body {
    background-color: #f8f9fa;
    height: 100%;
}

.matrix-container {
    display: inline-block;
    border: 1px solid #adb5bd;
    padding: 10px;
    border-radius: 8px;
    background-color: #ffffff;
    margin-top: 0 !important;
}

.matrix-row {
    display: flex;
}

.led-cell {
    width: 26px;
    height: 26px;
    margin: 2px;
    border: 1px solid #adb5bd;
    border-radius: 4px;
    cursor: pointer;
    background-color: #fff;
    transition: background-color 0.15s;
}

.led-cell.on {
    background-color: #0d6efd;
    box-shadow: 0 0 6px rgba(13, 110, 253, 0.7);
}

textarea {
    font-family: monospace;
    font-size: 0.9rem;
}

.frame-btn {
    min-width: 90px;
}


.matrix-section,
.code-section {
    flex: 1 1 350px;
}

.code-section textarea {
    min-height: 340px;
}


.controls-row {
    margin-bottom: 0.75rem;
}

#frameName.invalid {
    border-color: #dc3545;
}

#nameError {
    color: #dc3545;
    font-size: 0.8rem;
    display: none;
}