:root {
    --primary-color: #4f46e5;
    --secondary-color: #6b7280;
    --bg-color: #f3f4f6;
    --text-color: #111827;
    --card-bg: #ffffff;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
}
* { box-sizing: border-box; }
body {
    font-family: 'Poppins', sans-serif;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}
/* --- Login Screen --- */
#login-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 0.3s ease-in-out;
}
.login-card {
    background-color: var(--card-bg);
    padding: 3rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    text-align: center;
}
.login-card h1 {
    color: var(--primary-color);
    margin-bottom: 2rem;
}
.google-btn {
    background-color: #4285F4;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    transition: background-color 0.2s;
}
.google-btn:hover { background-color: #357ae8; }
.google-btn .fa-google { font-size: 1.2rem; }
.auth-note {
    margin-top: 1.5rem;
    font-size: 0.8rem;
    color: var(--secondary-color);
    max-width: 300px;
}

/* --- Main App Layout --- */
#app-container {
    display: none; /* Initially hidden */
    flex-direction: column;
    height: 100vh;
}
header {
    background-color: var(--card-bg);
    color: var(--text-color);
    padding: 1rem 2rem;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
}
header h1 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
nav button {
    background: none;
    border: none;
    color: var(--secondary-color);
    padding: 0.5rem 1rem;
    border-radius: 5px;
    cursor: pointer;
    margin-left: 1rem;
    font-weight: 500;
    transition: background-color 0.2s, color 0.2s;
}
nav button:hover { color: var(--primary-color); }
nav button.active {
    background-color: #e0e7ff;
    color: var(--primary-color);
}
#user-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
}
#user-menu button {
    background-color: var(--secondary-color);
    color: white;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    border: none;
    cursor: pointer;
    font-size: 1.1rem;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.2s;
}
#user-menu button:hover {
    background-color: #4f46e5;
}
.user-info {
    font-size: 0.9rem;
    color: var(--secondary-color);
}

main { flex: 1; padding: 2rem; overflow-y: auto; }
.container { max-width: 1400px; margin: 0 auto; }
.card {
    background-color: var(--card-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}
.chart-container {
     height: 300px; /* Important for Chart.js */
}

/* --- Tables & Forms --- */
.table-container {
    overflow-x: auto;
    position: relative; /* For loading overlay */
    min-height: 200px; /* Ensure space for loading */
}
table { width: 100%; border-collapse: collapse; margin-top: 1rem; }
th, td { padding: 0.75rem 1rem; text-align: left; border-bottom: 1px solid var(--border-color); }
th { background-color: #f9fafb; font-weight: 600; }
tbody tr:hover { background-color: #f9fafb; }
.status-badge {
    padding: 0.25em 0.6em; border-radius: 999px; font-size: 0.8em; font-weight: 500; text-transform: capitalize;
    display: inline-flex; align-items: center; gap: 0.3em;
}
.status-badge i { font-size: 0.9em; }
.status-paid, .status-active { background-color: #d1fae5; color: #065f46; }
.status-unpaid, .status-suspended { background-color: #fef3c7; color: #92400e; }
.status-late, .status-terminated { background-color: #fee2e2; color: #991b1b; }
.btn {
    padding: 0.6rem 1.2rem; border-radius: 8px; cursor: pointer; border: none; font-weight: 600; transition: opacity 0.2s;
    display: inline-flex; align-items: center; gap: 0.5rem;
}
.btn-primary { background-color: var(--primary-color); color: white; }
.btn-secondary { background-color: var(--secondary-color); color: white; }
.btn-success { background-color: var(--success); color: white; }
.btn-danger { background-color: var(--danger); color: white; }
.btn:hover { opacity: 0.85; }
.btn-sm {
    padding: 0.4rem 0.8rem;
    font-size: 0.8rem;
    border-radius: 6px;
}
.toolbar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1.5rem; flex-wrap: wrap; gap: 1rem;}
.search-bar { display: flex; gap: 0.5rem; flex-wrap: wrap;}
.search-bar input, .search-bar select { width: 200px; padding: 0.6rem; border: 1px solid var(--border-color); border-radius: 8px;}

