/**
 * MathsGuide.uk - Main Stylesheet
 * Clean, minimal design with colour-coded strands
 */

/* ============================================
   CSS CUSTOM PROPERTIES
   ============================================ */
:root {
    /* Strand colours */
    --color-number: #3B82F6;
    --color-algebra: #22C55E;
    --color-geometry: #F97316;
    --color-statistics: #A855F7;
    
    /* Core palette */
    --color-text: #1F2937;
    --color-text-muted: #6B7280;
    --color-text-light: #9CA3AF;
    --color-background: #FFFFFF;
    --color-surface: #F9FAFB;
    --color-border: #E5E7EB;
    --color-border-light: #F3F4F6;
    
    /* Semantic colours */
    --color-error: #EF4444;
    --color-warning: #F59E0B;
    --color-success: #10B981;
    --color-info: #3B82F6;
    
    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
    
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    
    --leading-tight: 1.25;
    --leading-normal: 1.5;
    --leading-relaxed: 1.625;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    
    /* Layout */
    --container-max: 72rem;
    --container-narrow: 48rem;
    --border-radius: 0.5rem;
    --border-radius-lg: 0.75rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1), 0 2px 4px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
}

/* ============================================
   DARK MODE OVERRIDES
   ============================================ */

[data-theme="dark"] {
    /* Invert Core Palette */
    --color-text: #F9FAFB;           /* Was dark grey, now off-white */
    --color-text-muted: #9CA3AF;     /* Lighter grey for secondary text */
    --color-text-light: #6B7280;     /* Even lighter for placeholders */
    
    --color-background: #111827;     /* Deep dark blue/grey (not pure black) */
    --color-surface: #1F2937;        /* Slightly lighter dark for cards */
    
    --color-border: #374151;         /* Dark grey border */
    --color-border-light: #4B5563;   
    
    /* Adjust Semantic Colours for dark backgrounds */
    --color-info: #60A5FA;           /* Brighter blue */
    --color-error: #F87171;          /* Softer red */
    --color-success: #34D399;        /* Brighter green */
    --color-warning: #FBBF24;        /* Brighter amber */
    
    /* Adjust Strand Colours (Optional - slightly pastel versions pop better on dark) */
    --color-number: #60A5FA;
    --color-algebra: #4ADE80;
    --color-geometry: #FB923C;
    --color-statistics: #C084FC;
}

/* Fix specific hardcoded backgrounds (if any remain) */
[data-theme="dark"] .night-before-hero {
    /* Keep gradients but maybe adjust opacity if needed */
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
}

[data-theme="dark"] .content img[src*="diagrams"],
[data-theme="dark"] .skill-content img[src*="diagrams"] {
    /* Light background for diagrams */
    background: #FFFFFF;
    padding: 1rem;
    border-radius: var(--border-radius);
}

/* Dark mode overrides for hardcoded backgrounds */
[data-theme="dark"] .trap-card {
    background: #7F1D1D;
    border-color: #991B1B;
}

[data-theme="dark"] .spot-segment.revealed.spot-segment-error {
    background-color: #7F1D1D;
}

[data-theme="dark"] .spot-feedback {
    background: #78350F;
}

[data-theme="dark"] .stuck-button {
    background: #1E3A5F;
    border-color: #1E40AF;
}

[data-theme="dark"] .stuck-button:hover {
    background: #1E40AF;
}

[data-theme="dark"] .hint {
    background: #78350F;
}

[data-theme="dark"] .tier-foundation {
    background: #1E3A5F;
    color: #93C5FD;
}

[data-theme="dark"] .tier-higher {
    background: #831843;
    color: #F9A8D4;
}

/* Examiner's view section dark mode */
[data-theme="dark"] .examiner-content {
    background: #1E3A5F;
    border-left-color: #60A5FA;
}

/* Misconception page boxes dark mode */
[data-theme="dark"] .mistake-box {
    background: #7F1D1D;
    border-left-color: #F87171;
}

[data-theme="dark"] .why-box {
    background: #78350F;
    border-left-color: #FBBF24;
}

[data-theme="dark"] .fix-box {
    background: #064E3B;
    border-left-color: #34D399;
}

/* Revision Hub hero card dark mode */
[data-theme="dark"] .hero-card {
    background: linear-gradient(135deg, #4C1D95 0%, #5B21B6 100%);
    border-color: #6D28D9;
}

