:root {
    --ui-element-fix-height: 25px;
    --gap-size: 4px;

    --ghost-min-size: min((100svw - (13 * var(--gap-size))) / 8, (100svh - (2 * var(--ui-element-fix-height)) - (24 * var(--gap-size)) - 10px) / 15);
    --card-min-size: calc(2 * var(--ghost-min-size) + 2 * var(--gap-size));
    
    --bg-color: #282c34;
    --ui-bg: #20232a;
    --card-back-color: #444;
    --text-muted: #888;
    --text-dark: #20232a;
    --color-btn: #D5A677;
    --color-label: #F4D373;
    --flip-duration: 500ms;
}

html, * {
    -webkit-touch-callout: none !important;
    -webkit-user-select: none !important;
    user-select: none !important;
}

body {
    font-family: 'Arial', sans-serif;
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    height: 100svh;
    margin: 0;
    overflow: hidden;
}

#master-container {
    padding: var(--gap-size);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    width: 100%;
}

#content-wrapper {
    width: min-content;
    height: min-content;
    display: flex;
    flex-direction: column;
    gap: var(--gap-size);
}

#top-container {
    display: flex;
    flex-direction: column;
    gap: var(--gap-size);
}

.top-row {
    display: flex;
    gap: var(--gap-size);
    width: 0; 
    min-width: 100%;
}

.ui-box {
    flex: 1;
    min-width: 0;
    white-space: nowrap;
    overflow: hidden;
    height: var(--ui-element-fix-height);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1em;
    border-radius: 4px;
    background-color: var(--ui-bg);
    color: var(--text-muted);
    border: none;
    outline: none;
    padding: 0;
    font-family: inherit;
    transition: background-color 0.2s, opacity 0.2s, color 0.2s;
    -webkit-tap-highlight-color: transparent;
}

.btn {
    cursor: pointer;
    background-color: var(--color-btn);
    color: var(--text-dark);
    opacity: 0.5;
}

.btn.active { 
    opacity: 1;
    cursor: default; 
}

@media (hover: hover) {
    .btn:not(:disabled):not(.active):hover {
        opacity: 1;
    }
}

.btn:disabled {
    background-color: var(--ui-bg);
    color: var(--text-muted);
    cursor: default;
    opacity: 0.6;
}

.label.active { 
    background-color: var(--color-label); 
    color: var(--text-dark); 
}

.board {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(6, 1fr);
    gap: var(--gap-size);
    width: 100%;
}

#bottom-container {
    display: flex;
    gap: var(--gap-size);
    width: 100%;
}

.discard-zone {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(3, 1fr);
    gap: var(--gap-size);
    background-color: var(--ui-bg);
    padding: var(--gap-size);
}

.card {
    min-width: var(--card-min-size);
    min-height: var(--card-min-size);
    aspect-ratio: 1 / 1;
    position: relative;
}

.ghost {
    min-width: var(--ghost-min-size);
    min-height: var(--ghost-min-size);
    width: 100%;
    aspect-ratio: 1 / 1;
    position: relative;
}

.card-inner {
    width: 100%;
    height: 100%;
    position: relative;
    transition: transform var(--flip-duration);
    transform-style: preserve-3d;
}

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

.card.is-matched { 
    visibility: hidden; 
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
}

.card-front { 
    background-color: var(--card-back-color); 
}

.card-back { 
    background-color: #fff; 
    transform: rotateY(180deg); 
}

.ghost.filled { 
    background-color: #fff; 
}

.card-back img, .ghost img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    pointer-events: none;
}

@media print {
    html, body {
        display: none !important;
    }
}