:root {
    --bg: #0f172a;
    --surface: #1e293b;
    --border: #334155;
    --text: #f1f5f9;
    --text-muted: #94a3b8;
    --accent: #38bdf8;
    --accent-hover: #7dd3fc;
    --success: #34d399;
    --warning: #fbbf24;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: 'Segoe UI', system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
}

.app {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.5rem;
}

.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
}

.header h1 {
    margin: 0;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--accent);
}

.back-link {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.95rem;
}

.back-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

.main {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.table-section {
    background: var(--surface);
    border-radius: 12px;
    padding: 1.25rem;
    border: 1px solid var(--border);
    overflow-x: auto;
}

.table-section h2 {
    margin: 0 0 1rem 0;
    font-size: 1.15rem;
    color: var(--text-muted);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th,
.data-table td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

.data-table tbody tr {
    vertical-align: middle;
}

.data-table tbody td {
    vertical-align: middle;
    position: relative;
}

.data-table tbody td.actions-cell {
    display: table-cell !important;
    vertical-align: middle;
    overflow: visible;
    height: auto;
    min-height: auto;
}

.data-table tbody td.actions-cell > * {
    vertical-align: middle;
}

.data-table th {
    font-weight: 600;
    color: var(--text-muted);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.data-table tbody tr:hover {
    background: rgba(56, 189, 248, 0.06);
}

.data-table .loading {
    color: var(--text-muted);
    text-align: center;
    padding: 2rem;
}

.data-table td.actions-cell {
    vertical-align: middle;
    text-align: left;
    padding: 0.75rem 1rem;
    position: relative;
}

.actions-cell {
    display: flex;
    flex-wrap: nowrap;
    gap: 0.5rem;
    align-items: center;
    justify-content: flex-start;
    white-space: nowrap;
    line-height: 1;
    margin: 0;
    padding: 0;
    vertical-align: middle;
    height: auto;
}

.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--accent);
    color: var(--bg);
    border: none;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.2s;
}

.btn:hover {
    background: var(--accent-hover);
    color: var(--bg);
}

.card {
    background: var(--surface);
    border-radius: 12px;
    padding: 1.25rem;
    border: 1px solid var(--border);
}

.flat-info.card h2,
.pending-section.card h2 {
    margin: 0 0 1rem 0;
    font-size: 1.15rem;
    color: var(--text-muted);
}

.flat-details {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 0.5rem 1.5rem;
    margin: 0;
}

.flat-details dt {
    color: var(--text-muted);
    font-weight: 500;
}

.flat-details dd {
    margin: 0;
}

.pending-section .pending-amount {
    font-size: 1.5rem;
    margin: 0 0 0.5rem 0;
}

.pending-section .pending-amount strong {
    color: var(--warning);
}

.pending-note {
    margin: 0;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.hidden {
    display: none !important;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.header-actions .user-info {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.logout-form {
    margin: 0;
}

.btn-ghost {
    background: transparent;
    color: var(--accent);
    border: 1px solid var(--border);
}

.btn-ghost:hover {
    background: rgba(56, 189, 248, 0.1);
    color: var(--accent-hover);
}

/* Login page */
.login-main {
    max-width: 400px;
}

@media (max-width: 768px) {
    .login-main {
        max-width: 100%;
    }

    .login-card {
        width: 100%;
    }
}

.login-card h2 {
    margin: 0 0 1rem 0;
    font-size: 1.25rem;
    color: var(--text-muted);
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.login-form label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.login-form input {
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg);
    color: var(--text);
    font-size: 1rem;
}

.btn-block {
    width: 100%;
    margin-top: 0.5rem;
}

.login-back {
    margin: 1rem 0 0 0;
    font-size: 0.9rem;
}

.login-back a {
    color: var(--accent);
    text-decoration: none;
}

.login-back a:hover {
    text-decoration: underline;
}

/* Modal */
.modal {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
}

.modal-content {
    position: relative;
    width: 100%;
    max-width: 440px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-content h2 {
    margin: 0 0 1rem 0;
    font-size: 1.25rem;
    color: var(--text-muted);
}

