.invoice-hero {
        background: linear-gradient(135deg, #1a5e5c 0%, #2d8a7a 100%);
        padding: 50px 0 40px;
        color: #fff;
        position: relative;
        overflow: hidden;
    }
    .invoice-hero::before {
        content: '';
        position: absolute;
        top: -50%;
        right: -10%;
        width: 500px;
        height: 500px;
        background: radial-gradient(circle, rgba(255,255,255,0.05) 0%, transparent 70%);
        border-radius: 50%;
    }
    .invoice-hero h1 {
        font-size: 36px;
        font-weight: 800;
        margin-bottom: 8px;
    }
    .invoice-hero p {
        color: rgba(255,255,255,0.85);
        font-size: 16px;
        max-width: 550px;
        line-height: 1.6;
        margin: 0 auto 12px;
    }
    .usage-badge {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        background: rgba(255,255,255,0.15);
        border: 1px solid rgba(255,255,255,0.2);
        padding: 8px 18px;
        border-radius: 30px;
        font-size: 13px;
        font-weight: 500;
    }

    /* Form Styles */
    .invoice-form-wrapper {
        padding: 40px 0 60px;
        background: #f8fafc;
    }
    .form-card {
        background: #fff;
        border-radius: 14px;
        padding: 30px;
        border: 1px solid #e8ecf1;
        margin-bottom: 24px;
        box-shadow: 0 4px 20px rgba(0,0,0,0.03);
    }
    .form-card .form-card-title {
        font-size: 18px;
        font-weight: 700;
        color: #1e293b;
        margin-bottom: 20px;
        padding-bottom: 14px;
        border-bottom: 2px solid #f1f3f5;
        display: flex;
        align-items: center;
        gap: 10px;
    }
    .form-card .form-card-title i {
        color: #1a5e5c;
    }
    .form-control:focus {
        border-color: #1a5e5c;
        box-shadow: 0 0 0 3px rgba(26,94,92,0.1);
    }
    label {
        font-weight: 600;
        font-size: 13px;
        color: #1e293b;
        margin-bottom: 6px;
    }
    .required-star {
        color: #dc2626;
    }

    /* Items Table */
    .items-table {
        width: 100%;
        border-collapse: collapse;
    }
    .items-table thead th {
        background: #1a1a1a;
        color: #fff;
        padding: 12px 14px;
        text-align: left;
        font-size: 13px;
        font-weight: 600;
        text-transform: uppercase;
        letter-spacing: 0.5px;
    }
    .items-table thead th:first-child {
        border-top-left-radius: 8px;
    }
    .items-table thead th:last-child {
        border-top-right-radius: 8px;
        text-align: right;
    }
    .items-table tbody td {
        padding: 10px 8px;
        border-bottom: 1px solid #f1f3f5;
        vertical-align: middle;
    }
    .items-table tbody input {
        width: 100%;
        padding: 8px 10px;
        border: 1px solid #e2e8f0;
        border-radius: 6px;
        font-size: 14px;
    }
    .items-table tbody input:focus {
        outline: none;
        border-color: #1a5e5c;
        box-shadow: 0 0 0 3px rgba(26,94,92,0.1);
    }
    .items-table .line-total {
        text-align: right;
        font-weight: 600;
        color: #1a5e5c;
        padding-right: 10px;
    }
    .btn-remove-item {
        background: #fee2e2;
        color: #dc2626;
        border: none;
        width: 34px;
        height: 34px;
        border-radius: 6px;
        cursor: pointer;
        transition: all 0.2s ease;
    }
    .btn-remove-item:hover {
        background: #dc2626;
        color: #fff;
    }

    /* Totals */
    .totals-box {
        background: #f8fafc;
        border-radius: 10px;
        padding: 20px;
        border: 1px solid #e8ecf1;
    }
    .totals-row {
        display: flex;
        justify-content: space-between;
        padding: 8px 0;
        font-size: 14px;
        color: #475569;
    }
    .totals-row.grand-total {
        border-top: 2px solid #1a5e5c;
        margin-top: 8px;
        padding-top: 14px;
        font-size: 20px;
        font-weight: 800;
        color: #1a5e5c;
    }

