/* ===========================
   React Native & Expo Course - Main CSS
   Mobile-first, Responsive, Accessible
   =========================== */

/* ===========================
   CSS Reset
   =========================== */
html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center, dl, dt, dd, ol, ul, li,
fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}

/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
    display: block;
}

body { line-height: 1; }
ol, ul { list-style: none; }
blockquote, q { quotes: none; }
blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; }
table { border-collapse: collapse; border-spacing: 0; }

/* ===========================
   Base Styles - Mobile First
   =========================== */

/* Use CSS Variables for easy theming */
:root {
    /* Colors */
    --primary-color: rgb(59, 130, 246);
    --primary-hover: rgb(37, 99, 235);
    --secondary-color: rgb(248, 250, 252);
    --text-color: rgb(51, 65, 85);
    --text-light: rgb(107, 114, 128);
    --border-color: rgb(226, 232, 240);
    --code-bg: #f6f8fa;
    --code-color: #383a42;

    /* Prism token colors (light) */
    --tok-comment: #6a737d;
    --tok-string:  #50a14f;
    --tok-keyword: #4078f2;
    --tok-function:#c18401;
    --tok-number:  #e45649;
    --tok-operator:#a626a4;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;

    /* Typography */
    --font-family-base: "Trebuchet MS", "Lucida Sans Unicode", "Lucida Grande", "Lucida Sans", Arial, sans-serif;
    --font-family-mono: 'Consolas', 'Monaco', 'Andale Mono', 'Ubuntu Mono', monospace;
    --line-height-base: 1.6;
    --line-height-heading: 1.2;

    /* Let native form controls adapt to dark mode automatically */
    color-scheme: light dark;
}

/* Auto dark mode (users' OS preference) */
@media (prefers-color-scheme: dark) {
    :root {
        --secondary-color: #1e1e1e;
        --text-color: #d4d4d4;
        --text-light: #a0a0a0;
        --border-color: #3e3e42;
        --code-bg: #2d2d30;
        --code-color: #d4d4d4;

        /* Token colors (dark) */
        --tok-comment: #9aa0a6;
        --tok-string:  #8bdc8b;
        --tok-keyword: #8ab4f8;
        --tok-function:#e6b673;
        --tok-number:  #ff8b8b;
        --tok-operator:#d293d2;
    }
}

/* Explicit theme override (wins over prefers-color-scheme) */
:root[data-theme="dark"] {
    --secondary-color: #1e1e1e;
    --text-color: #d4d4d4;
    --text-light: #a0a0a0;
    --border-color: #3e3e42;
    --code-bg: #2d2d30;
    --code-color: #d4d4d4;

    --tok-comment: #9aa0a6;
    --tok-string:  #8bdc8b;
    --tok-keyword: #8ab4f8;
    --tok-function:#e6b673;
    --tok-number:  #ff8b8b;
    --tok-operator:#d293d2;
}

:root[data-theme="light"] {
    /* Re-assert light tokens to force light regardless of OS */
    --secondary-color: rgb(248, 250, 252);
    --text-color: rgb(51, 65, 85);
    --text-light: rgb(107, 114, 128);
    --border-color: rgb(226, 232, 240);
    --code-bg: #f6f8fa;
    --code-color: #383a42;

    --tok-comment: #6a737d;
    --tok-string:  #50a14f;
    --tok-keyword: #4078f2;
    --tok-function:#c18401;
    --tok-number:  #e45649;
    --tok-operator:#a626a4;
}

/* Base body styles */
body {
    font-family: var(--font-family-base);
    font-size: 16px;
    line-height: var(--line-height-base);
    color: var(--text-color);
    background-color: var(--secondary-color);
    margin: 0;
    padding: var(--spacing-md);
    transition: background-color 0.3s, color 0.3s;

    /* iOS safe-area padding bottom for interactive pages */
    padding-bottom: calc(var(--spacing-md) + env(safe-area-inset-bottom));
}

/* Improve wrapping on small screens */
p, li, figcaption, blockquote { overflow-wrap: anywhere; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Responsive container helper */
.responsive-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===========================
   Typography
   =========================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: bold;
    line-height: var(--line-height-heading);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    color: var(--text-color);
}

h1 {
    font-size: 2rem;
    text-align: center;
    padding: var(--spacing-lg);
    background-color: var(--primary-color);
    color: white;
    margin: 0 0 var(--spacing-xl) 0;
    border-radius: 8px;
}

h2 {
    font-size: 1.75rem;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: var(--spacing-sm);
}

h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem; }

p { margin-bottom: var(--spacing-md); }
strong, b { font-weight: bold; }
em, i { font-style: italic; }
small { font-size: 0.875rem; }

