:root {
    /* Color Palette - Cyberpunk / Dark Mode (Default) */
    --bg-primary: 240, 20%, 10%;
    --bg-secondary: 240, 20%, 15%;
    --text-primary: 0, 0%, 100%;
    --text-secondary: 240, 10%, 70%;
    --accent-primary: 215, 90%, 60%;
    /* Blue */
    --accent-secondary: 170, 80%, 50%;
    /* Teal */
    --accent-tertiary: 35, 95%, 60%;
    /* Orange */

    /* Effects */
    --glass-bg: rgba(25, 25, 35, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --card-radius: 16px;
    --transition-speed: 0.3s;
    /* Colors (Solid) */
    --bg-dark: 230 25% 10%;
    --bg-light: 220 50% 95%;
    --text-primary: 0 0% 100%;
    --text-secondary: 220 20% 80%;
    --accent-primary: 215 90% 60%;
    /* Solid Blue */
    --accent-secondary: 170 80% 50%;
    /* Solid Teal */
    --accent-tertiary: 35 95% 60%;
    /* Solid Orange */

    --glass-bg: 230 25% 15%;
    /* Slightly opaque for glass */
    --glass-border: 255 255 255;

    --transition-speed: 0.3s;
}

[data-theme="light"] {
    --bg-dark: 220 50% 95%;
    --text-primary: 230 25% 10%;
    --text-secondary: 220 20% 40%;
    --glass-bg: 255 255 255;
    --glass-border: 0 0 0;
}

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

body {
    background-color: hsl(var(--bg-dark));
    color: hsl(var(--text-primary));
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

/* Background Grids */
.grid-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: 50px 50px;
    background-image:
        linear-gradient(to right, hsla(var(--glass-border), 0.05) 1px, transparent 1px),
        linear-gradient(to bottom, hsla(var(--glass-border), 0.05) 1px, transparent 1px);
    z-index: -2;
    mask-image: linear-gradient(to bottom, black 40%, transparent 100%);
    -webkit-mask-image: linear-gradient(to bottom, black 40%, transparent 100%);
}

#particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
}

.particle {
    position: absolute;
    background: white;
    border-radius: 50%;
    opacity: 0.3;
    animation: float var(--duration) ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-20px);
    }
}

/* Typography */
h1,
h2,
h3,
h4,
.module-section {
    font-weight: 800;
    margin-bottom: 1rem;
    scroll-margin-top: 120px;
    /* Account for Sticky Header */
}

h1 {
    font-size: 3.5rem;
    color: hsl(var(--text-primary));
    /* Solid color */
    letter-spacing: -0.05rem;
    background: none;
    -webkit-text-fill-color: initial;
}

h2 {
    font-size: 2.5rem;
    color: hsl(var(--accent-secondary));
    /* Solid color */
    margin-top: 3rem;
    background: none;
    -webkit-text-fill-color: initial;
}

h3 {
    font-size: 1.5rem;
    color: hsl(var(--accent-primary));
    /* Solid color */
}

p,
li {
    font-size: 1.1rem;
    color: hsl(var(--text-secondary));
    margin-bottom: 1rem;
}

a {
    color: hsl(var(--accent-primary));
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: hsl(var(--accent-secondary));
    text-decoration: underline;
}

/* Layout */
.app-container {
    display: flex;
    max-width: 1800px;
    /* Widened from 1400px */
    width: 95%;
    /* Take up more space */
    margin: 80px auto 0;
    padding: 0 1rem;
    /* Reduced padding */
    gap: 1.5rem;
    transition: all 0.3s ease;
}

.main-content {
    flex: 1;
    padding: 2rem;
    max-width: 100%;
    transition: margin-left 0.3s ease;
}

/* Sidebar */
.sidebar {
    width: 280px;
    position: sticky;
    top: 100px;
    height: calc(100vh - 120px);
    overflow-y: auto;
    background: hsla(var(--glass-bg), 0.6);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid hsla(var(--glass-border), 0.1);
    border-radius: 16px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    transition: width 0.3s ease, padding 0.3s ease, opacity 0.3s ease;
}

