/* ===== NATUMEX 2.0 - Premium CSS ===== */

/* ===== CSS Variables ===== */
:root {
    /* Mexican Colors - Enhanced */
    --green-primary: #006847;
    --green-light: #00a86b;
    --green-dark: #004d36;
    --green-neon: #00ff88;
    --red-primary: #ce1126;
    --red-light: #e63946;
    --red-dark: #a30d1e;
    --white: #ffffff;
    --gold: #ffd700;
    --gold-dark: #b8860b;

    /* Neutral Colors */
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;

    /* Theme Colors - Light */
    --bg-primary: #fafbfc;
    --bg-secondary: #f0f4f8;
    --bg-card: rgba(255, 255, 255, 0.95);
    --bg-glass: rgba(255, 255, 255, 0.7);
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --text-muted: #9ca3af;
    --border-color: rgba(0, 0, 0, 0.08);

    /* Premium Gradients */
    --gradient-mexican: linear-gradient(135deg, var(--green-primary) 0%, var(--green-light) 50%, var(--red-primary) 100%);
    --gradient-green: linear-gradient(135deg, var(--green-dark) 0%, var(--green-light) 100%);
    --gradient-red: linear-gradient(135deg, var(--red-dark) 0%, var(--red-light) 100%);
    --gradient-gold: linear-gradient(135deg, var(--gold-dark) 0%, var(--gold) 100%);
    --gradient-aurora: linear-gradient(-45deg, #006847, #00a86b, #004d36, #00ff88, #006847);
    --gradient-aurora-size: 400% 400%;
    --gradient-glass: linear-gradient(135deg, rgba(255, 255, 255, 0.9) 0%, rgba(255, 255, 255, 0.4) 100%);

    /* Shadows - Enhanced */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow-green: 0 0 30px rgba(0, 168, 107, 0.4);
    --shadow-glow-red: 0 0 30px rgba(206, 17, 38, 0.4);
    --shadow-glow-gold: 0 0 30px rgba(255, 215, 0, 0.5);
    --shadow-inner: inset 0 2px 4px rgba(0, 0, 0, 0.06);

    /* Typography */
    --font-family: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    --font-size-6xl: 3.75rem;

    /* Spacing */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.25rem;
    --radius-2xl: 1.5rem;
    --radius-3xl: 2rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* ===== Dark Theme - Premium ===== */
[data-theme="dark"] {
    --bg-primary: #0a0f1a;
    --bg-secondary: #111827;
    --bg-card: rgba(17, 24, 39, 0.95);
    --bg-glass: rgba(17, 24, 39, 0.7);
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-muted: #6b7280;
    --border-color: rgba(255, 255, 255, 0.08);
    --gradient-glass: linear-gradient(135deg, rgba(30, 36, 51, 0.9) 0%, rgba(30, 36, 51, 0.4) 100%);

    /* Dark mode neon accents */
    --green-neon: #00ff88;
    --shadow-glow-green: 0 0 40px rgba(0, 255, 136, 0.3);
}

/* ===== Reset & Base ===== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    min-height: 100vh;
    transition: background-color var(--transition-slow), color var(--transition-slow);
    overflow-x: hidden;
}

/* Aurora Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-aurora);
    background-size: var(--gradient-aurora-size);
    animation: aurora 15s ease infinite;
    opacity: 0.03;
    z-index: -2;
    pointer-events: none;
}

[data-theme="dark"] body::before {
    opacity: 0.08;
}

a {
    text-decoration: none;
    color: inherit;
}

button {
    font-family: inherit;
    color: inherit;
    cursor: pointer;
    border: none;
    background: none;
    transition: transform var(--transition-fast), background-color var(--transition-fast), box-shadow var(--transition-fast);
}

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

img {
    max-width: 100%;
    height: auto;
}

/* ===== Container ===== */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-6);
}

/* ===== Header - Glassmorphism ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition-base);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    font-size: var(--font-size-xl);
    font-weight: 800;
    transition: transform var(--transition-fast);
}

