:root {
    /* Light Mode (Brilliant.org inspired) */
    --bg-color: #F8FAFC;
    --card-bg: #FFFFFF;
    --card-shadow: 0 4px 12px rgba(15, 23, 42, 0.04), 0 2px 4px rgba(15, 23, 42, 0.02);
    
    --primary: #3b82f6;      /* Brilliant Blue */
    --primary-hover: #2563eb;
    
    --success: #10b981;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --warning: #f59e0b;
    
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --bond-color: #374151;
    
    --chain-hl: #3b82f6;
    --sidechain-hl: #f59e0b;
    --functional-hl: #10b981;
    
    /* New UI vars */
    --radius-md: 12px;
    --radius-lg: 20px;
    --font-base: 'Figtree', system-ui, -apple-system, sans-serif;
}

/* System Dark Mode */
@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) {
        --bg-color: #0f172a;
        --card-bg: #1e293b;
        --card-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
        --primary: #3b82f6;
        --primary-hover: #60a5fa;
        --text-main: #f8fafc;
        --text-muted: #94a3b8;
        --border-color: #334155;
        --bond-color: #cbd5e1;
    }
}

/* Manual Dark Mode Override */
body[data-theme="dark"] {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --card-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    --primary: #3b82f6;
    --primary-hover: #60a5fa;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --bond-color: #cbd5e1;
}

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

body {
    font-family: var(--font-base);
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
    padding-bottom: 60px;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4 {
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-main);
}

h1 { font-size: 2rem; text-align: center; margin-bottom: 0.5rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; margin-top: 1.5rem; }

p {
    font-size: 1rem;
    font-weight: 400;
    margin-bottom: 1rem;
}

/* Layout */
#app-content {
    width: 100%;
    max-width: 800px;
    padding: 20px;
    flex-grow: 1;
}

/* Header & Progress */
header {
    width: 100%;
    max-width: 800px;
    padding: 20px;
    position: sticky;
    top: 0;
    background-color: rgba(var(--bg-color), 0.95); /* We let it pick up the theme */
    background-color: var(--bg-color); /* Fallback to solid if transparency needs split vars. Actually let's use a trick: */
    /* Let's just use solid var bg to be safe, or semi transparent if we had RGB vars. */
    background-color: var(--bg-color);
    opacity: 0.98;
    backdrop-filter: blur(8px);
    z-index: 10;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
}

header.hidden {
    display: none !important;
}

.progress-container {
    flex-grow: 1;
    margin-right: 20px;
}

.progress-text {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.progress-bar {
    display: flex;
    gap: 4px;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-segment {
    flex: 1;
    background-color: transparent;
    transition: background-color 0.3s ease;
}

.progress-segment.active, .progress-segment.completed {
    background-color: var(--primary);
}
.progress-segment.active {
    opacity: 0.7;
}

.card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--card-shadow);
    padding: 32px;
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

/* Buttons */
button {
    font-family: var(--font-base);
    font-size: 1rem;
    font-weight: 600;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

button:active {
    transform: scale(0.97);
}

.btn-primary {
    background-color: var(--primary);
    color: white;
    box-shadow: 0 4px 6px rgba(59, 130, 246, 0.25);
}
.btn-primary:hover { 
    background-color: var(--primary-hover); 
    box-shadow: 0 6px 12px rgba(59, 130, 246, 0.3);
}

.btn-secondary {
    background-color: transparent;
    border-color: var(--border-color);
    color: var(--text-main);
}
.btn-secondary:hover { 
    border-color: var(--text-muted);
    background-color: rgba(0,0,0,0.03); 
}
body[data-theme="dark"] .btn-secondary:hover {
    background-color: rgba(255,255,255,0.05);
}
@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) .btn-secondary:hover {
        background-color: rgba(255,255,255,0.05);
    }
}

.btn-danger {
    background-color: var(--danger);
    color: white;
}
.btn-danger:hover { background-color: var(--danger-hover); }

.btn-icon {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 8px 16px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-radius: var(--radius-md);
}
.btn-icon:hover { 
    background-color: var(--bg-color); 
    border-color: var(--text-muted);
}

.btn-link {
    background: none;
    color: var(--text-muted);
    font-weight: 400;
    text-decoration: underline;
    font-size: 0.875rem;
}
.btn-link:hover { color: var(--text-main); }

