/* ==========================================================================
   LuyenAI.vn Homepage Styles
   Simple, elegant, mobile-first design
   ========================================================================== */

/* CSS Variables */
:root {
    /* Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-accent: #10b981;
    --color-accent-dark: #059669;

    --color-text: #1f2937;
    --color-text-light: #4b5563;
    --color-text-muted: #9ca3af;

    --color-bg: #ffffff;
    --color-bg-alt: #f9fafb;
    --color-bg-dark: #111827;

    --color-border: #e5e7eb;
    --color-border-dark: #d1d5db;

    /* Typography */
    --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 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;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;

    /* Layout */
    --container-max: 1200px;
    --header-height: 64px;

    /* Effects */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);

    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--header-height);
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* Skip to content link for accessibility */
.skip-to-content {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-primary);
    color: white;
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--radius-md);
    font-weight: 600;
    z-index: 9999;
    transition: top var(--transition-fast);
}

.skip-to-content:focus {
    top: var(--space-md);
    color: white;
}

/* Focus states for accessibility */
:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 3px;
}

/* Enhanced focus for buttons and links */
.btn:focus-visible,
.nav-link:focus-visible,
.mobile-nav-link:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 3px;
    box-shadow: 0 0 0 6px rgba(37, 99, 235, 0.2);
}

/* Focus for form inputs */
.form-input:focus-visible,
.form-select:focus-visible {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.15);
}

/* ==========================================================================
   Utilities
   ========================================================================== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-md);
}

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

.section {
    padding: var(--space-3xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.section-badge {
    display: inline-block;
    background: var(--color-primary);
    color: white;
    padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--space-md);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--space-sm);
    line-height: 1.2;
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-size: var(--font-size-base);
    font-weight: 600;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-accent:hover {
    background: var(--color-accent-dark);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(16, 185, 129, 0.4);
}

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

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

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

.btn-white:hover {
    background: var(--color-bg-alt);
    color: var(--color-text);
    transform: translateY(-2px);
}

.btn-lg {
    padding: var(--space-lg) var(--space-2xl);
    font-size: var(--font-size-lg);
}

.btn-sm {
    padding: var(--space-sm) var(--space-md);
    font-size: var(--font-size-sm);
}

/* Micro-interactions: active/pressed states */
.btn:active {
    transform: scale(0.98);
}

.btn-primary:active {
    background: var(--color-primary-dark);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

.btn-accent:active {
    background: var(--color-accent-dark);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

/* Streak/Login button - gradient yellow-orange */
.btn-streak {
    background: linear-gradient(135deg, #f59e0b 0%, #ea580c 100%);
    color: white;
    position: relative;
    overflow: visible;
}

.btn-streak:hover {
    background: linear-gradient(135deg, #d97706 0%, #c2410c 100%);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(234, 88, 12, 0.4);
}

.btn-streak:active {
    background: linear-gradient(135deg, #b45309 0%, #9a3412 100%);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

/* Confetti effect container */
.confetti-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

/* ==========================================================================
   Loading Overlay - High-tech loading effect
   ========================================================================== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, var(--color-bg-dark) 0%, #0f172a 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.loading-overlay.active {
    opacity: 1;
    visibility: visible;
}

/* Hexagon spinner */
.loading-spinner {
    position: relative;
    width: 80px;
    height: 80px;
    margin-bottom: 24px;
}

.loading-spinner::before,
.loading-spinner::after {
    content: '';
    position: absolute;
    inset: 0;
    border: 3px solid transparent;
    border-radius: 50%;
}

.loading-spinner::before {
    border-top-color: var(--color-accent);
    border-right-color: var(--color-accent);
    animation: spin-clockwise 1.2s linear infinite;
}

.loading-spinner::after {
    inset: 8px;
    border-bottom-color: var(--color-primary-light);
    border-left-color: var(--color-primary-light);
    animation: spin-counter 1.2s linear infinite;
}

@keyframes spin-clockwise {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@keyframes spin-counter {
    from { transform: rotate(0deg); }
    to { transform: rotate(-360deg); }
}

/* Loading dot in center */
.loading-spinner-dot {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 16px;
    height: 16px;
    background: var(--color-accent);
    border-radius: 50%;
    animation: pulse-dot 1.2s ease-in-out infinite;
}