[data-theme="dark"] .hero-card:hover {
    border-color: #8B5CF6;
}

[data-theme="dark"] .hero-card-cta {
    color: #C4B5FD;
}

/* ============================================
   RESET & BASE
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
}

* {
    margin: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: var(--leading-normal);
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

input, button, textarea, select {
    font: inherit;
}

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

/* ============================================
   ACCESSIBILITY
   ============================================ */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    padding: var(--space-2) var(--space-4);
    background: var(--color-text);
    color: var(--color-background);
    z-index: 100;
    transition: top var(--transition-fast);
}

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

/* ============================================
   LAYOUT
   ============================================ */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin-inline: auto;
    padding-inline: var(--space-4);
}

.container-narrow {
    max-width: var(--container-narrow);
}

.site-main {
    min-height: calc(100vh - 200px);
    padding-block: var(--space-8);
}

/* ============================================
   HEADER
   ============================================ */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: var(--color-background);
    border-bottom: 1px solid var(--color-border);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-6);
    padding-block: 0.05rem;
}

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--color-text);
}

.logo-img {
    height: 90px;
    width: auto;
    display: block;
}

.logo-dark {
    display: none;
}

[data-theme="dark"] .logo-light {
    display: none;
}

[data-theme="dark"] .logo-dark {
    display: block;
}

.logo-text {
    font-size: var(--text-xl);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.logo-tagline {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
}

/* Main navigation */
.main-nav {
    display: none;
}

@media (min-width: 1024px) {
    .main-nav {
        display: block;
    }
}

.nav-list {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    list-style: none;
    padding: 0;
}

.nav-link {
    display: block;
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-muted);
    text-decoration: none;
    border-radius: var(--border-radius);
    border: none;
    background: none;
    cursor: pointer;
    transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-text);
    background-color: var(--color-surface);
}

.nav-link-highlight {
    background-color: var(--color-error);
    color: white !important;
}

.nav-link-highlight:hover {
    background-color: #DC2626;
}

/* Dropdown */
.nav-dropdown {
    position: relative;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 220px;
    padding: var(--space-2);
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    list-style: none;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-fast);
}

.nav-dropdown:hover .dropdown-menu,
.nav-dropdown:focus-within .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu a {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-sm);
    color: var(--color-text);
    text-decoration: none;
    border-radius: var(--border-radius);
    transition: background-color var(--transition-fast);
}

.dropdown-menu a:hover {
    background-color: var(--color-surface);
}

.strand-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--strand-color);
}

/* Header controls */
.header-controls {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

/* Settings Dropdown */
.settings-dropdown {
    position: relative;
}

.settings-toggle {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    background: none;
    border: none;
    font-weight: 500;
    color: var(--color-text-muted);
    cursor: pointer;
    padding: var(--space-2);
    border-radius: var(--border-radius);
    transition: color 0.2s, background-color 0.2s;
}

.settings-toggle:hover, .settings-dropdown.active .settings-toggle {
    color: var(--color-text);
    background-color: var(--color-surface);
}

/* The actual dropdown menu */
.settings-menu {
    display: none; /* Hidden by default */
    position: absolute;
    top: 100%;
    right: 0; /* Aligns to right edge */
    width: 280px;
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    padding: var(--space-4);
    z-index: 100;
    margin-top: var(--space-2);
}

/* Show menu when active class is added via JS */
.settings-dropdown.active .settings-menu {
    display: block;
}

.settings-group {
    margin-bottom: var(--space-4);
}

.settings-group:last-child {
    margin-bottom: 0;
}

.settings-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-muted);
    margin-bottom: var(--space-2);
}

.btn-group {
    display: flex;
    gap: var(--space-2);
}

.btn-group .toggle-btn {
    flex: 1;
    text-align: center;
    padding: var(--space-2);
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--color-text-muted);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-group .toggle-btn:hover {
    border-color: var(--color-text-muted);
}

.btn-group .toggle-btn.active {
    color: var(--color-background);
    background-color: var(--color-text);
    border-color: var(--color-text);
}

.search-toggle,
.menu-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    padding: 0;
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

.search-toggle:hover,
.menu-toggle:hover {
    border-color: var(--color-text-muted);
}