.sidebar.collapsed {
    width: 0;
    padding: 0;
    overflow: hidden;
    opacity: 0;
    border: none;
}

/* Sidebar Toggle Button */
.sidebar-toggle {
    position: static;
    background: transparent;
    color: hsl(var(--accent-primary));
    border: 1px solid hsla(var(--glass-border), 0.2);
    width: 40px;
    height: 40px;
    border-radius: 8px;
    font-size: 1.1rem;
    cursor: pointer;
    box-shadow: none;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.sidebar-toggle:hover {
    background: hsla(var(--accent-primary), 0.1);
    border-color: hsl(var(--accent-primary));
    transform: translateY(-1px);
}


@media (min-width: 1024px) {
    .sidebar {
        display: flex;
    }
}



.nav-link:active {
    transform: translateY(4px);
    box-shadow: none;
    top: 0;
}

.toc-link {
    display: block;
    padding: 0.5rem 1rem;
    color: hsl(var(--text-secondary));
    text-decoration: none;
    border-radius: 8px;
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.toc-link:hover,
.toc-link.active {
    background: hsla(var(--accent-primary), 0.1);
    color: hsl(var(--accent-primary));
}

.toc-link.active {
    border-left-color: hsl(var(--accent-primary));
}

/* Timer Controls */
.timer-box {
    text-align: center;
    padding: 1rem;
    background: hsla(var(--glass-border), 0.05);
    border-radius: 12px;
}

/* Flip Clock Styles */
.flip-clock {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin: 1rem 0;
    font-family: 'Fira Code', monospace;
    font-weight: 700;
}

.flip-unit {
    position: relative;
    width: 40px;
    height: 50px;
    font-size: 1.8rem;
    line-height: 50px;
    text-align: center;
    background: hsl(var(--bg-dark));
    color: hsl(var(--accent-secondary));
    border-radius: 6px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}

.flip-colon {
    font-size: 1.8rem;
    line-height: 50px;
    color: hsl(var(--text-secondary));
}

.flip-card {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 6px;
    perspective: 1000px;
}

.top,
.bottom,
.top-flip,
.bottom-flip {
    position: absolute;
    left: 0;
    width: 100%;
    height: 50%;
    overflow: hidden;
    background: hsl(var(--bg-dark));
    color: hsl(var(--accent-secondary));
    border: 1px solid hsla(var(--glass-border), 0.1);
}

.top,
.top-flip {
    top: 0;
    border-radius: 6px 6px 0 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.5);
    transform-origin: bottom;
}

.bottom,
.bottom-flip {
    bottom: 0;
    border-radius: 0 0 6px 6px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    transform-origin: top;
    line-height: 0;
    /* Align text for bottom half */
}

/* Pseudo-elements for glossy effect */
.top::before,
.top-flip::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, rgba(255, 255, 255, 0.1) 0%, transparent 100%);
}

.top-flip {
    z-index: 2;
    transform: rotateX(0deg);
}

.bottom-flip {
    z-index: 1;
    transform: rotateX(90deg);
}

.flip-animate .top-flip {
    animation: flip-top 0.3s ease-in forwards;
}

.flip-animate .bottom-flip {
    animation: flip-bottom 0.3s ease-out 0.3s forwards;
}

@keyframes flip-top {
    100% {
        transform: rotateX(-90deg);
    }
}

@keyframes flip-bottom {
    0% {
        transform: rotateX(90deg);
    }

    100% {
        transform: rotateX(0deg);
    }
}

.mobile-nav-menu {
    display: none;
}

@media (max-width: 768px) {

    .mobile-nav-menu,
    .progress-box,
    .timer-box {
        display: none !important;
    }

    /* Light Mode Sidebar Contrast Fix */
    [data-theme="light"] .sidebar {
        background: #ffffff !important;
        border-right: 1px solid rgba(0, 0, 0, 0.1);
    }

    [data-theme="light"] .toc-link {
        color: hsl(var(--text-primary)) !important;
        font-weight: 600;
    }