/* Links */
a {
    color: var(--primary-color);
    text-decoration: underline;
    text-underline-offset: 2px;
    text-decoration-thickness: from-font;
    transition: color 0.2s, text-decoration-thickness 0.2s;
}

a:hover {
    color: var(--primary-hover);
    text-decoration-thickness: 3px;
}

a:focus-visible,
button:focus-visible,
[role="button"]:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* Lists */
ul, ol { margin: var(--spacing-md) 0; padding-left: var(--spacing-xl); }
ul { list-style-type: disc; }
ol { list-style-type: decimal; }
li { margin-bottom: var(--spacing-sm); }
ul ul, ol ol, ul ol, ol ul { margin-top: var(--spacing-sm); margin-bottom: var(--spacing-sm); }

/* ===========================
   Code and Pre
   =========================== */

code, pre {
    font-family: var(--font-family-mono);
    background-color: var(--code-bg);
    color: var(--code-color);
    border-radius: 4px;
}

code {
    padding: 0.2em 0.4em;
    font-size: 0.9em;
}

pre {
    padding: var(--spacing-md);
    overflow-x: auto;
    line-height: 1.5;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin: var(--spacing-md) 0;
    white-space: pre; /* keep code formatting */
}

pre code {
    padding: 0;
    background: transparent;
    font-size: 0.875rem;
}

/* Syntax highlighting classes (Prism.js compatible) via variables */
.token.comment,
.token.prolog,
.token.doctype,
.token.cdata { 
    color: var(--tok-comment); 
    font-style: italic; 
}

.token.punctuation { color: var(--code-color); }

.token.property,
.token.tag,
.token.boolean,
.token.number,
.token.constant,
.token.symbol,
.token.deleted { color: var(--tok-number); }

.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted { color: var(--tok-string); }

.token.operator,
.token.entity,
.token.url,
.language-css .token.string,
.style .token.string { color: var(--tok-operator); }

.token.atrule,
.token.attr-value,
.token.keyword { color: var(--tok-keyword); }

.token.function,
.token.class-name { color: var(--tok-function); }

.token.regex,
.token.important,
.token.variable { color: var(--tok-number); }

/* Line numbers for code blocks */
.line-numbers {
    position: relative;
    padding-left: 3.8em;
    counter-reset: linenumber;
}

.line-numbers > code {
    position: relative;
    white-space: inherit;
}

.line-numbers .line-numbers-rows {
    position: absolute;
    pointer-events: none;
    top: 0;
    font-size: 100%;
    left: -3.8em;
    width: 3em;
    letter-spacing: -1px;
    border-right: 1px solid var(--border-color);
    user-select: none;
}

.line-numbers-rows > span {
    display: block;
    counter-increment: linenumber;
}

.line-numbers-rows > span:before {
    content: counter(linenumber);
    color: var(--text-light);
    display: block;
    padding-right: 0.8em;
    text-align: right;
}

/* ===========================
   Tables (semantic, scroll wrapper)
   =========================== */

/* Use a wrapper for horizontal scroll instead of display:block on table */
.table-wrap { overflow-x: auto; }

table {
    width: 100%;
    margin: var(--spacing-md) 0;
    border-collapse: collapse;
}

th, td {
    padding: var(--spacing-sm);
    text-align: left;
    border: 1px solid var(--border-color);
}

th {
    background-color: var(--primary-color);
    color: white;
    font-weight: bold;
}

tr:nth-child(even) { background-color: rgba(0, 0, 0, 0.02); }

/* ===========================
   Blockquotes
   =========================== */

blockquote {
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: rgba(59, 130, 246, 0.05);
    border-left: 4px solid var(--primary-color);
    border-radius: 0 8px 8px 0;
    font-style: italic;
}

/* ===========================
   Images and Media
   =========================== */

img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: var(--spacing-md) auto;
    border-radius: 8px;
}

figure { margin: var(--spacing-lg) 0; text-align: center; }
figcaption { margin-top: var(--spacing-sm); font-size: 0.9rem; color: var(--text-light); }

/* Caption for diagrams and visualizations */
.caption {
    text-align: center;
    font-size: 0.9rem;
    color: var(--text-light);
    margin-top: var(--spacing-sm);
}

/* ===========================
   Canvas and SVG Wrappers
   =========================== */

.canvas-wrapper, .svg-wrapper {
    position: relative;
    width: 100%;
    max-width: 700px;
    margin: 20px auto;
    background: var(--code-bg);
    border-radius: 8px;
    padding: 10px;
}

