@font-face {
    font-family: 'NotoKufiArabic';
    src: url('fonts/NotoKufiArabic-VariableFont_wght.ttf') format('truetype');
    font-weight: 100 900;
    font-display: swap;
}

@font-face {
    font-family: 'KaiTiCustom';
    src: url('fonts/KaiTi Regular.ttf') format('truetype');
    font-weight: normal;
    font-display: swap;
}

@font-face {
    font-family: 'BMDohyeon';
    src: url('fonts/BMDohyeon-Regular.ttf') format('truetype');
    font-weight: normal;
    font-display: swap;
}


:root {
    --ui-scale: 2;
    --primary: #2c3e50;
    --accent: #2c3e50;
    --success: #2ecc71;
    --error: #e74c3c;
    --bg: #f4f6f9;
    --card-w: calc(85px * var(--ui-scale));
    --card-h: calc(120px * var(--ui-scale));
    --grid-row-h: calc(70px * var(--ui-scale));
    --grid-gap: calc(8px * var(--ui-scale));
    --side-img-size: calc(55px * var(--ui-scale));
}

/* html font-size no longer scaled globally — rem values below
   use calc(px * var(--ui-scale)) so the game looks the same while
   the shared header/footer from style.css render at normal size. */

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg);
    margin: 0;
    direction: ltr;
}

main {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: calc(32px * var(--ui-scale));
}

/* --- Grid Styling --- */
.grid-container {
    display: grid;
    grid-template-columns: repeat(6, calc(100px * var(--ui-scale)));
    grid-template-rows: repeat(5, var(--grid-row-h));
    gap: var(--grid-gap);
    margin-bottom: calc(32px * var(--ui-scale));
    direction: ltr;
}

.cell {
    background: white;
    border: 2px solid #ddd;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    transition: background-color 0.3s;
    user-select: none;
    text-align: center;
    font-size: calc(12.8px * var(--ui-scale));
}

.cell span {
    font-family: 'BMDohyeon', sans-serif;
}

/* Tone color classes */
.tone-1 { color: black; }
.tone-2 { color: #3d5ec1; } /* blue */
.tone-3 { color: #16a34a; } /* green */
.tone-4 { color: #dc2626; } /* red */
.tone-5 { color: #6b7280; } /* grey */

.header {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    font-size: calc(13.6px * var(--ui-scale));
    font-family: 'NotoKufiArabic', sans-serif;
}

.hidden-cell {
    visibility: hidden;
    pointer-events: none;
}

/* Feedback States */
.flash-success { background-color: var(--success) !important; color: white; }
.flash-error { background-color: var(--error) !important; color: white; }

/* --- New Stacked Deck Styling --- */
.deck-container {
    display: flex;
    justify-content: center;
    margin-top: 20px;
    height: var(--card-h); /* Reserve height */
}

/* The Single Stack (Acts as Pile + Active Slot) */
#single-stack {
    position: relative; /* Anchor for absolute card positioning */
    width: var(--card-w);
    height: var(--card-h);
    background: var(--primary);
    border-radius: 12px;
    border: 2px solid #34495e;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    /* Stack effect */
    box-shadow: 4px 4px 0px #bdc3c7, 8px 8px 0px #95a5a6;
    transition: transform 0.1s;
}

#single-stack:active {
    transform: translate(2px, 2px);
    box-shadow: 2px 2px 0px #bdc3c7, 6px 6px 0px #95a5a6;
}

/* When a card is active, the stack is just a placeholder underneath */
#single-stack.has-card {
    cursor: grab; /* Indicates draggable */
    background: #bdc3c7; /* Dim the pile underneath */
    box-shadow: none; /* Flatten pile visually when card is drawn */
}

/* Text on the empty pile */
.stack-msg {
    color: white;
    font-weight: bold;
    text-align: center;
    pointer-events: none;
}

/* Force the card to sit exactly on the stack */
.card-wrapper {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 10;
    width: var(--card-w);
    height: var(--card-h);
    perspective: 900px;
}

/* --- Card Styling --- */
.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.card-wrapper.flipped .card-inner {
    transform: rotateY(180deg);
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    border: 1px solid #ccc;
}

.card-front {
    background-color: var(--accent);
    color: white;
    font-size: calc(19.2px * var(--ui-scale));
}

.card-back {
    background-color: white;
    transform: rotateY(180deg);
    padding: 5px;
}

.chinese {
    font-family: 'KaiTiCustom', serif;
    font-size: calc(25.6px * var(--ui-scale));
    margin-bottom: 5px;
}
.pinyin { font-size: calc(14.4px * var(--ui-scale)); color: #666; }

