.potato-home-link {
    position: fixed;
    left: 16px;
    bottom: 16px;
    z-index: 20;
    padding: 8px 11px;
    border-radius: 999px;
    color: #fff7e8;
    background: rgba(23, 19, 13, 0.78);
    border: 1px solid rgba(255, 247, 232, 0.18);
    font: 700 13px system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    text-decoration: none;
    backdrop-filter: blur(10px);
}

.potato-home-link:hover {
    background: rgba(242, 184, 75, 0.22);
}

:root {
    --bg-color: #f0f2f5;
    --text-color: #2c3e50;
    --stats-color: #555;
    --card-bg: #3498db;
    --card-flipped-bg: #fff;
    --card-matched-bg: #2ecc71;
    --btn-bg: #e74c3c;
    --btn-hover-bg: #c0392b;
    --status-bg: rgba(44, 62, 80, 0.08);
    --status-border: rgba(44, 62, 80, 0.18);
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --stats-color: #b0b0b0;
    --card-bg: #1e3a5f;
    --card-flipped-bg: #2c3e50;
    --card-matched-bg: #1e5f3a;
    --btn-bg: #c0392b;
    --btn-hover-bg: #a93226;
    --status-bg: rgba(255, 247, 232, 0.06);
    --status-border: rgba(255, 247, 232, 0.14);
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
    padding: 28px 14px 72px;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

h1 {
    color: var(--text-color);
    margin: 0 0 10px;
    font-size: clamp(2rem, 8vw, 2.7rem);
    letter-spacing: -0.04em;
    text-align: center;
}

#stats {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px 18px;
    margin-bottom: 10px;
    font-size: clamp(1rem, 4vw, 1.15rem);
    color: var(--stats-color);
}

#game-status {
    min-height: 1.5em;
    max-width: min(92vw, 430px);
    margin: 0 0 15px;
    padding: 8px 12px;
    border: 1px solid var(--status-border);
    border-radius: 999px;
    color: var(--stats-color);
    background: var(--status-bg);
    font-size: 0.95rem;
    text-align: center;
}

#game-status.status-win {
    color: #fff7e8;
    border-color: rgba(46, 204, 113, 0.4);
    background: rgba(46, 204, 113, 0.24);
    font-weight: 700;
}

#game-board {
    perspective: 1000px;
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: clamp(8px, 2.5vw, 10px);
    width: min(92vw, 430px);
    margin-bottom: 18px;
}

.card {
    width: 100%;
    aspect-ratio: 1;
    background-color: var(--card-bg);
    border-radius: clamp(8px, 2vw, 10px);
    cursor: pointer;
    user-select: none;
    transition: transform 0.4s, background-color 0.3s, box-shadow 0.2s;
    transform-style: preserve-3d;
    position: relative;
    border: 0;
}

.card:hover,
.card:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px rgba(242, 184, 75, 0.65);
}

.card.flipped {
    transform: rotateY(180deg);
    background-color: var(--card-flipped-bg);
}

.card.matched {
    background-color: var(--card-matched-bg);
    cursor: default;
    animation: match-pulse 260ms ease-out;
}

.card-content {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: clamp(1.75rem, 9vw, 2.5rem);
    backface-visibility: hidden;
    transform: rotateY(180deg);
}

.card.flipped .card-content {
    transform: rotateY(0deg);
}

#reset-btn {
    padding: 12px 24px;
    font-size: 16px;
    cursor: pointer;
    background-color: var(--btn-bg);
    color: white;
    border: none;
    border-radius: 8px;
    transition: background-color 0.2s, transform 0.2s;
}

#reset-btn:hover {
    background-color: var(--btn-hover-bg);
    transform: translateY(-1px);
}

#theme-toggle {
    padding: 12px 24px;
    font-size: 16px;
    cursor: pointer;
    background-color: transparent;
    color: var(--text-color);
    border: 1px solid var(--text-color);
    border-radius: 8px;
    margin-top: 10px;
    transition: background-color 0.2s, color 0.2s;
}

#theme-toggle:hover {
    background-color: var(--text-color);
    color: var(--bg-color);
}

button:focus-visible,
.potato-home-link:focus-visible {
    outline: 3px solid rgba(242, 184, 75, 0.75);
    outline-offset: 3px;
}

@keyframes match-pulse {
    0% { transform: rotateY(180deg) scale(1); }
    50% { transform: rotateY(180deg) scale(1.05); }
    100% { transform: rotateY(180deg) scale(1); }
}