h1 {
    background:black;
    color:white;
    margin:0 0 2px 0;
    font-size: 20px;
    padding:2px 1px 5px 1px;
    text-align:center;
}

body {
    font-family:verdana,helvetica,arial,sans-serif;
    border:0; margin:0; padding:0;
    background:url(
    data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAIUlEQVQYV2N89urtfwYiACNIoZSYMCMhtaMK8YYQ0cEDAG5yJ8eLRhTfAAAAAElFTkSuQmCC
    ) repeat;
}

/* board */
.sudoku_board {
    margin:6px auto;

    overflow: hidden;

    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;

    box-shadow: 0 0 5px 5px #bdc3c7;
}

.sudoku_board .cell {
    width:11.11%;
    display: inline-block;
    float:left;
    cursor:pointer;
    text-align: center;
    overflow: hidden;

    -webkit-box-sizing: border-box; /* Safari/Chrome, other WebKit */
    -moz-box-sizing: border-box;    /* Firefox, other Gecko */
    box-sizing: border-box;

    box-shadow: 0 0 0 1px #bdc3c7;

    background:white;
}

.sudoku_board .cell.border_h {
    box-shadow: 0 0 0 1px #bdc3c7, inset 0 -2px 0 0 #34495e;
}

.sudoku_board .cell.border_v {
    box-shadow: 0 0 0 1px #bdc3c7, inset -2px 0 0 #34495e;
}

.sudoku_board .cell.border_h.border_v {
    box-shadow: 0 0 0 1px #bdc3c7, inset -2px 0 0 black, inset 0 -2px 0 black;
}

.sudoku_board .cell span {
    color:#2c3e50;
    font-size:14px;
    text-align:center;
}

.sudoku_board .cell.selected, .sudoku_board .cell.selected.fix {
    background:#FFE;
}

.sudoku_board .cell.selected.current {
    position:relative;
    background: #3498db;
    font-weight:bold;
    box-shadow: 0 0 3px 3px #bdc3c7;
}

.sudoku_board .cell.selected.current span {
    color:white;
}

.sudoku_board .cell.selected.group {
    color:blue;
}

.sudoku_board .cell span.samevalue, .sudoku_board .cell.fix span.samevalue {
    font-weight:bold;
    color:#3498db;
}

.sudoku_board .cell.notvalid, .sudoku_board .cell.selected.notvalid{
    font-weight:bold;
    color:white;;
    background:#e74c3c;
}

.sudoku_board .cell.fix {
    background:#ecf0f1;
    cursor:not-allowed;
}

.sudoku_board .cell.fix span {
    color:#7f8c8d;
}

.sudoku_board .cell .solution {
    font-size:10px;
    color:#d35400;
}

.sudoku_board .cell .note {
    color:#bdc3c7;
    width:50%;
    height:50%;
    display: inline-block;
    float:left;
    text-align:center;
    font-size:14px;

    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

.gameover_container .gameover {
    color:white;
    font-weight:bold;
    text-align:center;

    display:block;
    position:absolute;
    width:90%;
    padding:10px;
    background-color: #283593;
}


.restart {
    background: #1a8cb2;
    border-radius: 3px;
    color:#ecf0f1;
    line-height: 40px;
    padding: 0 40px;
    cursor: pointer;
    -webkit-transition: all .25s cubic-bezier(0.32, 0.74, 0.57, 1);
    transition: all .25s cubic-bezier(0.32, 0.74, 0.57, 1);
    white-space: nowrap;
    border: none;
    outline: none !important;
    -webkit-box-shadow: none;
    box-shadow: none;
}

/* console */
.board_console_container, .gameover_container {
    background-color: rgba(127, 140, 141, 0.7);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;

    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.board_console {
    display:block;
    position:absolute;
    width:50%;
    color:white;
    background-color: rgba(127, 140, 141, 0.7);
    box-shadow: 0 0 5px 5px #bdc3c7;
}

.board_console .num {
    width:33.33%;
    color:#2c3e50;
    padding: 1px;
    display: inline-block;
    font-weight:bold;
    font-size:24px;
    text-align: center;
    cursor:pointer;