.logo:hover {
    transform: scale(1.02);
}

.logo-icon {
    font-size: 1.75rem;
    animation: float 4s ease-in-out infinite;
}

.logo-text {
    background: var(--gradient-mexican);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientText 3s ease infinite;
}

.nav {
    display: flex;
    gap: var(--spacing-8);
}

.nav-link {
    font-weight: 600;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
    position: relative;
    padding: var(--spacing-2) 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--gradient-mexican);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
    transform: translateX(-50%);
}

.nav-link:hover {
    color: var(--green-primary);
}

.nav-link:hover::after {
    width: 100%;
}

.theme-toggle {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-xl);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    background: var(--bg-card);
    transform: rotate(20deg) scale(1.05);
    box-shadow: var(--shadow-glow-green);
}

/* ===== Hero Section - Premium ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 72px;
    position: relative;
    overflow: hidden;
    background: var(--bg-secondary);
}

/* Aurora orbs background */
.hero::before,
.hero::after {
    content: '';
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.5;
    z-index: 0;
    animation: auroraShift 8s ease-in-out infinite;
}

.hero::before {
    width: 600px;
    height: 600px;
    background: var(--green-primary);
    top: -200px;
    left: -200px;
    opacity: 0.15;
}

.hero::after {
    width: 500px;
    height: 500px;
    background: var(--red-primary);
    bottom: -150px;
    right: -150px;
    opacity: 0.1;
    animation-delay: 4s;
}

.hero .container {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-12);
    padding-top: var(--spacing-12);
    padding-bottom: var(--spacing-12);
}

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

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-2) var(--spacing-5);
    background: var(--gradient-green);
    color: white;
    font-size: var(--font-size-sm);
    font-weight: 600;
    border-radius: var(--radius-full);
    margin-bottom: var(--spacing-8);
    box-shadow: var(--shadow-glow-green);
    animation: pulseGlow 3s ease-in-out infinite;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, var(--font-size-6xl));
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: var(--spacing-6);
    letter-spacing: -0.02em;
}

.gradient-text {
    background: var(--gradient-mexican);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientText 4s ease infinite;
}

.hero-description {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    max-width: 640px;
    margin: 0 auto var(--spacing-10);
    line-height: 1.7;
}

/* Stats with glass effect */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-6);
    margin-bottom: var(--spacing-10);
}

.stat {
    text-align: center;
    padding: var(--spacing-4) var(--spacing-6);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    min-width: 100px;
    transition: all var(--transition-fast);
}

.stat:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    display: block;
    font-size: var(--font-size-3xl);
    font-weight: 800;
    background: var(--gradient-green);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
    font-weight: 500;
}

.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-4);
    justify-content: center;
}

/* Floating decoration */
.hero-decoration {
    display: none;
    position: relative;
    min-height: 450px;
}

.floating-card {
    position: absolute;
    font-size: 2.5rem;
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    padding: var(--spacing-5);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-xl);
    animation: float 6s ease-in-out infinite;
    transition: all var(--transition-fast);
}

.floating-card:hover {
    transform: scale(1.1) rotate(5deg);
    box-shadow: var(--shadow-2xl);
}

.card-1 {
    top: 5%;
    left: 10%;
    animation-delay: 0s;
}

.card-2 {
    top: 15%;
    right: 5%;
    animation-delay: 1s;
}

.card-3 {
    top: 50%;
    left: 0%;
    animation-delay: 2s;
}

.card-4 {
    bottom: 20%;
    right: 15%;
    animation-delay: 1.5s;
}

.card-5 {
    bottom: 5%;
    left: 20%;
    animation-delay: 0.5s;
}

/* ===== Buttons - Premium ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-6);
    font-size: var(--font-size-base);
    font-weight: 600;
    border-radius: var(--radius-xl);
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

.btn-lg {
    padding: var(--spacing-4) var(--spacing-10);
    font-size: var(--font-size-lg);
    border-radius: var(--radius-2xl);
}

.btn-primary {
    background: var(--gradient-green);
    color: white;
    box-shadow: var(--shadow-md), var(--shadow-glow-green);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl), 0 0 40px rgba(0, 168, 107, 0.5);
}