@keyframes pulse-dot {
    0%, 100% { transform: translate(-50%, -50%) scale(1); opacity: 1; }
    50% { transform: translate(-50%, -50%) scale(1.5); opacity: 0.5; }
}

/* Loading text */
.loading-text {
    color: white;
    font-size: var(--font-size-lg);
    font-weight: 600;
    letter-spacing: 0.05em;
    opacity: 0.95;
    min-height: 2em;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Loading quote - rotating inspirational messages */
.loading-quote {
    display: inline-block;
    transition: opacity 0.3s ease, transform 0.3s ease;
    text-align: center;
}

/* Loading progress bar */
.loading-progress {
    width: 200px;
    height: 3px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 2px;
    margin-top: 20px;
    overflow: hidden;
}

.loading-progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--color-accent), var(--color-primary-light));
    border-radius: 2px;
    animation: loading-progress 2s ease-out forwards;
}

@keyframes loading-progress {
    0% { width: 0%; }
    20% { width: 20%; }
    50% { width: 60%; }
    80% { width: 85%; }
    100% { width: 95%; }
}

.confetti {
    position: absolute;
    width: 10px;
    height: 10px;
    opacity: 0;
}

@keyframes confetti-fall {
    0% {
        opacity: 1;
        transform: translateY(0) rotate(0deg) scale(1);
    }
    100% {
        opacity: 0;
        transform: translateY(100px) rotate(720deg) scale(0);
    }
}

/* Pulse animation for streak button */
.btn-streak.pulse {
    animation: streak-pulse 0.6s ease;
}

@keyframes streak-pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); box-shadow: 0 0 20px rgba(245, 158, 11, 0.6); }
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: all var(--transition-base);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.logo-img {
    height: 36px;
    width: auto;
    border-radius: var(--radius-sm);
}

.logo-text {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
}

.logo-tagline {
    font-size: var(--font-size-xs);
    color: var(--color-text-light);
    display: none;
}

.nav-menu {
    display: none;
    align-items: center;
    gap: var(--space-lg);
}

.nav-link {
    color: var(--color-text);
    font-weight: 500;
    padding: var(--space-sm) 0;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width var(--transition-base);
}

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

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

.nav-cta {
    display: none;
}

/* Mobile menu toggle */
.menu-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-sm);
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-text);
    transition: all var(--transition-base);
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile navigation */
.mobile-nav {
    display: none;
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: white;
    padding: var(--space-xl);
    z-index: 999;
}

.mobile-nav.active {
    display: block;
}

.mobile-nav-menu {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.mobile-nav-link {
    display: block;
    padding: var(--space-md);
    font-size: var(--font-size-lg);
    font-weight: 500;
    color: var(--color-text);
    border-bottom: 1px solid var(--color-border);
}

.mobile-nav-link.active {
    color: var(--color-primary);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, var(--color-bg-dark) 0%, #0c1929 50%, #0f2744 100%);
    padding-top: var(--header-height);
    position: relative;
    overflow: hidden;
}

/* Network Mesh Canvas Background */
.hero-network-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    opacity: 0.7;
}

/* Gradient overlay for depth */
.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse at 20% 30%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 70%, rgba(16, 185, 129, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(0, 0, 0, 0.3) 0%, transparent 80%);
    z-index: 1;
    pointer-events: none;
}

/* Animated glow spots */
.hero::after {
    content: '';
    position: absolute;
    top: 20%;
    left: 10%;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, rgba(16, 185, 129, 0.2) 0%, transparent 70%);
    border-radius: 50%;
    animation: glow-float 8s ease-in-out infinite;
    z-index: 1;
    pointer-events: none;
}

@keyframes glow-float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
        opacity: 0.5;
    }
    25% {
        transform: translate(50px, 30px) scale(1.1);
        opacity: 0.7;
    }
    50% {
        transform: translate(100px, -20px) scale(0.9);
        opacity: 0.4;
    }
    75% {
        transform: translate(30px, -40px) scale(1.05);
        opacity: 0.6;
    }
}