/* Form Elements */
input[type="text"], input[type="number"], select, textarea {
    font-family: var(--font-base);
    font-size: 1rem;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    outline: none;
    transition: all 0.2s;
    background-color: var(--card-bg);
    color: var(--text-main);
}
input[type="text"]:focus, input[type="number"]:focus, select:focus, textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}

.input-container {
    margin-bottom: 16px;
}
.input-label {
    display: block;
    font-weight: 600;
    margin-bottom: 6px;
}

/* Molecules Display */
.molecules-display {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 40px;
    margin: 24px 0;
}
.molecules-display.column {
    flex-direction: column;
    align-items: center;
}
.molecules-display.compare {
    align-items: center;
}
.molecules-display.compare .vs-label {
    font-weight: 600;
    color: var(--text-muted);
    font-size: 1.2rem;
}

.molecule-container {
    display: flex;
    flex-direction: column;
    align-items: center;
}
.molecule-name {
    margin-top: 12px;
    font-weight: 600;
    color: var(--text-muted);
}
.molecule-svg-wrapper {
    /* For SVGs, we maintain the aspect ratio natively, but add max constraints if needed */
    max-width: 100%;
    overflow-x: auto;
}
svg {
    display: block;
}

/* Tables */
.fill-table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}
.fill-table th, .fill-table td {
    padding: 12px;
    border: 1px solid var(--border-color);
    text-align: left;
    color: var(--text-main);
}
.fill-table th {
    background-color: var(--bg-color);
    font-weight: 600;
}

/* Feedback blocks */
.feedback-box {
    margin-top: 24px;
    padding: 20px;
    border-radius: var(--radius-md);
    display: none;
    animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    font-weight: 500;
}
.feedback-box.correct {
    display: flex; gap: 12px; align-items: flex-start;
    background-color: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    color: var(--success);
}
.feedback-box.incorrect {
    display: flex; gap: 12px; align-items: flex-start;
    background-color: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: var(--danger);
}
.feedback-box.info {
    display: flex; gap: 12px; align-items: flex-start;
    background-color: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.3);
    color: var(--primary);
}

.feedback-box.feedback-ai {
    display: block;
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--primary);
    box-shadow: 0 4px 6px rgba(0,0,0,0.02);
    color: var(--text-main);
}

/* AI Hint box */
.hint-box {
  background: rgba(245, 158, 11, 0.1);
  border-left: 4px solid var(--warning);
  padding: 16px 20px;
  border-radius: var(--radius-md);
  margin-top: 16px;
  font-size: 0.95em;
  color: var(--text-main);
  animation: fadeIn 0.4s ease;
}
.hint-box.loading {
    opacity: 0.7;
    font-style: italic;
    color: var(--text-muted);
}



/* Multiple choice / Match */
.mc-options {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin: 24px 0;
}
.mc-option {
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 20px;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    background: var(--card-bg);
    color: var(--text-main);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 500;
}
.mc-option:hover {
    border-color: var(--text-muted);
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.mc-option.selected {
    border-color: var(--primary);
    background-color: rgba(59, 130, 246, 0.05);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
}

.mc-option.option-correct {
    border-color: var(--success);
    background-color: rgba(16, 185, 129, 0.05);
}
.mc-option.option-correct::after {
    content: " \2713"; /* Groen vinkje ✓ */
    color: var(--success);
    font-weight: 800;
    font-size: 1.2rem;
}

.mc-option.option-selected-incorrect {
    border-color: var(--danger);
    background-color: rgba(239, 68, 68, 0.05);
}
.mc-option.option-selected-incorrect::after {
    content: " \2717"; /* Rood kruisje ✗ */
    color: var(--danger);
    font-weight: 800;
    font-size: 1.2rem;
}

.mc-option.option-oranje {
    border-color: var(--warning);
    background-color: rgba(245, 158, 11, 0.05);
}
.mc-option.option-oranje::after {
    content: " \2713"; /* Oranje vinkje ✓ */
    color: var(--warning);
    font-weight: 800;
    font-size: 1.2rem;
}

/* Invulvelden feedback classes */
.field-correct {
    border: 2px solid var(--success) !important;
    background-color: rgba(16, 185, 129, 0.1) !important;
}
.field-incorrect {
    border: 2px solid var(--danger) !important;
    background-color: rgba(239, 68, 68, 0.1) !important;
}
.field-oranje {
    border: 2px solid var(--warning) !important;
    background-color: rgba(245, 158, 11, 0.1) !important;
}

