/* ==========================================================================
   Conway's Game of Life - Monotone Minimalist Styling
   ========================================================================== */

:root {
    --bg-primary: #0d0f12;
    --bg-secondary: #14171d;
    --bg-tertiary: #1b1f27;
    --bg-card: #181b22;
    --bg-hover: #262b36;
    --bg-active: #323846;

    --border-color: #272c38;
    --border-subtle: #1e222c;
    --border-focus: #525c6e;

    --text-primary: #f3f4f6;
    --text-secondary: #9ca3af;
    --text-muted: #6b7280;
    --text-inverse: #0d0f12;

    --cell-alive: #ffffff;
    --cell-ghost: rgba(255, 255, 255, 0.45);
    --grid-line: #1c202a;

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-full: 9999px;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.6);
    --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.8);

    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
}

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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    touch-action: manipulation;
}

/* App Root Container */
.app-container {
    display: flex;
    flex-direction: column;
    width: 100vw;
    height: 100vh;
    height: 100dvh;
    overflow: hidden;
}

/* ==========================================================================
   Header
   ========================================================================== */
.app-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 20px;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
    gap: 12px;
    z-index: 20;
}

.header-left {
    display: flex;
    align-items: center;
}

.app-logo {
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    font-size: 16px;
    color: var(--text-primary);
    line-height: 1;
}

.app-title {
    font-size: 16px;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    white-space: nowrap;
}

.header-stats {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.stat-badge {
    display: flex;
    align-items: center;
    gap: 6px;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    padding: 4px 10px;
    border-radius: var(--radius-full);
    font-size: 13px;
    white-space: nowrap;
    flex-shrink: 0;
}

.stat-label {
    color: var(--text-secondary);
    font-weight: 500;
    white-space: nowrap;
}

.stat-value {
    font-family: var(--font-mono);
    font-weight: 700;
    color: var(--text-primary);
    min-width: 28px;
    white-space: nowrap;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 8px;
}

/* ==========================================================================
   Main Layout & Canvas Section
   ========================================================================== */
.main-layout {
    display: flex;
    flex: 1;
    overflow: hidden;
    position: relative;
}

.canvas-section {
    display: flex;
    flex-direction: column;
    flex: 1;
    height: 100%;
    position: relative;
    overflow: hidden;
    background-color: var(--bg-primary);
}

/* Placement Banner */
.placement-banner {
    position: absolute;
    top: 14px;
    left: 50%;
    transform: translateX(-50%);
    background-color: rgba(24, 27, 34, 0.95);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--text-primary);
    border-radius: var(--radius-full);
    padding: 6px 14px;
    display: flex;
    align-items: center;
    gap: 16px;
    z-index: 15;
    box-shadow: var(--shadow-lg);
    animation: slideDown 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translate(-50%, -10px);
    }
    to {
        opacity: 1;
        transform: translate(-50%, 0);
    }
}

.placement-info {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
}

.placement-badge {
    color: var(--text-muted);
}

.placement-dim {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--text-secondary);
}

.placement-actions {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* Canvas Wrapper */
.canvas-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    padding: 12px;
}

#lifeCanvas {
    display: block;
    background-color: #07080a;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    cursor: crosshair;
    touch-action: none;
}

.canvas-hint {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background-color: rgba(20, 23, 29, 0.8);
    border: 1px solid var(--border-subtle);
    padding: 4px 12px;
    border-radius: var(--radius-full);
    font-size: 12px;
    color: var(--text-muted);
    pointer-events: none;
    transition: opacity 0.4s ease;
}

.canvas-hint.fade-out {
    opacity: 0;
}

/* ==========================================================================
   Control Panel
   ========================================================================== */
.control-panel {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    padding: 10px 20px;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    flex-shrink: 0;
    z-index: 10;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.control-label {
    font-size: 12px;
    font-weight: 500;
    color: var(--text-secondary);
}

/* Speed Controls */
.speed-group {
    background-color: var(--bg-tertiary);
    padding: 4px 10px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-subtle);
}

#speedSlider {
    -webkit-appearance: none;
    appearance: none;
    width: 90px;
    height: 4px;
    background: var(--bg-hover);
    border-radius: var(--radius-full);
    outline: none;
    cursor: pointer;
}

