.bf-betonrechner {
    max-width: 600px;
    margin: 2rem auto;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 2px 16px rgba(0,0,0,0.08);
    overflow: hidden;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.bf-rechner-header {
    background: linear-gradient(135deg, #2d3436 0%, #636e72 100%);
    padding: 1.5rem 2rem;
    color: #fff;
}

.bf-rechner-header h3 {
    margin: 0 0 0.25rem 0;
    font-size: 1.4rem;
    font-weight: 700;
}

.bf-rechner-subtitle {
    margin: 0;
    opacity: 0.8;
    font-size: 0.9rem;
}

.bf-rechner-body {
    padding: 1.5rem 2rem;
}

.bf-input-group {
    margin-bottom: 1.25rem;
}

.bf-input-group label {
    display: block;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 0.4rem;
    color: #2d3436;
}

.bf-input-group input[type="number"],
.bf-input-group select {
    width: 100%;
    padding: 0.7rem 1rem;
    border: 2px solid #dfe6e9;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
    box-sizing: border-box;
}

.bf-input-group input[type="number"]:focus,
.bf-input-group select:focus {
    border-color: #00b894;
    outline: none;
}

.bf-hint {
    display: block;
    font-size: 0.78rem;
    color: #636e72;
    margin-top: 0.3rem;
}

.bf-input-group input[type="range"] {
    width: 100%;
    accent-color: #00b894;
}

.bf-range-value {
    display: inline-block;
    font-weight: 600;
    color: #00b894;
    font-size: 0.9rem;
}

.bf-custom-ratio {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1.25rem;
}

.bf-ratio-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    gap: 0.75rem;
}

.bf-ratio-inputs label {
    display: block;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.bf-ratio-inputs input {
    width: 100%;
    padding: 0.5rem;
    border: 2px solid #dfe6e9;
    border-radius: 6px;
    font-size: 0.9rem;
    text-align: center;
    box-sizing: border-box;
}

.bf-btn-calculate {
    width: 100%;
    padding: 0.9rem;
    background: #00b894;
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.bf-btn-calculate:hover {
    background: #00a383;
    transform: translateY(-1px);
}

.bf-btn-calculate:active {
    transform: translateY(0);
}

.bf-rechner-result {
    padding: 1.5rem 2rem;
    background: #f0fff4;
    border-top: 3px solid #00b894;
}

.bf-rechner-result h4 {
    margin: 0 0 1rem 0;
    color: #2d3436;
    font-size: 1.1rem;
}

.bf-result-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.bf-result-item {
    background: #fff;
    padding: 1rem;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 1px 4px rgba(0,0,0,0.06);
}

.bf-result-label {
    display: block;
    font-size: 0.8rem;
    color: #636e72;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.3rem;
}

.bf-result-value {
    display: block;
    font-size: 1.6rem;
    font-weight: 700;
    color: #2d3436;
}

.bf-result-unit {
    display: block;
    font-size: 0.8rem;
    color: #636e72;
}

.bf-result-bags {
    display: block;
    font-size: 0.75rem;
    color: #00b894;
    margin-top: 0.2rem;
    font-weight: 600;
}

.bf-result-total {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: #2d3436;
    color: #fff;
    border-radius: 8px;
    text-align: center;
    font-size: 1rem;
    font-weight: 600;
}

.bf-result-hint {
    margin-top: 0.75rem;
    font-size: 0.78rem;
    color: #636e72;
}

.bf-result-hint p {
    margin: 0;
}

.bf-ratgeber-links {
    margin-top: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.bf-ratgeber-links a {
    display: block;
    padding: 0.6rem 1rem;
    background: #fff;
    border: 2px solid #00b894;
    border-radius: 8px;
    color: #00b894;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    transition: all 0.2s;
    text-align: center;
}

.bf-ratgeber-links a:hover {
    background: #00b894;
    color: #fff;
}

@media (max-width: 480px) {
    .bf-rechner-body,
    .bf-rechner-result {
        padding: 1rem 1.25rem;
    }
    .bf-result-grid {
        grid-template-columns: 1fr 1fr;
    }
    .bf-ratio-inputs {
        grid-template-columns: 1fr 1fr;
    }
}