/* =====================================================
   CSS - KiếmTiền Online Website
   Modern Landing Page với Dark Mode & Responsive Design
   ===================================================== */

/* =====================================================
   1. CSS VARIABLES (Biến toàn cục)
   ===================================================== */
:root {
    /* Màu sắc chính */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    
    /* Màu sắc cơ bản */
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --light-bg: #f8f9fa;
    --white: #ffffff;
    --text-dark: #2d3748;
    --text-light: #718096;
    --border-color: #e2e8f0;
    
    /* Dark Mode */
    --dark-bg: #1a202c;
    --dark-secondary: #2d3748;
    --dark-text: #f7fafc;
    --dark-text-light: #cbd5e0;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Timing */
    --transition: 0.3s ease-in-out;
    --transition-long: 0.5s ease-in-out;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
}

/* Dark Mode CSS Variables */
body.dark-mode {
    --light-bg: var(--dark-bg);
    --text-dark: var(--dark-text);
    --text-light: var(--dark-text-light);
    --white: var(--dark-secondary);
    --border-color: #4a5568;
}

/* =====================================================
   2. RESET & BASE STYLES
   ===================================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--light-bg);
    color: var(--text-dark);
    line-height: 1.6;
    transition: background-color var(--transition), color var(--transition);
}

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

/* =====================================================
   3. TYPOGRAPHY
   ===================================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
}

h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.75rem);
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

p {
    font-size: 1rem;
    color: var(--text-light);
}

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

/* =====================================================
   4. BUTTONS
   ===================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    position: relative;
}

.btn i {
    z-index: 1;
    position: relative;
}

.btn .fab {
    font-size: 1.1em;
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    position: relative;
    overflow: hidden;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn-primary:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.5);
}

.btn-secondary {
    background: var(--secondary-gradient);
    color: white;
    box-shadow: 0 10px 30px rgba(240, 147, 251, 0.3);
    position: relative;
    overflow: hidden;
}

.btn-secondary::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn-secondary:hover::before {
    width: 300px;
    height: 300px;
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(240, 147, 251, 0.5);
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-2xl);
    font-size: 1.1rem;
}

.btn-block {
    width: 100%;
    display: flex;
}

/* =====================================================
   5. NAVBAR
   ===================================================== */
.navbar {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition);
}

body.dark-mode .navbar {
    background: rgba(26, 32, 44, 0.95);
}

.navbar-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) 0;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.nav-link {
    font-weight: 600;
    color: var(--text-dark);
    position: relative;
    transition: color var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-gradient);
    transition: width var(--transition);
}

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

.nav-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.3rem;
    cursor: pointer;
    color: var(--text-dark);
    transition: color var(--transition);
}

.theme-toggle:hover {
    color: var(--primary-color);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    gap: 5px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-dark);
    border-radius: 2px;
    transition: all var(--transition);
}

/* =====================================================
   6. VISITORS COUNTER SECTION
   ===================================================== */
.visitors-section {
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05) 0%, rgba(240, 147, 251, 0.05) 100%);
    position: relative;
    overflow: hidden;
}

.visitors-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(102, 126, 234, 0.1) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: moveBackground 20s linear infinite;
}

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

.visitors-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl) var(--spacing-2xl);
    box-shadow: 0 10px 40px rgba(102, 126, 234, 0.15);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
    transition: all var(--transition-long);
}

.visitors-card:hover {
    box-shadow: 0 20px 60px rgba(102, 126, 234, 0.25);
    transform: translateY(-5px);
}

.visitors-icon {
    width: 100px;
    height: 100px;
    background: var(--primary-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
    flex-shrink: 0;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.visitors-text {
    flex-grow: 1;
}

.visitors-label {
    font-size: 1rem;
    color: var(--text-light);
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.visitors-count {
    font-size: 3rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: var(--spacing-md) 0;
    font-weight: 700;
}

.visitors-subtitle {
    font-size: 1rem;
    color: var(--text-light);
    font-style: italic;
}

/* =====================================================
   7. INTRODUCTION SECTION
   ===================================================== */
.intro-section {
    padding: var(--spacing-2xl) 0;
    background: var(--light-bg);
    position: relative;
    overflow: hidden;
}

.intro-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(240, 147, 251, 0.1) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: moveBackground 20s linear infinite;
}

.intro-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: var(--spacing-xl);
    position: relative;
    z-index: 1;
}

.intro-text h2 {
    font-size: 2.2rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

.intro-highlight {
    font-size: 1.3rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.intro-main-text {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: var(--spacing-md);
}

.intro-description {
    font-size: 1rem;
    color: var(--text-light);
    line-height: 1.8;
    margin-bottom: var(--spacing-lg);
}

.intro-features {
    margin: var(--spacing-lg) 0;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.feature-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: rgba(102, 126, 234, 0.08);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--primary-color);
    transition: all var(--transition);
}