    /* Ensure only visible on mobile */
    /* Ensure only visible on mobile */
    .app-container {
        flex-direction: column;
        margin-top: 50px;
        /* Reduced margin */
        width: 100% !important;
        /* Force full width */
        padding: 0 !important;
        /* Remove container padding */
        max-width: 100% !important;
    }

    /* Sidebar: Default Hidden on Mobile */
    .sidebar {
        position: fixed;
        left: 0;
        top: 60px;
        /* Match header height */
        height: calc(100vh - 60px);
        width: 80%;
        max-width: 280px;
        z-index: 1000;
        transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        background: hsla(var(--glass-bg), 0.98);
        /* Higher opacity */
        transform: translateX(-110%);
        /* Hidden by default */
        border-right: 1px solid hsla(var(--glass-border), 0.2);
    }

    /* Active class to show sidebar */
    .sidebar.active {
        transform: translateX(0);
        box-shadow: 10px 0 30px rgba(0, 0, 0, 0.3);
    }

    /* Overlay */
    .sidebar-overlay {
        display: block;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(0, 0, 0, 0.5);
        z-index: 999;
        backdrop-filter: blur(2px);
        opacity: 0;
        pointer-events: none;
        /* Interact only when active */
        transition: opacity 0.3s;
    }

    .sidebar.active+.sidebar-overlay {
        opacity: 1;
        pointer-events: auto;
    }

    /* Content Spacing Optimization (Ultra-Low) */
    .main-content {
        padding: 0.25rem;
        /* Ultra minimal padding */
        margin-left: 0 !important;
    }

    .glass-card {
        padding: 0.8rem;
        /* Tight card padding */
        margin-bottom: 0.5rem;
        border-radius: 12px;
    }

    /* Header */
    .nav-brand .logo {
        font-size: 1.1rem;
    }

    .nav-links {
        display: none;
    }

    /* Typography Adjustments */
    h1 {
        font-size: 1.5rem !important;
        margin-bottom: 0.5rem;
    }

    h2 {
        font-size: 1.2rem !important;
        margin-bottom: 0.5rem;
    }

    h3 {
        font-size: 1.1rem !important;
        margin-bottom: 0.5rem;
    }

    p {
        font-size: 0.95rem;
        line-height: 1.5;
        margin-bottom: 0.8rem;
    }

    /* Accordion Summary Font */
    details.accordion summary {
        font-size: 1rem !important;
        padding: 0.6rem 0.8rem;
    }

    /* Terminal Font */
    .terminal-window pre,
    .code-block pre {
        font-size: 0.8rem;
        padding: 0.8rem;
    }
}

.timer-controls {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    margin-top: 1rem;
}

.btn-timer {
    background: hsl(var(--accent-primary));
    color: white;
    border: none;
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 0 3px 0 hsl(215, 100%, 45%);
    transition: all 0.1s;
}

.btn-timer:hover {
    transform: translateY(-1px);
}

.btn-timer:active {
    transform: translateY(3px);
    box-shadow: none;
}

.timer-display {
    font-family: 'Fira Code', monospace;
    font-size: 2rem;
    font-weight: 700;
    color: hsl(var(--accent-secondary));
}

/* Navigation */
.glass-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: hsla(var(--glass-bg), 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid hsla(var(--glass-border), 0.1);
    z-index: 1000;
    padding: 1rem 0;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.logo {
    font-family: 'Fira Code', monospace;
    font-weight: 700;
    font-size: 1.5rem;
    color: hsl(var(--accent-primary));
    /* Solid Color */
    text-decoration: none;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-link {
    display: inline-block;
    padding: 0.5rem 1rem;
    margin: 0 0.25rem;
    color: white;
    background-color: hsl(var(--accent-primary));
    /* Solid Color */
    text-decoration: none;
    font-weight: 700;
    border-radius: 8px;
    box-shadow: 0 4px 0 hsl(215, 100%, 45%);
    /* Darker shade solid shadow */
    transition: all 0.1s;
    border: none;
    position: relative;
    top: 0;
}

.nav-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 0 hsl(215, 100%, 45%);
    filter: brightness(1.1);
}

.nav-link:active {
    transform: translateY(4px);
    box-shadow: none;
    top: 0;
}

