/* --- Root Variables (Theme) --- */
:root {
    /* Material 3 Baseline Palette (Light Theme) - Truncated for brevity, same as before */
    --md-sys-color-primary-light: #6750A4;
    --md-sys-color-on-primary-light: #FFFFFF;
    --md-sys-color-primary-container-light: #EADDFF;
    --md-sys-color-on-primary-container-light: #21005D;
    --md-sys-color-secondary-light: #625B71;
    --md-sys-color-on-secondary-light: #FFFFFF;
    --md-sys-color-secondary-container-light: #E8DEF8;
    --md-sys-color-on-secondary-container-light: #1D192B;
    --md-sys-color-tertiary-light: #7D5260;
    --md-sys-color-on-tertiary-light: #FFFFFF;
    --md-sys-color-tertiary-container-light: #FFD8E4;
    --md-sys-color-on-tertiary-container-light: #31111D;
    --md-sys-color-error-light: #B3261E;
    --md-sys-color-on-error-light: #FFFFFF;
    --md-sys-color-error-container-light: #F9DEDC;
    --md-sys-color-on-error-container-light: #410E0B;
    --md-sys-color-background-light: #FFFBFE;
    --md-sys-color-on-background-light: #1C1B1F;
    --md-sys-color-surface-light: #FFFBFE; /* Main background for components */
    --md-sys-color-on-surface-light: #1C1B1F; /* Text on surface */
    --md-sys-color-surface-variant-light: #E7E0EC; /* Subtle backgrounds, outlines */
    --md-sys-color-on-surface-variant-light: #49454F; /* Text on surface-variant */
    --md-sys-color-outline-light: #79747E;
    --md-sys-color-shadow-light: #000000;
    --md-sys-color-inverse-surface-light: #313033;
    --md-sys-color-inverse-on-surface-light: #F4EFF4;
    --md-sys-color-inverse-primary-light: #D0BCFF;
    --md-sys-color-surface-tint-light: var(--md-sys-color-primary-light); /* Surface tint is primary */
    --md-sys-color-surface-container-highest-light: #E6E0E9;
    --md-sys-color-surface-container-high-light: #ECE6F0;
    --md-sys-color-surface-container-light: #F3EDF7;
    --md-sys-color-surface-container-low-light: #F7F2FA;
    --md-sys-color-surface-container-lowest-light: #FFFFFF;
    --md-sys-color-surface-dim-light: #DED8E1; /* Scrim */
    --md-sys-color-surface-bright-light: #FFFBFE; /* Banners, etc. */

    /* Material 3 Baseline Palette (Dark Theme) - Truncated for brevity, same as before */
    --md-sys-color-primary-dark: #D0BCFF;
    --md-sys-color-on-primary-dark: #381E72;
    --md-sys-color-primary-container-dark: #4F378B;
    --md-sys-color-on-primary-container-dark: #EADDFF;
    --md-sys-color-secondary-dark: #CCC2DC;
    --md-sys-color-on-secondary-dark: #332D41;
    --md-sys-color-secondary-container-dark: #4A4458;
    --md-sys-color-on-secondary-container-dark: #E8DEF8;
    --md-sys-color-tertiary-dark: #EFB8C8;
    --md-sys-color-on-tertiary-dark: #492532;
    --md-sys-color-tertiary-container-dark: #633B48;
    --md-sys-color-on-tertiary-container-dark: #FFD8E4;
    --md-sys-color-error-dark: #F2B8B5;
    --md-sys-color-on-error-dark: #601410;
    --md-sys-color-error-container-dark: #8C1D18;
    --md-sys-color-on-error-container-dark: #F9DEDC;
    --md-sys-color-background-dark: #1C1B1F;
    --md-sys-color-on-background-dark: #E6E1E5;
    --md-sys-color-surface-dark: #1C1B1F;
    --md-sys-color-on-surface-dark: #E6E1E5;
    --md-sys-color-surface-variant-dark: #49454F;
    --md-sys-color-on-surface-variant-dark: #CAC4D0;
    --md-sys-color-outline-dark: #938F99;
    --md-sys-color-shadow-dark: #000000;
    --md-sys-color-inverse-surface-dark: #E6E1E5;
    --md-sys-color-inverse-on-surface-dark: #313033;
    --md-sys-color-inverse-primary-dark: #6750A4;
    --md-sys-color-surface-tint-dark: var(--md-sys-color-primary-dark);
    --md-sys-color-surface-container-highest-dark: #36343B;
    --md-sys-color-surface-container-high-dark: #2B2930;
    --md-sys-color-surface-container-dark: #211F26;
    --md-sys-color-surface-container-low-dark: #1D1B20;
    --md-sys-color-surface-container-lowest-dark: #100E14;
    --md-sys-color-surface-dim-dark: #141218;
    --md-sys-color-surface-bright-dark: #3B383E;