.flat-details-inline {
    background: var(--bg);
    border-radius: 8px;
    padding: 0.75rem 1rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.form {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.form label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.form input,
.form select {
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg);
    color: var(--text);
    font-size: 1rem;
}

.form select {
    cursor: pointer;
}

.form-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: flex-end;
    margin-top: 0.5rem;
}

/* Toast */
.toast-container {
    position: fixed;
    bottom: 1.5rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    pointer-events: none;
}

.toast {
    padding: 0.75rem 1.25rem;
    background: var(--surface);
    border: 1px solid var(--success);
    border-radius: 8px;
    color: var(--text);
    font-size: 0.95rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    animation: toast-in 0.25s ease-out;
}

.toast.success {
    border-color: var(--success);
    background: rgba(52, 211, 153, 0.15);
}

@keyframes toast-in {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Top Navigation Bar */
.top-nav {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 0.75rem 1.5rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.top-nav-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.app-title {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
}

.app-title a {
    color: inherit;
    text-decoration: none;
}

.app-title a:hover,
.app-title a:focus-visible {
    color: var(--accent-hover);
}

/* App Wrapper - Contains sidebar and main content */
.app-wrapper {
    display: flex;
    min-height: calc(100vh - 60px);
    max-width: 1400px;
    margin: 0 auto;
}

/* Sidebar Navigation (Desktop) */
.sidebar {
    width: 240px;
    background: var(--surface);
    border-right: 1px solid var(--border);
    padding: 1.5rem 0;
    flex-shrink: 0;
    display: none; /* Hidden on mobile, shown on desktop */
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    padding: 0 1rem;
}

.sidebar-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    color: var(--text-muted);
    text-decoration: none;
    border-radius: 8px;
    transition: all 0.2s;
    font-size: 0.95rem;
}

.sidebar-link span:first-child {
    font-size: 1.2rem;
}

.sidebar-link:hover {
    color: var(--accent);
    background: rgba(56, 189, 248, 0.1);
}

.sidebar-link.active {
    color: var(--accent);
    background: rgba(56, 189, 248, 0.15);
    font-weight: 600;
}

/* Main content area */
.app {
    flex: 1;
    padding: 1.5rem;
    overflow-x: hidden;
}

/* Mobile Navigation (Top Bar) - hidden by default, shown on mobile via media query */
.mobile-nav {
    display: none;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}

.mobile-nav-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0.5rem 1rem 0.75rem 1rem;
}

.mobile-nav-links {
    display: flex;
    gap: 0.5rem;
}

.mobile-nav-links a {
    flex: 1;
    text-align: center;
    padding: 0.6rem 0.75rem;
    border-radius: 999px;
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
    background: rgba(15, 23, 42, 0.9);
    border: 1px solid var(--border);
    transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.mobile-nav-links a:hover {
    color: var(--accent);
    border-color: rgba(56, 189, 248, 0.6);
    background: rgba(15, 23, 42, 1);
}

.mobile-nav-links a.active {
    color: var(--accent);
    background: rgba(56, 189, 248, 0.15);
    border-color: rgba(56, 189, 248, 0.7);
}

.summary-card {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.summary-item {
    background: var(--surface);
    border-radius: 12px;
    padding: 1.25rem;
    border: 1px solid var(--border);
}

.summary-item h3 {
    margin: 0 0 0.5rem 0;
    font-size: 0.85rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.summary-item .value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
}

.summary-item .value.positive {
    color: var(--success);
}

.summary-item .value.negative {
    color: #f87171;
}

.pending-month-tag {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    margin: 0.25rem;
    background: rgba(251, 191, 36, 0.2);
    border: 1px solid var(--warning);
    border-radius: 6px;
    font-size: 0.85rem;
    color: var(--warning);
    position: relative;
}

/* Paid For months display */
.paid-for-cell {
    min-width: 200px;
    max-width: 350px;
    padding: 0.5rem 1rem !important;
    vertical-align: middle;
}

