html, body {
    overflow: hidden;
  }
  
body {
    text-align: center;
    font-family: Helvetica, Arial, sans-serif;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    margin:0;
    position: relative;
}
  
main {
    flex: 1;
}

footer {
    background-color: var(--background-off);
    border-top: 1px solid var(--background-off2);
    color: #aaa;
    font-size: 0.8em;
}

footer a { 
    color: #aaa;
}

h1 {
    font-size: 1.6em;
}

#board-container {
    position: relative;
    display: inline-block;
    width: min(calc(100vh - 200px), 90%, 600px);
    margin: 0 auto;
}

#board .hint {
    background-color: #aabbff;
}
#board .highlight {
    box-shadow: inset 0 0 3px 3px #f7ee7a;
}

.overlay {
    display: none;
    background-color: rgba(0, 0, 0, 0.6);
    position: absolute;
    width:100%;
    height: 100%;
    top: 0;
    left: 0;
}

#game-over h3 {
    color: white;
    font-size: 5em;
    margin: 32% auto 30px;
    font-weight: lighter;
}

#game-over p {
    color: white;
}

#loading {
    display: block;
}

#loading .loader {
    margin: calc(50% - 25px) auto;
}

button {
    margin: 15px;
    padding: 10px 20px;
    background-color: #eee;
    border: 1px solid #aaa;
    color: black;
    border-radius: 5px;
    font-size: 1.5em;
    cursor: pointer;
}

.loader {
    width: 50px;
    padding: 8px;
    aspect-ratio: 1;
    border-radius: 50%;
    background: white;
    --_m: 
      conic-gradient(#0000 10%,#000),
      linear-gradient(#000 0 0) content-box;
    -webkit-mask: var(--_m);
            mask: var(--_m);
    -webkit-mask-composite: source-out;
            mask-composite: subtract;
    animation: l3 1s infinite linear;
  }
  @keyframes l3 {to{transform: rotate(1turn)}}