style.css

.cell-small, .cell-big{
	display: inline-block;
}
div{
	margin: 0px;
}
.cell-small{
	width: 45px;
	height: 45px;
	text-align: center;
	line-height: 45px;
	border: 1px solid black;
	margin-right: -1px;
	margin-bottom: -1px;
}
.cell-big{
	border: 1px solid blue;
	padding-right: 1px;
	padding-bottom: 1px;
	margin-bottom: -2px;
	margin-right: -2px;
}
.attempt{
	cursor: pointer;
}
.digits{
	position: absolute;
	border: 1px solid black;
	z-index: 100;
	background-color: #fff;
	display: none;
}
.digit{
	height: 40px;
	width: 40px;
	border: 1px solid black;
	line-height: 40px;
	text-align: center;
	display: inline-block;
	float: left;
	cursor: pointer;
}
.digit:hover{
	font-weight: bold;
}
.cell-small.active{
	background-color: lightyellow;
}
.cell-small.wrong{
	background-color: crimson;
}
.field{
	position: relative;
}
.hovered{
	background-color: lightblue;
}