.menu-toggle {
    flex-direction: column;
    gap: 4px;
}

@media (min-width: 1024px) {
    .menu-toggle {
        display: none;
    }
}

.menu-bar {
    width: 18px;
    height: 2px;
    background-color: var(--color-text);
    transition: transform var(--transition-fast);
}

/* Search overlay */
.search-overlay {
    position: fixed;
    inset: 0;
    z-index: 100;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding-top: 10vh;
}

.search-overlay[hidden] {
    display: none;
}

.search-container {
    width: 100%;
    max-width: 600px;
    margin-inline: var(--space-4);
    background: var(--color-background);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.search-form {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-4);
    border-bottom: 1px solid var(--color-border);
}

.search-input {
    flex: 1;
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-lg);
    border: none;
    outline: none;
}

.search-submit {
    padding: var(--space-2) var(--space-4);
    font-weight: 500;
    color: var(--color-background);
    background: var(--color-text);
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
}

.search-close {
    width: 40px;
    height: 40px;
    font-size: var(--text-2xl);
    color: var(--color-text-muted);
    background: none;
    border: none;
    cursor: pointer;
}

.search-results {
    max-height: 400px;
    overflow-y: auto;
    padding: var(--space-4);
}

.search-result {
    display: block;
    padding: var(--space-3);
    text-decoration: none;
    border-bottom: 1px solid var(--color-border-light);
    transition: background-color var(--transition-fast);
}

.search-result:last-child {
    border-bottom: none;
}

.search-result:hover,
.search-result:focus {
    background-color: var(--color-surface);
    border-radius: var(--border-radius);
    outline: none;
}

.search-result-type {
    display: block;
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-1);
}

.search-result-title {
    display: block;
    font-weight: 500;
    color: var(--color-text);
    font-size: var(--text-base);
}

.search-result:hover .search-result-title {
    color: var(--color-info);
}

/* ============================================
   FOOTER
   ============================================ */
.site-footer {
    margin-top: var(--space-16);
    padding-block: var(--space-12);
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: grid;
    gap: var(--space-8);
}

@media (min-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr 2fr;
    }
}

.footer-tagline {
    font-weight: 600;
    color: var(--color-text);
}

.footer-note {
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.footer-nav {
    display: grid;
    gap: var(--space-6);
}

@media (min-width: 640px) {
    .footer-nav {
        grid-template-columns: repeat(3, 1fr);
    }
}

.footer-col h3 {
    font-size: var(--text-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-3);
}

.footer-col ul {
    list-style: none;
    padding: 0;
}

.footer-col li {
    margin-bottom: var(--space-2);
}

.footer-col a {
    font-size: var(--text-sm);
    color: var(--color-text);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-col a:hover {
    color: var(--color-info);
}

.footer-bottom {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
    margin-top: var(--space-8);
    padding-top: var(--space-6);
    border-top: 1px solid var(--color-border);
}

.footer-bottom p {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.print-page-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

.print-page-btn:hover {
    border-color: var(--color-text-muted);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    line-height: var(--leading-tight);
    font-weight: 600;
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }
h5 { font-size: var(--text-base); }
h6 { font-size: var(--text-sm); }

@media (min-width: 768px) {
    h1 { font-size: var(--text-4xl); }
    h2 { font-size: var(--text-3xl); }
}

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

.page-title {
    margin-bottom: var(--space-2);
}

.page-description {
    font-size: var(--text-lg);
    color: var(--color-text-muted);
}

/* ============================================
   CONTENT
   ============================================ */
.content {
    max-width: var(--container-narrow);
}

.content > * + * {
    margin-top: var(--space-4);
}

.content h2 {
    margin-top: var(--space-8);
    margin-bottom: var(--space-4);
}

.content h3 {
    margin-top: var(--space-6);
    margin-bottom: var(--space-3);
}

.content ul, .content ol {
    padding-left: var(--space-6);
}

.content li {
    margin-bottom: var(--space-2);
}

.content blockquote {
    padding-left: var(--space-4);
    border-left: 4px solid var(--color-border);
    color: var(--color-text-muted);
    font-style: italic;
}

.content code {
    padding: var(--space-1) var(--space-2);
    font-family: var(--font-mono);
    font-size: 0.875em;
    background: var(--color-surface);
    border-radius: var(--border-radius);
}