.paid-for-container {
    display: flex;
    flex-wrap: wrap;
    gap: 0.35rem;
    align-items: center;
}

.paid-for-tag {
    display: inline-block;
    padding: 0.3rem 0.6rem;
    background: rgba(56, 189, 248, 0.15);
    border: 1px solid rgba(56, 189, 248, 0.4);
    border-radius: 6px;
    font-size: 0.8rem;
    color: var(--accent);
    white-space: nowrap;
    font-weight: 500;
}

.remove-override-btn {
    display: inline-block;
    margin-left: 0.25rem;
    padding: 0 0.4rem;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1.2rem;
    line-height: 1;
    cursor: pointer;
    border-radius: 4px;
    vertical-align: middle;
}

.remove-override-btn:hover {
    background: rgba(248, 113, 113, 0.2);
    color: #f87171;
}

/* Mobile Optimizations */
@media (max-width: 768px) {
    /* App container */
    .app {
        padding: 1rem;
    }

    /* Stack layout and show mobile nav on small screens */
    .app-wrapper {
        flex-direction: column;
    }

    .mobile-nav {
        display: block;
    }

    /* Navigation */
    .nav {
        padding: 0.75rem 1rem;
        margin-bottom: 1.5rem;
    }

    .nav-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
    }

    .nav-content h1 {
        font-size: 1.25rem;
    }

    .nav-links {
        width: 100%;
        flex-direction: column;
        gap: 0.5rem;
    }

    .nav-links a {
        width: 100%;
        text-align: center;
        padding: 0.75rem;
    }

    /* Header actions */
    .header-actions {
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .header-actions .btn,
    .header-actions a {
        font-size: 0.85rem;
        padding: 0.5rem 0.75rem;
    }

    /* Cards and sections */
    .card,
    .table-section {
        padding: 1rem;
        border-radius: 8px;
    }

    .card h2,
    .table-section h2 {
        font-size: 1rem;
    }

    /* Tables - make scrollable */
    .table-section {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .data-table {
        min-width: 600px; /* Force horizontal scroll on very small screens */
    }

    .data-table th,
    .data-table td {
        padding: 0.5rem 0.75rem;
        font-size: 0.85rem;
        vertical-align: middle;
    }

    .data-table th {
        font-size: 0.75rem;
        white-space: nowrap;
    }

    .data-table td.actions-cell {
        padding: 0.5rem 0.75rem;
    }

    .paid-for-cell {
        min-width: 150px;
        max-width: 250px;
        padding: 0.4rem 0.5rem !important;
    }

    .paid-for-tag {
        font-size: 0.75rem;
        padding: 0.25rem 0.5rem;
    }

    /* Buttons - larger touch targets */
    .btn {
        padding: 0.75rem 1rem;
        font-size: 1rem;
        min-height: 44px; /* iOS recommended touch target */
    }

    .btn-ghost {
        min-height: 44px;
    }

    /* Form inputs */
    .form input,
    .form select {
        padding: 0.75rem;
        font-size: 1rem;
        min-height: 44px;
    }

    .form label {
        font-size: 0.9rem;
    }

    /* Form actions */
    .form-actions {
        flex-direction: column;
        gap: 0.5rem;
    }

    .form-actions .btn {
        width: 100%;
    }

    /* Flat details */
    .flat-details {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .flat-details dt {
        font-weight: 600;
        margin-top: 0.5rem;
    }

    .flat-details dt:first-child {
        margin-top: 0;
    }

    /* Pending amount */
    .pending-section .pending-amount {
        font-size: 1.25rem;
    }

    .pending-note {
        font-size: 0.8rem;
    }

    /* Summary cards */
    .summary-card {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .summary-item {
        padding: 1rem;
    }

    .summary-item .value {
        font-size: 1.25rem;
    }

    /* Pending month tags */
    .pending-month-tag {
        font-size: 0.8rem;
        padding: 0.3rem 0.5rem;
        margin: 0.2rem;
    }

