:root {
    /* Chess.com Dark Theme Palette */
    --bg-dark: #302e2b;
    --bg-panel: #262421;
    --text-main: #ffffff;
    --text-muted: #bababa;

    --primary-accent: #81b64c;
    /* Chess.com Green button */
    --secondary-accent: #454341;

    /* Board Colors (Green Theme) */
    --board-white: #eeeed2;
    --board-black: #769656;

    --highlight-move: rgba(0, 0, 0, 0.14);
    /* Subtle dot shadow */
    --selected-square: rgba(247, 247, 105, 0.6);
    /* Standard Yellow */

    --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

body {
    font-family: var(--font-main);
    background-color: var(--bg-dark);
    color: var(--text-main);
    min-height: 100vh;
    overflow-x: hidden;
}

.app-container {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 2rem;
    gap: 2rem;
    max-width: 1400px;
    margin: 0 auto;
    min-height: 100vh;
}

/* Background Effects - Removed for clean look */
.bg-orb {
    display: none;
}

/* Glassmorphism Panel */
/* Removed as per instruction to remove space/orb effects and glassmorphism is no longer part of the theme */

/* Header */
.main-header {
    display: block;
    /* Restore visibility */
    text-align: center;
    padding: 1rem 0 2rem 0;
    width: 100%;
    margin-bottom: 1rem;
}

.main-header h1 {
    font-weight: 800;
    font-size: 3rem;
    margin: 0;
    /* Beautiful Gradient Text */
    background: linear-gradient(135deg, #ffffff 30%, var(--primary-accent) 100%);
    background-clip: text;
    /* Standard property */
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -1px;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.tagline {
    color: var(--text-muted);
    font-size: 1.1rem;
    font-weight: 400;
    margin-top: 0.5rem;
    opacity: 0.8;
    letter-spacing: 0.5px;
}

/* Layout */
.game-area {
    display: flex;
    gap: 0;
    /* Connected look */
    width: 100%;
    justify-content: center;
    align-items: flex-start;
    flex-wrap: wrap;
}

/* Board */
.board-container {
    padding: 5px;
    /* Border rim */
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    /* Deep shadow */
    border-radius: 4px;
    overflow: hidden;
    background: #262421;
    /* Dark rim matching sidebar */
    margin: 1rem 0;
    /* Spacing from bars */
    border: 3px solid #383633;
}

.chess-board {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    grid-template-rows: repeat(8, 1fr);
    width: 600px !important;
    height: 600px !important;
    max-width: 100%;
    aspect-ratio: 1/1;
    border: none;
    user-select: none;
    background-color: #302e2b;
    /* Fallback bg */
}

@media (max-width: 900px) {
    .app-container {
        flex-direction: column;
        align-items: center;
        padding: 1rem;
    }

    .game-area {
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }

    .chess-board {
        width: 90vw;
        height: 90vw;
    }
}

.square {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    cursor: pointer;
}

/* Fix empty ruleset if it exists here, or remove it */
/* Also ensuring board colors are robust */
:root {
    --board-white: #eeeed2;
    --board-black: #769656;
    /* ... other vars ... */
}

/* Ensuring .square has a background even if variables fail (unlikely but good for debug) */
.square.white {
    background-color: #eeeed2;
    /* Fallback */
    background-color: var(--board-white);
    color: var(--board-black);
}

.square.black {
    background-color: #769656;
    /* Fallback */
    background-color: var(--board-black);
    color: var(--board-white);
}

/* Highlight Styles - Matching User Reference */
.square.selected {
    background-color: rgba(246, 246, 105, 0.6) !important;
    /* Bright Yellow */
    box-shadow: none;
}

.square.highlight {
    cursor: pointer;
    background-color: rgba(20, 133, 30, 0.5);
    /* Green Overlay */
    box-shadow: none;
}

.square.highlight::after {
    content: '';
    position: absolute;
    width: 25%;
    height: 25%;
    background-color: rgba(0, 0, 0, 0.2);
    /* Semi-transparent dark dot */
    border-radius: 50%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.square.highlight.capture {
    background-color: rgba(20, 133, 30, 0.5);
    /* Keep green background for consistency or use red? */
    /* Usually games show captures with a ring or red corner. Let's stick to the green theme but maybe a ring for capture? */
    /* User specific image shows green square with dot. It didn't show capture. */
    /* Let's make capture distinct but consistent. */
}