.btn-primary:active {
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--green-primary);
    color: var(--green-primary);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.btn-icon {
    transition: transform var(--transition-fast);
}

.btn:hover .btn-icon {
    transform: translateX(4px);
}

/* ===== Dashboard Section ===== */
.dashboard-section {
    padding: var(--spacing-8) 0;
    display: none;
}

.dashboard-section.active {
    display: block;
}

.dashboard-card {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    padding: var(--spacing-6);
    margin-bottom: var(--spacing-6);
}

.dashboard-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-6);
}

.dashboard-greeting {
    font-size: var(--font-size-2xl);
    font-weight: 700;
}

.dashboard-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: var(--spacing-4);
}

.dashboard-stat {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-4);
    text-align: center;
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
}

.dashboard-stat:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Premium Select */
.premium-select {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: var(--spacing-2) var(--spacing-4);
    border-radius: var(--radius-lg);
    font-family: 'Outfit', sans-serif;
    font-size: var(--font-size-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    outline: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2300a86b'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    background-size: 16px;
    padding-right: 35px;
}

.premium-select:hover {
    border-color: var(--green-primary);
    box-shadow: 0 0 10px rgba(0, 168, 107, 0.2);
}

.premium-select:focus {
    border-color: var(--green-primary);
    box-shadow: 0 0 0 3px rgba(0, 168, 107, 0.1);
}

.empty-state {
    color: var(--text-muted);
    font-size: var(--font-size-sm);
    text-align: center;
    padding: var(--spacing-4);
    font-style: italic;
}

.dashboard-stat-icon {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-2);
}

.dashboard-stat-value {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--green-primary);
}

.dashboard-container {
    padding: var(--spacing-6);
}

.dashboard-welcome {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-8);
    gap: var(--spacing-4);
}

.dashboard-greeting {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    margin-bottom: var(--spacing-1);
    background: var(--gradient-mexican);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.motivational-message {
    color: var(--text-secondary);
    font-size: var(--font-size-lg);
}

.user-level-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    background: var(--bg-glass);
    padding: var(--spacing-3) var(--spacing-6);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
}

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

.level-info {
    display: flex;
    flex-direction: column;
}

.level-name {
    font-weight: 800;
    font-size: var(--font-size-xl);
    color: var(--green-primary);
}

.level-label {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* New Stats Grid */
.dashboard-grid-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-6);
    margin-bottom: var(--spacing-8);
}

.stat-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    background: var(--bg-card);
    padding: var(--spacing-6);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    transition: all var(--transition-bounce);
}

.stat-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: var(--green-primary);
}

.stat-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
}

.stat-content {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-size: var(--font-size-2xl);
    font-weight: 800;
    line-height: 1.2;
}

.stat-label {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
}

/* Layout Main */
.dashboard-layout-main {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-8);
}

.dashboard-col {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-8);
}

.inner-card {
    background: var(--bg-glass);
    padding: var(--spacing-6);
    border-radius: var(--radius-3xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
}

.card-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--spacing-6);
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

/* Streak Calendar Modern */
.streak-calendar-modern {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-8);
    background: var(--bg-secondary);
    padding: var(--spacing-4);
    border-radius: var(--radius-2xl);
}

.calendar-day {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-2);
}

.day-letter {
    font-size: var(--font-size-xs);
    font-weight: 700;
    color: var(--text-muted);
}

.day-dot {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background: var(--gray-200);
    transition: all var(--transition-base);
}

.calendar-day.completed .day-dot {
    background: var(--green-primary);
    box-shadow: var(--shadow-glow-green);
}

.calendar-day.today .day-dot {
    border: 2px solid var(--gold);
}

/* Progress Section Modern */
.progress-section-modern {
    margin-top: var(--spacing-4);
}

.progress-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-3);
    font-weight: 600;
}

.progress-bar-container {
    height: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.progress-bar-fill {
    height: 100%;
    background: var(--gradient-mexican);
    border-radius: var(--radius-full);
    transition: width 1s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Exam Summary */
.exam-stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-4);
    margin-bottom: var(--spacing-4);
}