.responsive-svg {
    width: 100%;
    height: auto;
    display: block;
}

/* Mobile diagram fallback note */
.mobile-diagram-note {
    display: none;
    padding: 15px;
    background: rgba(59, 130, 246, 0.1);
    border-radius: 5px;
    text-align: center;
    color: var(--text-color);
    margin: 20px 10px;
}

/* ===========================
   Navigation
   =========================== */

nav {
    background-color: white;
    border-bottom: 1px solid var(--border-color);
    padding: calc(var(--spacing-md) + env(safe-area-inset-top)) var(--spacing-md) var(--spacing-md);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative; /* for absolutely positioned mobile menu */
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: var(--spacing-lg);
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover { color: var(--primary-color); }

/* Mobile menu toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--primary-color);
}

/* ===========================
   Cards and Components
   =========================== */

.card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-lg);
    margin: var(--spacing-md) 0;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    transition: box-shadow 0.3s;
}

.card:hover { box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1); }
.lesson-card { border-left: 4px solid var(--primary-color); }

.exercise-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
}
.exercise-card h3 { color: white; }

/* Enhanced Exercise Cards */
.exercise-card-enhanced {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin: 20px 0;
    overflow: hidden;
    background: white;
}

.exercise-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px;
    background: var(--code-bg);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 10px;
}

.exercise-header h3 {
    margin: 0;
    padding: 0;
    background: none;
    color: var(--text-color);
    border: none;
}

.difficulty-badge {
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: bold;
}

.difficulty-badge.easy {
    background: #d4edda;
    color: #155724;
}

.difficulty-badge.medium {
    background: #fff3cd;
    color: #856404;
}

.difficulty-badge.hard {
    background: #f8d7da;
    color: #721c24;
}

.time-estimate {
    font-size: 12px;
    color: var(--text-light);
}

.exercise-body {
    padding: 15px;
}

.exercise-actions {
    padding: 15px;
    background: var(--code-bg);
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.exercise-actions button {
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    background: white;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.exercise-actions button:hover {
    background: var(--code-bg);
    border-color: var(--primary-color);
}

/* Reading time indicator */
.reading-time {
    display: inline-block;
    padding: 5px 10px;
    background: rgba(59, 130, 246, 0.1);
    border-radius: 20px;
    font-size: 14px;
    color: var(--text-color);
    margin: 10px 0;
}

.reading-time::before {
    content: "⏱️ ";
    margin-right: 5px;
}

/* ===========================
   Buttons
   =========================== */

.button, button {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.button:hover, button:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.button:active, button:active { transform: translateY(0); }

.button-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.button-secondary:hover {
    background-color: var(--primary-color);
    color: white;
}

/* ===========================
   Forms
   =========================== */

input, textarea, select {
    width: 100%;
    padding: var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.2s;
    background: inherit;
    color: inherit;
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

label { display: block; margin-bottom: var(--spacing-xs); font-weight: 500; }

/* ===========================
   Utility Classes
   =========================== */

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

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }
.flex { display: flex; }
.grid { display: grid; }

/* Screen reader only */
.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;
}

/* ===========================
   Skip to main content
   =========================== */

.skip-to-main {
    position: absolute;
    left: -10000px;
    top: 30px;
    z-index: 999;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 0 5px 5px 0;
}
.skip-to-main:focus { left: 0; }

/* ===========================
   Lesson Navigation
   =========================== */

.lesson-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: var(--spacing-xxl) 0;
    padding: var(--spacing-lg);
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.lesson-nav a {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: background-color 0.3s;
    font-weight: bold;
}

.lesson-nav a:hover { background: var(--primary-hover); }

.lesson-nav .home-link {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.lesson-nav .home-link:hover {
    background: var(--primary-color);
    color: white;
}

/* ===========================
   Breadcrumb Navigation
   =========================== */

.breadcrumb { padding: var(--spacing-md) 0; font-size: 0.9rem; }

.breadcrumb ul {
    display: flex;
    list-style: none;
    padding: 0;
    margin: 0;
    flex-wrap: wrap;
}

.breadcrumb li::after {
    content: "/";
    margin: 0 var(--spacing-sm);
    color: var(--text-light);
}

.breadcrumb li:last-child::after { content: ""; }

.breadcrumb a { color: var(--primary-color); text-decoration: none; }
.breadcrumb [aria-current="page"] { color: var(--text-color); font-weight: 500; }

/* ===========================
   Module Cards for Index Page
   =========================== */

.module-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-lg);
    margin: var(--spacing-md) 0;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.module-card h3 {
    margin-top: 0;
    color: var(--primary-color);
    border-bottom: none;
}