.square.highlight.capture::after {
    /* Ring for capture */
    display: block;
    width: 85%;
    height: 85%;
    background-color: transparent;
    border: 6px solid rgba(0, 0, 0, 0.2);
    border-radius: 50%;
}

/* Board Coordinates */
.coordinate {
    position: absolute;
    font-size: 0.75rem;
    font-weight: 700;
    pointer-events: none;
    user-select: none;
}

.coord-rank {
    top: 2px;
    left: 2px;
}

.coord-file {
    bottom: 2px;
    right: 2px;
}

.square.white .coordinate {
    color: var(--board-black);
}

.square.black .coordinate {
    color: var(--board-white);
}

/* Pieces with Shadow for Realism */
.piece {
    width: 85%;
    height: 85%;
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    transition: transform 0.2s cubic-bezier(0.2, 0.8, 0.2, 1);
    /* Ensure clicks pass through to square if we use square listeners, OR handle on piece */
    /* If we set pointer-events: none, we can't drag it easily unless drag is on square? */
    /* UI.js puts drag listener on PIECE. So we need pointer-events: all */
    pointer-events: auto;
    z-index: 2;
    filter: drop-shadow(0 4px 3px rgba(0, 0, 0, 0.3));
    /* Depth */
}

.piece:hover {
    transform: translateY(-2px) scale(1.05);
    /* Lift effect */
    filter: drop-shadow(0 8px 6px rgba(0, 0, 0, 0.4));
}

/* Layout Grid - 3 Columns */
.app-layout {
    display: flex;
    width: 100%;
    min-height: 100vh;
    background-color: var(--bg-dark);
}

/* 1. Sidebar Nav (Left) */
.sidebar-nav {
    width: 80px;
    /* Collapsed width style */
    background-color: #262421;
    display: flex;
    flex-direction: column;
    align-items: center;
    border-right: 1px solid #383633;
    padding-top: 1rem;
    flex-shrink: 0;
}

.logo-area {
    color: var(--primary-accent);
    font-weight: 800;
    margin-bottom: 2rem;
    font-size: 0.9rem;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.75rem;
    padding: 0.8rem 0;
    width: 100%;
    transition: background1 0.2s;
}

.nav-item:hover,
.nav-item.active {
    background-color: rgba(255, 255, 255, 0.05);
    color: #fff;
}

.nav-item .icon {
    font-size: 1.5rem;
    margin-bottom: 4px;
}

/* 2. Main Content (Board) */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    /* Allow header above board */
    justify-content: center;
    align-items: center;
    padding: 2rem;
    background-color: #302e2b;
}

/* Re-style header for inside main content */
.main-content .main-header {
    margin-bottom: 2rem;
    padding: 0;
}

.main-content .main-header h1 {
    font-size: 2.5rem;
}

.board-wrapper {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.player-bar {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: #fff;
    font-weight: 600;
    height: 40px;
}

.avatar-small {
    width: 32px;
    height: 32px;
    background-color: #ccc;
    border-radius: 4px;
}

.avatar-small.white {
    background: #eeeed2;
}

.avatar-small.black {
    background: #769656;
}

.captured-pieces {
    display: flex;
    gap: 2px;
    margin-left: auto;
    /* Push to right */
    background: none;
    /* Override old */
    padding: 0;
    margin-top: 0;
}

.captured-piece {
    width: 20px;
    height: 20px;
}

.board-container {
    padding: 5px;
    /* Border rim */
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    /* Deep shadow */
    border-radius: 4px;
    overflow: hidden;
    background: #262421;
    /* Dark rim matching sidebar */
    margin: 1rem 0;
    /* Spacing from bars */
    border: 3px solid #383633;
}

#chess-board {
    width: 600px;
    height: 600px;
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    grid-template-rows: repeat(8, 1fr);
    background-color: #769656;
    /* Backup color */
}

.square {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.square.white {
    background-color: #eeeed2;
}

