/* ============================================================
   app.css — Main Layout, Reset, CSS Variables, Dark Mode
   Money Tracker v5 — Apple-inspired design language
   ============================================================ */

/* ── Skip Link (accessibility) ────────────────────────────── */

.skip-link {
    position: absolute;
    top: -100%;
    left: 0;
    z-index: 9999;
    padding: 0.75rem 1.5rem;
    background: var(--color-primary);
    color: var(--color-primary-contrast);
    text-decoration: none;
    font-weight: 600;
    border-radius: 0 0 8px 0;
    transition: top 0.15s ease;
}

.skip-link:focus {
    top: 0;
}

/* ── Minimal CSS Reset ────────────────────────────────────── */

*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    scroll-behavior: smooth;
}

body {
    line-height: 1.5;
    min-height: 100vh;
    min-height: 100dvh;
}

img,
picture,
video,
canvas,
svg {
    display: block;
    max-width: 100%;
}

input,
button,
textarea,
select {
    font: inherit;
    font-size: 16px; /* Prevent iOS Safari auto-zoom on focus */
    color: inherit;
}

button {
    cursor: pointer;
    border: none;
    background: none;
}

a {
    color: inherit;
    text-decoration: none;
}

ul,
ol {
    list-style: none;
}

table {
    border-collapse: collapse;
    border-spacing: 0;
}

h1, h2, h3, h4, h5, h6 {
    overflow-wrap: break-word;
    font-weight: 600;
}

p {
    overflow-wrap: break-word;
}

/* ── CSS Custom Properties — Light Mode (default) ─────────── */

:root {
    /* ── Typography ── */
    --font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI',
        Roboto, Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
    --font-mono: 'SF Mono', SFMono-Regular, ui-monospace, 'DejaVu Sans Mono',
        Menlo, Consolas, monospace;

    --font-size-xs: 0.6875rem;    /* 11px */
    --font-size-sm: 0.8125rem;    /* 13px */
    --font-size-base: 0.9375rem;  /* 15px */
    --font-size-md: 1.0625rem;    /* 17px */
    --font-size-lg: 1.25rem;      /* 20px */
    --font-size-xl: 1.5rem;       /* 24px */
    --font-size-2xl: 1.75rem;     /* 28px */
    --font-size-3xl: 2.125rem;    /* 34px */
    --font-size-4xl: 2.5rem;      /* 40px */

    --font-weight-regular: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    --line-height-tight: 1.15;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* ── Colors — Semantic ── */
    --color-primary: #00FF88;
    --color-primary-hover: #00cc6a;
    --color-primary-active: #00b35e;
    --color-primary-light: rgba(0, 255, 136, 0.12);
    --color-primary-subtle: rgba(0, 255, 136, 0.08);

    --color-income: #22c55e;
    --color-income-hover: #1db954;
    --color-income-light: rgba(34, 197, 94, 0.12);
    --color-income-subtle: rgba(34, 197, 94, 0.08);

    --color-expense: #ef4444;
    --color-expense-hover: #e03b3b;
    --color-expense-light: rgba(239, 68, 68, 0.12);
    --color-expense-subtle: rgba(239, 68, 68, 0.08);

    --color-warning: #f59e0b;
    --color-warning-light: rgba(245, 158, 11, 0.12);

    --color-info: #3b82f6;
    --color-info-light: rgba(59, 130, 246, 0.12);

    /* ── Colors — Surfaces ── */
    --color-bg: #f5f5f7;
    --color-bg-secondary: #ececee;
    --color-surface: #ffffff;
    --color-surface-hover: #fafafa;
    --color-surface-active: #f5f5f5;
    --color-surface-elevated: #ffffff;
    --color-surface-overlay: rgba(255, 255, 255, 0.85);

    /* ── Colors — Text ── */
    --color-text-primary: #1d1d1f;
    --color-text-secondary: #6e6e73;
    --color-text-tertiary: #aeaeb2;
    --color-text-inverse: #ffffff;
    --color-text-link: #00FF88;

    /* ── Colors — Borders ── */
    --color-border: rgba(0, 0, 0, 0.08);
    --color-border-strong: rgba(0, 0, 0, 0.15);
    --color-border-focus: #00FF88;
    --color-divider: rgba(0, 0, 0, 0.06);