    /* Modal */
    .modal {
        padding: 0.5rem;
    }

    .modal-content {
        max-width: 100%;
        max-height: 95vh;
        padding: 1rem;
    }

    .modal-content h2 {
        font-size: 1.1rem;
    }

    /* Toast */
    .toast-container {
        left: 1rem;
        right: 1rem;
        transform: none;
        bottom: 1rem;
    }

    .toast {
        font-size: 0.9rem;
        padding: 0.75rem 1rem;
    }

    /* Actions cell - stack buttons on very small screens */
    .actions-cell {
        flex-direction: column;
        gap: 0.5rem;
        align-items: stretch;
    }

    .actions-cell .btn {
        width: 100%;
        font-size: 0.85rem;
    }

    /* Remove override button */
    .remove-override-btn {
        min-width: 32px;
        min-height: 32px;
        padding: 0.25rem;
    }
}

/* Extra small screens */
@media (max-width: 480px) {
    .app {
        padding: 0.75rem;
    }

    .nav-content h1 {
        font-size: 1.1rem;
    }

    .card,
    .table-section {
        padding: 0.75rem;
    }

    .data-table th,
    .data-table td {
        padding: 0.4rem 0.5rem;
        font-size: 0.8rem;
        vertical-align: middle;
    }

    .data-table th {
        font-size: 0.7rem;
    }

    .data-table td.actions-cell {
        padding: 0.4rem 0.5rem;
    }

    .paid-for-cell {
        min-width: 120px;
        max-width: 200px;
        padding: 0.35rem 0.4rem !important;
    }

    .paid-for-tag {
        font-size: 0.7rem;
        padding: 0.2rem 0.4rem;
    }

    .pending-section .pending-amount {
        font-size: 1.1rem;
    }

    .summary-item .value {
        font-size: 1.1rem;
    }

    /* Collection vs Expense page specific */
    .card > div[style*="display: flex"] {
        flex-direction: column;
        gap: 0.75rem;
    }

    .card > div[style*="display: flex"] > div {
        width: 100%;
    }

    .card > div[style*="display: flex"] > div[style*="align-self"] {
        align-self: stretch;
        margin-left: 0;
    }

    .card > div[style*="display: flex"] > div[style*="align-self"] .btn {
        width: 100%;
    }
}

/* Landscape orientation on mobile */
@media (max-width: 768px) and (orientation: landscape) {
    .modal-content {
        max-height: 85vh;
    }

    .mobile-nav-links {
        flex-direction: row;
    }
}

/* Desktop: Show sidebar */
@media (min-width: 769px) {
    .sidebar {
        display: block;
    }

    .mobile-nav {
        display: none;
    }
}

/* Touch-friendly improvements for all mobile */
@media (hover: none) and (pointer: coarse) {
    /* Larger touch targets */
    .btn,
    .btn-ghost {
        min-height: 44px;
    }

    /* Remove hover effects on touch devices */
    .data-table tbody tr:hover {
        background: transparent;
    }

    .nav-links a:hover {
        background: transparent;
    }

    /* Better focus states */
    .btn:focus,
    .btn-ghost:focus,
    .form input:focus,
    .form select:focus {
        outline: 2px solid var(--accent);
        outline-offset: 2px;
    }
}

/* Prevent text size adjustment on iOS */
@media screen and (max-width: 768px) {
    input,
    select,
    textarea {
        font-size: 16px !important; /* Prevents zoom on iOS */
    }
}

/* Improve scrolling on mobile */
@media (max-width: 768px) {
    body {
        -webkit-overflow-scrolling: touch;
    }

    .table-section {
        -webkit-overflow-scrolling: touch;
        scrollbar-width: thin;
    }

    /* Better scrollbar visibility */
    .table-section::-webkit-scrollbar {
        height: 8px;
    }

    .table-section::-webkit-scrollbar-track {
        background: var(--bg);
    }

    .table-section::-webkit-scrollbar-thumb {
        background: var(--border);
        border-radius: 4px;
    }
}