.square.black {
    background-color: #769656;
}

.square.highlight::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 24px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 50%;
}

.square.capture::after {
    width: 100%;
    height: 100%;
    background: none;
    border: 6px solid rgba(0, 0, 0, 0.2);
    border-radius: 0;
    /* Or circle? keeping it full square ring for capture */
    box-sizing: border-box;
    border-radius: 50%;
    /* Ring */
}

.piece {
    width: 100%;
    height: 100%;
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    cursor: grab;
}

.piece:active {
    cursor: grabbing;
}

/* 3. Right Side Panel */
.side-panel {
    width: 400px;
    background-color: #262421;
    padding: 2rem;
    border-left: 1px solid #383633;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    flex-shrink: 0;
}

.panel-header h2 {
    color: #fff;
    font-size: 2rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.panel-header h2::before {
    content: '♟️';
}

/* Menu Cards */
.play-menu {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.menu-card {
    display: flex;
    align-items: center;
    background-color: #3d3b38;
    /* Card BG */
    padding: 1rem;
    border-radius: 8px;
    /* Rounded corners */
    cursor: pointer;
    transition: transform 0.1s, background-color 0.2s;
    user-select: none;
    border-bottom: 4px solid rgba(0, 0, 0, 0.2);
}

.menu-card:hover {
    background-color: #4b4845;
    transform: translateY(-2px);
}



/* Icons */
.card-icon {
    font-size: 2.5rem;
    margin-right: 1.5rem;
}

#card-play-bot .card-icon {
    color: #f1c40f;
}

/* Yellowish */
#card-play-friend .card-icon {
    color: #eebb99;
}

/* Handshake color */
#card-puzzles .card-icon {
    color: #81b64c;
}

/* Green */

.card-info h3 {
    margin: 0;
    font-size: 1.2rem;
    color: #fff;
}

.card-info p {
    margin: 0;
    font-size: 0.9rem;
    color: #ababab;
}

/* Game Controls Area (Bottom of sidebar) */
.game-controls-area {
    margin-top: auto;
    background: #21201d;
    padding: 1.5rem;
    border-radius: 8px;
}

.action-buttons-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.action-btn {
    background: #3d3b38;
    border: none;
    color: #ccc;
    padding: 0.8rem;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.action-btn:hover {
    background: #504d4a;
    color: #fff;
}

.status-box {
    text-align: center;
    color: #fff;
    font-weight: 700;
    font-size: 1.1rem;
    padding-top: 0.5rem;
    border-top: 1px solid #444;
}

/* Settings Panel (Bot Level) */
.settings-panel {
    background: #302e2b;
    padding: 1rem;
    border-radius: 6px;
    margin-bottom: 1rem;
}

/* Pro Documentation Styles */
.tutorial-content {
    text-align: left;
    max-height: 60vh;
    /* Taller on large screens */
    overflow-y: auto;
    padding-right: 1.5rem;
    font-size: 1rem;
    line-height: 1.7;
    color: #e0e0e0;
}

.doc-section {
    margin-bottom: 3rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 1rem;
}

.doc-section:last-child {
    border-bottom: none;
}

.doc-header {
    color: var(--primary-accent);
    font-size: 1.5rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.doc-sub-header {
    color: #fff;
    font-size: 1.2rem;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.doc-text {
    margin-bottom: 1rem;
}

/* Highlight Box for Special Rules */
.highlight-box {
    background: rgba(129, 182, 76, 0.15);
    /* Tint of primary green */
    border-left: 4px solid var(--primary-accent);
    padding: 1rem;
    border-radius: 4px;
    margin: 1rem 0;
    font-style: italic;
}

.highlight-box strong {
    color: #fff;
}

/* Strategy Table */
.strategy-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
    background: #262421;
    border-radius: 6px;
    overflow: hidden;
}

.strategy-table th,
.strategy-table td {
    padding: 0.8rem;
    text-align: left;
    border-bottom: 1px solid #383633;
}

.strategy-table th {
    background: #383633;
    color: var(--primary-accent);
}

.strategy-table td:last-child {
    font-weight: bold;
    color: #fff;
}

/* Bullet lists */
.doc-list {
    list-style-type: none;
    padding-left: 1rem;
}