    /* ── Spacing ── */
    --space-1: 0.25rem;   /* 4px */
    --space-2: 0.5rem;    /* 8px */
    --space-3: 0.75rem;   /* 12px */
    --space-4: 1rem;       /* 16px */
    --space-5: 1.25rem;   /* 20px */
    --space-6: 1.5rem;    /* 24px */
    --space-8: 2rem;       /* 32px */
    --space-10: 2.5rem;   /* 40px */
    --space-12: 3rem;     /* 48px */
    --space-16: 4rem;     /* 64px */

    /* ── Border Radius ── */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-2xl: 24px;
    --radius-full: 9999px;

    /* ── Shadows ── */
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04),
                 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.05),
                 0 2px 4px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08),
                 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.12),
                 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-focus: 0 0 0 4px rgba(0, 255, 136, 0.24);
    --shadow-focus-error: 0 0 0 4px rgba(239, 68, 68, 0.24);

    /* ── Transitions ── */
    --ease-out: cubic-bezier(0.25, 0.1, 0.25, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --duration-fast: 150ms;
    --duration-base: 300ms;
    --duration-slow: 500ms;

    /* ── Layout ── */
    --color-primary-contrast: #000000;
    --sidebar-width: 240px;
    --sidebar-collapsed-width: 72px;
    --header-height: 0px;
    --content-max-width: 1400px;
    --content-padding: var(--space-8);
    --z-sidebar: 100;
    --z-overlay: 200;
    --z-modal: 300;
    --z-toast: 400;
    --z-fab: 50;

    /* ── Glass Morphism ── */
    --glass-bg: rgba(255, 255, 255, 0.72);
    --glass-border: rgba(255, 255, 255, 0.2);
    --glass-blur: blur(20px);
    --glass-saturate: saturate(180%);
}

/* ── Dark Mode — [data-theme="dark"] ──────────────────────── */

[data-theme="dark"] {
    --color-bg: #0a0a0a;
    --color-bg-secondary: #111111;
    --color-surface: #111111;
    --color-surface-hover: #1a1a1a;
    --color-surface-active: #222222;
    --color-surface-elevated: #1a1a1a;
    --color-surface-overlay: rgba(10, 10, 10, 0.88);

    --color-text-primary: #ffffff;
    --color-text-secondary: #888888;
    --color-text-tertiary: #555555;
    --color-text-inverse: #0a0a0a;
    --color-text-link: #00FF88;

    --color-border: rgba(255, 255, 255, 0.06);
    --color-border-strong: rgba(255, 255, 255, 0.12);
    --color-border-focus: #00FF88;
    --color-divider: rgba(255, 255, 255, 0.06);

    --color-primary: #00FF88;
    --color-primary-hover: #00cc6a;
    --color-primary-active: #00b35e;
    --color-primary-light: rgba(0, 255, 136, 0.15);
    --color-primary-subtle: rgba(0, 255, 136, 0.08);

    --color-income-light: rgba(34, 197, 94, 0.18);
    --color-income-subtle: rgba(34, 197, 94, 0.1);

    --color-expense-light: rgba(239, 68, 68, 0.18);
    --color-expense-subtle: rgba(239, 68, 68, 0.1);

    --color-warning-light: rgba(245, 158, 11, 0.18);
    --color-info-light: rgba(59, 130, 246, 0.18);

    --shadow-xs: none;
    --shadow-sm: none;
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
    --shadow-focus: 0 0 0 4px rgba(0, 255, 136, 0.24);

    --glass-bg: rgba(17, 17, 17, 0.8);
    --glass-border: rgba(255, 255, 255, 0.06);
}

/* ── System Mode — respects OS preference ─────────────────── */

@media (prefers-color-scheme: dark) {
    [data-theme="system"] {
        --color-bg: #0a0a0a;
        --color-bg-secondary: #111111;
        --color-surface: #111111;
        --color-surface-hover: #1a1a1a;
        --color-surface-active: #222222;
        --color-surface-elevated: #1a1a1a;
        --color-surface-overlay: rgba(10, 10, 10, 0.88);