    /* Default to light theme variables */
    --primary: var(--md-sys-color-primary-light);
    --on-primary: var(--md-sys-color-on-primary-light);
    --primary-container: var(--md-sys-color-primary-container-light);
    --on-primary-container: var(--md-sys-color-on-primary-container-light);
    --secondary: var(--md-sys-color-secondary-light);
    --on-secondary: var(--md-sys-color-on-secondary-light);
    --secondary-container: var(--md-sys-color-secondary-container-light);
    --on-secondary-container: var(--md-sys-color-on-secondary-container-light);
    --tertiary: var(--md-sys-color-tertiary-light);
    --on-tertiary: var(--md-sys-color-on-tertiary-light);
    --tertiary-container: var(--md-sys-color-tertiary-container-light);
    --on-tertiary-container: var(--md-sys-color-on-tertiary-container-light);
    --error: var(--md-sys-color-error-light);
    --on-error: var(--md-sys-color-on-error-light);
    --error-container: var(--md-sys-color-error-container-light);
    --on-error-container: var(--md-sys-color-on-error-container-light);
    --background: var(--md-sys-color-background-light);
    --on-background: var(--md-sys-color-on-background-light);
    --surface: var(--md-sys-color-surface-light);
    --on-surface: var(--md-sys-color-on-surface-light);
    --surface-variant: var(--md-sys-color-surface-variant-light);
    --on-surface-variant: var(--md-sys-color-on-surface-variant-light);
    --outline: var(--md-sys-color-outline-light);
    --shadow: var(--md-sys-color-shadow-light);
    --inverse-surface: var(--md-sys-color-inverse-surface-light);
    --inverse-on-surface: var(--md-sys-color-inverse-on-surface-light);
    --inverse-primary: var(--md-sys-color-inverse-primary-light);
    --surface-tint-color: var(--md-sys-color-surface-tint-light);
    --surface-container-highest: var(--md-sys-color-surface-container-highest-light);
    --surface-container-high: var(--md-sys-color-surface-container-high-light);
    --surface-container: var(--md-sys-color-surface-container-light);
    --surface-container-low: var(--md-sys-color-surface-container-low-light);
    --surface-container-lowest: var(--md-sys-color-surface-container-lowest-light);
    --surface-dim: var(--md-sys-color-surface-dim-light);
    --surface-bright: var(--md-sys-color-surface-bright-light);


    /* Shape */
    --md-sys-shape-corner-none: 0px;
    --md-sys-shape-corner-xs: 4px;
    --md-sys-shape-corner-s: 8px;
    --md-sys-shape-corner-m: 12px;
    --md-sys-shape-corner-l: 16px;
    --md-sys-shape-corner-xl: 28px;
    --md-sys-shape-corner-full: 9999px;

    /* Elevation (shadows) - Using simplified M3 levels */
    --md-sys-elevation-level0: none;
    --md-sys-elevation-level1: 0px 1px 2px rgba(0, 0, 0, 0.3), 0px 1px 3px 1px rgba(0, 0, 0, 0.15);
    --md-sys-elevation-level2: 0px 1px 2px rgba(0, 0, 0, 0.3), 0px 2px 6px 2px rgba(0, 0, 0, 0.15);
    --md-sys-elevation-level3: 0px 4px 8px 3px rgba(0, 0, 0, 0.15), 0px 1px 3px rgba(0, 0, 0, 0.3);
    --md-sys-elevation-level4: 0px 6px 10px 4px rgba(0, 0, 0, 0.15), 0px 2px 3px rgba(0, 0, 0, 0.3);
    --md-sys-elevation-level5: 0px 8px 12px 6px rgba(0, 0, 0, 0.15), 0px 4px 4px rgba(0, 0, 0, 0.3);
    
    /* Typography (simplified) */
    --md-sys-typescale-font-family-brand: 'Roboto', 'Segoe UI', Helvetica, Arial, sans-serif;
    --md-sys-typescale-font-family-plain: 'Roboto', 'Segoe UI', Helvetica, Arial, sans-serif;