/* --- Modal --- */
.modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-color: rgba(0,0,0,0.5); display: none; justify-content: center;
    align-items: center; z-index: 500;
}
.modal-content {
    background: white; padding: 2rem; border-radius: 12px; width: 90%; max-width: 600px; /* Increased max-width for detail view */
    box-shadow: var(--shadow);
    animation: fadeInScale 0.3s ease-out forwards;
    position: relative; /* Needed for positioning modal-loading-overlay inside it */
}
.modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1.5rem;}
.modal-header h3 { margin: 0; }
.close-btn { background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--secondary-color); }
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; margin-bottom: 0.5rem; font-weight: 500; }
.form-group input, .form-group select, .form-group textarea {
    width: 100%; padding: 0.75rem; border: 1px solid var(--border-color); border-radius: 8px;
    font-family: 'Poppins', sans-serif; /* Ensure consistent font */
}
.form-actions { display: flex; justify-content: flex-end; gap: 1rem; margin-top: 1.5rem;}
.detail-item {
    margin-bottom: 0.75rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px dashed var(--border-color);
}
.detail-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}
.detail-item strong {
    color: var(--primary-color);
    margin-right: 0.5rem;
}
.detail-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}
.history-log {
    background-color: var(--bg-color);
    padding: 0.75rem;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    font-size: 0.9em;
}
.history-log span {
    font-weight: 500;
    color: var(--text-color);
}
.history-log small {
    color: var(--secondary-color);
    margin-left: 0.5rem;
}

/* --- Toast Notifications --- */
#toast-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1000;
}
.toast {
    background-color: #333;
    color: white;
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 10px;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.3s ease-in-out, transform 0.3s ease-in-out;
    box-shadow: var(--shadow);
    min-width: 250px;
}
.toast.show {
    opacity: 1;
    transform: translateY(0);
}
.toast.success { background-color: var(--success); }
.toast.error { background-color: var(--danger); }
.toast.warning { background-color: var(--warning); }

/* --- Loading Overlay --- */
#loading-overlay, #table-loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1001;
    display: none; /* Hidden by default */
}

#table-loading-overlay {
    position: absolute; /* Relative to table-container */
    background-color: rgba(255, 255, 255, 0.6);
    z-index: 499; /* Below main modal, above table */
}

.modal-loading-overlay {
    position: absolute; /* Positioned relative to .modal-content */
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.7); /* Slightly transparent white */
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 501; /* Higher than modal content but lower than toast */
    border-radius: 12px; /* Match modal content border-radius */
    /* Initially hidden, will be controlled by JS */
    display: none;
}

.spinner {
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-left-color: var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}
@keyframes fadeInScale {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}
.pagination-controls {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1.5rem;
}
.pagination-controls button {
    background-color: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    font-weight: 600;
}
.pagination-controls button:disabled {
    background-color: var(--secondary-color);
    cursor: not-allowed;
}

/* Invoice Styles (for printing or PDF generation) */
@media print {
    body {
        margin: 0;
        padding: 0;
        -webkit-print-color-adjust: exact; /* For better color printing */
    }
    #app-container, #login-overlay, #modal, #toast-container, #loading-overlay, #table-loading-overlay, .modal-loading-overlay { /* Added modal-loading-overlay to hide on print */
        display: none !important;
    }
    .invoice-print-area {
        display: block !important;
        width: 210mm; /* A4 width */
        min-height: 297mm; /* A4 height */
        margin: 0 auto;
        padding: 20mm;
        box-shadow: none;
        font-family: 'Poppins', sans-serif;
        color: #333;
    }
    .invoice-print-area h1, .invoice-print-area h2, .invoice-print-area h3 {
        color: var(--primary-color);
    }
    .invoice-header, .invoice-footer {
        text-align: center;
        margin-bottom: 20px;
    }
    .invoice-details, .invoice-items, .invoice-summary {
        margin-bottom: 20px;
        border: 1px solid #eee;
        padding: 15px;
        border-radius: 8px;
    }
    .invoice-items table {
        width: 100%;
        border-collapse: collapse;
    }
    .invoice-items th, .invoice-items td {
        border: 1px solid #eee;
        padding: 8px;
        text-align: left;
    }
    .invoice-items th {
        background-color: #f9f9f9;
    }
    .invoice-summary .total {
        font-size: 1.5em;
        font-weight: bold;
        text-align: right;
        margin-top: 15px;
    }
}

/* --- Mobile Responsiveness --- */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        padding: 1rem;
        gap: 1rem;
    }
    header h1 {
        font-size: 1.2rem;
    }
    nav button {
        margin: 0 0.5rem;
        padding: 0.4rem 0.8rem;
        font-size: 0.9rem;
    }
    main {
        padding: 1rem;
    }
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    .toolbar {
        flex-direction: column;
        align-items: stretch;
    }
    .search-bar {
        flex-direction: column;
        width: 100%;
    }
    .search-bar input, .search-bar select {
        width: 100%;
    }
    .btn {
        width: 100%;
        justify-content: center;
    }
    .modal-content {
        padding: 1.5rem;
    }
}