/* Secondary floating glow */
.hero-glow-secondary {
    position: absolute;
    bottom: 30%;
    right: 15%;
    width: 250px;
    height: 250px;
    background: radial-gradient(circle, rgba(37, 99, 235, 0.15) 0%, transparent 70%);
    border-radius: 50%;
    animation: glow-float-reverse 10s ease-in-out infinite;
    z-index: 1;
    pointer-events: none;
}

@keyframes glow-float-reverse {
    0%, 100% {
        transform: translate(0, 0) scale(1);
        opacity: 0.4;
    }
    33% {
        transform: translate(-60px, 40px) scale(1.15);
        opacity: 0.6;
    }
    66% {
        transform: translate(-30px, -50px) scale(0.85);
        opacity: 0.3;
    }
}

.hero-content {
    position: relative;
    z-index: 10;
    text-align: center;
    color: white;
    padding: var(--space-xl) 0;
}

.hero-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--space-lg);
}

.hero-title-highlight {
    color: var(--color-accent);
}

.hero-subtitle {
    font-size: var(--font-size-base);
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto var(--space-xl);
    line-height: 1.7;
}

/* Social proof stats */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-xl);
    margin-bottom: var(--space-2xl);
    flex-wrap: wrap;
}

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

.stat-number {
    display: block;
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-accent);
}

.stat-label {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

/* Hero buttons */
.hero-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    align-items: center;
}

.hero-note {
    font-size: var(--font-size-sm);
    opacity: 0.7;
    margin-top: var(--space-md);
}

/* Scroll indicator */
.scroll-indicator {
    position: absolute;
    bottom: var(--space-xl);
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
    z-index: 10;
}

.scroll-indicator svg {
    width: 24px;
    height: 24px;
    fill: white;
    opacity: 0.7;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
    40% { transform: translateX(-50%) translateY(-10px); }
    60% { transform: translateX(-50%) translateY(-5px); }
}

/* ==========================================================================
   Why Section
   ========================================================================== */
.why {
    background: var(--color-bg-alt);
}

.why-content {
    max-width: 800px;
    margin: 0 auto;
}

.why-problem {
    background: white;
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-xl);
    border-left: 4px solid var(--color-primary);
}

.why-problem h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.why-problem p {
    color: var(--color-text-light);
    line-height: 1.7;
}

.why-solution {
    margin-bottom: var(--space-xl);
}

.why-solution h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-md);
    color: var(--color-accent);
}

.why-solution p {
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

.benefits-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.benefit-item {
    display: flex;
    align-items: flex-start;
    gap: var(--space-md);
    padding: var(--space-md);
    background: white;
    border-radius: var(--radius-md);
    transition: transform var(--transition-base);
}

.benefit-item:hover {
    transform: translateX(5px);
}

.benefit-icon {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    background: var(--color-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
}

.benefit-icon svg {
    width: 20px;
    height: 20px;
    fill: white;
}

.benefit-text h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.benefit-text p {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

/* ==========================================================================
   Journey Section (15 minutes)
   ========================================================================== */
.journey {
    background: white;
}

.journey-steps {
    display: grid;
    gap: var(--space-xl);
    margin-bottom: var(--space-2xl);
}

.step-card {
    background: var(--color-bg-alt);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    position: relative;
    overflow: hidden;
}

.step-number {
    position: absolute;
    top: var(--space-md);
    right: var(--space-md);
    width: 36px;
    height: 36px;
    background: var(--color-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: var(--font-size-sm);
}

.step-icon {
    width: 56px;
    height: 56px;
    background: white;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-md);
    box-shadow: var(--shadow-sm);
}

.step-icon svg {
    width: 28px;
    height: 28px;
    fill: var(--color-primary);
}

.step-card h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.step-card p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

.step-time {
    display: inline-block;
    background: var(--color-accent);
    color: white;
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: 600;
    margin-top: var(--space-md);
}

/* Rewards box */
.journey-rewards {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    color: white;
    text-align: center;
}

.journey-rewards h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-lg);
}

.rewards-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.reward-item {
    background: rgba(255, 255, 255, 0.15);
    padding: var(--space-md);
    border-radius: var(--radius-md);
}

