.numbers-to-words-converter {
    max-width: 600px;
    margin: 20px auto;
    padding: 30px;
    background: #f8f9fa;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
}

.ntw-form-group {
    margin-bottom: 25px;
}

.ntw-form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #2c3338;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.ntw-textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e1e5e9;
    border-radius: 8px;
    font-size: 16px;
    line-height: 1.5;
    resize: vertical;
    transition: all 0.3s ease;
    background: #ffffff;
    box-sizing: border-box;
}

.ntw-textarea:focus {
    outline: none;
    border-color: #007cba;
    box-shadow: 0 0 0 3px rgba(0, 124, 186, 0.1);
}

.ntw-output {
    background-color: #f8f9fa;
    color: #495057;
    font-weight: 500;
}

.ntw-select {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e1e5e9;
    border-radius: 8px;
    font-size: 16px;
    background: #ffffff;
    cursor: pointer;
    transition: all 0.3s ease;
    appearance: none;
    background-image: url("data:image/svg+xml;charset=US-ASCII,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 4 5'><path fill='%23333' d='M2 0L0 2h4zm0 5L0 3h4z'/></svg>");
    background-repeat: no-repeat;
    background-position: right 15px center;
    background-size: 12px;
}

.ntw-select:focus {
    outline: none;
    border-color: #007cba;
    box-shadow: 0 0 0 3px rgba(0, 124, 186, 0.1);
}

.ntw-buttons {
    display: flex;
    gap: 15px;
    margin-top: 30px;
}

.ntw-btn {
    flex: 1;
    padding: 14px 20px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.ntw-btn-primary {
    background: #007cba;
    color: white;
}

.ntw-btn-primary:hover {
    background: #005a87;
    transform: translateY(-2px);
}

.ntw-btn-primary:disabled {
    background: #a0a5aa;
    cursor: not-allowed;
    transform: none;
}

.ntw-btn-secondary {
    background: #6c757d;
    color: white;
}

.ntw-btn-secondary:hover {
    background: #545b62;
    transform: translateY(-2px);
}

.ntw-error-message {
    color: #dc3232;
    font-size: 14px;
    margin-top: 8px;
    font-weight: 500;
}

.ntw-success-message {
    color: #46b450;
    font-size: 14px;
    margin-top: 15px;
    font-weight: 500;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
}

.ntw-success-message.show {
    opacity: 1;
    transform: translateY(0);
}

.ntw-success-message.error {
    color: #dc3232;
}

/* Responsive Design */
@media (max-width: 768px) {
    .numbers-to-words-converter {
        margin: 10px;
        padding: 20px;
    }
    
    .ntw-buttons {
        flex-direction: column;
    }
    
    .ntw-btn {
        flex: none;
    }
}

/* Loading animation */
@keyframes ntw-loading {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.ntw-loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid #ffffff;
    border-radius: 50%;
    border-top-color: transparent;
    animation: ntw-loading 1s ease-in-out infinite;
    margin-right: 10px;
}