    --md-sys-typescale-headline-large-font: var(--md-sys-typescale-font-family-brand);
    --md-sys-typescale-headline-large-size: 32px;
    --md-sys-typescale-headline-large-weight: 400;
    --md-sys-typescale-headline-large-line-height: 40px;

    --md-sys-typescale-title-large-font: var(--md-sys-typescale-font-family-brand);
    --md-sys-typescale-title-large-size: 22px;
    --md-sys-typescale-title-large-weight: 400;
    --md-sys-typescale-title-large-line-height: 28px;
    
    --md-sys-typescale-body-large-font: var(--md-sys-typescale-font-family-plain);
    --md-sys-typescale-body-large-size: 16px;
    --md-sys-typescale-body-large-weight: 400;
    --md-sys-typescale-body-large-line-height: 24px;

    --md-sys-typescale-label-large-font: var(--md-sys-typescale-font-family-plain);
    --md-sys-typescale-label-large-size: 14px;
    --md-sys-typescale-label-large-weight: 500;
    --md-sys-typescale-label-large-line-height: 20px;

    /* Transitions */
    --md-sys-motion-easing-standard: cubic-bezier(0.4, 0.0, 0.2, 1);
    --md-sys-motion-easing-emphasized: cubic-bezier(0.2, 0.0, 0.0, 1.0);
    --md-sys-motion-easing-decelerated: cubic-bezier(0.0, 0.0, 0.2, 1);
    --md-sys-motion-easing-accelerated: cubic-bezier(0.4, 0.0, 1.0, 1.0);
    
    --md-sys-motion-duration-xs: 100ms;
    --md-sys-motion-duration-s: 200ms;
    --md-sys-motion-duration-m: 300ms;
    --md-sys-motion-duration-l: 400ms;
    --md-sys-motion-duration-xl: 500ms;

    /* Safe Area Insets */
    --safe-area-inset-top: env(safe-area-inset-top, 0px);
    --safe-area-inset-right: env(safe-area-inset-right, 0px);
    --safe-area-inset-bottom: env(safe-area-inset-bottom, 0px);
    --safe-area-inset-left: env(safe-area-inset-left, 0px);
}

html[data-theme="dark"] {
    --primary: var(--md-sys-color-primary-dark);
    --on-primary: var(--md-sys-color-on-primary-dark);
    --primary-container: var(--md-sys-color-primary-container-dark);
    --on-primary-container: var(--md-sys-color-on-primary-container-dark);
    --secondary: var(--md-sys-color-secondary-dark);
    --on-secondary: var(--md-sys-color-on-secondary-dark);
    --secondary-container: var(--md-sys-color-secondary-container-dark);
    --on-secondary-container: var(--md-sys-color-on-secondary-container-dark);
    --tertiary: var(--md-sys-color-tertiary-dark);
    --on-tertiary: var(--md-sys-color-on-tertiary-dark);
    --tertiary-container: var(--md-sys-color-tertiary-container-dark);
    --on-tertiary-container: var(--md-sys-color-on-tertiary-container-dark);
    --error: var(--md-sys-color-error-dark);
    --on-error: var(--md-sys-color-on-error-dark);
    --error-container: var(--md-sys-color-error-container-dark);
    --on-error-container: var(--md-sys-color-on-error-container-dark);
    --background: var(--md-sys-color-background-dark);
    --on-background: var(--md-sys-color-on-background-dark);
    --surface: var(--md-sys-color-surface-dark);
    --on-surface: var(--md-sys-color-on-surface-dark);
    --surface-variant: var(--md-sys-color-surface-variant-dark);
    --on-surface-variant: var(--md-sys-color-on-surface-variant-dark);
    --outline: var(--md-sys-color-outline-dark);
    --shadow: var(--md-sys-color-shadow-dark); /* Shadows are typically not changed for dark theme, but opacity might be adjusted */
    --inverse-surface: var(--md-sys-color-inverse-surface-dark);
    --inverse-on-surface: var(--md-sys-color-inverse-on-surface-dark);
    --inverse-primary: var(--md-sys-color-inverse-primary-dark);
    --surface-tint-color: var(--md-sys-color-surface-tint-dark);
    --surface-container-highest: var(--md-sys-color-surface-container-highest-dark);
    --surface-container-high: var(--md-sys-color-surface-container-high-dark);
    --surface-container: var(--md-sys-color-surface-container-dark);
    --surface-container-low: var(--md-sys-color-surface-container-low-dark);
    --surface-container-lowest: var(--md-sys-color-surface-container-lowest-dark);
    --surface-dim: var(--md-sys-color-surface-dim-dark);
    --surface-bright: var(--md-sys-color-surface-bright-dark);
}

