.main-wrapper { width: 100%; max-width: 500px; margin: auto; padding: 20px 10px; }
.calculator-card { background: #ffffff; padding: 25px; border-radius: 15px; box-shadow: 0 10px 25px rgba(0,0,0,0.1); border: 2px solid #27ae60; }
.calculator-card h1 { text-align: center; color: #000; font-size: 24px; margin-bottom: 20px; }
.input-group { margin-bottom: 15px; }
.input-group label { display: block; font-weight: bold; margin-bottom: 5px; color: #333; }
.input-group select, .input-group input { width: 100%; padding: 10px; border: 1px solid #ccc; border-radius: 5px; font-weight: bold; }
.formula-box { background: #f4f4f4; padding: 10px; border-left: 4px solid #27ae60; margin-bottom: 15px; font-size: 14px; }
.button-row { display: flex; gap: 10px; }
.btn { flex: 1; padding: 12px; border: none; border-radius: 5px; cursor: pointer; font-weight: bold; }
.btn-calc { background: #27ae60; color: white; }
.btn-reset { background: #95a5a6; color: white; }
.result-area { margin-top: 20px; padding: 15px; background: #e8f8f5; border: 1px solid #27ae60; border-radius: 10px; display: none; }
.result-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 5px; text-align: center; }
.res-item h2 { font-size: 14px; margin: 0; color: #27ae60; }
.btn-png { background: #3498db; color: white; width: 100%; margin-top: 10px; display: none; }
.formula-section { margin-top: 20px; border-top: 1px solid #ddd; padding-top: 20px; }
.formula-item { display: flex; justify-content: space-between; padding: 5px 0; border-bottom: 1px hide solid #eee; font-size: 13px; }