/* Row-level feedback for tables */
.row-correct {
    background-color: rgba(16, 185, 129, 0.1) !important;
}
.row-incorrect {
    background-color: rgba(239, 68, 68, 0.1) !important;
}
.row-oranje {
    background-color: rgba(245, 158, 11, 0.1) !important;
}

.row-correct td:first-child, .row-incorrect td:first-child {
    font-weight: 700;
}

.row-correct td:first-child {
    color: var(--success);
}

.row-incorrect td:first-child {
    color: var(--danger);
}

.input-feedback-icon {
    margin-left: 8px;
    font-weight: bold;
}
.input-feedback-icon.correct {
    color: var(--success);
}
.input-feedback-icon.incorrect {
    color: var(--danger);
}
.input-feedback-icon.oranje {
    color: var(--warning);
}

.correct-answer-text {
    color: var(--success);
    font-size: 0.9em;
    font-weight: 600;
    margin-top: 4px;
    display: block;
}

/* Modals */
.modal {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    padding: 24px;
    backdrop-filter: blur(4px);
}
.modal.hidden {
    display: none;
}
.modal-content {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: 32px;
    width: 100%;
    max-width: 500px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}
.modal-large {
    max-width: 700px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}
.modal-body {
    overflow-y: auto;
    padding-right: 8px;
}
.btn-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
    padding: 4px;
}
.btn-close:hover { color: var(--text-main); }
.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    margin-top: 24px;
}

/* Tables inside modals */
.modal-body table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 24px;
}
.modal-body th, .modal-body td {
    padding: 10px;
    border: 1px solid var(--border-color);
    text-align: left;
}
.modal-body th { 
    background-color: var(--bg-color); 
    color: var(--text-main);
}

/* Utilities */
.hidden { display: none !important; }
.text-center { text-align: center; }
.mt-4 { margin-top: 16px; }
.mb-4 { margin-bottom: 16px; }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-5px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Step container for partial logic */
.step-container {
    border-left: 3px solid var(--border-color);
    padding-left: 16px;
    margin-bottom: 20px;
}
.step-container.active {
    border-left-color: var(--primary);
}

/* Sidebar Navigation - Hierarchical Redesign */
#sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 280px;
    height: 100vh;
    background-color: var(--card-bg);
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    z-index: 50;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), background-color 0.3s;
    display: flex;
    flex-direction: column;
}

/* Sidebar Progress Summary */
.sb-progress-summary {
    padding: 24px 20px;
    background: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
}

.sb-progress-summary h3 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.sb-progress-stats {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.sb-stat-item {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-main);
    display: flex;
    justify-content: space-between;
}

.sb-stat-item span:last-child {
    color: var(--primary);
    font-weight: 700;
}

/* Sidebar Hierarchy */
.sb-nav-container {
    padding: 12px 0;
    flex-grow: 1;
}

.sb-block-container {
    margin-bottom: 4px;
}

.sb-block-header {
    width: 100%;
    padding: 12px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: none;
    border: none;
    cursor: pointer;
    text-align: left;
    transition: background 0.2s;
    border-radius: 0;
    color: var(--text-main);
}

.sb-block-header:hover {
    background-color: var(--bg-color);
}

.sb-block-title {
    font-weight: 700;
    font-size: 0.9375rem;
}

.sb-block-chevron {
    font-size: 0.75rem;
    color: var(--text-muted);
    transition: transform 0.2s;
}

.sb-block-container.expanded .sb-block-chevron {
    transform: rotate(180deg);
}

.sb-block-content {
    display: none;
    background-color: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
}

.sb-block-container.expanded .sb-block-content {
    display: block;
}

/* Rounds inside Block */
.sb-round-item {
    margin-bottom: 2px;
}

.sb-round-header {
    width: 100%;
    padding: 10px 20px 10px 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: none;
    border: none;
    cursor: pointer;
    text-align: left;
    transition: background 0.2s;
    border-radius: 0;
}

.sb-round-header:hover {
    background-color: rgba(0,0,0,0.03);
}
body[data-theme="dark"] .sb-round-header:hover {
    background-color: rgba(255,255,255,0.03);
}
@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) .sb-round-header:hover {
        background-color: rgba(255,255,255,0.03);
    }
}

