#puzzle-container {
    display: grid;
    grid-template-columns: repeat(2, 100px);
    grid-template-rows: repeat(2, 100px);
    gap: 2px;
    width: 204px; /* 2 columns of 100px each plus 4px gap */
    height: 204px; /* 2 rows of 100px each plus 4px gap */
}

.puzzle-piece {
    width: 100px;
    height: 100px;
    background-color: #ccc;
    border: 1px solid #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: border-color 0.3s;
}

.puzzle-piece.correct {
    background-color: #8bc34a;
}

.puzzle-piece.selected {
    border-color: #00f; /* Hellblauer Rand */
}

.puzzle-piece img{
	width: 100px;
	height: 100px;
}