/* ===================================
   Vương Kim Bảo - User Guide Handbook
   Theme: Phong Thủy (Gold & Red)
   =================================== */

:root {
    /* Primary Colors - Vương Kim Bảo Brand Colors */
    --primary-red: #8B1538;
    --primary-dark-red: #6B0F2A;
    --primary-gold: #D4AF37;
    --primary-dark-gold: #B8941F;
    
    /* Secondary Colors */
    --secondary-red: #A01D44;
    --secondary-gold: #FFD700;
    --accent-red: #DC143C;
    
    /* Neutral Colors */
    --white: #FFFFFF;
    --light-gray: #F8F9FA;
    --light-cream: #FFF8F0;
    --gray: #E9ECEF;
    --dark-gray: #6C757D;
    --black: #1A1A1A;
    
    /* Accent Colors */
    --success: #28A745;
    --info: #17A2B8;
    --warning: #FFC107;
    
    /* Gradients - Red & Gold Theme */
    --gradient-primary: linear-gradient(135deg, #8B1538 0%, #A01D44 100%);
    --gradient-gold: linear-gradient(135deg, #D4AF37 0%, #FFD700 100%);
    --gradient-red-gold: linear-gradient(135deg, #8B1538 0%, #D4AF37 100%);
    --gradient-dark: linear-gradient(135deg, #1A1A1A 0%, #2D2D2D 100%);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 12px 24px rgba(0, 0, 0, 0.18);
    
    /* Transitions */
    --transition: all 0.3s ease;
}

/* ===================================
   Reset & Base Styles
   =================================== */

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--black);
    background-color: var(--white);
    overflow-x: hidden;
}

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

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

ul {
    list-style: none;
}

/* ===================================
   Container & Layout
   =================================== */

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

.section {
    padding: var(--spacing-xxl) 0;
}

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

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--black);
    margin-bottom: var(--spacing-sm);
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--gradient-gold);
    border-radius: 2px;
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--dark-gray);
    margin-top: var(--spacing-md);
}

/* ===================================
   Header
   =================================== */

.header {
    background: var(--gradient-primary);
    color: var(--white);
    padding: var(--spacing-lg) 0;
    box-shadow: var(--shadow-md);
    border-bottom: 3px solid var(--primary-gold);
}

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

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

.logo-img {
    width: 60px;
    height: 60px;
    object-fit: contain;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.logo i {
    font-size: 2.5rem;
    color: var(--primary-gold);
    animation: rotate 20s linear infinite;
}

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

.logo h1 {
    font-size: 2rem;
    font-weight: 700;
    background: var(--gradient-gold);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    font-size: 1rem;
    color: var(--gray);
    font-weight: 300;
}

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

.nav {
    background-color: var(--white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 3px solid var(--primary-red);
}

.nav-list {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) 0;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: var(--spacing-xs) var(--spacing-md);
    color: var(--black);
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.nav-link:hover {
    background: var(--gradient-red-gold);
    color: var(--white);
    transform: translateY(-2px);
}

.nav-link i {
    font-size: 1rem;
}

/* ===================================
   Hero Section
   =================================== */

.hero {
    background: var(--gradient-red-gold);
    color: var(--white);
    padding: var(--spacing-xxl) 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 120"><path d="M0,0 Q300,60 600,30 T1200,60 L1200,120 L0,120 Z" fill="rgba(255,255,255,0.1)"/></svg>') repeat-x bottom;
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-lg);
    opacity: 0.95;
}

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

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

.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    border: 2px solid transparent;
    transition: var(--transition);
    text-align: center;
}

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

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

.btn-outline {
    background: transparent;
    color: var(--white);
    border-color: var(--white);
}

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

.btn-app {
    background: var(--black);
    color: var(--white);
    width: 100%;
    margin-top: var(--spacing-md);
}

.btn-app:hover {
    background: var(--primary-gold);
    transform: translateY(-2px);
}

.btn-course {
    background: var(--gradient-red-gold);
    color: var(--white);
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1.125rem;
}

.btn-course:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

/* ===================================
   Product Showcase Section
   =================================== */