        --color-text-primary: #ffffff;
        --color-text-secondary: #888888;
        --color-text-tertiary: #555555;
        --color-text-inverse: #0a0a0a;
        --color-text-link: #00FF88;

        --color-border: rgba(255, 255, 255, 0.06);
        --color-border-strong: rgba(255, 255, 255, 0.12);
        --color-border-focus: #00FF88;
        --color-divider: rgba(255, 255, 255, 0.06);

        --color-primary: #00FF88;
        --color-primary-hover: #00cc6a;
        --color-primary-active: #00b35e;
        --color-primary-light: rgba(0, 255, 136, 0.15);
        --color-primary-subtle: rgba(0, 255, 136, 0.08);

        --color-income-light: rgba(34, 197, 94, 0.18);
        --color-income-subtle: rgba(34, 197, 94, 0.1);

        --color-expense-light: rgba(239, 68, 68, 0.18);
        --color-expense-subtle: rgba(239, 68, 68, 0.1);

        --color-warning-light: rgba(245, 158, 11, 0.18);
        --color-info-light: rgba(59, 130, 246, 0.18);

        --shadow-xs: none;
        --shadow-sm: none;
        --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
        --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
        --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
        --shadow-focus: 0 0 0 4px rgba(0, 255, 136, 0.24);

        --glass-bg: rgba(17, 17, 17, 0.8);
        --glass-border: rgba(255, 255, 255, 0.06);
    }
}

/* ── Base Styles ──────────────────────────────────────────── */

html {
    font-size: 16px;
    height: 100%;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-regular);
    line-height: var(--line-height-normal);
    color: var(--color-text-primary);
    background-color: var(--color-bg);
    min-height: 100%;
    overflow-x: hidden;
    transition: background-color var(--duration-base) var(--ease-out),
                color var(--duration-base) var(--ease-out);
}

::selection {
    background-color: var(--color-primary-light);
    color: var(--color-text-primary);
}

:focus-visible {
    outline: 2px solid var(--color-border-focus);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background-color: var(--color-text-tertiary);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background-color: var(--color-text-secondary);
}

/* Firefox scrollbar */
* {
    scrollbar-width: thin;
    scrollbar-color: var(--color-text-tertiary) transparent;
}

/* ── Typography Utilities ─────────────────────────────────── */

.text-xs { font-size: var(--font-size-xs); }
.text-sm { font-size: var(--font-size-sm); }
.text-base { font-size: var(--font-size-base); }
.text-md { font-size: var(--font-size-md); }
.text-lg { font-size: var(--font-size-lg); }
.text-xl { font-size: var(--font-size-xl); }
.text-2xl { font-size: var(--font-size-2xl); }
.text-3xl { font-size: var(--font-size-3xl); }

.font-medium { font-weight: var(--font-weight-medium); }
.font-semibold { font-weight: var(--font-weight-semibold); }
.font-bold { font-weight: var(--font-weight-bold); }

.text-secondary { color: var(--color-text-secondary); }
.text-tertiary { color: var(--color-text-tertiary); }
.text-income { color: var(--color-income); }
.text-expense { color: var(--color-expense); }
.text-primary-color { color: var(--color-primary); }

.page-title {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
    letter-spacing: -0.02em;
    color: var(--color-text-primary);
}

.page-subtitle {
    font-size: var(--font-size-md);
    font-weight: var(--font-weight-regular);
    color: var(--color-text-secondary);
    margin-top: var(--space-1);
}

.section-title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    letter-spacing: -0.01em;
}

/* ── App Layout ───────────────────────────────────────────── */

.app-layout {
    display: flex;
    min-height: 100vh;
    min-height: 100dvh;
    width: 100%;
    overflow-x: hidden;
}

/* ── Sidebar ──────────────────────────────────────────────── */

.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    z-index: var(--z-sidebar);
    display: flex;
    flex-direction: column;
    padding: var(--space-6) var(--space-4);
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur) var(--glass-saturate);
    -webkit-backdrop-filter: var(--glass-blur) var(--glass-saturate);
    border-right: 1px solid var(--glass-border);
    transition: transform var(--duration-base) var(--ease-out),
                background-color var(--duration-base) var(--ease-out);
    overflow-y: auto;
    overflow-x: hidden;
}