.exam-stat-item {
    text-align: center;
    padding: var(--spacing-4);
    background: var(--bg-secondary);
    border-radius: var(--radius-xl);
}

.exam-stat-val {
    display: block;
    font-size: var(--font-size-2xl);
    font-weight: 800;
}

.exam-stat-lbl {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

.exam-average-banner {
    background: var(--gradient-gold);
    color: var(--green-dark);
    padding: var(--spacing-3);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-sm);
    text-align: center;
    font-weight: 600;
}

/* Knowledge Ranking */
.ranking-section {
    margin-bottom: var(--spacing-8);
}

.ranking-title {
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-4);
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
}

.ranking-title.strength {
    color: var(--green-primary);
}

.ranking-title.weak {
    color: var(--red-primary);
}

.ranking-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-4);
    padding: var(--spacing-2) 0;
}

.ranking-info {
    flex: 1;
    margin-right: var(--spacing-4);
}

.rank-name {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--spacing-2);
}

.rank-bar-mini {
    height: 6px;
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.rank-fill {
    height: 100%;
    border-radius: var(--radius-full);
}

.rank-fill.strength {
    background: var(--green-primary);
}

.rank-fill.weak {
    background: var(--red-primary);
}

.rank-pct {
    font-weight: 700;
    font-size: var(--font-size-sm);
}

@media (max-width: 1024px) {
    .dashboard-layout-main {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .dashboard-welcome {
        flex-direction: column;
        align-items: flex-start;
    }
}

.streak-calendar {
    display: flex;
    gap: var(--spacing-2);
    justify-content: center;
    padding: var(--spacing-4);
    background: var(--bg-card);
    border-radius: var(--radius-xl);
}

.streak-day {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-sm);
    font-weight: 600;
    background: var(--bg-secondary);
    color: var(--text-muted);
    transition: all var(--transition-fast);
}

.streak-day.completed {
    background: var(--gradient-green);
    color: white;
    box-shadow: var(--shadow-glow-green);
}

.streak-day.today {
    border: 2px solid var(--green-primary);
    animation: pulseGlow 2s ease-in-out infinite;
}

/* ===== Topics Section ===== */
.topics-section {
    padding: var(--spacing-20) 0;
    background: var(--bg-primary);
    position: relative;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-12);
}

.section-title {
    font-size: clamp(2rem, 5vw, var(--font-size-4xl));
    font-weight: 800;
    margin-bottom: var(--spacing-4);
    letter-spacing: -0.02em;
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: var(--font-size-lg);
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-6);
}

/* ===== Topic Card - Glassmorphism + 3D ===== */
.topic-card {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-6);
    border: 1px solid var(--border-color);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    transform-style: preserve-3d;
    perspective: 1000px;
}

.topic-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-mexican);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.topic-card::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent 40%, rgba(255, 255, 255, 0.1) 50%, transparent 60%);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.topic-card:hover {
    transform: translateY(-8px) rotateX(2deg);
    box-shadow: var(--shadow-2xl), var(--shadow-glow-green);
    border-color: var(--green-light);
}

.topic-card:hover::before {
    opacity: 1;
}

.topic-card:hover::after {
    opacity: 1;
}

.topic-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-4);
    display: inline-block;
    transition: transform var(--transition-bounce);
}

.topic-card:hover .topic-icon {
    transform: scale(1.2) rotate(-5deg);
}

.topic-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--spacing-2);
}

.topic-description {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    margin-bottom: var(--spacing-4);
    line-height: 1.6;
}

.topic-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: auto;
}

.topic-count {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
    font-weight: 500;
}

.topic-progress {
    width: 80px;
    height: 8px;
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
    overflow: hidden;
    position: relative;
}

.topic-progress-bar {
    height: 100%;
    background: var(--gradient-green);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
    position: relative;
}

.topic-progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

/* Topic mastery badges */
.topic-mastery {
    position: absolute;
    top: var(--spacing-4);
    right: var(--spacing-4);
    font-size: 1.25rem;
}