.product-showcase {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-xl);
    margin: var(--spacing-xxl) 0;
}

.product-image-container {
    position: relative;
    background: var(--white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    border: 3px solid var(--primary-red);
    overflow: hidden;
}

.product-image-container:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(139, 21, 56, 0.3);
}

.product-img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
    display: block;
}

.product-badge {
    position: absolute;
    top: 20px;
    right: 20px;
    background: var(--gradient-red-gold);
    color: var(--white);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 600;
    box-shadow: var(--shadow-md);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.product-badge i {
    font-size: 1.125rem;
}

/* ===================================
   Company Introduction Styles
   =================================== */

.company-intro-box {
    background: linear-gradient(135deg, #FFF8F0 0%, var(--white) 100%);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xxl);
    margin: var(--spacing-xl) 0;
    box-shadow: var(--shadow-lg);
    border: 3px solid var(--primary-red);
}

.company-mission h3 {
    font-size: 1.75rem;
    color: var(--primary-red);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.company-mission h3 i {
    color: var(--primary-gold);
}

.mission-text {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--dark-gray);
    margin-bottom: var(--spacing-lg);
}

.mission-text strong {
    color: var(--primary-red);
    font-weight: 700;
}

.company-philosophy {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    background: var(--white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border-left: 5px solid var(--primary-gold);
    margin-top: var(--spacing-lg);
}

.philosophy-icon {
    flex-shrink: 0;
    width: 80px;
    height: 80px;
    background: var(--gradient-red-gold);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
}

.philosophy-icon i {
    font-size: 2.5rem;
    color: var(--white);
}

.philosophy-text h4 {
    font-size: 1.25rem;
    color: var(--black);
    margin-bottom: var(--spacing-xs);
}

.highlight-quote {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-red);
    font-style: italic;
    margin: 0;
}

/* Ecosystem Section */
.ecosystem-section {
    margin: var(--spacing-xxl) 0;
}

.ecosystem-title {
    text-align: center;
    font-size: 1.75rem;
    color: var(--black);
    margin-bottom: var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.ecosystem-title i {
    color: var(--primary-gold);
    font-size: 2rem;
}

.ecosystem-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.ecosystem-card {
    background: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    border: 2px solid var(--gray);
    transition: var(--transition);
}

.ecosystem-card:hover {
    border-color: var(--primary-red);
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.ecosystem-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto var(--spacing-md);
    background: var(--gradient-red-gold);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ecosystem-icon i {
    font-size: 2rem;
    color: var(--white);
}

.ecosystem-card h4 {
    font-size: 1.25rem;
    color: var(--primary-red);
    margin-bottom: var(--spacing-sm);
}

.ecosystem-card p {
    color: var(--dark-gray);
    line-height: 1.7;
}

/* ===================================
   Introduction Section
   =================================== */

.intro-section {
    background: var(--light-cream);
}

.intro-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.intro-card {
    background: var(--white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.intro-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.intro-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-md);
    background: var(--gradient-red-gold);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.intro-icon i {
    font-size: 2.5rem;
    color: var(--white);
}

.intro-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--black);
}

.intro-card p {
    color: var(--dark-gray);
    line-height: 1.8;
}

/* ===================================
   Info & Warning Boxes
   =================================== */

.info-box, .warning-box, .success-box, .payment-box {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
    box-shadow: var(--shadow-md);
    border-left: 5px solid var(--primary-red);
}

.warning-box {
    border-left-color: var(--warning);
    background: #FFF9E6;
}

.success-box {
    border-left-color: var(--success);
    background: #E8F8F0;
}

.payment-box {
    border-left-color: var(--info);
    background: #E6F7FB;
}

.info-box h3, .warning-box strong, .success-box strong, .payment-box h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
    color: var(--black);
}

.info-box i, .warning-box i, .success-box i, .payment-box i {
    font-size: 1.5rem;
    color: var(--primary-red);
}

.warning-box i {
    color: var(--warning);
}

.success-box i {
    color: var(--success);
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.info-item {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-start;
    padding: var(--spacing-sm);
    background: var(--light-gray);
    border-radius: var(--radius-md);
}