#speedSlider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--text-primary);
    cursor: pointer;
    transition: transform var(--transition-fast);
}

#speedSlider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

#speedSlider::-moz-range-thumb {
    width: 14px;
    height: 14px;
    border: none;
    border-radius: 50%;
    background: var(--text-primary);
    cursor: pointer;
}

.speed-indicator {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--text-primary);
    min-width: 82px;
    text-align: right;
}

/* Grid Size Select */
.select-wrapper {
    display: flex;
    align-items: center;
    gap: 6px;
}

select {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-subtle);
    padding: 6px 10px;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 13px;
    outline: none;
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

select:hover, select:focus {
    border-color: var(--border-focus);
}

.toggles-wrapper {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* ==========================================================================
   Buttons & UI Elements
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 7px 14px;
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
    white-space: nowrap;
    text-decoration: none;
}

.btn-primary {
    background-color: var(--text-primary);
    color: var(--text-inverse);
    border-color: var(--text-primary);
    font-weight: 600;
}

.btn-primary:hover {
    background-color: #e5e7eb;
    border-color: #e5e7eb;
}

.btn-primary:active {
    transform: scale(0.98);
}

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

.btn-secondary:hover {
    background-color: var(--bg-hover);
    border-color: var(--border-focus);
}

.btn-secondary:active {
    background-color: var(--bg-active);
}

.btn-secondary.active {
    background-color: var(--bg-hover);
    border-color: var(--text-primary);
}

.btn-danger {
    background-color: var(--bg-tertiary);
    color: #f87171;
    border-color: rgba(248, 113, 113, 0.3);
}

.btn-danger:hover {
    background-color: rgba(248, 113, 113, 0.15);
    border-color: #f87171;
}

.btn-small {
    padding: 4px 10px;
    font-size: 12px;
}

.btn-mini {
    padding: 3px 8px;
    font-size: 11px;
    font-family: var(--font-mono);
}

.icon-btn {
    padding: 7px;
}

.lang-btn {
    padding: 5px 9px;
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 12px;
}

.main-play-btn {
    min-width: 90px;
}

/* ==========================================================================
   Presets Sidebar / Panel
   ========================================================================== */
.presets-sidebar {
    width: 320px;
    background-color: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    z-index: 18;
    transition: transform var(--transition-normal), width var(--transition-normal);
}

.presets-sidebar.collapsed {
    display: none;
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 16px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-title {
    display: flex;
    align-items: center;
    gap: 8px;
}

.sidebar-title h2 {
    font-size: 14px;
    font-weight: 600;
}

.close-sidebar-btn {
    display: none;
}

/* Category Tabs */
.preset-tabs {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 4px;
    gap: 4px;
}

.preset-tab {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-family: var(--font-sans);
    font-size: 12px;
    font-weight: 500;
    padding: 6px 2px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    text-align: center;
    transition: all var(--transition-fast);
}

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

.preset-tab.active {
    color: var(--text-primary);
    background-color: var(--bg-tertiary);
    font-weight: 600;
}

/* Presets List */
.presets-list {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.preset-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 10px;
    display: flex;
    gap: 10px;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.preset-card:hover {
    border-color: var(--border-focus);
    background-color: var(--bg-hover);
    transform: translateY(-1px);
}

.preset-card.selected {
    border-color: var(--text-primary);
    background-color: var(--bg-active);
}

.preset-thumbnail {
    width: 54px;
    height: 54px;
    background-color: #07080a;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.preset-thumbnail canvas {
    image-rendering: pixelated;
}

.preset-details {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-width: 0;
}

.preset-meta-top {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 6px;
}

.preset-name {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preset-size {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    flex-shrink: 0;
}

.preset-desc {
    font-size: 11px;
    color: var(--text-secondary);
    line-height: 1.35;
    margin-top: 2px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.preset-card-actions {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-top: 6px;
}

/* ==========================================================================
   Help Modal
   ========================================================================== */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    padding: 20px;
    opacity: 1;
    transition: opacity var(--transition-normal);
}

.modal-backdrop.hidden {
    display: none;
    opacity: 0;
}

.modal-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 720px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
    animation: modalIn 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes modalIn {
    from {
        opacity: 0;
        transform: scale(0.96) translateY(8px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 16px;
    font-weight: 700;
}