/* ===== Modal - Premium ===== */
.modal {
    position: fixed;
    inset: 0;
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-4);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
}

.modal-container {
    position: relative;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-3xl);
    width: 100%;
    max-width: 700px;
    max-height: 90vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-2xl);
    border: 1px solid var(--border-color);
    transform: scale(0.9) translateY(20px);
    transition: transform var(--transition-bounce);
}

.modal.active .modal-container {
    transform: scale(1) translateY(0);
}

.modal-lg {
    max-width: 850px;
}

.modal-xl {
    max-width: 1000px;
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-6);
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-glass);
}

.modal-title-group {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

.modal-icon {
    font-size: 1.75rem;
}

.modal-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
}

.modal-close {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-xl);
    background: var(--bg-secondary);
    font-size: 1.5rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--red-primary);
    color: white;
    transform: rotate(90deg);
}

.modal-tabs {
    display: flex;
    gap: var(--spacing-2);
    padding: var(--spacing-4) var(--spacing-6);
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-glass);
}

.tab {
    padding: var(--spacing-3) var(--spacing-5);
    border-radius: var(--radius-xl);
    font-weight: 600;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.tab:hover {
    color: var(--text-primary);
    background: var(--bg-card);
}

.tab.active {
    background: var(--gradient-green);
    color: white;
    box-shadow: var(--shadow-md), var(--shadow-glow-green);
}

.modal-body {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-6);
}

/* ===== Reading Mode ===== */
.reading-content {
    line-height: 1.8;
}

.qa-item {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-5);
    margin-bottom: var(--spacing-4);
    border-left: 4px solid var(--green-primary);
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
}

.qa-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
    border-left-color: var(--green-light);
}

.qa-question {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
    font-size: var(--font-size-base);
}

.qa-answer {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    white-space: pre-line;
    line-height: 1.8;
}

/* ===== Flashcard Mode - Premium ===== */
.flashcard-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-8);
}

.flashcard-progress {
    text-align: center;
    color: var(--text-muted);
    font-weight: 500;
}

.flashcard {
    width: 100%;
    max-width: 520px;
    min-height: 320px;
    perspective: 1000px;
    cursor: pointer;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    min-height: 320px;
    transition: transform 0.8s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    min-height: 320px;
    backface-visibility: hidden;
    border-radius: var(--radius-2xl);
    padding: var(--spacing-8);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.flashcard-front {
    background: var(--gradient-green);
    color: white;
    box-shadow: var(--shadow-xl), var(--shadow-glow-green);
}

.flashcard-back {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border: 2px solid var(--green-primary);
    transform: rotateY(180deg);
    box-shadow: var(--shadow-xl);
}

.flashcard-label {
    font-size: var(--font-size-sm);
    opacity: 0.8;
    margin-bottom: var(--spacing-4);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 600;
}

.flashcard-text {
    font-size: var(--font-size-lg);
    font-weight: 500;
    line-height: 1.8;
    white-space: pre-line;
    text-align: center;
    max-height: 220px;
    overflow-y: auto;
    padding: var(--spacing-2);
}

.flashcard-hint {
    margin-top: var(--spacing-6);
    font-size: var(--font-size-sm);
    opacity: 0.7;
}

.flashcard-controls {
    display: flex;
    gap: var(--spacing-4);
}

.flashcard-btn {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-full);
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 2px solid var(--border-color);
    transition: all var(--transition-fast);
}

.flashcard-btn:hover:not(:disabled) {
    border-color: var(--green-primary);
    color: var(--green-primary);
    transform: scale(1.1);
    box-shadow: var(--shadow-glow-green);
}

.flashcard-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

/* ===== Quiz Mode - Premium ===== */
.quiz-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-6);
}

.quiz-progress {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-4) var(--spacing-5);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
}

.quiz-score {
    font-weight: 700;
    color: var(--green-primary);
}

.quiz-question-container {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-8);
    border: 1px solid var(--border-color);
}

.quiz-question {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--spacing-8);
    line-height: 1.5;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
}

