html,
body {
    height: 100%;
    margin: 0;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: #343541;   /* ChatGPT dark background */
    color: #ececf1;        /* ChatGPT text */
}

table {
    border-collapse: collapse;
    margin-top: 20px;
    background: #40414f;   /* Surface panel */
    border: 1px solid #4b4c5a;
}

td {
    width: 40px;
    height: 40px;
    text-align: center;
    vertical-align: middle;
    border: 1px solid #4b4c5a; /* Soft grid lines */
    font-size: 24px;
    color: #ececf1;
}

a {
    text-decoration: none;
    display: block;
    width: 100%;
    height: 100%;
    color: #ececf1;
    transition: background 0.15s ease, color 0.15s ease;
}

a:hover {
    background: #4b4c5a;   /* Hover highlight */
}

a:active {
    background: #;
}

.e {
color: #9999FF;
}

h3 {
color: #9999FF;
}