.reward-item svg {
    width: 32px;
    height: 32px;
    fill: var(--color-accent);
    margin-bottom: var(--space-sm);
}

.reward-item span {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* ==========================================================================
   Audience Section (4 personas)
   ========================================================================== */
.audience {
    background: var(--color-bg-alt);
}

.persona-grid {
    display: grid;
    gap: var(--space-lg);
}

.persona-card {
    background: white;
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.persona-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.persona-icon {
    width: 64px;
    height: 64px;
    background: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-md);
}

.persona-icon svg {
    width: 32px;
    height: 32px;
    fill: var(--color-primary);
}

.persona-card h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.persona-tag {
    display: inline-block;
    background: var(--color-accent);
    color: white;
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-full);
    font-size: var(--font-size-xs);
    font-weight: 600;
    margin-bottom: var(--space-md);
}

.persona-card p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    margin-bottom: var(--space-lg);
}

/* Different colors for persona tags */
.persona-card:nth-child(1) .persona-tag { background: #8b5cf6; }
.persona-card:nth-child(2) .persona-tag { background: #ec4899; }
.persona-card:nth-child(3) .persona-tag { background: var(--color-accent); }
.persona-card:nth-child(4) .persona-tag { background: #f59e0b; }

.persona-card:nth-child(1) .persona-icon svg { fill: #8b5cf6; }
.persona-card:nth-child(2) .persona-icon svg { fill: #ec4899; }
.persona-card:nth-child(3) .persona-icon svg { fill: var(--color-accent); }
.persona-card:nth-child(4) .persona-icon svg { fill: #f59e0b; }

/* ==========================================================================
   Values Section (Benefits grid)
   ========================================================================== */
.values {
    background: white;
}

.values-grid {
    display: grid;
    gap: var(--space-md);
}

.value-card {
    background: var(--color-bg-alt);
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all var(--transition-base);
}

.value-card:hover {
    background: white;
    box-shadow: var(--shadow-md);
}

.value-icon {
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--space-md);
}

.value-icon svg {
    width: 24px;
    height: 24px;
    fill: white;
}

.value-card h3 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.value-card p {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    line-height: 1.5;
}

/* ==========================================================================
   Testimonials Section
   ========================================================================== */
.testimonials {
    background: var(--color-bg-alt);
}

.testimonial-grid {
    display: grid;
    gap: var(--space-lg);
}

.testimonial-card {
    background: white;
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.testimonial-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.testimonial-quote {
    font-size: var(--font-size-base);
    color: var(--color-text);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
    position: relative;
    padding-left: var(--space-lg);
}

.testimonial-quote::before {
    content: '"';
    position: absolute;
    left: 0;
    top: -10px;
    font-size: var(--font-size-4xl);
    color: var(--color-primary);
    opacity: 0.3;
    font-family: Georgia, serif;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.testimonial-avatar {
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
}

.testimonial-info h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
}

.testimonial-info p {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

/* Partner logos */
.partner-logos {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-xl);
    flex-wrap: wrap;
    margin-top: var(--space-2xl);
    padding-top: var(--space-2xl);
    border-top: 1px solid var(--color-border);
}

.partner-logo {
    width: 100px;
    height: 40px;
    background: var(--color-border);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

/* ==========================================================================
   FAQ Section
   ========================================================================== */
.faq {
    background: white;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--color-border);
}

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

.faq-question {
    width: 100%;
    padding: var(--space-lg) 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    text-align: left;
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text);
    cursor: pointer;
}

.faq-question svg {
    width: 20px;
    height: 20px;
    fill: var(--color-text-light);
    transition: transform var(--transition-base);
    flex-shrink: 0;
}

.faq-item[open] .faq-question svg {
    transform: rotate(180deg);
}

.faq-answer {
    padding-bottom: var(--space-lg);
    color: var(--color-text-light);
    line-height: 1.7;
    animation: fadeSlideIn 0.3s ease;
}

@keyframes fadeSlideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==========================================================================
   CTA / Signup Section
   ========================================================================== */
.cta-section {
    background: linear-gradient(135deg, var(--color-bg-dark) 0%, #1e3a5f 100%);
    color: white;
    text-align: center;
}

.cta-content {
    max-width: 1100px;
    margin: 0 auto;
}

.cta-content h2 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--space-md);
}