/* Hero Button */
.btn-glow {
    display: inline-block;
    padding: 1rem 2rem;
    background-color: hsl(var(--accent-tertiary));
    /* Solid Pink */
    background-image: none;
    color: white;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 700;
    transition: all 0.1s;
    box-shadow: 0 6px 0 hsl(35, 100%, 45%);
    /* Solid Shadow */
    position: relative;
    top: 0;
}

.btn-glow:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 0 hsl(35, 100%, 45%);
}

.btn-glow:active {
    transform: translateY(4px);
    box-shadow: none;
    top: 0;
}

/* Instructor / Social Section */
.social-links {
    margin: 3rem 0;
    padding: 2rem;
    background: hsla(var(--glass-bg), 0.4);
    backdrop-filter: blur(12px);
    border: 1px solid hsla(var(--glass-border), 0.1);
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.social-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.social-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    border: 3px solid hsl(var(--accent-secondary));
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    transition: transform 0.3s;
    background: hsl(var(--glass-bg));
}

.social-avatar:hover {
    transform: scale(1.05) rotate(5deg);
}

.social-name {
    font-size: 1.5rem;
    font-weight: 800;
    color: hsl(var(--text-primary));
}

.social-links-wrapper {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

.social-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    color: white;
    transition: all 0.1s;
    box-shadow: 0 4px 0 rgba(0, 0, 0, 0.2);
    position: relative;
    top: 0;
}

.social-link i {
    font-size: 1.1rem;
}

.social-link-youtube {
    background-color: #ff0000;
    box-shadow: 0 4px 0 #cc0000;
}

.social-link-facebook {
    background-color: #1877f2;
    box-shadow: 0 4px 0 #0d65d9;
}

.social-link-threads {
    background-color: #ffffff;
    color: #000000;
    box-shadow: 0 4px 0 #cccccc;
    border: none;
}

.social-link-threads:hover {
    box-shadow: 0 6px 0 #cccccc;
    color: #000000;
}

.social-link:active {
    transform: translateY(4px);
    box-shadow: none !important;
    top: 0;
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: hsl(var(--text-primary));
    font-size: 1.2rem;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background 0.2s;
}

.theme-toggle:hover {
    background: hsla(var(--text-primary), 0.1);
}

.nav-icon-link {
    background: none;
    border: none;
    cursor: pointer;
    color: hsl(var(--text-primary));
    font-size: 1.2rem;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background 0.2s, color 0.2s;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
}

.nav-icon-link:hover {
    background: hsla(var(--text-primary), 0.1);
    color: hsl(var(--accent-primary));
    text-decoration: none;
}

/* Hero Section */
.hero {
    min-height: 80vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 2rem;
}

.hero p {
    max-width: 600px;
    margin: 1.5rem auto;
}

.btn-glow {
    display: inline-block;
    padding: 1rem 2.5rem;
    background: linear-gradient(90deg, hsl(var(--accent-primary)), hsl(var(--accent-secondary)));
    color: white;
    font-weight: 700;
    text-decoration: none;
    border-radius: 50px;
    box-shadow: 0 0 20px hsla(var(--accent-primary), 0.5);
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-glow:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 40px hsla(var(--accent-primary), 0.7);
}

/* Content Modules - 3D Card Effect */
.module-section {
    padding: 4rem 0;
    min-height: 80vh;
}

.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: var(--card-radius);
    padding: 2.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--glass-shadow);
    transition: transform 0.1s ease, box-shadow 0.3s ease;
    /* Fast transform for mouse move */
    transform-style: preserve-3d;
    perspective: 1000px;
}

.glass-card:hover {
    border-color: hsla(var(--accent-secondary), 0.3);
}

/* Code Blocks */
pre {
    background: hsl(var(--bg-dark) / 0.8);
    padding: 1.5rem;
    border-radius: 8px;
    overflow-x: auto;
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    border: 1px solid var(--glass-border);
    margin: 1rem 0;
    position: relative;
}

pre::before {
    content: attr(data-lang);
    position: absolute;
    top: 0.5rem;
    right: 0.8rem;
    font-size: 0.7rem;
    color: hsl(var(--text-secondary));
    text-transform: uppercase;
    opacity: 0.5;
    right: 2.5rem;
    /* Make room for copy button */
}

