.calculator-wrapper {
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
    padding: 30px;
    margin: 20px 0;
    max-width: 750px;
}
.tabs { display: flex; gap: 10px; margin-bottom: 20px; }
.tab-btn { flex: 1; padding: 10px; background: #f2f2f2; border: none; cursor: pointer; font-weight: 600;}
.tab-btn.active { background: #3498db; color: #fff; }
.tab-content { display: none; }
.tab-content.active { display: block; }
.form-group { margin-bottom: 15px; }
.form-group label { font-weight: 500; margin-bottom: 2px; display: block; }
.form-group input, .form-group select { padding: 8px; width: 100%; font-size: 16px; border: 1px solid #e0e0e0; border-radius: 5px; }
button[type="submit"] { background: #3498db; color: #fff; padding: 12px 25px; border: none; border-radius: 6px; cursor: pointer; font-weight: 700;}
#risultati-diretta, #risultati-inversa { margin-top: 16px; background: #f7f7f7; border-radius: 6px; padding: 16px; font-size: 15px; }
.alert { background: #ffeaa7; border-left: 4px solid #f39c12; margin: 8px 0; padding: 13px;}
.alert-danger { background: #ffd6d6; border-color: #e74c3c;}
.alert-icon { font-size: 18px; }
.badge-success { background: #d4f4df; color: #27ae60; padding: 3px 9px; border-radius: 5px; font-weight: 600;}
.badge-warning { background: #f7f0d0; color: #f39c12; padding: 3px 9px; border-radius: 5px; font-weight: 600;}
.badge-danger { background: #ffd9e0; color: #e74c3c; padding: 3px 9px; border-radius: 5px; font-weight: 600;}