.content pre {
    padding: var(--space-4);
    background: var(--color-surface);
    border-radius: var(--border-radius);
    overflow-x: auto;
}

.content pre code {
    padding: 0;
    background: none;
}

/* ============================================
   TABLES
   ============================================ */
.content table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-6) 0; /* Vertical spacing */
    font-size: var(--text-sm); /* Slightly smaller text usually looks sharper in data tables */
    border-radius: var(--border-radius); /* Optional: rounded corners on the wrapper */
    overflow: hidden; /* Keeps borders inside rounded corners */
    box-shadow: var(--shadow-sm); /* Subtle lift */
}

.content th,
.content td {
    padding: var(--space-3) var(--space-4);
    border-bottom: 1px solid var(--color-border);
    text-align: left;
    line-height: var(--leading-relaxed);
}

/* Header Styling */
.content th {
    background-color: var(--color-surface);
    font-weight: 600;
    color: var(--color-text);
    border-bottom: 2px solid var(--color-border); /* Thicker bottom border for header */
}

/* Zebra Striping (Optional but recommended for readability) */
.content tr:nth-child(even) {
    background-color: var(--color-surface);
    /* In dark mode, this might need transparency if surface is too light, 
       but your current variables handle this well. */
}

/* Remove bottom border from the very last row */
.content tr:last-child td {
    border-bottom: none;
}

/* Responsive Wrapper: Ensures table scrolls on mobile instead of breaking layout */
.table-wrapper {
    overflow-x: auto;
    margin-bottom: var(--space-6);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
}

/* If you can't add a wrapper div in Parsedown easily, 
   you can set display: block and overflow on the table itself for mobile: */
@media (max-width: 640px) {
    .content table {
        display: block;
        overflow-x: auto;
        white-space: nowrap;
    }
}

/* ============================================
   CARDS & COMPONENTS
   ============================================ */
.card {
    padding: var(--space-6);
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
}

.card-strand {
    border-left: 4px solid var(--strand-color, var(--color-border));
}

.card-title {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-2);
}

.card-meta {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

/* Strand grid (homepage) */
.strand-grid {
    display: grid;
    gap: var(--space-4);
}

@media (min-width: 640px) {
    .strand-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .strand-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.strand-card {
    display: flex;
    flex-direction: column;
    padding: var(--space-6);
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    text-decoration: none;
    color: var(--color-text);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.strand-card:hover {
    border-color: var(--strand-color);
    box-shadow: var(--shadow-md);
}

.strand-card-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--strand-color);
    color: white;
    border-radius: var(--border-radius);
    margin-bottom: var(--space-4);
}

.strand-card-title {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-1);
}

.strand-card-count {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

/* ============================================
   MISCONCEPTION CARDS
   ============================================ */
.trap-card {
    padding: var(--space-6);
    background: #FEF2F2;
    border: 1px solid #FECACA;
    border-left: 4px solid var(--color-error);
    border-radius: var(--border-radius-lg);
}

.trap-card-header {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    margin-bottom: var(--space-4);
}

.trap-icon {
    font-size: var(--text-xl);
}

.trap-title {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--color-error);
}

.trap-section {
    margin-top: var(--space-4);
}

.trap-section-title {
    font-size: var(--text-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-2);
}

/* Spot the mistake interactive */
.spot-mistake {
    padding: var(--space-4);
    background: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
}

.spot-segment {
    display: block;
    padding: var(--space-2);
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: background-color var(--transition-fast);
}

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

.spot-segment.revealed.spot-segment-error {
    background-color: #FEE2E2;
    border: 1px solid var(--color-error);
}

.spot-segment.revealed.spot-segment-correct {
    opacity: 0.5;
}

.spot-instruction {
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    font-style: italic;
}

.spot-feedback {
    margin-top: var(--space-4);
    padding: var(--space-4);
    background: #FEF3C7;
    border-radius: var(--border-radius);
}

/* ============================================
   STUCK BUTTON & HINTS
   ============================================ */
.stuck-hints {
    margin-top: var(--space-4);
}

.stuck-button {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    font-weight: 500;
    color: var(--color-info);
    background: #EFF6FF;
    border: 1px solid #BFDBFE;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.stuck-button:hover {
    background: #DBEAFE;
}

.hints-container {
    margin-top: var(--space-3);
}

.hint {
    padding: var(--space-3);
    background: #FEF3C7;
    border-radius: var(--border-radius);
    margin-bottom: var(--space-2);
}