.quiz-option {
    padding: var(--spacing-4) var(--spacing-5);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-xl);
    color: var(--text-primary);
    text-align: left;
    font-weight: 500;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
    white-space: pre-line;
    line-height: 1.6;
}

.quiz-option::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: var(--green-primary);
    transform: scaleY(0);
    transition: transform var(--transition-fast);
}

.quiz-option:hover:not(:disabled) {
    border-color: var(--green-primary);
    transform: translateX(8px);
    box-shadow: var(--shadow-md);
}

.quiz-option:hover:not(:disabled)::before {
    transform: scaleY(1);
}

.quiz-option.correct {
    background: rgba(0, 168, 107, 0.15);
    border-color: var(--green-primary);
    animation: bounceIn 0.5s ease;
}

.quiz-option.correct::before {
    transform: scaleY(1);
}

.quiz-option.incorrect {
    background: rgba(206, 17, 38, 0.15);
    border-color: var(--red-primary);
    animation: shake 0.5s ease;
}

.quiz-option.incorrect::before {
    background: var(--red-primary);
    transform: scaleY(1);
}

.quiz-option:disabled {
    cursor: not-allowed;
}

.quiz-feedback {
    padding: var(--spacing-4) var(--spacing-5);
    border-radius: var(--radius-xl);
    display: none;
    font-weight: 600;
    white-space: pre-line;
    line-height: 1.6;
}

.quiz-feedback.show {
    display: block;
    animation: fadeInUp 0.3s ease;
}

.quiz-feedback.correct {
    background: rgba(0, 168, 107, 0.1);
    border: 2px solid var(--green-primary);
    color: var(--green-primary);
}

.quiz-feedback.incorrect {
    background: rgba(206, 17, 38, 0.1);
    border: 2px solid var(--red-primary);
    color: var(--red-primary);
}

.quiz-actions {
    display: flex;
    justify-content: center;
    gap: var(--spacing-4);
}

/* ===== Exam Mode - Premium ===== */
.exam-header {
    background: var(--gradient-green);
    color: white;
}

.exam-header .modal-close {
    background: rgba(255, 255, 255, 0.15);
    color: white;
}

.exam-header .modal-close:hover {
    background: var(--red-primary);
}

.exam-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-2);
}

.exam-stats {
    display: flex;
    gap: var(--spacing-4);
    font-size: var(--font-size-sm);
    opacity: 0.9;
}

.exam-timer {
    font-weight: 700;
}

.exam-body {
    background: var(--bg-secondary);
}

.exam-start {
    text-align: center;
    padding: var(--spacing-12);
}

.exam-start h2 {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-4);
    font-weight: 800;
}

.exam-start p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-8);
    font-size: var(--font-size-lg);
}

.exam-info-list {
    text-align: left;
    max-width: 420px;
    margin: 0 auto var(--spacing-10);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    padding: var(--spacing-6);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
}

.exam-info-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    padding: var(--spacing-4) 0;
    border-bottom: 1px solid var(--border-color);
    font-weight: 500;
}

.exam-info-item:last-child {
    border-bottom: none;
}

.exam-info-item span:first-child {
    font-size: 1.5rem;
}

.exam-results {
    text-align: center;
    padding: var(--spacing-12);
}

.exam-score-circle {
    width: 180px;
    height: 180px;
    border-radius: var(--radius-full);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-8);
    font-size: var(--font-size-4xl);
    font-weight: 800;
    animation: bounceIn 0.6s ease;
}

.exam-score-circle.pass {
    background: rgba(0, 168, 107, 0.15);
    border: 4px solid var(--green-primary);
    color: var(--green-primary);
    box-shadow: var(--shadow-glow-green);
}

.exam-score-circle.fail {
    background: rgba(206, 17, 38, 0.15);
    border: 4px solid var(--red-primary);
    color: var(--red-primary);
    box-shadow: var(--shadow-glow-red);
}

.exam-result-message {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-2);
    font-weight: 700;
}

.exam-result-detail {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-8);
    line-height: 1.7;
}

/* ===== Achievement Modal ===== */
.achievement-modal {
    position: fixed;
    inset: 0;
    z-index: 300;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(10px);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.achievement-modal.active {
    opacity: 1;
    visibility: visible;
}

