body {
    font-family: sans-serif;
    margin: 0;
}

/* Base styling for the main content area */
.billing-container {
    margin-left: 250px; /* Default for desktop with sidebar */
    padding: 20px;
}

/* Utility classes */
.header-section {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}
.margin-top-large {
    margin-top: 1.5rem;
}
.margin-bottom-small {
    margin-bottom: 1rem;
}
.margin-bottom-medium {
    margin-bottom: 1.5rem;
}
.padding-y-medium {
    padding-top: 0.75rem;
    padding-bottom: 0.75rem;
}
.padding-x-medium {
    padding-left: 1rem;
    padding-right: 1rem;
}
.rounded {
    border-radius: 0.5rem;
}
.shadow-small {
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
}
.text-center {
    text-align: center;
}
.text-muted {
    color: #6c757d;
}
.font-bold {
    font-weight: 700;
}
.hidden {
    display: none;
}
.flex {
    display: flex;
}
.width-full {
    width: 100%;
}
.margin-right-small {
    margin-right: 0.5rem;
}

/* Buttons */
.btn {
    border: 1px solid transparent;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 600;
}
.btn-light {
    background-color: #e9ecef;
    color: #495057;
}
.btn-light:hover {
    background-color: #dae0e5;
}
.btn-primary {
    background-color: #FFC222;
    color: white;
    font-weight: bold;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}
.btn-primary:hover {
    background-color: #f5b921;
}

/* Dropdown styling */
.dropdown-container {
    position: relative;
}
.dropdown-list {
    position: absolute;
    top: 100%;
    right: 0;
    z-index: 1000;
    background-color: #e9ecef;
    min-width: 10rem;
    padding: 0.5rem 0;
    margin-top: 0.5rem;
    border-radius: 0.5rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    list-style: none;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-0.5rem);
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
}
.dropdown-container.show .dropdown-list {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.dropdown-link {
    display: block;
    width: 100%;
    padding: 0.5rem 1rem;
    clear: both;
    font-weight: 400;
    color: #212529;
    text-align: inherit;
    white-space: nowrap;
    background-color: transparent;
    border: 0;
    cursor: pointer;
}
.dropdown-link:hover {
    background-color: #dae0e5;
}
        
/* Form elements */
.form-label {
    margin-bottom: 0.5rem;
}
.form-input {
    display: block;
    width: 98%;
    padding: 10px;
    font-size: 16px;
    font-weight: 400;
    line-height: 1.5;
    color: #495057;
    background-color: #fff;
    background-clip: padding-box;
    border: 1px solid #ced4da;
    border-radius: 4px;
}
label.required::before {
    content: '*';
    color: hsl(0, 72%, 51%);
    margin-right: 4px;
}   
.input-group {
    position: relative;
    display: flex;
    flex-wrap: wrap;
    align-items: stretch;
    width: 100%;
}
.input-group .form-input {
    flex: 1 1 auto;
    border-top-left-radius: 0;
    border-bottom-left-radius: 0;
}
.input-icon {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: #495057;
    text-align: center;
    background-color: white;
    border: 1px solid #ced4da;
    border-right: none;
    border-radius: 0.5rem 0 0 0.5rem;
}

/* Styling for the invoices */
.invoice-box {
    background-color: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    padding: 24px;
    margin-bottom: 24px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}
.invoice-header {
    margin-bottom: 20px;
    color: #333;
}
.invoice-header .user-info {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    align-items: center;
    margin-bottom: 10px;
}
.invoice-header .username {
    font-weight: bold;
    flex-grow: 1;
}
.invoice-header .invoice-number, .invoice-header .date {
    font-size: 0.9em;
    color: #666;
    margin-left: 10px;
}
.invoice-header .address, .invoice-header .payment-type {
    font-size: 0.9em;
    color: #555;
    margin: 4px 0;
}
.invoice-items table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9em;
}
.invoice-items th, .invoice-items td {
    text-align: left;
    padding: 8px 0;
}
.invoice-items th {
    color: #888;
    font-weight: normal;
    text-transform: uppercase;
}
.invoice-items td {
    color: #333;
}
.invoice-items tr td:nth-child(2) {
    font-weight: bold;
}
.invoice-summary {
    margin-top: 20px;
    text-align: right;
    font-size: 1em;
}
.invoice-summary .summary-line {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    margin: 4px 0;
}
.invoice-summary .label {
    color: #555;
    margin-right: 10px;
}
.invoice-summary .delivery-fee-label {
    color: #dc3545;
}
.invoice-summary .value {
    font-weight: bold;
}

/* Media Queries for Responsiveness */

/* Tablets (landscape) and larger phones (landscape) - roughly 768px to 1024px */
@media (max-width: 1024px) {
    .billing-container {
        margin-left: 0; /* Remove left margin for sidebar on smaller screens */
        padding: 15px;
    }

    .header-section {
        flex-direction: column; /* Stack buttons vertically */
        align-items: flex-start; /* Align to the start */
        gap: 1rem; /* Space between stacked buttons */
    }

    .dropdown-container {
        width: 100%; /* Make dropdown take full width */
    }

    .btn-light.rounded.shadow-small {
        width: 100%; /* Make buttons full width */
        text-align: center;
    }

    .payment-form {
        padding: 15px;
    }
}

/* Mobile devices (portrait and landscape) - up to 767px */
@media (max-width: 767px) {
    .billing-container {
        padding: 10px;
    }

    .header-section {
        margin-bottom: 1.5rem;
    }

    .btn, .dropdown-link {
        padding: 0.6rem 0.8rem;
        font-size: 0.9rem;
    }

    .dropdown-list {
        min-width: unset; /* Remove min-width constraint */
        width: 100%; /* Make dropdown list full width */
        right: auto; /* Reset right alignment */
        left: 0; /* Align to the left */
    }

    .form-input {
        padding: 8px;
        font-size: 15px;
    }

    .payment-form {
        padding: 10px;
        border-radius: 5px;
    }

    .btn-primary {
        padding: 10px 15px;
        font-size: 1rem;
    }

    .input-group .form-input {
        border-top-left-radius: 4px; /* Adjust radius for consistency */
        border-bottom-left-radius: 4px;
    }

    .input-icon {
        padding: 0.5rem 0.75rem;
        font-size: 0.9rem;
        border-radius: 4px 0 0 4px;
    }
}

/* Small mobile devices (e.g., iPhone 5/SE) - up to 374px */
@media (max-width: 374px) {
    .header-section {
        gap: 0.75rem;
    }

    .btn-light.rounded.shadow-small, .btn-primary {
        padding-top: 10px;
        padding-bottom: 10px;
    }
}