.info-item i {
    color: var(--primary-red);
    font-size: 1.25rem;
    margin-top: 0.25rem;
}

.info-item strong {
    display: block;
    margin-bottom: 0.25rem;
    color: var(--black);
}

.info-item p {
    color: var(--dark-gray);
    font-size: 0.9rem;
}

/* ===================================
   Steps Container
   =================================== */

.steps-container {
    margin: var(--spacing-xl) 0;
}

.steps-title {
    font-size: 1.75rem;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--black);
}

.step {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    background: var(--white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.step:hover {
    box-shadow: var(--shadow-lg);
    transform: translateX(10px);
}

.step-number {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    background: var(--gradient-red-gold);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    box-shadow: var(--shadow-md);
}

.step-content {
    flex: 1;
}

.step-content h4 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--black);
}

.step-content p {
    color: var(--dark-gray);
    margin-bottom: var(--spacing-sm);
    line-height: 1.8;
}

.step-content ul {
    list-style: none;
    padding-left: 0;
}

.step-content ul li {
    padding: var(--spacing-xs) 0;
    padding-left: var(--spacing-lg);
    position: relative;
    color: var(--dark-gray);
    line-height: 1.8;
}

.step-content ul li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: 700;
}

.step-content strong {
    color: var(--primary-red);
}

/* Info List in Steps */
.info-list {
    margin-top: var(--spacing-md);
    background: var(--light-gray);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
}

.info-row {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xs) 0;
    color: var(--dark-gray);
}

.info-row.important {
    background: #FFF9E6;
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    margin: var(--spacing-xs) 0;
}

.info-row i {
    color: var(--primary-gold);
    font-size: 1.125rem;
}

/* Filter Options & Sim Details */
.filter-options, .sim-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-sm);
    margin: var(--spacing-md) 0;
    background: var(--light-gray);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
}

.filter-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--dark-gray);
}

.filter-item i {
    color: var(--primary-gold);
}

.sim-details {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.sim-details span {
    color: var(--dark-gray);
}

/* ===================================
   App Download Section
   =================================== */

.app-section {
    background: var(--light-gray);
}

.app-download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.app-card {
    background: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.app-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.app-icon {
    width: 100px;
    height: 100px;
    margin: 0 auto var(--spacing-md);
    background: var(--gradient-red-gold);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
}

.app-icon i {
    font-size: 3.5rem;
    color: var(--white);
}

.app-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--black);
}

.app-steps {
    text-align: left;
    margin: var(--spacing-lg) 0;
}

.app-step {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    align-items: flex-start;
}

.step-badge {
    flex-shrink: 0;
    width: 30px;
    height: 30px;
    background: var(--primary-red);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.875rem;
}

.app-step p {
    color: var(--dark-gray);
    line-height: 1.8;
}

.app-features {
    background: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.app-features h3 {
    text-align: center;
    font-size: 1.75rem;
    margin-bottom: var(--spacing-lg);
    color: var(--black);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.feature-item {
    text-align: center;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.feature-item:hover {
    background: var(--light-gray);
}

.feature-item i {
    font-size: 2.5rem;
    color: var(--primary-red);
    margin-bottom: var(--spacing-sm);
}

.feature-item h4 {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xs);
    color: var(--black);
}

.feature-item p {
    color: var(--dark-gray);
    font-size: 0.9rem;
}

/* ===================================
   Course Section
   =================================== */

.course-section {
    background: var(--white);
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.course-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    transition: var(--transition);
    border: 2px solid var(--gray);
    position: relative;
}

.course-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-red);
}

.course-card.featured {
    border: 3px solid var(--primary-red);
    transform: scale(1.05);
}

.course-badge {
    position: absolute;
    top: 20px;
    right: 20px;
    background: var(--dark-gray);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    z-index: 10;
}

.course-badge.popular {
    background: var(--gradient-primary);
}

.course-badge.premium {
    background: var(--gradient-dark);
}

.course-header {
    background: var(--gradient-red-gold);
    color: var(--white);
    padding: var(--spacing-xl);
    text-align: center;
}