.dragging { opacity: 0.5; }

#finish-message {
    margin-top: 10px;
    font-size: calc(19.2px * var(--ui-scale));
    text-align: center;
}

/* Body Flash Animations */
@keyframes flashGreen {
    0% { background-color: var(--bg); }
    50% { background-color: rgba(46, 204, 113, 0.3); }
    100% { background-color: var(--bg); }
}

@keyframes flashRed {
    0% { background-color: var(--bg); }
    50% { background-color: rgba(231, 76, 60, 0.3); }
    100% { background-color: var(--bg); }
}

.body-flash-success { animation: flashGreen 0.6s ease-out; }
.body-flash-error { animation: flashRed 0.6s ease-out; }

.card-logo {
    width: calc(42px * var(--ui-scale));
    height: calc(42px * var(--ui-scale));
    border-radius: 50%;
    object-fit: cover;
}



/* =============================
   Side Images (Left Column)
   ============================= */

.grid-wrapper {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    direction: ltr;
}

.side-images {
    display: flex;
    flex-direction: column;
    /* header row + gap + half of (row height - image size) */
    margin-top: calc(var(--grid-row-h) + var(--grid-gap) + (var(--grid-row-h) - var(--side-img-size)) / 2);

    /* distance between data-row centers minus image size */
    gap: calc((var(--grid-row-h) + var(--grid-gap)) - var(--side-img-size));
}

.side-img {
    width: var(--side-img-size);
    height: var(--side-img-size);
    object-fit: contain;
}

/* Responsive adjustment for side images */
@media (max-width: 760px) {
    :root {
        --ui-scale: 1.25;
        --grid-row-h: calc(70px * var(--ui-scale));
        --grid-gap: calc(8px * var(--ui-scale));
        --side-img-size: calc(45px * var(--ui-scale));
    }
    .grid-wrapper {
        gap: 10px;
    }
}



/* =============================
   Toggle switch
   ============================= */

.toggle-row {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: 'NotoKufiArabic', sans-serif;
    font-weight: 600;
    align-self: flex-start;
    margin-right: auto;
}


.toggle-label {
    user-select: none;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 52px;
    height: 30px;
    cursor: pointer;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    inset: 0;
    background: rgba(255, 255, 255, 0.18);
    border: 1px solid rgba(0, 0, 0, 0.12);
    border-radius: 999px;
    transition: 0.18s ease;
}

.toggle-slider::before {
    content: "";
    position: absolute;
    height: 22px;
    width: 22px;
    left: 4px;
    top: 50%;
    transform: translateY(-50%);
    background: #fff;
    border-radius: 50%;
    box-shadow: 0 2px 6px rgba(0,0,0,0.18);
    transition: 0.18s ease;
}

.toggle-switch input:checked + .toggle-slider {
    background: rgba(44, 62, 80);
    border-color: var(--accent);
}

.toggle-switch input:checked + .toggle-slider::before {
    transform: translateY(-50%) translateX(22px);
}

.toggle-switch input:focus-visible + .toggle-slider {
    outline: 2px solid rgba(44, 62, 80, 0.45);
    outline-offset: 3px;
}

@media (max-width: 760px) {
    .toggle-switch {
        width: 46px;
        height: 28px;
    }

    .toggle-slider::before {
        height: 20px;
        width: 20px;
    }

    .toggle-switch input:checked + .toggle-slider::before {
        transform: translateY(-50%) translateX(18px);
    }
}


/* =============================
   Bottom Layout
   ============================= */

.bottom-section {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-top: 25px;
    width: 100%;
    max-width: 100%;
    padding: 0 clamp(10px, 3vw, 40px);
    gap: 0;
}

.bottom-left {
    display: flex;
    flex-direction: column;
    gap: 18px;
    order: 1;
    align-items: flex-start;
}

.bottom-right {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-left: auto;
    order: 2;
}

.score-board {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
}



/* =============================
   Animal Mode (Tone Icons)
   ============================= */‘

.tone-pair {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-size: calc(19.2px * var(--ui-scale));
    font-weight: 800;
    opacity: 0.95;
}

.tone-plus {
    font-family: 'BMDohyeon', sans-serif;
    font-size: calc(17.6px * var(--ui-scale));
}

.tone-symbol {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 22px;
}

.tone-animal {
    width: calc(35px * var(--ui-scale));
    height: calc(35px * var(--ui-scale));
    object-fit: contain;
    pointer-events: none;
}

/* Slightly enlarge animals for better visual balance */
.cell .tone-symbol img {
    transform: scale(1.05);
}

/* Responsive adjustment */
@media (max-width: 760px) {
    .tone-animal {
        width: calc(26px * var(--ui-scale));
        height: calc(26px * var(--ui-scale));
    }
}