.sb-round-title {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sb-round-status {
    font-size: 0.875rem;
    margin-left: 8px;
}

.sb-round-content {
    display: none;
    padding: 4px 0 8px 0;
    background-color: var(--card-bg);
}

.sb-round-item.expanded .sb-round-content {
    display: block;
}

.sb-round-item.active .sb-round-title {
    color: var(--primary);
    font-weight: 700;
}

/* Questions inside Round */
.sb-question-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(36px, 1fr));
    gap: 8px;
    padding: 8px 20px 8px 48px;
}

.sb-question-item {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm, 8px);
    font-size: 0.8125rem;
    font-weight: 600;
    background-color: var(--bg-color);
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s;
    border: 1px solid transparent;
}

.sb-question-item:hover {
    background-color: var(--border-color);
    color: var(--text-main);
}

.sb-question-item.completed {
    background-color: rgba(16, 185, 129, 0.15);
    color: var(--success);
}

.sb-question-item.completed-1 {
    background-color: rgba(16, 185, 129, 0.15);
    color: var(--success);
}

.sb-question-item.completed-2 {
    background-color: rgba(245, 158, 11, 0.15);
    color: var(--warning);
}

.sb-question-item.failed {
    background-color: rgba(239, 68, 68, 0.15);
    color: var(--danger);
}

.sb-question-item.current {
    background-color: var(--primary);
    color: white;
    box-shadow: 0 4px 6px rgba(59, 130, 246, 0.4);
}

.sb-question-item.locked {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Breadcrumbs */
.breadcrumb-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto 12px auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.8125rem;
    color: #94a3b8;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    gap: 8px;
}

.breadcrumb-item:not(:last-child)::after {
    content: "›";
    font-size: 1.1rem;
}

.breadcrumb-active {
    color: #475569;
    font-weight: 600;
}

/* Hamburger Button */
.btn-hamburger {
    position: fixed;
    top: 16px;
    left: 16px;
    z-index: 60;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    cursor: pointer;
    color: var(--text-main);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

/* Responsiveness for Sidebar */
@media (min-width: 1025px) {
    body { padding-left: 280px; }
    #sidebar { width: 280px; transform: translateX(0); }
    .btn-hamburger { display: none !important; }
}
@media (min-width: 768px) and (max-width: 1024px) {
    body { padding-left: 240px; }
    #sidebar { width: 240px; transform: translateX(0); }
    .btn-hamburger { display: none !important; }
}
@media (max-width: 767px) {
    body { padding-left: 0; }
    #sidebar {
        width: 280px;
        transform: translateX(-100%);
        box-shadow: none;
    }
    #sidebar.mobile-open {
        transform: translateX(0);
        box-shadow: 10px 0 30px rgba(0,0,0,0.1);
    }
    .btn-hamburger { display: flex; }
    
    #app-content {
        padding-top: 80px;
    }
}

/* ── Introductie-modus (geen navigatie) ────────────────────── */
body.intro-mode {
    padding-left: 0 !important;
}

body.intro-mode #sidebar,
body.intro-mode .btn-hamburger,
body.intro-mode #app-header,
body.intro-mode #breadcrumb-container {
    display: none !important;
}


/* ── Introductiescherm (Redesign) ──────────────────────────── */
.intro-scherm {
    max-width: 900px;
    margin: 0 auto;
    padding: 60px 24px;
    display: flex;
    flex-direction: column;
    gap: 48px;
}
.intro-scherm.hidden {
    display: none;
}

/* Hero Section */
.hero-section {
    text-align: center;
    animation: fadeIn 0.6s ease-out;
}
.hero-section h1 {
    font-size: 2.8rem;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}
.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-muted);
    max-width: 650px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Level Selection */
.level-selectie {
    text-align: center;
}
.level-selectie h2 {
    font-size: 1.5rem;
    margin-bottom: 24px;
    color: var(--text-main);
}
.level-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 16px;
    justify-content: center;
}
.level-card {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 24px 16px;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 6px rgba(0,0,0,0.02);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}
.level-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: 0 10px 15px -3px rgba(59, 130, 246, 0.1);
}
.level-card.selected {
    border-color: var(--primary);
    background: rgba(59, 130, 246, 0.05);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.15);
}
.level-card-icon {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--primary);
    background: rgba(59, 130, 246, 0.1);
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}
.level-card h3 {
    margin: 0;
    font-size: 1.1rem;
    color: var(--text-main);
}