    -webkit-box-sizing: border-box; /* Safari/Chrome, other WebKit */
    -moz-box-sizing: border-box;    /* Firefox, other Gecko */
    box-sizing: border-box;

    box-shadow: 0 0 0 1px #bdc3c7;
}


.board_console .num:hover {
    color:white;
    background:#f1c40f;
}

.board_console .num.remove {
    width:66.66%;
}

.board_console .num.note {
    background:#95a5a6;
    color:#ecf0f1;
}

.board_console .num.note:hover {
    background:#95a5a6;
    color:#f1c40f;
}

.board_console .num.selected {
    background:#f1c40f;
    box-shadow: 0 0 3px 3px #bdc3c7;
}

.board_console .num.note.selected {
    background:#f1c40f;
    box-shadow: 0 0 3px 3px #bdc3c7;
}

.board_console .num.note.selected:hover {
    color:white;
}

.board_console .num.no:hover {
    color:white;
    cursor:not-allowed;
}

.board_console .num.remove:hover {
    color:white;
    background:#c0392b;
}

.statistics {
    text-align:center;
}

#sudoku_menu {
    background-color: black;
    position: absolute;
    z-index:2;
    width: 100%;
    height: 100%;
    left: -100%;
    box-sizing: border-box;
    -moz-box-sizing: border-box;
}

#sudoku_menu ul {
    margin: 0;
    padding: 100px 0 0 0;
    list-style: none;
}

#sudoku_menu ul li{
    margin: 0 50px;
}

#sudoku_menu ul li a {
    text-align:center;
    padding: 15px 20px;
    font-size: 28px;
    font-weight: bold;
    color: white;
    text-decoration: none;
    display: block;
    border-bottom: 1px solid #2c3e50;
}

#sudoku_menu.open-sidebar {
    left:0;
}

#sidebar-toggle {
    z-index:3;
    background: #bdc3c7;
    border-radius: 3px;
    display: block;
    position: relative;
    padding: 22px 18px;
    float: left;
}

#sidebar-toggle .bar {
    display: block;
    width: 28px;
    margin-bottom: 4px;
    height: 4px;
    background-color: #f0f0f0;
    border-radius: 1px;
}

#sidebar-toggle .bar:last-child{
    margin-bottom: 0;
}

.btn-instruction-icon {
    position: absolute;
    top: 3px;
    right: 8px;
    display: block;
    text-align: center;
    color: #fff;
    width: 20px;
    height: 20px;
    border: 2px solid;
    border-radius: 3px;
    font-weight: 600;
    text-decoration: none;
}
.popup-block-title {
    margin-bottom: 15px;
    font-weight: 600;
}
.sudoku-instruction-img {
    max-width: 100%;
    height: auto;
    object-fit: contain;
}

/*Responsive Stuff*/
@media screen and (min-width: 768px) {
    .btn-instruction-icon {
        top: 22px;
        right: 20px;
    }
}
@media all and (orientation:portrait) and (min-width: 640px){
    h1 { font-size:50px; }
    .statistics { font-size:30px; }
    .sudoku_board .cell span { font-size:60px; }
    .board_console .num { font-size:60px; }
}

@media all and (orientation:landscape) and (min-height: 640px){
    h1 { font-size:50px; }
    .statistics { font-size:30px; }
    .sudoku_board .cell span { font-size:50px; }
    .board_console .num { font-size:50px; }
}

@media all and (orientation:portrait) and (max-width: 1000px){
    .sudoku_board .cell span { font-size:30px; }
}
@media screen and (max-width: 768px) {
    #sidebar-toggle {
        padding: 8px;
        background-color: black;
    }
    #sidebar-toggle .bar {
        width: 20px;
        height: 2px;
    }
    #sudoku_menu ul li a {
        font-size: 16px;
    }
}
@media all and (orientation:portrait) and (max-width: 640px){
    .sudoku_board .cell span { font-size:24px; }
    .sudoku_board .cell .note { font-size:10px; }
}

@media all and (orientation:portrait) and (max-width: 470px){
    .sudoku_board .cell span { font-size:16px; }
    .sudoku_board .cell .note { font-size:8px; }
}

@media all and (orientation:portrait) and (max-width: 320px){
    .sudoku_board .cell span { font-size:12px; }
    .sudoku_board .cell .note { font-size:8px; }
}

@media all and (orientation:portrait) and  (max-width: 240px){
    .sudoku_board .cell span { font-size:10px; }
}