.feature-item:hover {
    background: rgba(102, 126, 234, 0.15);
    transform: translateX(5px);
}

.feature-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
    min-width: 30px;
}

.feature-item span {
    font-size: 1rem;
    color: var(--text-dark);
    font-weight: 500;
}

.intro-note {
    font-size: 1rem;
    font-style: italic;
    color: var(--text-light);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: rgba(102, 126, 234, 0.05);
    border-radius: var(--radius-md);
}

.intro-cta {
    background: var(--secondary-gradient);
    color: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
}

.intro-cta h3 {
    color: white;
    font-size: 1.2rem;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.intro-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.intro-illustration {
    width: 280px;
    height: 280px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 7rem;
    color: rgba(255, 255, 255, 0.9);
    animation: float 3s ease-in-out infinite;
    box-shadow: 0 20px 60px rgba(240, 147, 251, 0.3);
}

/* =====================================================
   8. HERO SECTION
   ===================================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    overflow: hidden;
    padding: var(--spacing-2xl) 0;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
}

.gradient-blob {
    position: absolute;
    width: 500px;
    height: 500px;
    background: var(--primary-gradient);
    border-radius: 45% 55% 60% 40% / 55% 45% 45% 55%;
    opacity: 0.1;
    animation: blob 7s infinite;
    top: -100px;
    right: -100px;
}

.gradient-blob-2 {
    position: absolute;
    width: 400px;
    height: 400px;
    background: var(--secondary-gradient);
    border-radius: 35% 65% 50% 50% / 50% 50% 50% 50%;
    opacity: 0.1;
    animation: blob 8s infinite reverse;
    bottom: -50px;
    left: -50px;
}

@keyframes blob {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -50px) scale(1.1); }
    66% { transform: translate(-20px, 20px) scale(0.9); }
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: var(--spacing-xl);
    z-index: 1;
}

.hero-text h1 {
    font-size: clamp(2.5rem, 6vw, 4rem);
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

.typing-text {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xl);
    color: var(--text-light);
    max-width: 500px;
}

.hero .btn {
    display: inline-flex;
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-illustration {
    width: 300px;
    height: 300px;
    background: var(--secondary-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 8rem;
    color: rgba(255, 255, 255, 0.9);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

/* =====================================================
   8. JOBS SECTION
   ===================================================== */
.jobs-section {
    padding: var(--spacing-2xl) 0;
    background: var(--light-bg);
}

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

.section-header h2 {
    margin-bottom: var(--spacing-md);
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-header p {
    font-size: 1.1rem;
    max-width: 500px;
    margin: 0 auto;
}

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

.job-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all var(--transition-long);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.job-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 4px;
    background: var(--primary-gradient);
    transition: left var(--transition-long);
    z-index: 0;
}

.job-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--primary-gradient);
    opacity: 0.03;
    transition: left var(--transition-long);
    z-index: -1;
}

.job-card:hover::before {
    left: 0;
}

.job-card:hover::after {
    left: 0;
}

.job-card:hover {
    transform: translateY(-12px);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.18);
    border-color: var(--primary-color);
}

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

.job-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-gradient);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
}

.job-salary {
    background: var(--secondary-gradient);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-md);
    font-weight: 700;
    font-size: 1.1rem;
}

.job-title {
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

.job-description {
    margin-bottom: var(--spacing-md);
    color: var(--text-light);
    flex-grow: 1;
}

.job-requirements {
    margin: var(--spacing-md) 0;
    padding: var(--spacing-md);
    background: rgba(102, 126, 234, 0.05);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--primary-color);
}

.job-requirements h4 {
    color: var(--text-dark);
    margin-bottom: var(--spacing-sm);
    font-size: 1rem;
}

.job-requirements ul {
    list-style: none;
    padding-left: var(--spacing-md);
}

.job-requirements li {
    color: var(--text-light);
    margin-bottom: var(--spacing-xs);
    position: relative;
    font-size: 0.95rem;
}

.job-requirements li::before {
    content: '✓';
    position: absolute;
    left: negative(var(--spacing-md));
    color: var(--primary-color);
    font-weight: bold;
}

.job-safety {
    margin: var(--spacing-md) 0;
    padding: var(--spacing-md);
    background: rgba(34, 197, 94, 0.05);
    border-radius: var(--radius-md);
    border-left: 3px solid #22c55e;
}

.job-safety p {
    color: var(--text-light);
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.job-safety i {
    color: #22c55e;
}

.job-card .btn {
    margin-top: var(--spacing-md);
    margin-top: auto;
}

/* =====================================================
   9. STATISTICS SECTION
   ===================================================== */
.stats-section {
    padding: var(--spacing-2xl) 0;
    background: var(--primary-gradient);
    color: white;
    position: relative;
    overflow: hidden;
}