/* Actions */
.intro-actions {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}
.primary-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    justify-content: center;
}
.secondary-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    justify-content: center;
}

.btn-hero-primary {
    background: var(--primary);
    color: white;
    border: none;
    padding: 18px 48px;
    border-radius: var(--radius-lg);
    font-size: 1.25rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 8px 16px rgba(59, 130, 246, 0.25);
}
.btn-hero-primary:disabled {
    background: var(--border-color);
    color: var(--text-muted);
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
}
.btn-hero-primary:not(:disabled):hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 12px 20px rgba(59, 130, 246, 0.3);
}

.btn-hero-secondary {
    background: transparent;
    color: var(--text-main);
    border: 2px solid var(--border-color);
    padding: 12px 32px;
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}
.btn-hero-secondary:hover {
    border-color: var(--text-muted);
    background: rgba(0,0,0,0.03);
}
body[data-theme="dark"] .btn-hero-secondary:hover {
    background: rgba(255,255,255,0.05);
}
@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) .btn-hero-secondary:hover {
        background: rgba(255,255,255,0.05);
    }
}

/* Features Section */
.features-section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 40px;
    margin-top: 16px;
    box-shadow: var(--card-shadow);
}
.features-section h2 {
    text-align: center;
    margin-bottom: 32px;
    font-size: 1.5rem;
}
.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px 32px;
    margin-bottom: 32px;
}
@media (max-width: 640px) {
    .features-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }
}
.feature-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 16px;
}
.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
    background: var(--bg-color);
    width: 70px;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 16px;
    border: 1px solid var(--border-color);
}
.feature-card h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--text-main);
}
.feature-card p {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin: 0;
}

.hulptabellen-info {
    text-align: center;
    font-size: 0.95rem;
    color: var(--text-muted);
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
    margin: 0;
}

/* Compact button inside modals for round start */
.btn-ronde-start {
    background: var(--primary);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background 0.2s;
}
.btn-ronde-start:hover {
    background: var(--primary-hover);
}

/* Intro & Modal Tables */
.intro-tabel {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 24px;
    font-size: 0.95rem;
    color: var(--text-main);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}
.intro-tabel th {
    background: var(--bg-color);
    border-bottom: 2px solid var(--border-color);
    padding: 12px 16px;
    text-align: left;
    font-weight: 700;
    color: var(--text-main);
}
.intro-tabel td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-color);
    vertical-align: middle;
}
.intro-tabel tr:last-child td {
    border-bottom: none;
}
.intro-tabel tr:nth-child(even) {
    background: rgba(0, 0, 0, 0.02);
}
body[data-theme="dark"] .intro-tabel tr:nth-child(even) {
    background: rgba(255, 255, 255, 0.03);
}
@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) .intro-tabel tr:nth-child(even) {
        background: rgba(255, 255, 255, 0.03);
    }
}

/* ── Terugkeermelding ──────────────────────────────────────── */
.terugkeer-melding {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-main);
    color: var(--bg-color);
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 0.95rem;
    z-index: 9999;
    animation: fadeUit 3s forwards;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}
@keyframes fadeUit {
    0%   { opacity: 1; }
    70%  { opacity: 1; }
    100% { opacity: 0; }
}

@media (max-width: 768px) {
    .intro-tabellen-rij { flex-direction: column; }
    .intro-header h1 { font-size: 1.5rem; }
    .knop-start { width: 100%; }
}

/* ================= PRANK & FINAL QUESTION ================= */

.prank-monster-name {
    background: #f8fafc;
    border: 1px solid var(--border-color);
    padding: 15px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    line-height: 1.6;
    word-break: break-all;
    max-width: 600px;
    margin: 20px auto;
    color: var(--primary);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.05);
}

.prank-reveal {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 300px;
    animation: prankBounceIn 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.prank-reveal-emoji {
    font-size: 5rem;
    margin-bottom: 20px;
}

.prank-reveal-text {
    font-size: 3rem;
    font-weight: 900;
    color: var(--primary);
    text-shadow: 2px 2px 0px rgba(0,0,0,0.05);
}

@keyframes prankBounceIn {
    0% { transform: scale(0.3); opacity: 0; }
    50% { transform: scale(1.05); opacity: 1; }
    70% { transform: scale(0.9); }
    100% { transform: scale(1); }
}