/* --- Base Styles --- */
*, *::before, *::after {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    font-size: 100%; /* Typically 16px */
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: var(--md-sys-typescale-body-large-font);
    font-size: var(--md-sys-typescale-body-large-size);
    font-weight: var(--md-sys-typescale-body-large-weight);
    line-height: var(--md-sys-typescale-body-large-line-height);
    background-color: var(--background);
    color: var(--on-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    display: flex; 
    min-height: 100vh;
    /* Safe area padding applied directly for full-bleed effect if needed */
    padding-top: var(--safe-area-inset-top);
    padding-left: var(--safe-area-inset-left);
    padding-right: var(--safe-area-inset-right);
    /* padding-bottom: var(--safe-area-inset-bottom); Will be handled by bottom-nav or content */
    overflow-x: hidden; /* Prevent horizontal scroll on body */
}

/* --- Main Layout Structure --- */
.app-container { 
    display: flex; 
    flex-grow: 1; 
    overflow: hidden; 
    width: 100%;
    height: calc(100vh - var(--safe-area-inset-top) - var(--safe-area-inset-bottom)); /* Adjust for safe areas */
}

.sidebar {
    width: 256px;
    background-color: var(--surface-container-low);
    padding: 16px;
    transition: width var(--md-sys-motion-duration-m) var(--md-sys-motion-easing-standard),
                transform var(--md-sys-motion-duration-m) var(--md-sys-motion-easing-standard);
    border-right: 1px solid var(--outline);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    z-index: 200; 
    flex-shrink: 0; 
}
.sidebar.collapsed { width: 80px; }
.sidebar.collapsed .sidebar-item-text, 
.sidebar.collapsed .sidebar-header h1,
.sidebar.collapsed .sidebar-footer { display: none; }
.sidebar.collapsed .sidebar-header .button.icon-button { margin: 0 auto; /* Center toggle when collapsed */ }


.sidebar-header { 
    padding-bottom: 8px; /* Align with M3 spec for nav drawer header */
    margin-bottom: 8px; 
    display: flex; 
    align-items: center; 
    min-height: 56px; /* M3 nav drawer header height */
}
.sidebar-header h1 { 
    font-family: var(--md-sys-typescale-title-large-font);
    font-size: var(--md-sys-typescale-title-large-size);
    font-weight: var(--md-sys-typescale-title-large-weight);
    line-height: var(--md-sys-typescale-title-large-line-height);
    color: var(--on-surface-variant); 
    margin: 0; 
    margin-left: 16px; 
}
.sidebar-nav ul { list-style: none; padding: 0; margin: 0; }
.sidebar-nav li a {
    display: flex; 
    align-items: center; 
    padding: 0 16px; /* M3: 12px vertical, 16px horizontal with icon */
    height: 56px; /* M3 nav item height */
    border-radius: var(--md-sys-shape-corner-full);
    text-decoration: none; 
    color: var(--on-surface-variant); 
    font-family: var(--md-sys-typescale-label-large-font);
    font-size: var(--md-sys-typescale-label-large-size);
    font-weight: var(--md-sys-typescale-label-large-weight);
    transition: background-color var(--md-sys-motion-duration-s) var(--md-sys-motion-easing-standard), 
                color var(--md-sys-motion-duration-s) var(--md-sys-motion-easing-standard);
    gap: 12px; 
    margin-bottom: 4px; 
    position: relative; /* For ripple */
    overflow: hidden;
}
.sidebar-nav li a:hover { background-color: var(--surface-container-high); }
.sidebar-nav li a.active { 
    background-color: var(--secondary-container); 
    color: var(--on-secondary-container); 
    font-weight: bold; /* M3 active state often has bolder font */
}
.sidebar-nav li a svg { 
    width: 24px; 
    height: 24px; 
    fill: currentColor; 
    flex-shrink: 0; 
}
.sidebar.collapsed .sidebar-nav li a {
    justify-content: center; /* Center icon when collapsed */
    padding: 0;
}
.sidebar.collapsed .sidebar-nav li a svg {
    margin: 0; /* Remove gap when only icon */
}

.sidebar-footer {
    margin-top: auto;
    padding-top: 16px;
    border-top: 1px solid var(--outline);
}

.main-wrapper {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    overflow: hidden; 
}

