html {
    font-size: 24pt;
    font-family: sans-serif;
}

.page-container {
    position: fixed;
    left: 0;
    top: 0;
    width: 100vw;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.row-container {
    display: flex;
    justify-content: stretch;
}

.square {
    box-sizing: content-box;
    width: 2em;
    height: 2em;
    line-height: 2em;
    text-align: center;
    position: relative;
    z-index: 1;
}

.invalid {
    background-color: #fcc;
}

.highlight {
    background-color: #ffc;
}

.highlight.invalid {
    background-color: #fec;
}

.solver-select {
    box-shadow: inset 0 0 8px 2px #9cf;
}

.solver-error {
    background-color: #fcc;
    box-shadow: inset 0 0 8px 2px #f99;
}

.solver-solved {
    color: #39f;
}

.border {
    border: 1px solid black;
}

.hints {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: stretch;
    justify-content: stretch;
    flex-direction: column;
    color: gray;
    font-size: 0.25em;
    z-index: -1;
    line-height: 1;
}

.hints-container {
    width: 100%;
    display: flex;
    justify-content: stretch;
    flex: 1 0 0;
}

.hints-square {
    display: flex;
    align-items: center;
    justify-content: center;
    flex: 1 0 0;
    align-items: center;
    justify-content: center;
}