.module-card ul {
    margin-bottom: 0;
}

.module-card a {
    text-decoration: none;
}

.module-card a:hover {
    text-decoration: underline;
}

/* ===========================
   Responsive Design
   =========================== */

/* Tablet styles */
@media (min-width: 768px) {
    body { padding: var(--spacing-lg); }
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    .container { padding: 0 var(--spacing-lg); }

    /* Grid for cards on larger screens */
    .card-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
        gap: var(--spacing-lg);
    }
}

/* Desktop styles */
@media (min-width: 1024px) {
    body { padding: var(--spacing-xl); }
    h1 { font-size: 3rem; }
    .container { padding: 0 var(--spacing-xl); }
}

/* Mobile-specific adjustments */
@media (max-width: 767px) {
    /* Show mobile menu toggle */
    .mobile-menu-toggle { display: block; }

    /* Hide nav links by default on mobile, use [hidden] for AX-friendly state */
    .nav-links[hidden] { display: none; }
    .nav-links {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        border-top: 1px solid var(--border-color);
        flex-direction: column;
        padding: var(--spacing-md);
    }

    /* Stack lesson navigation vertically */
    .lesson-nav { flex-direction: column; }
    .lesson-nav a { width: 100%; text-align: center; }

    /* Adjust table text for mobile */
    table { font-size: 0.875rem; }

    /* Reduce heading sizes on mobile */
    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.25rem; }

    /* Show mobile diagram note when needed */
    .mobile-diagram-note.active { display: block; }
}

/* ===========================
   Print Styles
   =========================== */

@media print {
    body { background: white; color: black; }

    nav, .lesson-nav, .skip-to-main,
    .mobile-menu-toggle, .copy-button, button { display: none !important; }

    h1, h2, h3, h4, h5, h6 {
        background: none !important;
        color: black !important;
        page-break-after: avoid;
    }

    a { color: black; text-decoration: underline; }
    pre { page-break-inside: avoid; border: 1px solid #ccc; }
    img { page-break-inside: avoid; }
}

/* ===========================
   Accessibility Features
   =========================== */

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #0052cc;
        --text-color: #000;
        --secondary-color: #fff;
        --border-color: #000;
    }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* Focus visible for keyboard nav (reinforced) */
.keyboard-nav *:focus {
    outline: 3px solid var(--primary-color) !important;
    outline-offset: 2px !important;
}

/* ===========================
   Dark Mode Surface Tweaks
   =========================== */

@media (prefers-color-scheme: dark) {
    nav, .card, .lesson-nav, .module-card, .exercise-card-enhanced { background: #2d2d30; }
    th { background-color: #2d53a3; }
    .exercise-card {
        background: linear-gradient(135deg, #3b5bb5 0%, #5a3f86 100%);
    }
    .exercise-header, .exercise-actions { background: #252526; }
}

:root[data-theme="dark"] {
    nav, .card, .lesson-nav, .module-card, .exercise-card-enhanced { background: #2d2d30; }
    th { background-color: #2d53a3; }
    .exercise-card {
        background: linear-gradient(135deg, #3b5bb5 0%, #5a3f86 100%);
    }
    .exercise-header, .exercise-actions { background: #252526; }
}

/* ===========================
   Custom Scrollbar
   =========================== */

/* WebKit */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--secondary-color); }
::-webkit-scrollbar-thumb { background: var(--primary-color); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-hover); }

/* Firefox */
* { scrollbar-width: thin; scrollbar-color: var(--primary-color) var(--secondary-color); }

/* ===========================
   Touch UX polish
   =========================== */
* { -webkit-tap-highlight-color: rgba(0,0,0,0.1); }

/* ===========================
   Quiz Styles
   =========================== */

.quiz-container {
    margin: var(--spacing-lg) 0;
}

.quiz-question {
    margin-bottom: var(--spacing-lg);
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.quiz-option {
    text-align: left;
    padding: var(--spacing-md);
    background: var(--code-bg);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.quiz-option:hover {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.05);
}

.quiz-option.selected {
    border-color: var(--primary-color);
}

.quiz-option.correct {
    border-color: #4CAF50;
    background: #e8f5e9;
}

.quiz-option.incorrect {
    border-color: #f44336;
    background: #ffebee;
}

.quiz-feedback {
    margin-top: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 4px;
    font-weight: 500;
}

.quiz-feedback.correct {
    background: #e8f5e9;
    color: #2e7d32;
}

.quiz-feedback.incorrect {
    background: #ffebee;
    color: #c62828;
}