.achievement-content {
    text-align: center;
    padding: var(--spacing-12);
    animation: bounceIn 0.6s ease;
}

.achievement-badge {
    font-size: 6rem;
    margin-bottom: var(--spacing-6);
    animation: badgeUnlock 0.8s ease;
}

.achievement-title {
    font-size: var(--font-size-2xl);
    font-weight: 800;
    color: var(--gold);
    margin-bottom: var(--spacing-2);
    text-shadow: 0 0 20px rgba(255, 215, 0, 0.5);
}

.achievement-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-4);
}

.achievement-xp {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--green-primary);
}

/* ===== XP Popup ===== */
.xp-popup {
    position: fixed;
    top: 100px;
    right: 30px;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    padding: var(--spacing-4) var(--spacing-6);
    border-radius: var(--radius-xl);
    border: 2px solid var(--green-primary);
    box-shadow: var(--shadow-xl), var(--shadow-glow-green);
    z-index: 250;
    animation: fadeInRight 0.3s ease, fadeOut 0.3s ease 2s forwards;
}

.xp-popup-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

.xp-popup-value {
    font-size: var(--font-size-xl);
    font-weight: 800;
    color: var(--green-primary);
    animation: xpCount 0.5s ease;
}

@keyframes fadeOut {
    to {
        opacity: 0;
        transform: translateX(100px);
    }
}

/* ===== Toast - Premium ===== */
.toast-container {
    position: fixed;
    bottom: var(--spacing-8);
    right: var(--spacing-8);
    z-index: 300;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
}

.toast {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    padding: var(--spacing-4) var(--spacing-6);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    animation: fadeInRight 0.4s ease;
    border: 1px solid var(--border-color);
    min-width: 280px;
}

.toast.success {
    border-left: 4px solid var(--green-primary);
}

.toast.error {
    border-left: 4px solid var(--red-primary);
}

.toast-icon {
    font-size: 1.25rem;
}

.toast-message {
    font-weight: 500;
}

/* ===== Responsive ===== */
@media (min-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr 1fr;
        align-items: center;
    }

    .hero-content {
        text-align: left;
    }

    .hero-stats {
        justify-content: flex-start;
    }

    .hero-buttons {
        justify-content: flex-start;
    }

    .hero-description {
        margin-left: 0;
    }

    .hero-decoration {
        display: block;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 var(--spacing-4);
    }

    .nav {
        display: none;
    }

    .hero-title {
        font-size: var(--font-size-4xl);
    }

    .hero-stats {
        flex-wrap: wrap;
        gap: var(--spacing-3);
    }

    .stat {
        min-width: 90px;
        padding: var(--spacing-3) var(--spacing-4);
    }

    .stat-number {
        font-size: var(--font-size-2xl);
    }

    .hero-buttons {
        flex-direction: column;
    }

    .btn-lg {
        width: 100%;
    }

    .modal-tabs {
        flex-wrap: wrap;
        gap: var(--spacing-2);
    }

    .tab {
        flex: 1;
        justify-content: center;
        padding: var(--spacing-2) var(--spacing-3);
        font-size: var(--font-size-sm);
    }

    .topics-grid {
        grid-template-columns: 1fr;
    }

    .exam-stats {
        flex-direction: column;
        gap: var(--spacing-1);
    }

    .flashcard {
        max-width: 100%;
    }

    .flashcard-text {
        font-size: var(--font-size-lg);
    }
}

/* ===== Scrollbar - Premium ===== */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--gradient-green);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--green-primary);
}

/* ===== Selection ===== */
::selection {
    background: var(--green-primary);
    color: white;
}

/* ===== Focus States ===== */
:focus-visible {
    outline: 2px solid var(--green-primary);
    outline-offset: 2px;
}

button:focus-visible {
    outline: 2px solid var(--green-primary);
    outline-offset: 2px;
}

/* ===== Header Actions ===== */
.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

