/* Import Font */
@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&family=Montserrat:wght@400;500;600;700&display=swap');

/* Variables */
:root {
    /* Vietnamese flag colors */
    --red: #da251d;
    --yellow: #ffff00;
    
    /* Supporting colors */
    --white: #ffffff;
    --black: #000000;
    --dark: #222222;
    --gray: #f5f5f5;
    --gray-dark: #666666;
    
    /* UI variables */
    --font-primary: 'Roboto', sans-serif;
    --font-heading: 'Montserrat', sans-serif;
    --border-radius: 8px;
    --border-radius-lg: 16px;
    --transition: all 0.3s ease;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
}

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

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

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--dark);
    background-color: var(--white);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    line-height: 1.3;
    margin-bottom: 20px;
    color: var(--dark);
}

h1 {
    font-size: 3rem;
    font-weight: 700;
}

h2 {
    font-size: 2.5rem;
    font-weight: 700;
}

h3 {
    font-size: 1.5rem;
    font-weight: 600;
}

p {
    margin-bottom: 20px;
}

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

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

ul, ol {
    list-style: none;
}

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

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-title {
    text-align: center;
    margin-bottom: 15px;
    position: relative;
    color: var(--dark);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--red);
    border-radius: 2px;
}

.section-desc {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 60px;
    color: var(--gray-dark);
    font-size: 1.1rem;
}

/* Buttons */
.btn-primary,
.btn-secondary,
.btn-cta {
    display: inline-block;
    padding: 12px 24px;
    font-weight: 600;
    text-align: center;
    border-radius: var(--border-radius);
    transition: var(--transition);
    cursor: pointer;
}

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

.btn-primary:hover {
    background-color: #c11c15;
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: var(--white);
    color: var(--red);
    border: 2px solid var(--red);
}

.btn-secondary:hover {
    background-color: var(--red);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.btn-cta {
    background-color: var(--yellow);
    color: var(--red);
    font-size: 1.1rem;
    padding: 14px 28px;
    font-weight: 700;
    box-shadow: var(--shadow);
}

.btn-cta:hover {
    background-color: #f0f000;
    color: var(--red);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: var(--white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
    padding: 15px 0;
    transition: var(--transition);
}

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

.logo a {
    display: flex;
    align-items: center;
    color: var(--dark);
    font-weight: 700;
    font-size: 1.5rem;
}

.logo a svg {
    margin-right: 10px;
}

.main-nav ul {
    display: flex;
    align-items: center;
}

.main-nav ul li {
    margin: 0 15px;
}

.main-nav ul li a {
    color: var(--dark);
    font-weight: 500;
    position: relative;
}

.main-nav ul li a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--red);
    transition: var(--transition);
}

.main-nav ul li a:hover {
    color: var(--red);
}

.main-nav ul li a:hover::after {
    width: 100%;
}

.menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 20px;
    cursor: pointer;
}

.menu-toggle span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--dark);
    transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

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

.menu-toggle.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* Hero Section */
.hero {
    padding: 150px 0 100px;
    background: linear-gradient(135deg, rgba(218, 37, 29, 0.05) 0%, rgba(255, 255, 0, 0.05) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M11 18c3.866 0 7-3.134 7-7s-3.134-7-7-7-7 3.134-7 7 3.134 7 7 7zm48 25c3.866 0 7-3.134 7-7s-3.134-7-7-7-7 3.134-7 7 3.134 7 7 7zm-43-7c1.657 0 3-1.343 3-3s-1.343-3-3-3-3 1.343-3 3 1.343 3 3 3zm63 31c1.657 0 3-1.343 3-3s-1.343-3-3-3-3 1.343-3 3 1.343 3 3 3zM34 90c1.657 0 3-1.343 3-3s-1.343-3-3-3-3 1.343-3 3 1.343 3 3 3z' fill='%23da251d' fill-opacity='0.03' fill-rule='evenodd'/%3E%3C/svg%3E");
    pointer-events: none;
}

.hero .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
    z-index: 1;
}

.hero-content {
    max-width: 600px;
}

.hero-content h1 {
    color: var(--red);
    margin-bottom: 10px;
    font-weight: 700;
}

.hero-content h2 {
    font-size: 2.5rem;
    margin-bottom: 25px;
}

.hero-content p {
    font-size: 1.1rem;
    margin-bottom: 30px;
    color: var(--gray-dark);
}

.hero-buttons {
    display: flex;
    gap: 20px;
}

.hero-graphic {
    max-width: 400px;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-15px);
    }
    100% {
        transform: translateY(0);
    }
}

/* Features Section */
.features {
    padding: 100px 0;
    background-color: var(--white);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-item {
    background-color: var(--white);
    border-radius: var(--border-radius);
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(218, 37, 29, 0.1);
}

.feature-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--red);
}

.feature-item:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    margin: 0 auto 20px;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: rgba(218, 37, 29, 0.05);
    border-radius: 50%;
}

.feature-item h3 {
    margin-bottom: 15px;
    color: var(--dark);
}

.feature-item p {
    color: var(--gray-dark);
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* How It Works Section */
.how-it-works {
    padding: 100px 0;
    background-color: var(--gray);
    position: relative;
}

