:root {
    --c-bg: #FFF4D6;
    --c-card: #FFFFFF;
    --c-text: #2D2D2D;
    --c-1: #FF6B6B; /* Red/Pink */
    --c-2: #4ECDC4; /* Teal */
    --c-3: #FFE66D; /* Yellow */
    --c-4: #FF9F43; /* Orange */
    --c-5: #9D8DF1; /* Purple */
    --c-white-piece: #ffffff;
    --c-black-piece: #2D2D2D;
    --border: 4px solid var(--c-text);
    --shadow: 6px 6px 0px var(--c-text);
    --shadow-hover: 8px 8px 0px var(--c-text);
    --board-light: #FFF4D6;
    --board-dark: #4ECDC4;
    --highlight: rgba(255, 230, 109, 0.8); /* Yellow highlight */
    --highlight-move: rgba(157, 141, 241, 0.6); /* Purple move hint */
    --highlight-capture: rgba(255, 107, 107, 0.6); /* Red capture hint */
}

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

body {
    font-family: 'Fredoka', sans-serif;
    background-color: var(--c-bg);
    background-image: radial-gradient(var(--c-2) 15%, transparent 16%), radial-gradient(var(--c-1) 15%, transparent 16%);
    background-size: 60px 60px;
    background-position: 0 0, 30px 30px;
    color: var(--c-text);
    height: 100vh;
    height: 100dvh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.game-container {
    width: 100%;
    height: 100%;
    max-width: 1200px;
    max-height: 100vh;
    max-height: 100dvh;
    padding: 1rem;
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    gap: 2rem;
}

.game-sidebar {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    flex-shrink: 0;
}

header {
    text-align: center;
    background: var(--c-card);
    padding: 1rem 2rem;
    border-radius: 16px;
    border: var(--border);
    box-shadow: var(--shadow);
    transform: rotate(-2deg);
}

h1 {
    font-family: 'Rubik Bubbles', cursive;
    font-size: 3rem;
    color: var(--c-1);
    text-shadow: 3px 3px 0px var(--c-text);
    line-height: 1;
}

.controls {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    background: var(--c-card);
    padding: 1.5rem;
    border-radius: 16px;
    border: var(--border);
    box-shadow: var(--shadow);
    transform: rotate(1deg);
}

.turn-indicator {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--c-text);
    background: var(--c-3);
    padding: 0.5rem 1.5rem;
    border-radius: 50px;
    border: 2px solid var(--c-text);
    white-space: nowrap;
}

.check-indicator {
    font-size: 1.2rem;
    font-weight: 700;
    color: white;
    background: var(--c-1);
    padding: 0.4rem 1rem;
    border-radius: 50px;
    border: 2px solid var(--c-text);
    animation: pulse 1s infinite;
}

.check-indicator.hidden {
    display: none;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.board-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: 85vh; /* Constrain width by height */
}

.chess-board {
    display: grid;
    grid-template-columns: repeat(8, 1fr);
    grid-template-rows: repeat(8, 1fr);
    width: 100%;
    aspect-ratio: 1;
    border: var(--border);
    box-shadow: var(--shadow);
    background: var(--c-bg);
    border-radius: 8px;
    overflow: hidden;
}

.square {
    position: relative;
    cursor: pointer;
    user-select: none;
    display: flex;
    justify-content: center;
    align-items: center;
    container-type: size;
}

.square.light {
    background-color: var(--board-light);
}

.square.dark {
    background-color: var(--board-dark);
}

.square.selected {
    background-color: var(--highlight) !important;
}

.square.valid-move::after {
    content: '';
    position: absolute;
    width: 30%;
    height: 30%;
    background-color: var(--highlight-move);
    border-radius: 50%;
}

.square.valid-capture {
    background-color: var(--highlight-capture) !important;
}

/* Pieces */
.piece {
    font-family: "Noto Sans Symbols 2", "Segoe UI Symbol", "DejaVu Sans", sans-serif;
    font-size: 100cqmin;
    line-height: 1;
    pointer-events: none;
    transform: translateY(10%);
}

.piece.white {
    color: var(--c-white-piece);
    text-shadow: 
        1px 1px 0 var(--c-text),
        -1px 1px 0 var(--c-text),
        1px -1px 0 var(--c-text),
        -1px -1px 0 var(--c-text),
        2px 2px 3px rgba(0,0,0,0.3);
}

.piece.black {
    color: var(--c-text);
    text-shadow: 
        1px 1px 0 #fff,
        -1px 1px 0 #fff,
        1px -1px 0 #fff,
        -1px -1px 0 #fff,
        2px 2px 3px rgba(0,0,0,0.2);
}

.btn {
    font-family: 'Fredoka', sans-serif;
    font-size: 1.2rem;
    font-weight: 700;
    padding: 0.6rem 1.5rem;
    border: 3px solid var(--c-text);
    border-radius: 50px;
    background: var(--c-2);
    color: var(--c-text);
    cursor: pointer;
    box-shadow: 4px 4px 0px var(--c-text);
    transition: all 0.1s;
}

.btn:active {
    transform: translate(2px, 2px);
    box-shadow: 2px 2px 0px var(--c-text);
}

.message {
    font-size: 1rem;
    font-weight: 700;
    text-align: center;
    color: var(--c-1);
    min-height: 1.2em;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: var(--c-card);
    padding: 2rem;
    border-radius: 16px;
    border: var(--border);
    box-shadow: var(--shadow);
    text-align: center;
}

.promotion-options {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
    justify-content: center;
}

.promo-piece {
    font-family: "Noto Sans Symbols 2", "Segoe UI Symbol", "DejaVu Sans", sans-serif;
    font-size: 3rem;
    cursor: pointer;
    padding: 0.5rem;
    border: 2px solid transparent;
    border-radius: 8px;
}

.promo-piece:hover {
    background: var(--c-3);
    border-color: var(--c-text);
}

/* Mobile Layout */
@media (max-width: 800px) {
    .game-container {
        flex-direction: column;
        gap: 1rem;
        padding: 0.5rem;
    }

    .game-sidebar {
        width: 100%;
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        gap: 0.5rem;
    }

    header {
        padding: 0.4rem 1rem;
        margin: 0;
        transform: rotate(-1deg);
    }

    h1 { font-size: 1.5rem; text-shadow: 2px 2px 0px var(--c-text); }

    .controls {
        flex-direction: row;
        padding: 0.4rem;
        transform: rotate(0deg);
        gap: 0.5rem;
        background: transparent;
        border: none;
        box-shadow: none;
    }

    .turn-indicator {
        font-size: 0.9rem;
        padding: 0.3rem 0.8rem;
    }
    
    .check-indicator {
        font-size: 0.8rem;
        padding: 0.2rem 0.6rem;
    }

    .btn {
        font-size: 0.9rem;
        padding: 0.3rem 0.8rem;
        border-width: 2px;
        box-shadow: 2px 2px 0px var(--c-text);
    }

    .message {
        display: none; /* Hide text message on mobile to save space, use indicators */
    }
    
    .board-container {
        width: 100%;
        max-width: 100%;
    }

    .chess-board {
        width: min(100%, calc(100vh - 120px));
    }
}