/* ===== Auth Button ===== */
.auth-button {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-2) var(--spacing-4);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: var(--font-size-sm);
    color: var(--text-primary);
    transition: all var(--transition-fast);
    cursor: pointer;
}

.auth-button:hover {
    border-color: var(--green-primary);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    object-fit: cover;
    border: 2px solid var(--green-primary);
}

.user-name {
    max-width: 100px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ===== User Menu ===== */
.user-menu {
    position: fixed;
    top: 80px;
    right: 20px;
    width: 280px;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-2xl);
    z-index: 200;
    animation: fadeInDown 0.2s ease;
    overflow: hidden;
}

.user-menu-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    padding: var(--spacing-5);
    background: var(--bg-glass);
    border-bottom: 1px solid var(--border-color);
}

.user-menu-avatar {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    object-fit: cover;
    border: 2px solid var(--green-primary);
}

.user-menu-name {
    font-weight: 700;
    font-size: var(--font-size-base);
}

.user-menu-email {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

.user-menu-divider {
    height: 1px;
    background: var(--border-color);
    margin: var(--spacing-2) 0;
}

.user-menu-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    width: 100%;
    padding: var(--spacing-4) var(--spacing-5);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--text-primary);
    transition: all var(--transition-fast);
    text-align: left;
}

.user-menu-item:hover {
    background: var(--bg-secondary);
}

.user-menu-logout {
    color: var(--red-primary);
}

.user-menu-logout:hover {
    background: rgba(206, 17, 38, 0.1);
}

/* ===== Leaderboard ===== */
.leaderboard-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
}

.leaderboard-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    padding: var(--spacing-4);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    transition: all var(--transition-fast);
}

.leaderboard-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.leaderboard-item.is-current-user {
    border-color: var(--green-primary);
    background: rgba(0, 168, 107, 0.1);
}

.leaderboard-rank {
    font-size: var(--font-size-xl);
    font-weight: 800;
    width: 40px;
    text-align: center;
}

.leaderboard-avatar {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    object-fit: cover;
}

.leaderboard-info {
    flex: 1;
}

.leaderboard-name {
    font-weight: 600;
    font-size: var(--font-size-base);
}

.leaderboard-stats {
    font-size: var(--font-size-xs);
    color: var(--text-muted);
}

.leaderboard-xp {
    font-weight: 700;
    font-size: var(--font-size-lg);
    color: var(--green-primary);
}

/* ===== Cloud Sync Indicator ===== */
.sync-indicator {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    padding: var(--spacing-2);
}

.sync-indicator.syncing {
    color: var(--green-primary);
}

.sync-indicator.syncing::before {
    content: '';
    width: 8px;
    height: 8px;
    background: var(--green-primary);
    border-radius: 50%;
    animation: pulseGlow 1s ease-in-out infinite;
}

/* ===== Mobile Auth ===== */
@media (max-width: 768px) {
    .auth-button {
        padding: var(--spacing-2) var(--spacing-3);
    }

    .user-menu {
        right: 10px;
        left: 10px;
        width: auto;
    }

    .user-name {
        display: none;
    }
}

/* ===== Formato Multi-Línea y Textos (Evitar amontonamiento) ===== */
.qa-answer,
.flashcard-text,
.quiz-option,
.quiz-question {
    white-space: pre-line;
}

/* ===== Estilos Premium para las Opciones del Quiz ===== */
.quiz-option {
    display: block;
    width: 100%;
    margin-bottom: var(--spacing-3);
    padding: var(--spacing-4);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    color: var(--text-primary);
    /* Solución al texto negro reportado */
    font-size: var(--font-size-md);
    text-align: left;
    transition: all var(--transition-base);
    cursor: pointer;
    backdrop-filter: blur(5px);
}

.quiz-option:hover:not([disabled]) {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
    border-color: rgba(255, 255, 255, 0.2);
}

.quiz-option.correct {
    background: rgba(46, 204, 113, 0.2);
    border-color: var(--green-primary);
    color: var(--green-primary);
}

.quiz-option.incorrect {
    background: rgba(231, 76, 60, 0.2);
    border-color: #e74c3c;
    color: #e74c3c;
}