/* ================================================================
   Income & Expense Tracker — Site CSS
   WCAG 2.1 AA compliant colour palette and utility styles
   ================================================================ */

/* --- CSS Custom Properties (Design Tokens) -------------------- */
:root {
    --clr-primary:        #1a56db;
    --clr-primary-dark:   #1443b8;
    --clr-primary-light:  #e8f0fe;
    --clr-income:         #0d9488;
    --clr-income-bg:      #f0fdfa;
    --clr-expense:        #dc2626;
    --clr-expense-bg:     #fef2f2;
    --clr-balance:        #7c3aed;
    --clr-balance-bg:     #f5f3ff;
    --clr-neutral:        #6b7280;
    --clr-neutral-bg:     #f9fafb;

    --clr-surface:        #ffffff;
    --clr-body-bg:        #f3f4f6;
    --clr-sidebar-bg:     #1e293b;
    --clr-sidebar-text:   #cbd5e1;
    --clr-sidebar-hover:  #334155;
    --clr-sidebar-active: #1a56db;

    --clr-text-primary:   #111827;
    --clr-text-secondary: #374151;
    --clr-text-muted:     #6b7280;
    --clr-border:         #e5e7eb;

    --radius-sm:  0.375rem;
    --radius-md:  0.625rem;
    --radius-lg:  1rem;

    --shadow-sm:  0 1px 3px rgba(0,0,0,.10), 0 1px 2px rgba(0,0,0,.06);
    --shadow-md:  0 4px 6px -1px rgba(0,0,0,.10), 0 2px 4px -2px rgba(0,0,0,.06);
    --shadow-lg:  0 10px 15px -3px rgba(0,0,0,.10), 0 4px 6px -4px rgba(0,0,0,.05);

    --sidebar-width: 260px;
    --topbar-height: 64px;
}

/* --- Base Reset ------------------------------------------------ */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    font-size: 1rem;
    color: var(--clr-text-primary);
    background-color: var(--clr-body-bg);
    margin: 0;
    min-height: 100vh;
}

/* --- WCAG: Skip-to-content link ------------------------------- */
.skip-link {
    position: absolute;
    top: -100%;
    left: 1rem;
    z-index: 9999;
    padding: 0.5rem 1rem;
    background: var(--clr-primary);
    color: #fff;
    border-radius: 0 0 var(--radius-sm) var(--radius-sm);
    font-weight: 600;
    text-decoration: none;
    transition: top 0.1s;
}
.skip-link:focus {
    top: 0;
}

/* --- WCAG: Focus indicators ----------------------------------- */
:focus-visible {
    outline: 3px solid var(--clr-primary);
    outline-offset: 3px;
    border-radius: var(--radius-sm);
}
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    outline: 3px solid var(--clr-primary);
    outline-offset: 2px;
}

/* --- App Shell ------------------------------------------------ */
.app-wrapper {
    display: flex;
    min-height: 100vh;
    width: 100%;
    overflow-x: hidden;
}

/* --- Sidebar -------------------------------------------------- */
.sidebar {
    width: var(--sidebar-width);
    background: var(--clr-sidebar-bg);
    color: var(--clr-sidebar-text);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    z-index: 1000;
    transition: transform 0.3s ease;
    overflow-y: auto;
}
.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid #334155;
    text-decoration: none;
    color: #fff;
    font-weight: 700;
    font-size: 1.125rem;
    letter-spacing: -0.01em;
}
.sidebar-brand-icon {
    width: 36px;
    height: 36px;
    background: var(--clr-primary);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    flex-shrink: 0;
}
.sidebar-section-title {
    padding: 1.25rem 1.5rem 0.375rem;
    font-size: 0.6875rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: #64748b;
    font-weight: 600;
}
.sidebar-nav {
    padding: 0.5rem 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.125rem;
    list-style: none;
    margin: 0;
}
.sidebar-nav .nav-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.625rem 0.75rem;
    border-radius: var(--radius-sm);
    color: var(--clr-sidebar-text);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: background 0.15s, color 0.15s;
}
.sidebar-nav .nav-link:hover,
.sidebar-nav .nav-link:focus-visible {
    background: var(--clr-sidebar-hover);
    color: #fff;
}
.sidebar-nav .nav-link.active {
    background: var(--clr-primary);
    color: #fff;
}
.sidebar-nav .nav-link i {
    font-size: 1rem;
    width: 20px;
    text-align: center;
    flex-shrink: 0;
}
.sidebar-nav-group {
    display: flex;
    flex-direction: column;
}
.sidebar-nav-sub {
    list-style: none;
    margin: 0.125rem 0 0.25rem;
    padding: 0 0 0 0.35rem;
    display: flex;
    flex-direction: column;
    gap: 0.0625rem;
    border-left: 2px solid #334155;
    margin-left: 1.35rem;
}
.sidebar-nav-sub .nav-link {
    padding: 0.45rem 0.65rem 0.45rem 0.85rem;
    font-size: 0.8125rem;
}
.sidebar-nav-sub .nav-link-sub-primary {
    color: #93c5fd;
}
.sidebar-nav-sub .nav-link-sub-primary:hover,
.sidebar-nav-sub .nav-link-sub-primary:focus-visible,
.sidebar-nav-sub .nav-link-sub-primary.active {
    color: #fff;
}
.sidebar-footer {
    margin-top: auto;
    padding: 1rem 0.75rem;
    border-top: 1px solid #334155;
}