/* Code Copy Button */
.code-wrapper {
    position: relative;
    margin: 1rem 0;
}

.code-wrapper pre {
    margin: 0;
}

.copy-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: hsla(var(--glass-bg), 0.8);
    border: 1px solid hsla(var(--glass-border), 0.3);
    color: hsl(var(--text-secondary));
    width: 28px;
    height: 28px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s ease;
    z-index: 10;
    opacity: 0;
}

.code-wrapper:hover .copy-btn {
    opacity: 1;
}

.copy-btn:hover {
    background: hsl(var(--accent-primary));
    color: white;
    border-color: hsl(var(--accent-primary));
}

.copy-btn.copied {
    background: hsl(150, 60%, 40%);
    color: white;
    border-color: hsl(150, 60%, 40%);
}

code {
    font-family: 'Fira Code', monospace;
    color: hsl(var(--accent-secondary));
}

/* Collapsible Accordion (using <details>/<summary>) */
details.accordion {
    margin-bottom: 1rem;
    border-radius: 8px;
    background: hsla(var(--glass-bg), 0.3);
    border: 1px solid hsla(var(--glass-border), 0.1);
    overflow: hidden;
    transition: all 0.3s ease;
}

details.accordion[open] {
    background: hsla(var(--glass-bg), 0.5);
}

details.accordion summary {
    cursor: pointer;
    padding: 1rem 1.5rem;
    font-weight: 700;
    color: hsl(var(--text-primary));
    list-style: none;
    /* Hide default marker */
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.2s;
    font-size: 1.25rem;
}

details.accordion summary::-webkit-details-marker {
    display: none;
}

details.accordion summary::after {
    content: '▼';
    font-size: 0.8rem;
    color: hsl(var(--accent-primary));
    transition: transform 0.3s ease;
}

details.accordion[open] summary::after {
    transform: rotate(180deg);
}

details.accordion[open] summary {
    border-bottom: 1px solid hsl(var(--accent-primary) / 0.5);
    border-left: 5px solid hsl(var(--accent-primary));
    background: hsl(var(--accent-primary) / 0.15);
}

details.accordion summary:hover {
    background: hsl(var(--accent-primary) / 0.1);
}

details.accordion .accordion-content {
    padding: 1.5rem 1.5rem;
    color: hsl(var(--text-secondary));
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Horizontal Scan Effect */
details.accordion .accordion-content {
    position: relative;
    overflow: hidden;
    /* Ensure scan line doesn't overflow */
}

details.accordion[open] .accordion-content::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, hsl(var(--accent-primary) / 0.5), transparent);
    animation: scan-horizontal 0.6s ease-out forwards;
    pointer-events: none;
    z-index: 1;
}

@keyframes scan-horizontal {
    0% {
        left: -100%;
    }

    100% {
        left: 100%;
    }
}

/* Quiz Section */
.quiz-container {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--glass-border);
}

.quiz-question {
    margin-bottom: 2rem;
}

.quiz-question h4 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: hsl(var(--text-primary));
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.quiz-opt-btn {
    padding: 1rem;
    background: rgba(var(--bg-primary), 0.1);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: hsl(var(--text-secondary));
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
    font-family: inherit;
}

.quiz-opt-btn:hover {
    background: rgba(var(--text-primary), 0.05);
    border-color: hsl(var(--accent-secondary));
}

.quiz-opt-btn.correct {
    background: hsla(140, 70%, 50%, 0.2);
    border-color: hsl(140, 70%, 50%);
    color: hsl(140, 70%, 50%);
}

.quiz-opt-btn.incorrect {
    background: hsla(0, 70%, 50%, 0.2);
    border-color: hsl(0, 70%, 50%);
    color: hsl(0, 70%, 50%);
}

.feedback-msg {
    margin-top: 1rem;
    font-weight: 600;
    min-height: 1.6rem;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    border-top: 1px solid var(--glass-border);
    margin-top: 2rem;
}