#prank-timer-wrap {
    width: 100%;
    height: 12px;
    background: #e2e8f0;
    border-radius: 6px;
    margin: 20px 0;
    overflow: hidden;
    position: relative;
    border: 1px solid rgba(0,0,0,0.05);
}

#prank-timer-bar-inner {
    height: 100%;
    width: 100%;
    background: var(--success);
    transition: width 1s linear, background-color 0.3s ease;
}

#prank-timer-bar-inner.prank-timer-low {
    background: var(--danger);
}

#prank-timer-label {
    position: absolute;
    right: 0;
    top: -25px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
}


/* Priority Rules Styles */
.rules-summary-container {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    margin: 20px 0;
    border: 1px solid var(--border-color);
}

.rules-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin: 15px 0;
    font-size: 0.95rem;
}

.rules-table th {
    background: rgba(0, 0, 0, 0.03);
    color: var(--text-main);
    font-weight: 700;
    padding: 12px 15px;
    text-align: left;
    border-bottom: 2px solid #e2e8f0;
}

.rules-table td {
    padding: 15px;
    border-bottom: 1px solid var(--border-color);
    vertical-align: middle;
    color: var(--text-main);
}

.rules-table tr:last-child td {
    border-bottom: none;
}

.rules-table tr:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

body[data-theme="dark"] .rules-table tr:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

@media (prefers-color-scheme: dark) {
    body:not([data-theme="light"]) .rules-table tr:hover {
        background-color: rgba(255, 255, 255, 0.05);
    }
}

.mol-mini {
    width: 260px;
    height: 140px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.03);
    border-radius: 8px;
    padding: 10px;
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.mol-mini svg {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.info-page-container h3 {
    color: var(--primary);
    border-left: 4px solid var(--primary);
    padding-left: 12px;
    margin-top: 25px;
}

/* Centered layout for question card */
#q-card .modal-actions {
    justify-content: center;
}
#q-card #open-hint-rij {
    text-align: center;
}

/* Sticky question header */
.q-sticky-header {
    position: sticky;
    top: var(--app-header-height, 70px);
    background: var(--card-bg);
    z-index: 5;
    padding-bottom: 12px;
    margin-bottom: 8px;
    border-bottom: 1px solid var(--border-color);
}

/* Intro dark mode toggle */
.intro-theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-top: 24px;
    padding-bottom: 8px;
}
.intro-theme-label {
    font-size: 0.95rem;
    color: var(--text-muted);
    font-weight: 500;
    user-select: none;
}
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 48px;
    height: 26px;
    cursor: pointer;
}
.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
    position: absolute;
}
.toggle-slider {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: var(--border-color);
    border-radius: 26px;
    transition: background-color 0.2s;
}
.toggle-slider::before {
    content: "";
    position: absolute;
    height: 18px;
    width: 18px;
    left: 4px;
    bottom: 4px;
    background-color: #fff;
    border-radius: 50%;
    transition: transform 0.2s;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
.toggle-switch input:checked + .toggle-slider {
    background-color: var(--primary);
}
.toggle-switch input:checked + .toggle-slider::before {
    transform: translateX(22px);
}

/* Easter egg: chemistry joke trigger */
@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50%       { transform: translateY(5px); }
}

.joke-hint-label {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 6px;
    display: flex;
    align-items: center;
    gap: 4px;
}

.joke-arrow {
    display: inline-block;
    animation: bounce 1.4s ease-in-out infinite;
}

.feature-icon-btn {
    cursor: pointer;
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    transition: border-color 0.2s, transform 0.15s;
    padding: 0;
}
.feature-icon-btn:hover {
    border-color: var(--primary);
    transform: scale(1.08);
}

#joke-container {
    width: 100%;
    text-align: left;
}

/* Footer & Credits (Systeembreed) */
footer {
    width: 100%;
    max-width: 800px;
    margin-top: auto;
    padding: 24px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    border-top: 1px solid var(--border-color);
}

/* Home-pagina specifieke credits */
.intro-footer {
    width: 100%;
    max-width: 800px;
    margin: 48px auto 24px;
    text-align: center;
    border-top: 1px solid var(--border-color);
    padding-top: 24px;
}

.author-credits {
    font-size: 0.85rem;
    color: var(--text-muted);
}