/* --- Main area ------------------------------------------------ */
.main-area {
    margin-left: var(--sidebar-width);
    flex: 1;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    min-width: 0;
}

/* --- Topbar --------------------------------------------------- */
.topbar {
    background: var(--clr-surface);
    border-bottom: 1px solid var(--clr-border);
    height: var(--topbar-height);
    display: flex;
    align-items: center;
    padding: 0 1.5rem;
    gap: 1rem;
    position: sticky;
    top: 0;
    z-index: 900;
    box-shadow: var(--shadow-sm);
}
.topbar-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--clr-text-secondary);
    cursor: pointer;
    padding: 0.375rem;
    border-radius: var(--radius-sm);
}
.topbar-title {
    font-weight: 600;
    font-size: 1.125rem;
    color: var(--clr-text-primary);
    flex: 1;
}
.topbar-user {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--clr-text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
}
.avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--clr-primary);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.875rem;
    flex-shrink: 0;
}

/* --- Page content --------------------------------------------- */
.page-content {
    padding: 1.75rem 1.5rem;
    flex: 1;
}
.page-header {
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}
.page-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--clr-text-primary);
    margin: 0;
}
.page-breadcrumb {
    font-size: 0.8125rem;
    color: var(--clr-text-muted);
    margin-top: 0.125rem;
}

/* --- KPI Cards ------------------------------------------------ */
.kpi-card {
    background: var(--clr-surface);
    border-radius: var(--radius-lg);
    padding: 1.375rem 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--clr-border);
    display: flex;
    align-items: center;
    gap: 1rem;
}
.kpi-card-icon {
    width: 52px;
    height: 52px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.375rem;
    flex-shrink: 0;
}
.kpi-card-body { flex: 1; min-width: 0; }
.kpi-card-label {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--clr-text-muted);
    margin-bottom: 0.125rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.kpi-card-value {
    font-size: 1.625rem;
    font-weight: 700;
    line-height: 1.2;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.kpi-income  { background: var(--clr-income-bg); }
.kpi-income  .kpi-card-icon  { background: var(--clr-income); color: #fff; }
.kpi-income  .kpi-card-value { color: var(--clr-income); }

.kpi-expense { background: var(--clr-expense-bg); }
.kpi-expense .kpi-card-icon  { background: var(--clr-expense); color: #fff; }
.kpi-expense .kpi-card-value { color: var(--clr-expense); }

.kpi-balance { background: var(--clr-balance-bg); }
.kpi-balance .kpi-card-icon  { background: var(--clr-balance); color: #fff; }
.kpi-balance .kpi-card-value { color: var(--clr-balance); }

.kpi-total   { background: var(--clr-primary-light); }
.kpi-total   .kpi-card-icon  { background: var(--clr-primary); color: #fff; }
.kpi-total   .kpi-card-value { color: var(--clr-primary); }

/* --- Chart Cards ---------------------------------------------- */
.chart-card {
    background: var(--clr-surface);
    border-radius: var(--radius-lg);
    padding: 1.375rem 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--clr-border);
}
.chart-card-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--clr-text-primary);
    margin-bottom: 1rem;
}

/* --- Tables --------------------------------------------------- */
.table-card {
    background: var(--clr-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--clr-border);
    overflow: hidden;
}
.table-card-header {
    padding: 1rem 1.375rem;
    border-bottom: 1px solid var(--clr-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.75rem;
}
.table-card-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--clr-text-primary);
    margin: 0;
}
.table { margin-bottom: 0; }
.table th {
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    font-weight: 600;
    color: var(--clr-text-muted);
    background: var(--clr-neutral-bg);
    border-bottom-width: 1px;
    white-space: nowrap;
    padding: 0.625rem 1rem;
}
.table td {
    padding: 0.75rem 1rem;
    vertical-align: middle;
    border-color: var(--clr-border);
    font-size: 0.9rem;
    color: var(--clr-text-secondary);
}
.table tr:hover td { background: var(--clr-neutral-bg); }