.modal-close-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 18px;
    cursor: pointer;
    padding: 4px;
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast);
}

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

.modal-body {
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.rules-heading, .help-section h3 {
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.rules-intro {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 16px;
}

.rules-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
}

.rule-card {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: 14px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.rule-header {
    display: flex;
    align-items: center;
    gap: 8px;
}

.rule-badge {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 700;
    font-family: var(--font-mono);
    background-color: var(--text-primary);
    color: var(--text-inverse);
}

.rule-header h4 {
    font-size: 14px;
    font-weight: 600;
}

.rule-card p {
    font-size: 12px;
    color: var(--text-secondary);
    line-height: 1.45;
}

.rule-card p strong {
    color: var(--text-primary);
}

.rule-diagram {
    display: grid;
    grid-template-columns: repeat(3, 20px);
    grid-template-rows: repeat(3, 20px);
    gap: 3px;
    margin: 4px auto;
    background-color: #07080a;
    padding: 4px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-subtle);
}

.diagram-cell {
    width: 20px;
    height: 20px;
    border-radius: 2px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 10px;
    font-family: var(--font-mono);
}

.diagram-cell.dead {
    background-color: var(--bg-secondary);
    color: var(--text-muted);
}

.diagram-cell.alive {
    background-color: var(--cell-alive);
    color: var(--text-inverse);
}

.diagram-cell.center-target {
    border: 1px solid #9ca3af;
}

.diagram-arrow {
    text-align: center;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-primary);
    font-family: var(--font-mono);
}

.shortcuts-table-wrapper {
    overflow-x: auto;
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
}

.shortcuts-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
    text-align: left;
}

.shortcuts-table th, .shortcuts-table td {
    padding: 10px 14px;
    border-bottom: 1px solid var(--border-subtle);
}

.shortcuts-table th {
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 12px;
}

.shortcuts-table tr:last-child td {
    border-bottom: none;
}

kbd {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-focus);
    border-radius: var(--radius-sm);
    padding: 2px 6px;
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-primary);
    box-shadow: 0 1px 0 var(--border-focus);
}

.modal-footer {
    padding: 14px 20px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
}

/* Helpers */
.hidden {
    display: none !important;
}

/* ==========================================================================
   Responsive Design (Mobile / Tablet)
   ========================================================================== */
@media (max-width: 900px) {
    .btn-label-desktop {
        display: none;
    }

    .stat-badge {
        padding: 4px 8px;
        font-size: 12px;
    }

    .rules-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .app-header {
        padding: 8px 12px;
    }

    .app-title {
        font-size: 14px;
    }

    .btn-text {
        display: none;
    }

    .stat-badge {
        padding: 3px 8px;
        font-size: 12px;
        gap: 4px;
    }

    .presets-sidebar {
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100vw;
        height: 60vh;
        max-height: 480px;
        border-left: none;
        border-top: 1px solid var(--border-color);
        box-shadow: var(--shadow-lg);
        transform: translateY(0);
        z-index: 50;
    }

    .presets-sidebar.collapsed {
        display: block;
        transform: translateY(100%);
    }

    .close-sidebar-btn {
        display: block;
    }

    .control-panel {
        padding: 8px 12px;
        gap: 8px;
    }

    .control-group {
        width: 100%;
        justify-content: space-between;
    }

    .playback-group {
        order: 1;
        justify-content: space-around;
    }

    .speed-group {
        order: 2;
        flex: 1;
    }

    .options-group {
        order: 3;
        flex: 1;
        justify-content: space-between;
    }

    #speedSlider {
        width: 70px;
    }

    .placement-banner {
        width: calc(100% - 24px);
        flex-direction: column;
        gap: 8px;
        border-radius: var(--radius-md);
        padding: 8px 12px;
    }
}

@media (max-width: 600px) {
    .app-header {
        padding: 6px 10px;
        flex-wrap: wrap;
        gap: 6px 10px;
    }

    .header-left {
        order: 1;
    }

    .header-right {
        order: 2;
    }

    .header-stats {
        order: 3;
        width: 100%;
        justify-content: center;
        gap: 8px;
        padding-top: 2px;
    }

    .stat-badge {
        padding: 2px 8px;
        font-size: 11px;
    }
}