.pv-calculator {
  max-width: 520px;
  margin: 20px auto;
  padding: 16px;
  border: 2px solid #2ecc71;
  border-radius: 14px;
  background: #f9f9f9;
  box-shadow: 0 6px 18px rgba(0,0,0,0.05);
}
.pv-calculator h3 { text-align:center; color:#1e874b; margin:0 0 10px 0; }
.pv-calculator label { display:block; margin-top:10px; font-weight:600; }
.pv-calculator input, .pv-calculator select { width:100%; padding:10px; margin-top:6px; border-radius:8px; border:1px solid #cfd9cf; background:#fff; }
#pv_calc_btn { margin-top:16px; width:100%; padding:12px; background:#27ae60; color:#fff; border:none; border-radius:10px; cursor:pointer; font-weight:700; }
#pv_calc_btn:hover { background:#2ecc71; }
#pv_result { margin-top:16px; padding:12px; background:#ecfdf5; border-radius:10px; border:1px solid #a7f3d0; }
.pv-help { margin-top:12px; font-size:0.9rem; color:#333; }