/* --- Badges --------------------------------------------------- */
.badge-income  { background: var(--clr-income-bg);  color: var(--clr-income);  border: 1px solid #99f6e4; }
.badge-expense { background: var(--clr-expense-bg); color: var(--clr-expense); border: 1px solid #fecaca; }

/* --- Forms (WCAG) --------------------------------------------- */
.form-card {
    background: var(--clr-surface);
    border-radius: var(--radius-lg);
    padding: 1.75rem 2rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--clr-border);
    max-width: 680px;
}
.form-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--clr-text-secondary);
    margin-bottom: 0.375rem;
}
.form-label .required-mark {
    color: var(--clr-expense);
    margin-left: 2px;
}
.form-control, .form-select {
    border: 1.5px solid var(--clr-border);
    border-radius: var(--radius-sm);
    padding: 0.5625rem 0.875rem;
    font-size: 0.9375rem;
    color: var(--clr-text-primary);
    background-color: var(--clr-surface);
    transition: border-color 0.15s, box-shadow 0.15s;
}
.form-control:focus, .form-select:focus {
    border-color: var(--clr-primary);
    box-shadow: 0 0 0 3px rgba(26,86,219,0.15);
    outline: none;
}
.form-control.is-invalid, .form-select.is-invalid {
    border-color: var(--clr-expense);
}
.invalid-feedback { font-size: 0.8125rem; color: var(--clr-expense); }

/* --- Buttons -------------------------------------------------- */
.btn {
    font-weight: 500;
    border-radius: var(--radius-sm);
    padding: 0.5rem 1.125rem;
    font-size: 0.9rem;
    transition: all 0.15s;
}
.btn-primary  { background: var(--clr-primary);  border-color: var(--clr-primary); }
.btn-primary:hover { background: var(--clr-primary-dark); border-color: var(--clr-primary-dark); }
.btn-success  { background: var(--clr-income);  border-color: var(--clr-income); color: #fff; }
.btn-success:hover { opacity: 0.9; color: #fff; }
.btn-danger   { background: var(--clr-expense); border-color: var(--clr-expense); }

/* --- Alerts --------------------------------------------------- */
.alert {
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    border-width: 1px;
}

/* --- Transaction amount display ------------------------------- */
.amount-income  { color: var(--clr-income);  font-weight: 600; }
.amount-expense { color: var(--clr-expense); font-weight: 600; }

/* --- Category color swatch ------------------------------------ */
.color-swatch {
    display: inline-block;
    width: 14px;
    height: 14px;
    border-radius: 3px;
    border: 1px solid rgba(0,0,0,0.15);
    vertical-align: middle;
    margin-right: 0.375rem;
}

/* --- Auth pages ----------------------------------------------- */
.auth-wrapper {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #1e293b 0%, #1a3a6e 50%, #1e293b 100%);
    padding: 1rem;
}
.auth-card {
    background: var(--clr-surface);
    border-radius: var(--radius-lg);
    padding: 2.5rem 2rem;
    width: 100%;
    max-width: 440px;
    box-shadow: var(--shadow-lg);
}
.auth-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    justify-content: center;
    margin-bottom: 1.75rem;
}
.auth-logo-icon {
    width: 44px;
    height: 44px;
    background: var(--clr-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.25rem;
}
.auth-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--clr-text-primary);
    text-align: center;
    margin-bottom: 0.25rem;
}
.auth-subtitle {
    font-size: 0.875rem;
    color: var(--clr-text-muted);
    text-align: center;
    margin-bottom: 1.75rem;
}

/* --- Pagination ----------------------------------------------- */
.pagination .page-link {
    color: var(--clr-primary);
    border-color: var(--clr-border);
    font-size: 0.875rem;
}
.pagination .page-item.active .page-link {
    background-color: var(--clr-primary);
    border-color: var(--clr-primary);
}

/* --- Responsive ----------------------------------------------- */
@media (max-width: 991.98px) {
    .sidebar {
        transform: translateX(-100%);
    }
    .sidebar.is-open {
        transform: translateX(0);
    }
    .main-area {
        margin-left: 0;
    }
    .topbar-toggle {
        display: block;
    }
}

.sidebar-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 999;
}

@media (min-width: 992px) {
    .sidebar-backdrop {
        display: none !important;
    }
}

@media (max-width: 575.98px) {
    .page-content { padding: 1rem; }
    .kpi-card-value { font-size: 1.25rem; }
    .form-card { padding: 1.25rem 1rem; }
    .auth-card { padding: 1.75rem 1.25rem; }
}

/* --- Reduced motion ------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        transition-duration: 0.01ms !important;
        animation-duration: 0.01ms !important;
    }
}