    /* Buttons */
    .btn-primary-action {
        background: #1a5e5c;
        color: #fff;
        padding: 14px 32px;
        border: none;
        border-radius: 8px;
        font-weight: 700;
        font-size: 15px;
        transition: all 0.3s ease;
        cursor: pointer;
        display: inline-flex;
        align-items: center;
        gap: 8px;
    }
    .btn-primary-action:hover {
        background: #0f4a48;
        transform: translateY(-2px);
        box-shadow: 0 6px 20px rgba(26,94,92,0.3);
    }
    .btn-secondary-action {
        background: #f1f5f9;
        color: #475569;
        padding: 14px 24px;
        border: none;
        border-radius: 8px;
        font-weight: 600;
        font-size: 15px;
        transition: all 0.3s ease;
        cursor: pointer;
        display: inline-flex;
        align-items: center;
        gap: 8px;
    }
    .btn-secondary-action:hover {
        background: #e2e8f0;
    }
    .btn-add-item {
        background: transparent;
        color: #1a5e5c;
        padding: 10px 20px;
        border: 2px dashed #1a5e5c;
        border-radius: 8px;
        font-weight: 600;
        font-size: 14px;
        cursor: pointer;
        transition: all 0.3s ease;
        width: 100%;
        margin-top: 12px;
    }
    .btn-add-item:hover {
        background: #f0fdfa;
    }

    /* Modal */
    .modal-overlay {
        position: fixed;
        inset: 0;
        background: rgba(0,0,0,0.6);
        z-index: 9999;
        display: none;
        align-items: center;
        justify-content: center;
        padding: 20px;
    }
    .modal-overlay.active {
        display: flex;
    }
    .modal-content-box {
        background: #fff;
        border-radius: 16px;
        max-width: 500px;
        width: 100%;
        padding: 40px 32px;
        text-align: center;
        animation: modalPop 0.3s ease;
    }
    @keyframes modalPop {
        from { transform: scale(0.9); opacity: 0; }
        to { transform: scale(1); opacity: 1; }
    }
    .modal-content-box .success-icon {
        width: 70px;
        height: 70px;
        border-radius: 50%;
        background: #dcfce7;
        color: #16a34a;
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 32px;
        margin: 0 auto 20px;
    }
    .modal-content-box h3 {
        color: #1e293b;
        font-size: 22px;
        font-weight: 700;
        margin-bottom: 8px;
    }
    .modal-content-box p {
        color: #64748b;
        font-size: 14px;
        margin-bottom: 24px;
    }
    .modal-btn-group {
        display: flex;
        flex-direction: column;
        gap: 10px;
    }
    .modal-btn-group a,
    .modal-btn-group button {
        padding: 12px;
        border-radius: 8px;
        font-weight: 600;
        font-size: 14px;
        text-decoration: none;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 8px;
        transition: all 0.3s ease;
        border: none;
        cursor: pointer;
    }

    /* Expiry notice inside modal */
    .expiry-notice {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        background: #fef3c7;
        border: 1px solid #fde68a;
        color: #92400e;
        font-size: 13px;
        padding: 8px 14px;
        border-radius: 8px;
        margin-top: 4px;
        margin-bottom: 18px;
    }
    .expiry-notice i {
        color: #d97706;
    }
    .expiry-notice strong {
        font-variant-numeric: tabular-nums;
        color: #78350f;
    }

    @media (max-width: 768px) {
        .invoice-hero h1 { font-size: 26px; }
        .invoice-hero p { font-size: 14px; }
        .form-card { padding: 20px; }
        .form-card .form-card-title { font-size: 16px; }
        .items-table thead th { font-size: 11px; padding: 8px; }
        .items-table tbody td { padding: 6px 4px; }
    }