:root {
    --rtbn-primary: #6366f1;
    --rtbn-primary-hover: #4f46e5;
    --rtbn-text: #1f2937;
    --rtbn-bg: #ffffff;
    --rtbn-border: #e5e7eb;
    --rtbn-error: #ef4444;
    --rtbn-radius: 8px;
    --rtbn-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

.rtbn-form {
    max-width: 600px;
    margin: 2rem 0;
    padding: 2.5rem;
    background: var(--rtbn-bg);
    border-radius: var(--rtbn-radius);
    box-shadow: var(--rtbn-shadow);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    border: 1px solid var(--rtbn-border);
}

.rtbn-field-group {
    margin-bottom: 1.5rem;
}

.rtbn-field-group label {
    display: block;
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--rtbn-text);
    margin-bottom: 0.5rem;
}

.rtbn-field-group label .required {
    color: var(--rtbn-error);
    margin-left: 0.25rem;
}

.rtbn-field-group input[type="text"],
.rtbn-field-group input[type="email"],
.rtbn-field-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1.5px solid var(--rtbn-border);
    border-radius: var(--rtbn-radius);
    font-size: 1rem;
    transition: all 0.2s ease;
    background: #f9fafb;
}

.rtbn-field-group input:focus,
.rtbn-field-group textarea:focus {
    outline: none;
    border-color: var(--rtbn-primary);
    background: #fff;
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.rtbn-submit-button {
    background: var(--rtbn-primary);
    color: white;
    padding: 0.75rem 2rem;
    border-radius: var(--rtbn-radius);
    border: none;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s ease, transform 0.1s active;
    display: inline-block;
}

.rtbn-submit-button:hover {
    background: var(--rtbn-primary-hover);
}

.rtbn-submit-button:active {
    transform: scale(0.98);
}

.rtbn-error-message {
    background: #fef2f2;
    color: var(--rtbn-error);
    padding: 1rem;
    border-radius: var(--rtbn-radius);
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--rtbn-error);
    font-size: 0.875rem;
}

.rtbn-success-message {
    background: #f0fdf4;
    color: #166534;
    padding: 1rem;
    border-radius: var(--rtbn-radius);
    margin-bottom: 1.5rem;
    border-left: 4px solid #22c55e;
    font-size: 0.875rem;
}
.rtbn-radio-group,
.rtbn-checkbox-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.rtbn-radio-item,
.rtbn-checkbox-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.rtbn-radio-item input,
.rtbn-checkbox-item input {
    margin: 0;
    width: auto;
}

.rtbn-radio-item label,
.rtbn-checkbox-item label {
    margin: 0;
    font-weight: 400;
    cursor: pointer;
}

.rtbn-checkbox-single {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.rtbn-checkbox-single input {
    margin: 0;
    width: auto;
}