.steps-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 50px 0;
}

.step-card {
    background-color: var(--white);
    border-radius: var(--border-radius);
    padding: 30px;
    text-align: center;
    box-shadow: var(--shadow);
    flex: 1;
    max-width: 300px;
    margin: 0 10px;
    position: relative;
    transition: var(--transition);
}

.step-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.step-number {
    width: 40px;
    height: 40px;
    background-color: var(--red);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    margin: 0 auto 20px;
}

.step-card h3 {
    margin-bottom: 15px;
    color: var(--dark);
}

.step-card p {
    color: var(--gray-dark);
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.step-icon {
    margin-top: 10px;
}

.step-arrow {
    flex: 0 0 auto;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--red);
}

.action-center {
    text-align: center;
    margin-top: 40px;
}

/* FAQ Section */
.faq-section {
    padding: 100px 0;
    background-color: var(--white);
}

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

.accordion-item {
    background-color: var(--white);
    border-radius: var(--border-radius);
    margin-bottom: 20px;
    overflow: hidden;
    box-shadow: var(--shadow);
    border: 1px solid rgba(218, 37, 29, 0.1);
}

.accordion-header {
    padding: 20px 25px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.accordion-header h3 {
    font-size: 1.1rem;
    margin: 0;
    color: var(--dark);
}

.accordion-icon {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--red);
    transition: var(--transition);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    padding: 0 25px;
    transition: max-height 0.3s ease;
}

.accordion-item.active .accordion-content {
    max-height: 300px;
    padding-bottom: 20px;
}

.accordion-content p {
    color: var(--gray-dark);
    margin: 0;
    padding-top: 10px;
}

/* CTA Section */
.cta-section {
    padding: 80px 0;
    background-color: var(--gray);
}

.cta-box {
    background: linear-gradient(120deg, var(--red), #c11c15);
    border-radius: var(--border-radius-lg);
    padding: 60px 40px;
    color: var(--white);
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.cta-box::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background-image: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 20l20 20-20-20L20 0 0 20z' fill='%23ffff00' fill-opacity='0.1' fill-rule='evenodd'/%3E%3C/svg%3E");
    animation: ctaBackground 30s linear infinite;
    z-index: 0;
}

@keyframes ctaBackground {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

.cta-box h2 {
    color: var(--white);
    margin-bottom: 20px;
    position: relative;
    z-index: 1;
}

.cta-box p {
    color: rgba(255, 255, 255, 0.9);
    max-width: 700px;
    margin: 0 auto 30px;
    position: relative;
    z-index: 1;
}

/* Footer */
.site-footer {
    background-color: var(--dark);
    color: var(--white);
    padding: 80px 0 20px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    margin-bottom: 60px;
}

.footer-brand {
    display: flex;
    margin-bottom: 30px;
    max-width: 350px;
}

.footer-logo {
    margin-right: 15px;
}

.footer-brand-text h3 {
    color: var(--white);
    margin-bottom: 10px;
}

.footer-brand-text p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0;
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 60px;
}

.footer-column h4 {
    color: var(--white);
    margin-bottom: 20px;
    position: relative;
}

.footer-column h4::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 30px;
    height: 2px;
    background-color: var(--yellow);
}

.footer-column ul li {
    margin-bottom: 12px;
}

.footer-column ul li a {
    color: rgba(255, 255, 255, 0.7);
    transition: var(--transition);
}

.footer-column ul li a:hover {
    color: var(--yellow);
    padding-left: 5px;
}

.keywords li {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.85rem;
    margin-bottom: 8px;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.5);
}

/* Responsive Styles */
@media (max-width: 1024px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .hero-content h2 {
        font-size: 2.2rem;
    }
}

@media (max-width: 992px) {
    .steps-wrapper {
        flex-direction: column;
        gap: 30px;
    }
    
    .step-card {
        width: 100%;
        max-width: 100%;
        margin: 0;
    }
    
    .step-arrow {
        transform: rotate(90deg);
        margin: 10px 0;
    }
    
    .footer-content {
        flex-direction: column;
    }
    
    .footer-links {
        margin-top: 30px;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 15px;
    }
    
    h1 {
        font-size: 2.5rem;
    }
    
    h2 {
        font-size: 2rem;
    }
    
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 120px 0 80px;
    }
    
    .hero .container {
        flex-direction: column;
    }
    
    .hero-content {
        text-align: center;
        margin-bottom: 50px;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .menu-toggle {
        display: flex;
    }
    
    .main-nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        height: 100vh;
        background-color: var(--white);
        z-index: 1000;
        padding: 80px 30px 30px;
        box-shadow: -5px 0 30px rgba(0, 0, 0, 0.1);
        transition: var(--transition);
    }
    
    .main-nav.active {
        right: 0;
    }
    
    .main-nav ul {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .main-nav ul li {
        margin: 0 0 20px;
        width: 100%;
    }
    
    .main-nav ul li a {
        display: block;
        padding: 10px 0;
        font-size: 1.1rem;
    }
    
    .cta-nav a {
        display: block;
        text-align: center;
        margin-top: 10px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 2.2rem;
    }
    
    .hero-content h2 {
        font-size: 1.8rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        gap: 15px;
    }
    
    .hero-buttons a {
        width: 100%;
        text-align: center;
    }
    
    .cta-box {
        padding: 40px 20px;
    }
    
    .accordion-header {
        padding: 15px 20px;
    }
    
    .accordion-header h3 {
        font-size: 1rem;
        max-width: 80%;
    }
}