.doc-list li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.5rem;
}

.doc-list li::before {
    content: '♟️';
    position: absolute;
    left: 0;
    font-size: 0.8rem;
    color: var(--primary-accent);
    top: 4px;
}

#level-name {
    color: var(--primary-accent);
}

/* Hidden but accessible helpers */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 1200px) {
    .app-layout {
        flex-direction: column;
    }

    .sidebar-nav {
        width: 100%;
        flex-direction: row;
        justify-content: center;
        height: auto;
        border-bottom: 1px solid #333;
    }

    .nav-item {
        padding: 0.5rem 1rem;
        width: auto;
    }

    .side-panel {
        width: 100%;
        padding: 1rem;
    }

    .board-wrapper {
        width: 100%;
        max-width: 600px;
        margin: 0 auto;
    }

    .chess-board {
        width: 100%;
        height: auto;
        aspect-ratio: 1/1;
    }
}

#status-text {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.modal.show {
    opacity: 1;
    pointer-events: auto;
}

.modal-content {
    background-color: var(--bg-panel);
    width: 400px;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.5);
    text-align: center;
    transform: translateY(20px);
    transition: transform 0.3s cubic-bezier(0.18, 0.89, 0.32, 1.28);
}

.modal.show .modal-content {
    transform: translateY(0);
}

.modal-header h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}

.modal-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.result-display {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
    background: #21201d;
    padding: 1.5rem;
    border-radius: 8px;
}

.player-result {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    opacity: 0.5;
    transition: opacity 0.3s;
}

.player-result.winner {
    opacity: 1;
    transform: scale(1.1);
}

.avatar-circle {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    position: relative;
}

.avatar-circle.white {
    background-color: #eeeed2;
    border: 2px solid #fff;
}

.avatar-circle.black {
    background-color: #769656;
    border: 2px solid #000;
}

.player-result.winner .avatar-circle {
    box-shadow: 0 0 15px var(--primary-accent);
    border-color: var(--primary-accent);
}

/* Crown icon for winner logic could go here */

.vs-divider {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--text-muted);
}

.score {
    font-size: 1.5rem;
    font-weight: 800;
}

.player-result.winner .score {
    color: var(--primary-accent);
}

.modal-actions {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.btn-primary {
    background-color: var(--primary-accent);
    color: white;
    font-size: 1.1rem;
    padding: 1rem;
}

/* Tutorial Styles */
.tutorial-content {
    text-align: left;
    max-height: 300px;
    overflow-y: auto;
    padding-right: 1rem;
    font-size: 0.95rem;
    line-height: 1.6;
}

.tutorial-section {
    margin-bottom: 1.5rem;
}

.tutorial-section h3 {
    color: var(--primary-accent);
    margin-bottom: 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 0.2rem;
}

.tutorial-section ul {
    list-style-type: none;
    padding-left: 0.5rem;
}

.tutorial-section li {
    margin-bottom: 0.5rem;
}

/* Scrollbar for modal */
.tutorial-content::-webkit-scrollbar {
    width: 8px;
}

.tutorial-content::-webkit-scrollbar-thumb {
    background: #444;
    border-radius: 4px;
}

/* Puzzle Banner Animation */
.puzzle-banner {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: linear-gradient(90deg, #2c3e50, #262421);
    padding: 1rem;
    border-radius: 8px;
    border-left: 5px solid var(--primary-accent);
    margin-bottom: 1rem;
    animation: slideDown 0.5s ease-out;
}

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

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

.puzzle-icon {
    font-size: 2rem;
}

.puzzle-info {
    display: flex;
    flex-direction: column;
}

.puzzle-title {
    font-weight: 800;
    color: var(--primary-accent);
    text-transform: uppercase;
    font-size: 0.9rem;
}

.puzzle-desc {
    color: #fff;
    font-weight: 600;
}

.pulse-text {
    animation: pulse 2s infinite;
    color: var(--primary-accent);
}

@keyframes pulse {
    0% {
        opacity: 0.8;
    }

    50% {
        opacity: 1;
        text-shadow: 0 0 10px var(--primary-accent);
    }

    100% {
        opacity: 0.8;
    }
}