.hint[hidden] {
    display: none;
}

/* ============================================
   TIER BADGES
   ============================================ */
.tier-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    font-size: var(--text-xs);
    font-weight: 600;
    border-radius: 50%;
}

.tier-foundation {
    background: #DBEAFE;
    color: #1E40AF;
}

.tier-higher {
    background: #FCE7F3;
    color: #9D174D;
}

/* Higher-only content visibility */
body[data-tier="foundation"] .higher-only {
    display: none;
}

/* ============================================
   BREADCRUMBS
   ============================================ */
.breadcrumbs {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-2);
    margin-bottom: var(--space-6);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

.breadcrumbs a {
    color: var(--color-text-muted);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.breadcrumbs a:hover {
    color: var(--color-text);
}

.breadcrumbs-separator {
    color: var(--color-text-light);
}

/* ============================================
   NIGHT BEFORE PAGE
   ============================================ */
.night-before-hero {
    padding: var(--space-8);
    background: linear-gradient(135deg, #1E3A8A 0%, #7C3AED 100%);
    color: white;
    border-radius: var(--border-radius-lg);
    text-align: center;
    margin-bottom: var(--space-8);
}

.night-before-hero h1 {
    font-size: var(--text-3xl);
    margin-bottom: var(--space-2);
}

.night-before-hero p {
    opacity: 0.9;
}

/* ============================================
   LATEX STYLING
   ============================================ */
.latex-block {
    display: block;
    text-align: center;
    margin: var(--space-4) 0;
    overflow-x: auto;
}

.latex-inline {
    display: inline;
}

/* ============================================
   UTILITIES
   ============================================ */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.text-muted {
    color: var(--color-text-muted);
}

.text-center {
    text-align: center;
}

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

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

/* ============================================
   MOBILE MENU STATE
   ============================================ */
   @media (max-width: 1023px) {
    .main-nav.is-open {
        display: block;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--color-background);
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-lg);
        padding: var(--space-2) var(--space-4) var(--space-4);
        z-index: 49;
    }

    .main-nav.is-open .nav-list {
        flex-direction: column;
        align-items: stretch;
        gap: var(--space-1);
    }

    .main-nav.is-open .nav-link {
        padding: var(--space-3);
        border-radius: var(--border-radius);
    }

    .main-nav.is-open .nav-link:hover {
        background-color: var(--color-surface);
    }

    /* Adjust dropdowns inside the mobile menu to be static/always visible or clickable */
    .main-nav.is-open .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: none;
        padding-left: var(--space-4);
        margin-top: 0;
        margin-bottom: var(--space-2);
        display: none; /* Hide sub-items by default on mobile to save space */
    }

    /* Optional: Show sub-menu when parent is clicked (requires aria-expanded logic in JS) */
    .main-nav.is-open .nav-link[aria-expanded="true"] + .dropdown-menu {
        display: block;
    }
}

/* ============================================
   CONTENT IMAGES
   Add this to your style.css
   ============================================ */

   .content-image {
    display: block;
    max-width: 100%;
    height: auto;
    margin: var(--space-4) auto;
    border-radius: var(--border-radius);
}

/* Center images in content areas */
.content img,
.skill-content img {
    display: block;
    max-width: 100%;
    height: auto;
    margin: 1.5rem auto;
}

/* SVG diagrams should respect their intrinsic size but not overflow */
.content img[src$=".svg"],
.skill-content img[src$=".svg"] {
    max-width: min(100%, 400px);
}

/* SVG size presets */

/* Specificity increased to override .content img[src$=".svg"] rule */

.content .content-image.svg-size-small,

.skill-content .content-image.svg-size-small {

    max-width: 200px;

    width: auto;

}

.content .content-image.svg-size-medium,

.skill-content .content-image.svg-size-medium {

    max-width: 400px;

    width: auto;

}

.content .content-image.svg-size-large,

.skill-content .content-image.svg-size-large {

    max-width: 600px;

    width: auto;

}

.content .content-image.svg-size-full-width,

.skill-content .content-image.svg-size-full-width {

    width: 100%;

    max-width: 100%;

}

/* Add a subtle background for diagrams */
.content img[src*="diagrams"],
.skill-content img[src*="diagrams"] {
    background: #fafafa;
    padding: 1rem;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
}

