body {
    background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
    color: #fff;
    font-family: 'Poppins', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
}

h1 {
    margin: 30px 0 20px;
    font-size: 3rem;
    text-align: center;
    color: white;
}

.bingo-card {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    grid-template-rows: repeat(5, 1fr);
    width: 90vmin;
    height: 90vmin;
    border: 3px solid #fff;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
    margin-bottom: 30px;
}

.bingo-cell {
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    border: 1px solid #ffffff50;
    font-weight: 600;
    font-size: clamp(0.8rem, 1.5vw, 1.5rem);
    background-color: rgba(255, 255, 255, 0.05);
    transition: background-color 0.2s, transform 0.2s;
    padding: 5px;
    box-sizing: border-box;
    width: 100%;
    height: 100%;
    min-width: 0;
    min-height: 0;
    overflow-wrap: break-word;
    word-break: break-word;
    white-space: normal;
    overflow: hidden;
}

.bingo-cell:hover {
    background-color: rgba(255, 255, 255, 0.15);
    transform: scale(1.02);
    cursor: pointer;
}

.bingo-cell.selected {
    background-color: rgba(255, 255, 255, 0.3);
}

.bingo-cell.bingo {
    background-color: rgba(0, 255, 0, 0.3);
    font-weight: bold;
    border: 2px solid #0f0;
}

textarea {
    width: 100%;
    max-width: 700px;
    resize: none;
}

#gutter {
    min-width: 2em;
    border: 1px solid #444;
    border-right: none;
    background: #222;
    color: #aaa;
    padding: 8px 6px 8px 0;
    font-family: monospace;
    font-size: 1rem;
    line-height: 1.5;
    border-radius: 6px 0 0 6px;
    user-select: none;
    text-align: right;
    height: 100%;
    box-sizing: border-box;
}

#textImportArea {
    border-radius: 0 6px 6px 0;
    border-left: none;
    font-family: inherit;
    font-size: 1rem;
    line-height: 1.5;
    min-height: 37.5px;
    box-sizing: border-box;
    resize: none;
}

#textImportArea:focus {
    outline: none;
    box-shadow: none;
    border-color: #ccc;
}

.btn-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 20px;
}

.github-link {
    margin-top: 10px;
    margin-bottom: 25px;
    font-size: 2rem;
    color: #eee;
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    transition: color 0.2s;
}

.github-link:hover {
    color: #6cc644;
    text-decoration: underline;
}

.github-link svg {
    fill: currentColor;
    width: 2rem;
    height: 2rem;
}

@media (max-width: 600px) {
    .bingo-card {
        width: 95vmin;
        height: 95vmin;
    }

    .bingo-cell {
        font-size: 0.56rem;
        padding: 3px;
    }

    .github-link {
        margin-top: 10px;
        margin-bottom: 25px;
        font-size: 1rem;
        color: #eee;
        display: flex;
        align-items: center;
        gap: 8px;
        text-decoration: none;
        transition: color 0.2s;
    }

    .github-link svg {
        fill: currentColor;
        width: 20px;
        height: 20px;
    }
}