.course-header h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-md);
}

.course-price {
    margin-top: var(--spacing-sm);
}

.price {
    font-size: 2rem;
    font-weight: 700;
}

.course-body {
    padding: var(--spacing-lg);
}

.course-info {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    background: var(--light-gray);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
}

.course-info i {
    color: var(--primary-gold);
}

.course-content {
    margin: var(--spacing-md) 0;
}

.course-content h4 {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-sm);
    color: var(--black);
}

.course-content i {
    color: var(--primary-red);
}

.course-content ul {
    list-style: none;
    padding-left: 0;
}

.course-content li {
    padding: var(--spacing-xs) 0;
    padding-left: var(--spacing-lg);
    position: relative;
    color: var(--dark-gray);
}

.course-content li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--primary-red);
    font-weight: 700;
}

.course-gift {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    background: #E8F8F0;
    padding: var(--spacing-sm);
    border-radius: var(--radius-md);
    margin: var(--spacing-md) 0;
}

.course-gift i {
    color: var(--success);
    font-size: 1.25rem;
}

.course-target {
    background: var(--light-gray);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-top: var(--spacing-md);
}

.course-target strong {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--black);
}

.course-target p {
    color: var(--dark-gray);
    font-size: 0.9rem;
    line-height: 1.6;
}

.course-note {
    background: #FFF9E6;
    border-left: 4px solid var(--warning);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    display: flex;
    gap: var(--spacing-sm);
}

.course-note i {
    color: var(--warning);
    font-size: 1.5rem;
    flex-shrink: 0;
}

/* ===================================
   Screenshots & Image Gallery
   =================================== */

.app-preview {
    text-align: center;
    margin: var(--spacing-xl) auto;
    max-width: 400px;
}

.screenshot {
    width: 100%;
    max-width: 350px;
    height: auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    border: 3px solid var(--primary-red);
    transition: var(--transition);
    margin: 0 auto;
    display: block;
}

.screenshot:hover {
    transform: scale(1.05);
    box-shadow: 0 12px 40px rgba(139, 21, 56, 0.3);
}

.preview-caption {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--white);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.preview-caption i {
    color: var(--primary-red);
    font-size: 1.25rem;
}

.preview-caption p {
    color: var(--dark-gray);
    font-style: italic;
    margin: 0;
}

.screenshot-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin: var(--spacing-xl) 0;
}

.gallery-item {
    text-align: center;
    background: var(--white);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.gallery-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.gallery-caption {
    margin-top: var(--spacing-md);
    color: var(--dark-gray);
    font-weight: 600;
    line-height: 1.6;
}

.step-screenshot {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--light-gray);
    border-radius: var(--radius-md);
    border: 2px dashed var(--primary-red);
}

.screenshot-inline {
    width: 100%;
    max-width: 300px;
    height: auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    margin: 0 auto var(--spacing-sm);
    display: block;
    border: 2px solid var(--primary-red);
}

.screenshot-note {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--dark-gray);
    font-size: 0.9rem;
    font-style: italic;
    margin-top: var(--spacing-sm);
    padding: var(--spacing-xs);
}

.screenshot-note i {
    color: var(--primary-red);
    font-size: 1rem;
}

/* ===================================
   2 Methods for Finding SIM
   =================================== */

.sim-methods {
    margin: var(--spacing-xxl) 0;
}

.methods-title {
    text-align: center;
    font-size: 1.75rem;
    margin-bottom: var(--spacing-xl);
    color: var(--black);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.methods-title i {
    color: var(--primary-gold);
    font-size: 2rem;
}

.method-card {
    background: var(--white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    border: 3px solid var(--gray);
    position: relative;
    transition: var(--transition);
}

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

.method-recommended {
    border-color: var(--primary-red);
    background: linear-gradient(to bottom, #FFF8F0 0%, var(--white) 100%);
}

.method-badge {
    position: absolute;
    top: -15px;
    right: 30px;
    background: var(--gradient-red-gold);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-lg);
    border-radius: var(--radius-lg);
    font-weight: 700;
    font-size: 0.875rem;
    box-shadow: var(--shadow-md);
    animation: pulse 2s infinite;
}