.sidebar-header {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: 0 var(--space-2);
    margin-bottom: var(--space-8);
    flex-shrink: 0;
}

.sidebar-logo {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-md);
    background: linear-gradient(135deg, var(--color-primary), #00cc6a);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-primary-contrast);
    flex-shrink: 0;
}

.sidebar-logo svg,
.sidebar-logo i {
    width: 20px;
    height: 20px;
}

.sidebar-brand {
    font-size: var(--font-size-md);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    letter-spacing: -0.01em;
}

/* Sidebar: credit link */
.sidebar-credit {
    display: block;
    text-align: center;
    font-size: var(--font-size-xs);
    color: var(--color-text-tertiary);
    text-decoration: none;
    opacity: 0.4;
    margin-top: var(--space-3);
    transition: opacity var(--transition-fast);
}

.sidebar-credit:hover {
    opacity: 1;
    color: var(--color-primary);
}

/* Sidebar: add transaction button */
.sidebar-add-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    width: 100%;
    padding: var(--space-3) var(--space-4);
    margin-bottom: var(--space-6);
    background: var(--color-primary);
    color: var(--color-primary-contrast);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-md);
    transition: background-color var(--duration-fast) var(--ease-out),
                transform var(--duration-fast) var(--ease-out),
                box-shadow var(--duration-fast) var(--ease-out);
    flex-shrink: 0;
}

.sidebar-add-btn:hover {
    background: var(--color-primary-hover);
    transform: scale(1.02);
    box-shadow: 0 4px 12px rgba(0, 255, 136, 0.3);
}

.sidebar-add-btn:active {
    background: var(--color-primary-active);
    transform: scale(0.98);
}

.sidebar-add-btn svg,
.sidebar-add-btn i {
    width: 18px;
    height: 18px;
}

/* Sidebar: navigation */
.sidebar-nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
}

.sidebar-section-label {
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    padding: var(--space-4) var(--space-3) var(--space-2);
}

.sidebar-link {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-3);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    transition: background-color var(--duration-fast) var(--ease-out),
                color var(--duration-fast) var(--ease-out);
    position: relative;
}

.sidebar-link svg,
.sidebar-link i {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    opacity: 0.7;
    transition: opacity var(--duration-fast) var(--ease-out);
}

.sidebar-link:hover {
    background-color: var(--color-primary-subtle);
    color: var(--color-text-primary);
}

.sidebar-link:hover svg,
.sidebar-link:hover i {
    opacity: 1;
}

.sidebar-link.active {
    background-color: var(--color-primary-light);
    color: var(--color-primary);
    font-weight: var(--font-weight-semibold);
}

.sidebar-link.active svg,
.sidebar-link.active i {
    opacity: 1;
    color: var(--color-primary);
}

/* Sidebar: footer (logout) */
.sidebar-footer {
    flex-shrink: 0;
    padding-top: var(--space-4);
    margin-top: var(--space-4);
    border-top: 1px solid var(--color-divider);
}

.sidebar-user {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-2) var(--space-3);
    margin-bottom: var(--space-2);
}

.sidebar-user-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background: var(--color-primary-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    color: var(--color-primary);
    flex-shrink: 0;
}

.sidebar-user-name {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sidebar-logout {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    width: 100%;
    padding: var(--space-3) var(--space-3);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-tertiary);
    transition: background-color var(--duration-fast) var(--ease-out),
                color var(--duration-fast) var(--ease-out);
}

.sidebar-logout svg,
.sidebar-logout i {
    width: 20px;
    height: 20px;
    opacity: 0.6;
}

.sidebar-logout:hover {
    background-color: var(--color-expense-subtle);
    color: var(--color-expense);
}

.sidebar-logout:hover svg,
.sidebar-logout:hover i {
    opacity: 1;
}

/* ── Main Content Area ────────────────────────────────────── */

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    min-height: 100vh;
    min-height: 100dvh;
    transition: margin-left var(--duration-base) var(--ease-out);
}

