/* Page layout */
body {
    font-family: Arial, sans-serif;
    background: #050505;
    color: #ffffff;
    text-align: center;
    margin: 0;
    padding: 20px;
}

h1 {
    margin-bottom: 4px;
}

.subtitle {
    margin-top: 0;
    margin-bottom: 20px;
    font-size: 1.05rem;
    opacity: 0.85;
}

/* Puzzle container */
#puzzle-container {
    width: 600px;
    height: 600px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    gap: 2px;
    border: 3px solid #ffffff;
    background: #000;
}

/* Tiles */
.tile {
    width: 100%;
    height: 100%;
    background-size: 600px 600px; /* force square crop */
    background-repeat: no-repeat;
    cursor: pointer;
    transition: transform 0.12s ease, box-shadow 0.12s ease;
}

.tile:hover {
    transform: scale(1.03);
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.4);
}

/* Empty tile */
.tile.empty {
    background: #000;
    cursor: default;
    box-shadow: none;
}
#reset-btn {
    background: #ffffff;
    color: #000000;
    border: none;
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
    margin-bottom: 20px;
    border-radius: 4px;
    transition: background 0.2s ease;
}

#reset-btn:hover {
    background: #e0e0e0;
}