.cta-content p {
    font-size: var(--font-size-lg);
    opacity: 0.9;
    margin-bottom: var(--space-xl);
}

/* Pricing cards */
.pricing-cards {
    display: grid;
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
}

.pricing-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: var(--space-2xl);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.2);
    min-width: 0;
}

.pricing-card.featured {
    background: white;
    color: var(--color-text);
    border: 2px solid var(--color-accent);
}

.pricing-card h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.pricing-card .price {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--space-md);
}

.pricing-card.featured .price {
    color: var(--color-accent);
}

.pricing-card ul {
    text-align: left;
    margin-bottom: var(--space-lg);
}

.pricing-card li {
    padding: var(--space-sm) 0;
    display: flex;
    align-items: flex-start;
    gap: var(--space-sm);
    font-size: var(--font-size-sm);
}

.pricing-card li svg {
    width: 16px;
    height: 16px;
    fill: var(--color-accent);
    flex-shrink: 0;
    margin-top: 2px;
}

/* Trust note */
.trust-note {
    font-size: var(--font-size-sm);
    opacity: 0.7;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
}

.trust-note svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
    background: var(--color-bg-dark);
    color: white;
    padding: var(--space-2xl) 0 var(--space-lg);
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
}

.footer-brand p {
    opacity: 0.7;
    font-size: var(--font-size-sm);
    margin-top: var(--space-sm);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.footer-links h4 {
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-md);
}

.footer-links a {
    display: block;
    color: rgba(255, 255, 255, 0.7);
    padding: var(--space-xs) 0;
    font-size: var(--font-size-sm);
}

.footer-links a:hover {
    color: white;
}

.footer-contact a {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: var(--space-sm);
}

.footer-contact svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
}

.footer-social {
    display: flex;
    gap: var(--space-md);
    margin-top: var(--space-md);
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition-base);
}

.footer-social a:hover {
    background: var(--color-primary);
}

.footer-social svg {
    width: 18px;
    height: 18px;
    fill: white;
}

.footer-social-stats {
    font-size: var(--font-size-xs);
    color: var(--color-accent);
    margin-top: var(--space-sm);
    font-weight: 500;
}

.footer-bottom {
    padding-top: var(--space-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    text-align: center;
}

.footer-bottom p {
    font-size: var(--font-size-sm);
    opacity: 0.7;
}

.footer-bottom-links {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
}

.footer-bottom-links a {
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.7);
}

/* Back to top button */
.back-to-top {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: 1000 !important;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--color-primary-dark);
    transform: translateY(-3px);
}

.back-to-top svg {
    width: 24px;
    height: 24px;
    fill: currentColor;
}

/* Sticky CTA bar */
.sticky-cta-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--color-bg-dark);
    padding: var(--space-md);
    z-index: 900;
    transform: translateY(100%);
    transition: transform var(--transition-base);
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
}

.sticky-cta-bar.visible {
    transform: translateY(0);
}

.sticky-cta-content {
    max-width: var(--container-max);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
}

.sticky-cta-text {
    color: white;
    font-weight: 500;
    font-size: var(--font-size-sm);
}

@media (max-width: 480px) {
    .sticky-cta-text {
        display: none;
    }

    .sticky-cta-bar .btn {
        width: 100%;
    }
}

/* ==========================================================================
   Modal
   ========================================================================== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-md);
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

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

.modal {
    background: white;
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    transform: translateY(20px);
    transition: transform var(--transition-base);
}

.modal-overlay.active .modal {
    transform: translateY(0);
}

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

.modal-header h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
}

.modal-close {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-light);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--color-bg-alt);
    color: var(--color-text);
}

.modal-close svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

.modal-body {
    padding: var(--space-lg);
}

/* Form styles */
.form-group {
    margin-bottom: var(--space-md);
}

.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 500;
    margin-bottom: var(--space-xs);
    color: var(--color-text);
}

.form-input,
.form-select {
    width: 100%;
    padding: var(--space-md);
    font-size: var(--font-size-base);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color var(--transition-fast);
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

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

/* Form error states */
.form-input.error,
.form-select.error {
    border-color: #ef4444;
    background-color: #fef2f2;
}