.stats-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: moveBackground 20s linear infinite;
}

@keyframes moveBackground {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    position: relative;
    z-index: 1;
}

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

.stat-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.8;
}

.stat-item h3 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
    font-weight: 700;
}

.stat-item p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
}

/* =====================================================
   10. REVIEWS SECTION (Swiper)
   ===================================================== */
.reviews-section {
    padding: var(--spacing-2xl) 0;
    background: var(--light-bg);
}

.reviewsSwiper {
    padding: var(--spacing-xl) 0;
}

.review-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    border: 1px solid var(--border-color);
    height: 100%;
    display: flex;
    flex-direction: column;
    transition: all var(--transition);
}

.review-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.review-rating {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
    color: #fbbf24;
    font-size: 1.2rem;
}

.review-text {
    font-size: 1rem;
    font-style: italic;
    color: var(--text-dark);
    margin-bottom: var(--spacing-lg);
    flex-grow: 1;
    line-height: 1.8;
}

.review-author {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    border-top: 1px solid var(--border-color);
    padding-top: var(--spacing-md);
}

.author-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--primary-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 1.2rem;
}

.review-author h4 {
    margin-bottom: var(--spacing-xs);
    color: var(--text-dark);
}

.review-author p {
    font-size: 0.9rem;
}

.swiper-pagination-bullet {
    background: var(--primary-color);
}

.swiper-pagination-bullet-active {
    background: var(--secondary-color);
}

/* =====================================================
   11. CTA SECTION
   ===================================================== */
.cta-section {
    padding: var(--spacing-2xl) 0;
    background: var(--secondary-gradient);
    color: white;
    text-align: center;
}

.cta-content h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
    color: white;
}

.cta-content p {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-xl);
    color: rgba(255, 255, 255, 0.9);
}

.cta-content .btn {
    background: white;
    color: var(--secondary-color);
    font-weight: 700;
}

.cta-content .btn:hover {
    transform: translateY(-2px);
}

/* =====================================================
   12. FOOTER
   ===================================================== */
.footer {
    background: var(--dark-secondary);
    color: var(--dark-text-light);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

body.dark-mode .footer {
    background: #0f1419;
}

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

.footer-col h4 {
    color: white;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.footer-col p {
    color: var(--dark-text-light);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

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

.footer-col ul li {
    margin-bottom: var(--spacing-sm);
}

.footer-col a {
    color: var(--dark-text-light);
    transition: color var(--transition);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

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

.social-links {
    display: flex;
    gap: 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: all var(--transition);
}

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

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

.footer-bottom p {
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xs);
}

/* =====================================================
   13. BACK TO TOP BUTTON
   ===================================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    z-index: 999;
}

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

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.4);
}

/* =====================================================
   15. ZALO SUPPORT BUTTON
   ===================================================== */
.zalo-support-btn {
    position: fixed;
    bottom: 100px;
    right: 30px;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #0084ff 0%, #0073e6 100%);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    box-shadow: 0 10px 30px rgba(0, 132, 255, 0.4);
    transition: all var(--transition);
    z-index: 998;
    text-decoration: none;
}

.zalo-support-btn:hover {
    transform: scale(1.15) translateY(-3px);
    box-shadow: 0 15px 50px rgba(0, 132, 255, 0.6);
}

.zalo-support-btn:active {
    transform: scale(0.95);
}

.pulse {
    position: absolute;
    top: -10px;
    right: -10px;
    width: 12px;
    height: 12px;
    background: #ff4444;
    border-radius: 50%;
    animation: pulse-animation 2s ease-in-out infinite;
}

@keyframes pulse-animation {
    0% {
        box-shadow: 0 0 0 0 rgba(255, 68, 68, 0.7);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(255, 68, 68, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(255, 68, 68, 0);
    }
}

/* Zalo Notification */
.zalo-notification {
    position: fixed;
    bottom: 30px;
    right: 100px;
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.2);
    z-index: 999;
    max-width: 320px;
    border: 1px solid #e0e0e0;
    opacity: 0;
    visibility: hidden;
    transform: translateX(400px);
    transition: all 0.4s ease-in-out;
}

.zalo-notification.show {
    opacity: 1;
    visibility: visible;
    transform: translateX(0);
}

.zalo-notification.hide {
    opacity: 0;
    visibility: hidden;
    transform: translateX(400px);
}

.notification-content {
    padding: var(--spacing-lg);
}

.notification-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    color: #0084ff;
    font-weight: 700;
}

.notification-header i {
    font-size: 1.3rem;
}

.notification-header span {
    flex-grow: 1;
    font-size: 1rem;
}

.notification-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: #999;
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color var(--transition);
}

.notification-close:hover {
    color: #333;
}

.notification-body {
    margin-bottom: var(--spacing-md);
}

.notification-body p {
    font-size: 0.95rem;
    color: var(--text-dark);
    line-height: 1.6;
    margin: 0;
}

