/* ================================
   RESET & BASE
================================ */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg:        #0d0d0f;
    --surface:   #16161a;
    --surface2:  #1e1e24;
    --border:    #2a2a35;
    --accent:    #e8c97e;
    --accent2:   #7ec8e8;
    --green:     #7ee8a2;
    --red:       #e87e7e;
    --text:      #e8e8e0;
    --muted:     #666670;
    --radius:    12px;
    --radius-sm: 6px;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Segoe UI', Arial, sans-serif;
    font-size: 14px;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 30px 16px;
}

/* ================================
   APP WRAPPER
================================ */
.app {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    width: 100%;
    max-width: 580px;
}

/* ================================
   HEADER
================================ */
.app-header {
    text-align: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text);
    letter-spacing: -0.5px;
}

.logo span {
    color: var(--accent);
}

.tagline {
    color: var(--muted);
    font-size: 12px;
    margin-top: 4px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

/* ================================
   CONTROLS BAR
================================ */
.controls-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 99px;
    padding: 8px 16px;
    flex-wrap: wrap;
    justify-content: center;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 6px;
}

.control-label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--muted);
    margin-right: 2px;
}

.divider {
    width: 1px;
    height: 20px;
    background: var(--border);
}

.ctrl-btn {
    padding: 6px 16px;
    border-radius: 99px;
    border: 1px solid transparent;
    background: transparent;
    color: var(--muted);
    font-family: inherit;
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    letter-spacing: 0.03em;
}

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

.ctrl-btn.active {
    background: var(--accent);
    color: #1a1400;
    border-color: var(--accent);
}

.ctrl-btn.active-dark {
    background: #2a2a35;
    color: var(--text);
    border-color: var(--border);
}

/* ================================
   BOARD
================================ */
.board-wrap {
    width: 100%;
    max-width: 520px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px;
    box-shadow: 0 8px 40px rgba(0,0,0,0.5);
}

#board {
    width: 100% !important;
    position: relative;
}

/* chessboard.js overrides for dark theme */
.board-b72b1 {
    border: 2px solid #333 !important;
    border-radius: 4px;
    overflow: hidden;
}

/* ================================
   LEGEND
================================ */
.legend {
    width: 100%;
    max-width: 520px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 20px;
}

.legend-title {
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--muted);
    text-align: center;
    margin-bottom: 14px;
    font-weight: 700;
}

.legend-stripe {
    display: flex;
    flex-wrap: wrap;
    gap: 10px 20px;
    justify-content: center;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: #c8c8c0;
}

.swatch {
    width: 22px;
    height: 22px;
    border-radius: 5px;
    border: 1px solid rgba(255,255,255,0.08);
    flex-shrink: 0;
}

.stripe-swatch {
    width: 52px;
    background: repeating-linear-gradient(
        45deg,
        rgba(100,160,255,0.8) 0px,
        rgba(100,160,255,0.8) 8px,
        rgba(80,200,120,0.8) 8px,
        rgba(80,200,120,0.8) 16px
    );
}

.legend-stripe-note {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 10px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    color: var(--muted);
    font-size: 12px;
}

/* heatmap legend */
.legend-heatmap {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.heat-bar {
    width: 100%;
    max-width: 420px;
    height: 18px;
    border-radius: 99px;
    background: linear-gradient(to right,
        rgba(30,100,255,0.9),
        rgba(30,100,255,0.3),
        rgba(100,100,100,0.15),
        rgba(255,50,50,0.3),
        rgba(255,50,50,0.9)
    );
    border: 1px solid rgba(255,255,255,0.06);
}

.heat-labels {
    width: 100%;
    max-width: 420px;
    display: flex;
    justify-content: space-between;
    font-size: 11px;
    color: var(--muted);
}

.heat-note {
    font-size: 11px;
    color: var(--muted);
    text-align: center;
    margin-top: 2px;
}

/* ================================
   FOOTER
================================ */
.app-footer {
    font-size: 11px;
    color: var(--muted);
    text-align: center;
    letter-spacing: 0.06em;
    opacity: 0.5;
}

.footer-link {
    color: var(--accent2);
    text-decoration: none;
    font-weight: 700;
}

.footer-link:hover {
    text-decoration: underline;
}

/* ================================
   RESPONSIVE (mobile)
================================ */

/* spare pieces trays (chessboard.js) */
[class*="spare-pieces"] {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 6px;
    padding: 8px 0;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

@media (max-width: 520px) {
    body {
        padding: 18px 12px;
        align-items: flex-start;
    }

    .app {
        gap: 14px;
        max-width: 520px;
    }

    .logo {
        font-size: 1.5rem;
    }

    .controls-bar {
        padding: 10px 12px;
        gap: 10px;
        border-radius: 16px;
    }

    .divider {
        display: none;
    }

    .ctrl-btn {
        padding: 8px 12px;
    }

    .board-wrap {
        padding: 10px;
    }

    .legend {
        padding: 14px 14px;
    }

    .legend-item {
        font-size: 12px;
    }

    .heat-labels {
        font-size: 10px;
    }
}

@media (max-width: 380px) {
    .logo {
        font-size: 1.35rem;
    }

    .ctrl-btn {
        padding: 8px 10px;
        font-size: 11px;
    }
}