.method-badge-advanced {
    background: var(--gradient-dark);
}

.method-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--primary-red);
}

.method-number {
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    background: var(--gradient-red-gold);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    box-shadow: var(--shadow-md);
}

.method-header h4 {
    font-size: 1.5rem;
    color: var(--black);
    margin: 0;
}

.method-description {
    background: var(--light-cream);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--primary-gold);
    margin-bottom: var(--spacing-lg);
    font-size: 1.05rem;
    line-height: 1.8;
}

.method-description i {
    color: var(--primary-gold);
    margin-right: var(--spacing-xs);
}

.method-steps {
    margin: var(--spacing-lg) 0;
}

.mini-step {
    display: flex;
    gap: var(--spacing-md);
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--light-gray);
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.mini-step:hover {
    background: #FFE8D6;
    transform: translateX(5px);
}

.mini-step-number {
    flex-shrink: 0;
    width: 30px;
    height: 30px;
    background: var(--primary-red);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.875rem;
}

.mini-step p {
    margin: 0;
    color: var(--dark-gray);
    line-height: 1.8;
}

.method-screenshot {
    margin: var(--spacing-lg) 0;
    text-align: center;
}

.method-benefits {
    background: #E8F8F0;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-top: var(--spacing-lg);
    border-left: 4px solid var(--success);
}

.method-benefits h5 {
    color: var(--black);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.method-benefits i {
    color: var(--success);
}

.method-benefits ul {
    list-style: none;
    padding-left: 0;
}

.method-benefits li {
    padding: var(--spacing-xs) 0;
    color: var(--dark-gray);
    line-height: 1.8;
}

/* Filter Guide Styles */
.filter-guide {
    margin: var(--spacing-lg) 0;
}

.filter-guide h5 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
    color: var(--black);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.filter-guide h5 i {
    color: var(--primary-red);
}

.filter-item-guide {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--light-gray);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--primary-red);
    transition: var(--transition);
}

.filter-item-guide:hover {
    background: var(--light-cream);
    transform: translateX(5px);
}

.filter-icon-wrapper {
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    background: var(--gradient-red-gold);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.filter-icon-wrapper i {
    font-size: 1.5rem;
    color: var(--white);
}

.filter-detail {
    flex: 1;
}

.filter-detail h6 {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xs);
    color: var(--primary-red);
}

.filter-detail p {
    margin: var(--spacing-xs) 0;
    color: var(--dark-gray);
    line-height: 1.6;
}

.filter-tip {
    color: var(--primary-gold) !important;
    font-weight: 600;
    font-style: italic;
    margin-top: var(--spacing-xs) !important;
}

.menh-icons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin: var(--spacing-sm) 0;
}

.menh-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--white);
}

.menh-kim { background: linear-gradient(135deg, #C0C0C0 0%, #E8E8E8 100%); color: #333; }
.menh-moc { background: linear-gradient(135deg, #28A745 0%, #5CB85C 100%); }
.menh-thuy { background: linear-gradient(135deg, #17A2B8 0%, #5BC0DE 100%); }
.menh-hoa { background: linear-gradient(135deg, #DC3545 0%, #F8796C 100%); }
.menh-tho { background: linear-gradient(135deg, #8B4513 0%, #A0522D 100%); }

.que-list {
    list-style: none;
    padding-left: 0;
    margin: var(--spacing-sm) 0;
}

.que-list li {
    padding: 0.25rem 0;
    color: var(--dark-gray);
}

.filter-actions {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.action-button {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    border: 2px solid;
    transition: var(--transition);
    cursor: pointer;
}

.action-reset {
    background: var(--white);
    border-color: var(--dark-gray);
    color: var(--dark-gray);
}

.action-reset:hover {
    background: var(--light-gray);
}

.action-apply {
    background: var(--gradient-red-gold);
    border-color: var(--primary-red);
    color: var(--white);
}

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

.action-button i {
    font-size: 1.25rem;
}

/* ===================================
   Map & Sim Sections
   =================================== */

.map-section, .sim-section {
    background: var(--light-gray);
}

.map-intro, .sim-intro {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    background: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--spacing-xl);
}