/* Print styles for images */
@media print {
    .content-image,
    .content img {
        max-width: 80% !important;
        page-break-inside: avoid;
    }
}

/* Featured Night Before Card */
.night-before-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-6);
    margin-bottom: var(--space-8);
    background: linear-gradient(135deg, #1E3A8A 0%, #7C3AED 100%);
    border-radius: var(--border-radius-lg);
    color: white;
    text-decoration: none;
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.night-before-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.nb-card-content {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.nb-icon {
    font-size: 2.5rem;
}

.night-before-card h3 {
    font-size: var(--text-xl);
    margin-bottom: var(--space-1);
    color: white;
}

.night-before-card p {
    color: rgba(255, 255, 255, 0.9);
    margin: 0;
}

.nb-arrow {
    font-size: 2rem;
    color: rgba(255, 255, 255, 0.8);
}

@media (max-width: 640px) {
    .night-before-card {
        flex-direction: column;
        text-align: center;
        gap: var(--space-4);
    }
    
    .nb-card-content {
        flex-direction: column;
    }
    
    .nb-arrow {
        display: none;
    }
}

/* ============================================
   MAGAZINE LAYOUT UTILITIES
   ============================================ */

/* --- Magazine Layout Updates --- */

/* 1. Trigger the grid earlier (at 640px instead of 768px) */
@media (min-width: 640px) {
    .technique-grid, .do-dont-grid {
        display: grid;
        grid-template-columns: 1fr 1fr; /* Two equal columns */
        gap: var(--space-4);
        align-items: stretch; /* Forces equal height */
    }
    
    /* SAFETY TWEAK: Prevents content from forcing the column wider than 50% */
    .technique-grid > div, .do-dont-grid > div {
        min-width: 0;
    }
}

/* Base grid styles */
.technique-grid {
    margin-bottom: var(--space-6);
}

.do-dont-grid {
    margin-bottom: var(--space-6);
}

/* Info Cards (Gray Box) */
.info-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--space-5);
}

.info-card h3 {
    margin-top: 0;
    font-size: var(--text-lg);
    color: var(--color-info);
}

/* Alert Boxes (Emergency/Warning) */
.alert-box {
    background: #FFF4E5; /* Light Orange */
    border-left: 4px solid #F59E0B;
    padding: var(--space-4);
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    margin-bottom: var(--space-6);
}

/* --- 1. Fix Card Alignment & Heights --- */

/* 2. Ensure cards fill the height */
.info-card, .card-do, .card-dont {
    height: 100%;
    display: flex;
    flex-direction: column;
}

.card-do {
    background: #ECFDF5;
    border: 1px solid #10B981;
    border-radius: var(--border-radius);
    padding: var(--space-4);
}

.card-dont {
    background: #FEF2F2;
    border: 1px solid #EF4444;
    border-radius: var(--border-radius);
    padding: var(--space-4);
}

.card-do h3 { color: #047857; margin-top: 0; }
.card-dont h3 { color: #B91C1C; margin-top: 0; }

/* Ensure lists inside cards line up nicely */
.info-card ul, .card-do ul, .card-dont ul, .alert-box ul {
    margin-top: 0.5rem;
    margin-bottom: 0;
    padding-left: 1.2rem; /* Consistent indentation for bullets */
}

/* 3. Push content to fill space so bullet points align */
.info-card ul, .card-do ul, .card-dont ul {
    flex: 1; /* Pushes bottom content down if we add footers later */
}

.info-card li, .card-do li, .card-dont li, .alert-box li {
    margin-bottom: 0.25rem; /* Breathing room between items */
}

/* --- 2. Fix Timeline Number Alignment --- */

/* This puts the Number (1) and Content side-by-side */
.timeline-step {
    display: flex;           
    
    gap: var(--space-4);     
    
    margin-bottom: var(--space-4);
    
    align-items: flex-start; 
}

/* Circle Styling for the Number */
.step-number {
    background: var(--color-info);
    color: white;
    font-weight: bold;
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    
    /* Center the number inside the circle */
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;          /* Prevents the circle from squashing */
    line-height: 1;          /* Ensures vertical centering */
}

.step-content {
    flex: 1;                 /* Takes up the rest of the line */
    padding-top: 0.25rem;    /* Aligns text visually with the number */
}