.top-navbar {
    background-color: var(--surface); /* M3 top app bar surface */
    padding: 0 16px; /* M3 top app bar padding */
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--md-sys-elevation-level0); /* M3: level0 for standard, level2 if scrolled under */
    height: 64px; /* M3 top app bar height */
    position: sticky; 
    top: 0; 
    z-index: 101;
    flex-shrink: 0; 
    border-bottom: 1px solid var(--outline); /* Subtle separator */
}
.top-navbar.scrolled { /* Add this class with JS if content scrolls under */
    box-shadow: var(--md-sys-elevation-level2);
    background-color: var(--surface-container-low); /* Or other surface elevation color */
}
.top-navbar h1 { 
    font-family: var(--md-sys-typescale-title-large-font);
    font-size: var(--md-sys-typescale-title-large-size);
    font-weight: var(--md-sys-typescale-title-large-weight);
    color: var(--on-surface); 
    margin: 0; 
}
.top-navbar .menu-toggle { display: none; } 

.main-content {
    flex-grow: 1;
    padding: 24px; /* Default padding */
    overflow-y: auto; 
    display: flex;
    flex-direction: column;
}
.page-content { 
    display: none; 
    flex-grow: 1; 
    flex-direction: column; 
}
.page-content.active { display: flex; }

.page-content > h2 { 
    font-family: var(--md-sys-typescale-headline-large-font);
    font-size: var(--md-sys-typescale-headline-large-size);
    font-weight: var(--md-sys-typescale-headline-large-weight);
    line-height: var(--md-sys-typescale-headline-large-line-height);
    color: var(--primary);
    margin-top: 0;
    margin-bottom: 24px;
    padding-bottom: 8px;
}

.bottom-nav {
    display: none; 
    position: fixed; bottom: 0; left: 0; right: 0;
    height: calc(80px + var(--safe-area-inset-bottom)); /* M3 bottom nav height 80px */
    padding-bottom: var(--safe-area-inset-bottom);
    background-color: var(--surface-container); 
    box-shadow: var(--md-sys-elevation-level2);
    z-index: 100; 
}
.bottom-nav-item {
    flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center;
    padding: 12px 0 16px 0; /* M3 padding */
    color: var(--on-surface-variant); text-decoration: none !important; 
    font-family: var(--md-sys-typescale-label-large-font);
    font-size: var(--md-sys-typescale-label-large-size);
    font-weight: var(--md-sys-typescale-label-large-weight);
    border-radius: var(--md-sys-shape-corner-m);
    transition: color var(--md-sys-motion-duration-s) var(--md-sys-motion-easing-standard);
    position: relative; 
    overflow: hidden; /* For ripple and indicator */
}
.bottom-nav-item.active { color: var(--on-secondary-container); }
.bottom-nav-item .nav-indicator { /* Pill shape indicator */
    width: 64px; height: 32px; background-color: transparent; 
    border-radius: var(--md-sys-shape-corner-full);
    position: absolute; 
    top: 8px; /* Position pill above icon/text vertically */
    left: 50%; transform: translateX(-50%);
    z-index: -1;
    transition: background-color var(--md-sys-motion-duration-m) var(--md-sys-motion-easing-standard);
}
.bottom-nav-item.active .nav-indicator { background-color: var(--secondary-container); }
.bottom-nav-item svg { width: 24px; height: 24px; margin-bottom: 4px; position: relative; }
.bottom-nav-item .label { position: relative; }


/* --- Responsive Adjustments --- */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0; 
        height: 100%;
        transform: translateX(-100%); 
    }
    .sidebar.open { transform: translateX(0); box-shadow: var(--md-sys-elevation-level3); }
    .sidebar.collapsed:not(.open) { transform: translateX(-100%); }

    .top-navbar .menu-toggle { display: flex !important; } /* Important to override inline style */
    .bottom-nav { display: flex; justify-content: space-around; align-items: stretch; } /* Stretch items */
    .main-content { 
        padding: 16px; 
        padding-bottom: calc(80px + 16px + var(--safe-area-inset-bottom)); /* Account for taller bottom nav */
    }
}

/* Utility classes */
.hidden { display: none !important; }
.sr-only { 
    position: absolute; 
    width: 1px; height: 1px; 
    padding: 0; margin: -1px; 
    overflow: hidden; 
    clip: rect(0,0,0,0); 
    white-space: nowrap; 
    border: 0; 
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Table responsive wrapper for sheets */
.table-responsive-wrapper {
    width: 100%;
    overflow-x: auto;
    flex-grow: 1; /* Allow it to take available space and scroll */
    -webkit-overflow-scrolling: touch; /* Smooth scrolling on iOS */
}