.map-intro-icon, .sim-intro-icon {
    flex-shrink: 0;
    width: 100px;
    height: 100px;
    background: var(--gradient-red-gold);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.map-intro-icon i, .sim-intro-icon i {
    font-size: 3rem;
    color: var(--white);
}

.map-intro-text h3, .sim-intro-text h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--black);
}

.map-intro-text p, .sim-intro-text p {
    color: var(--dark-gray);
    line-height: 1.8;
}

.payment-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.payment-item {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
    padding: var(--spacing-sm);
    background: var(--white);
    border-radius: var(--radius-md);
}

.payment-item i {
    color: var(--success);
    font-size: 1.25rem;
}

/* ===================================
   Footer
   =================================== */

.footer {
    background: var(--gradient-primary);
    color: var(--white);
    padding: var(--spacing-xxl) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
}

.footer-section h3 i {
    color: var(--primary-gold);
}

.footer-section h4 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
    color: var(--secondary-gold);
}

.footer-section p {
    color: var(--gray);
    margin-bottom: var(--spacing-xs);
    line-height: 1.6;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: var(--spacing-xs);
}

.footer-section ul li a {
    color: var(--gray);
    transition: var(--transition);
}

.footer-section ul li a:hover {
    color: var(--primary-gold);
    padding-left: var(--spacing-xs);
}

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

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

.social-links a:hover {
    background: var(--primary-red);
    transform: translateY(-3px);
}

.social-links i {
    font-size: 1.25rem;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--gray);
}

/* ===================================
   Scroll to Top Button
   =================================== */

.scroll-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-red-gold);
    color: var(--white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    z-index: 999;
}

.scroll-top:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.scroll-top.show {
    display: flex;
}

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

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .nav-list {
        flex-direction: column;
        align-items: stretch;
    }
    
    .nav-link {
        justify-content: center;
    }
    
    .step {
        flex-direction: column;
    }
    
    .step-number {
        margin: 0 auto;
    }
    
    .map-intro, .sim-intro {
        flex-direction: column;
        text-align: center;
    }
    
    .map-intro-icon, .sim-intro-icon {
        margin: 0 auto;
    }
    
    .app-download-grid,
    .course-grid {
        grid-template-columns: 1fr;
    }
    
    .course-card.featured {
        transform: scale(1);
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
    }
    
    /* Screenshot responsive */
    .screenshot-gallery {
        grid-template-columns: 1fr;
    }
    
    .app-preview {
        max-width: 100%;
    }
    
    .screenshot,
    .screenshot-inline {
        max-width: 100%;
    }
    
    /* Product showcase responsive */
    .product-showcase {
        grid-template-columns: 1fr;
    }
    
    .product-badge {
        font-size: 0.875rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .logo-img {
        width: 50px;
        height: 50px;
    }
    
    /* Method cards responsive */
    .method-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .method-badge {
        font-size: 0.75rem;
        padding: 0.25rem 0.5rem;
        right: 15px;
    }
    
    .filter-item-guide {
        flex-direction: column;
    }
    
    .filter-actions {
        grid-template-columns: 1fr;
    }
    
    /* Company intro responsive */
    .company-philosophy {
        flex-direction: column;
        text-align: center;
    }
    
    .ecosystem-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .section {
        padding: var(--spacing-lg) 0;
    }
    
    .logo h1 {
        font-size: 1.5rem;
    }
    
    .logo-img {
        width: 40px;
        height: 40px;
    }
    
    .intro-grid,
    .info-grid,
    .feature-grid {
        grid-template-columns: 1fr;
    }
    
    .scroll-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
    }
    
    .product-showcase {
        gap: var(--spacing-md);
    }
    
    .product-image-container {
        padding: var(--spacing-sm);
    }
    
    .product-badge {
        font-size: 0.75rem;
        padding: 0.25rem 0.5rem;
        top: 10px;
        right: 10px;
    }
}

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

@media print {
    .nav,
    .hero,
    .scroll-top,
    .btn {
        display: none;
    }
    
    .section {
        page-break-inside: avoid;
    }
}