.rcta-calc {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: #f8f9fa;
    border-radius: 8px;
    padding: 32px 24px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    max-width: 100%;
    margin: 0 auto 24px;
    box-sizing: border-box;
}

.rcta-calc h3 {
    margin: 0 0 20px;
    font-size: 24px;
    color: #333;
    text-align: center;
}

.rcta-calc label {
    display: block;
    font-size: 15px;
    font-weight: 600;
    margin: 18px 0 6px;
    color: #444;
}

.rcta-calc input[type="number"],
.rcta-calc select {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 16px;
    box-sizing: border-box;
    font-family: inherit;
}

.rcta-calc .group-select {
    display: flex;
    gap: 20px;
    margin-bottom: 20px;
}

.rcta-calc .group-select label {
    font-weight: normal;
    cursor: pointer;
}

.rcta-calc input[type="checkbox"] {
    margin-right: 8px;
}

.rcta-calc button.rcta-submit {
    width: 100%;
    margin-top: 24px;
    padding: 14px;
    background: #0066cc;
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 17px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.rcta-calc button.rcta-submit:hover {
    background: #0052a3;
}

.rcta-calc .rcta-error {
    color: #cc0000;
    font-size: 15px;
    margin-top: 12px;
    display: none;
}

.rcta-calc .rcta-result {
    margin-top: 24px;
    padding: 18px;
    background: #e9ecef;
    border-radius: 6px;
    text-align: center;
    font-size: 17px;
    color: #222;
    display: none;
}

.rcta-calc .rcta-class-name {
    font-size: 28px;
    font-weight: bold;
    color: #0066cc;
    display: block;
    margin: 6px 0;
}