag-place_queen { background: rgba(34, 197, 94, 0.15); color: #4ade80; border: 1px solid rgba(34, 197, 94, 0.6); }
.log-tag.tag-conflict_detected { background: #3f151c; color: #f43f5e; border: 1px solid #f43f5e; }
.log-tag.tag-backtrack { background: #1c1917; color: #a8a29e; }
.log-tag.tag-solution_found,
.log-tag.tag-complete { background: #052e16; color: #22c55e; border: 1px solid #22c55e; font-weight: 800; }

/* Safe placements highlighted in a lighter green */
.log-entry.log-place_queen {
    border-left-color: rgba(34, 197, 94, 0.7);
}

.log-entry.log-place_queen .log-text {
    color: #86efac;
}

.log-entry.log-place_queen.active {
    background: rgba(34, 197, 94, 0.1);
    border-left-color: #22c55e;
}

/* Success / completion entries highlighted in green */
.log-entry.log-solution_found,
.log-entry.log-complete {
    background: rgba(34, 197, 94, 0.08);
    border-color: rgba(34, 197, 94, 0.35);
    border-left-color: #22c55e;
}

.log-entry.log-solution_found .log-text,
.log-entry.log-complete .log-text {
    color: #4ade80;
}

.log-entry.log-solution_found.active,
.log-entry.log-complete.active {
    background: rgba(34, 197, 94, 0.15);
    border-left-color: #22c55e;
    box-shadow: 0 0 10px rgba(34, 197, 94, 0.2);
}

.log-step-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 10.5px;
    color: var(--text-muted);
}

.log-text {
    color: var(--text-secondary);
    font-size: 11.5px;
}

.log-entry.active .log-text {
    color: var(--text-primary);
}

/* 3. Recursion Depth & Complexity Combined Card */
.depth-complexity-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.depth-progress-container {
    width: 100%;
    height: 5px;
    background: #09090b;
    border-radius: 2px;
    overflow: hidden;
    margin-top: 2px;
}

.depth-progress-bar {
    height: 100%;
    width: 0%;
    background: #ffffff;
    transition: width 0.15s ease;
}

.complexity-subheading {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
    padding-top: 8px;
    border-top: 1px solid var(--border-subtle);
}

.complexity-breakdown {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.comp-item {
    background: #09090b;
    padding: 10px;
    border-radius: 6px;
    border: 1px solid var(--border-subtle);
}

.comp-title {
    color: var(--text-muted);
    font-size: 10.5px;
    margin-bottom: 4px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.comp-math {
    font-family: 'JetBrains Mono', monospace;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
}

/* ==========================================================================
   BOTTOM DRAWER: SOLUTIONS GALLERY
   ========================================================================== */

.solutions-drawer {
    border-top: 1px solid var(--border-subtle);
    background: #0c0c0e;
    padding: 20px 36px 32px 36px;
}

.app-footer {
    border-top: 1px solid var(--border-subtle);
    background: #09090b;
    padding: 16px 36px;
    text-align: center;
    font-size: 12px;
    color: var(--text-muted);
}

.app-footer strong {
    color: var(--text-primary);
    font-weight: 600;
}

.drawer-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.drawer-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.solutions-grid {
    display: flex;
    gap: 14px;
    overflow-x: auto;
    padding-bottom: 8px;
}

.solution-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    padding: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    min-width: 130px;
    transition: var(--transition);
}

.solution-card:hover {
    transform: translateY(-2px);
    border-color: #ffffff;
}

.mini-chessboard {
    display: grid;
    grid-template-columns: repeat(var(--mini-n, 8), 1fr);
    grid-template-rows: repeat(var(--mini-n, 8), 1fr);
    width: 100px;
    height: 100px;
    border-radius: 3px;
    overflow: hidden;
    border: 1px solid var(--border-subtle);
}

.mini-cell {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 8px;
}

.mini-cell.light { background: #e4e4e7; }
.mini-cell.dark  { background: #27272a; }

.mini-cell.has-queen {
    background: #ffffff !important;
    color: #000000;
    font-weight: bold;
}

.sol-label {
    font-size: 11.5px;
    font-weight: 600;
    color: var(--text-primary);
}

.sol-notation {
    font-family: 'JetBrains Mono', monospace;
    font-size: 9.5px;
    color: var(--text-muted);
    text-align: center;
    max-width: 110px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.empty-gallery {
    font-size: 12px;
    color: var(--text-muted);
    padding: 16px 0;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 5px;
    height: 5px;
}
::-webkit-scrollbar-track {
    background: var(--bg-canvas);
}
::-webkit-scrollbar-thumb {
    background: var(--border-subtle);
    border-radius: 2px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--border-medium);
}

/* ==========================================================================
   RESPONSIVE DESIGN
   ========================================================================== */

@media (max-width: 1100px) {
    .app-main {
        grid-template-columns: 1fr;
    }
    .board-card {
        padding: 16px;
    }
}

@media (max-width: 640px) {
    .app-header {
        padding: 12px 16px;
        flex-direction: column;
        gap: 12px;
        align-items: flex-start;
    }
    .app-main {
        padding: 16px;
    }
    .telemetry-grid {
        grid-template-columns: 1fr;
    }
    .complexity-breakdown {
        grid-template-columns: 1fr;
    }
}