.notification-btn {
    display: inline-block;
    background: var(--primary-gradient);
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    text-align: center;
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition);
    width: 100%;
    box-sizing: border-box;
}

.notification-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
}

/* =====================================================
   15. RESPONSIVE DESIGN
   ===================================================== */
@media (max-width: 768px) {
    /* Navigation */
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--white);
        padding: var(--spacing-lg) var(--spacing-md);
        gap: var(--spacing-md);
        border-bottom: 1px solid var(--border-color);
        z-index: 999;
    }

    .nav-links.active {
        display: flex;
    }

    .menu-toggle {
        display: flex;
    }

    /* Hero Section */
    .hero .container {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .hero-illustration {
        width: 200px;
        height: 200px;
        font-size: 5rem;
    }

    /* Intro Section */
    .intro-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .intro-text h2 {
        font-size: 1.75rem;
    }

    .intro-illustration {
        width: 200px;
        height: 200px;
        font-size: 5rem;
    }

    /* Visitors Card */
    .visitors-card {
        flex-direction: column;
        text-align: center;
        padding: var(--spacing-lg);
    }

    .visitors-icon {
        width: 80px;
        height: 80px;
        font-size: 2rem;
    }

    .visitors-count {
        font-size: 2.5rem;
    }

    /* Jobs Grid */
    .jobs-grid {
        grid-template-columns: 1fr;
    }

    /* Stats Grid */
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Footer */
    .footer-grid {
        grid-template-columns: 1fr;
    }

    /* Back to Top */
    .back-to-top {
        width: 45px;
        height: 45px;
        bottom: 20px;
        right: 20px;
    }

    /* Zalo Support */
    .zalo-support-btn {
        width: 50px;
        height: 50px;
        bottom: 80px;
        right: 20px;
        font-size: 1.5rem;
    }

    .pulse {
        top: -8px;
        right: -8px;
        width: 10px;
        height: 10px;
    }
}

@media (max-width: 480px) {
    /* Base */
    .container {
        padding: 0 var(--spacing-sm);
    }

    /* Navigation */
    .navbar-content {
        height: 60px;
    }

    .logo span {
        display: none;
    }

    .logo {
        font-size: 1.2rem;
    }

    /* Hero */
    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .hero .btn {
        width: 100%;
    }

    /* Intro */
    .intro-text h2 {
        font-size: 1.5rem;
    }

    .intro-highlight {
        font-size: 1.1rem;
    }

    .intro-features {
        gap: var(--spacing-sm);
    }

    .feature-item {
        padding: var(--spacing-sm);
        font-size: 0.9rem;
    }

    .intro-illustration {
        width: 150px;
        height: 150px;
        font-size: 3.5rem;
    }

    /* Visitors Card */
    .visitors-card {
        flex-direction: column;
        text-align: center;
        padding: var(--spacing-lg);
    }

    .visitors-icon {
        width: 70px;
        height: 70px;
        font-size: 1.5rem;
    }

    .visitors-count {
        font-size: 2rem;
    }

    .visitors-label {
        font-size: 0.9rem;
    }

    .visitors-subtitle {
        font-size: 0.9rem;
    }

    /* Section Header */
    .section-header h2 {
        font-size: 1.75rem;
    }

    /* Jobs */
    .job-card {
        padding: var(--spacing-lg);
    }

    /* Stats */
    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .stat-item h3 {
        font-size: 2rem;
    }

    /* CTA */
    .cta-content h2 {
        font-size: 1.75rem;
    }

    .cta-content p {
        font-size: 1rem;
    }

    /* Zalo Support */
    .zalo-support-btn {
        width: 55px;
        height: 55px;
        bottom: 70px;
        right: 15px;
        font-size: 1.4rem;
    }
}

/* =====================================================
   16. ANIMATIONS & TRANSITIONS
   ===================================================== */
@keyframes slideInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Typing Animation */
.typing-wrapper {
    display: inline-block;
    animation: typing 3s steps(30, end), blink-caret 0.75s step-end infinite;
    overflow: hidden;
    white-space: nowrap;
    border-right: 2px solid;
}

@keyframes typing {
    from {
        width: 0;
    }
    to {
        width: 100%;
    }
}

@keyframes blink-caret {
    from, to {
        border-color: transparent;
    }
    50% {
        border-color: var(--primary-color);
    }
}

/* AOS Custom Animation Override */
[data-aos] {
    opacity: 0;
}

[data-aos].aos-animate {
    animation: fadeIn 0.6s ease-out;
}

/* =====================================================
   17. PRINT STYLES
   ===================================================== */
@media print {
    .navbar,
    .back-to-top,
    .menu-toggle,
    .theme-toggle {
        display: none;
    }
}