.main-content-inner {
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: var(--space-8) var(--content-padding);
}

/* ── Mobile Header ────────────────────────────────────────── */

.mobile-header {
    display: none;
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    height: 56px;
    padding: 0 var(--space-4);
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur) var(--glass-saturate);
    -webkit-backdrop-filter: var(--glass-blur) var(--glass-saturate);
    border-bottom: 1px solid var(--glass-border);
    z-index: calc(var(--z-sidebar) - 1);
    align-items: center;
    justify-content: space-between;
}

.mobile-header-title {
    font-size: var(--font-size-md);
    font-weight: var(--font-weight-semibold);
}

/* ── Sidebar Overlay (mobile) ─────────────────────────────── */

.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
    z-index: calc(var(--z-sidebar) - 1);
    opacity: 0;
    transition: opacity var(--duration-base) var(--ease-out);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

.sidebar-overlay.visible {
    opacity: 1;
}

/* ── Page Transitions ─────────────────────────────────────── */

.page-content {
    animation: pageFadeIn var(--duration-base) var(--ease-out) both;
}

@keyframes pageFadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.page-header {
    margin-bottom: var(--space-8);
}

.page-header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
    flex-wrap: wrap;
}

/* ── Hamburger Button ─────────────────────────────────────── */

.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    padding: var(--space-2);
    border-radius: var(--radius-md);
    transition: background-color var(--duration-fast) var(--ease-out);
    gap: 5px;
}

.hamburger:hover {
    background-color: var(--color-surface-hover);
}

.hamburger-line {
    display: block;
    width: 20px;
    height: 2px;
    background-color: var(--color-text-primary);
    border-radius: var(--radius-full);
    transition: transform var(--duration-base) var(--ease-out),
                opacity var(--duration-fast) var(--ease-out);
}

.hamburger.active .hamburger-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.hamburger.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

.hamburger.active .hamburger-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ── Responsive — Tablet (max-width: 768px) ───────────────── */

@media (max-width: 768px) {
    :root {
        --content-padding: var(--space-4);
    }

    .hamburger {
        display: flex;
    }

    .app-layout {
        flex-direction: column;
    }

    .mobile-header {
        display: flex;
        width: 100%;
    }

    .sidebar {
        transform: translateX(-100%);
        box-shadow: none;
    }

    .sidebar.open {
        transform: translateX(0);
        box-shadow: var(--shadow-xl);
    }

    .sidebar-overlay.open {
        display: block;
    }

    .main-content {
        margin-left: 0;
        width: 100%;
    }

    .main-content-inner {
        padding: var(--space-4);
        padding-top: var(--space-6);
    }

    .page-title {
        font-size: var(--font-size-2xl);
    }

    .page-header-row {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* ── Responsive — Mobile (max-width: 480px) ───────────────── */

@media (max-width: 480px) {
    :root {
        --content-padding: var(--space-3);
    }

    .main-content-inner {
        padding: var(--space-3);
        padding-top: var(--space-4);
    }

    .page-title {
        font-size: var(--font-size-xl);
    }
}

/* ── Utility: Visibility ──────────────────────────────────── */

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.desktop-only {
    display: block;
}

.mobile-only {
    display: none;
}

@media (max-width: 768px) {
    .desktop-only {
        display: none !important;
    }

    .mobile-only {
        display: block !important;
    }
}

/* ── Utility: Spacing ─────────────────────────────────────── */

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

/* ── Utility: Flexbox ─────────────────────────────────────── */

.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.flex-1 { flex: 1; }

/* ── Utility: Grid ────────────────────────────────────────── */

.grid { display: grid; }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 768px) {
    .grid-cols-2,
    .grid-cols-3,
    .grid-cols-4 {
        grid-template-columns: 1fr;
    }
}

/* ── Utility: Text ────────────────────────────────────────── */

.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }
.truncate {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ── Print Styles ─────────────────────────────────────────── */

@media print {
    .sidebar,
    .mobile-header,
    .fab,
    .sidebar-overlay {
        display: none !important;
    }

    .main-content {
        margin-left: 0 !important;
    }

    body {
        background: white;
        color: black;
    }
}