.form-input.error:focus,
.form-select.error:focus {
    border-color: #ef4444;
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.15);
}

.form-error {
    display: none;
    color: #ef4444;
    font-size: var(--font-size-sm);
    margin-top: var(--space-xs);
}

.form-error.visible {
    display: block;
}

.form-success {
    color: var(--color-accent);
    font-size: var(--font-size-sm);
    text-align: center;
    margin-top: var(--space-md);
    padding: var(--space-md);
    background: rgba(16, 185, 129, 0.1);
    border-radius: var(--radius-md);
}

/* ==========================================================================
   Responsive Styles
   ========================================================================== */

/* Tablet (768px+) */
@media (min-width: 768px) {
    .section {
        padding: var(--space-4xl) 0;
    }

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

    /* Header */
    .menu-toggle {
        display: none;
    }

    .nav-menu {
        display: flex;
    }

    .nav-cta {
        display: block;
    }

    .logo-tagline {
        display: block;
    }

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

    .hero-subtitle {
        font-size: var(--font-size-lg);
    }

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

    /* Journey */
    .journey-steps {
        grid-template-columns: repeat(3, 1fr);
    }

    .rewards-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    /* Audience */
    .persona-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Values */
    .values-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Testimonials */
    .testimonial-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Pricing - 2 columns on tablet for wider cards */
    .pricing-cards {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Footer */
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
    }

    .footer-links {
        flex-direction: row;
        gap: var(--space-2xl);
    }

    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
        text-align: left;
    }
}

/* Desktop (1024px+) */
@media (min-width: 1024px) {
    .container {
        padding: 0 var(--space-xl);
    }

    .section-title {
        font-size: var(--font-size-5xl);
    }

    /* Hero - desktop */
    .hero-title {
        font-size: var(--font-size-5xl);
    }

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

    .hero-content {
        padding: var(--space-2xl) 0;
    }

    /* Audience */
    .persona-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    /* Values */
    .values-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    /* Testimonials */
    .testimonial-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    /* Pricing - 3 columns on desktop */
    .pricing-cards {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ==========================================================================
   Earning Section (Kiếm tiền với AI)
   ========================================================================== */
.earning {
    background: linear-gradient(180deg, #f0f9ff 0%, #ffffff 100%);
}

.earning-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    margin-top: var(--space-2xl);
}

.earning-card {
    background: white;
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    border-left: 4px solid var(--color-accent);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.earning-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
}

.earning-level {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

.level-badge {
    background: linear-gradient(135deg, var(--color-accent), var(--color-accent-dark));
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: var(--font-size-xs);
    font-weight: 700;
    text-transform: uppercase;
}

.level-skill {
    background: var(--color-primary);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

.level-phase {
    background: #f59e0b;
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

.earning-card h3 {
    color: var(--color-text);
    font-size: var(--font-size-lg);
    margin-bottom: var(--space-sm);
}

.earning-card p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

.earning-note {
    margin-top: var(--space-2xl);
    padding: var(--space-lg) var(--space-xl);
    background: linear-gradient(135deg, #f0f9ff, #e0f2fe);
    border-radius: var(--radius-lg);
    text-align: center;
}

.earning-note p {
    color: var(--color-text);
    margin-bottom: var(--space-sm);
}

.earning-note .highlight {
    color: var(--color-accent);
    font-size: var(--font-size-lg);
    font-weight: 600;
}

/* Responsive - Tablet */
@media (min-width: 768px) {
    .earning-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Responsive - Desktop */
@media (min-width: 1024px) {
    .earning-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    /* Last 2 cards centered in their row */
    .earning-card:nth-child(4),
    .earning-card:nth-child(5) {
        grid-column: span 1;
    }
}

/* 5-card layout adjustment for large screens */
@media (min-width: 1200px) {
    .earning-grid {
        grid-template-columns: repeat(5, 1fr);
    }
}

/* Print styles */
@media print {
    .header,
    .back-to-top,
    .modal-overlay {
        display: none;
    }

    .hero {
        min-height: auto;
        padding: var(--space-xl) 0;
    }

    .section {
        padding: var(--space-xl) 0;
    }
}