/* Biến CSS */
:root {
    --primary-color: #007bff; /* Xanh dương - màu chủ đạo */
    --secondary-color: #ff8c00; /* Cam - màu nhấn */
    --text-dark: #333;
    --text-light: #f8f9fa;
    --bg-light: #f8f9fa;
    --bg-dark: #343a40;
    --card-bg: #fff;
    --border-light: #eee;
}

/* Reset và Typography cơ bản */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
    scroll-behavior: smooth;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.3s ease;
}

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

ul {
    list-style: none;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: auto;
    overflow: hidden;
    padding: 20px 0;
}

h1, h2, h3, h4 {
    font-family: 'Oswald', sans-serif;
    color: var(--text-dark);
    margin-bottom: 1rem;
}

/* Header */
.header {
    background: var(--card-bg);
    padding: 15px 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0;
}

.header .logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.header .logo img {
    height: 40px;
    width: 40px;
    border-radius: 5px;
}

.header .logo h1 {
    margin: 0;
    font-size: 1.8rem;
    color: var(--primary-color);
}

.header nav ul {
    display: flex;
    gap: 25px;
}

.header nav ul li a {
    color: var(--text-dark);
    font-weight: 500;
    font-size: 1rem;
    position: relative;
    padding-bottom: 5px;
}

.header nav ul li a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

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

.contact-header {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.1rem;
}

.contact-header i {
    color: var(--secondary-color);
    font-size: 1.3rem;
}

.contact-header a {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(rgba(0, 123, 255, 0.7), rgba(0, 123, 255, 0.7)), url('https://via.placeholder.com/1500x500/007bff/ffffff?text=Background+Dien+Lanh') no-repeat center center/cover;
    color: var(--text-light);
    text-align: center;
    padding: 80px 0;
}

.hero h2 {
    font-size: 3rem;
    margin-bottom: 15px;
    color: var(--text-light);
    line-height: 1.2;
}

.hero h2 strong {
    color: var(--secondary-color);
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 30px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.cta-button {
    display: inline-block;
    background: var(--secondary-color);
    color: var(--text-light);
    padding: 12px 25px;
    border-radius: 5px;
    font-size: 1.1rem;
    font-weight: 700;
    margin: 0 10px 10px 10px;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.cta-button:hover {
    background: #e67e00; /* Darker orange */
    transform: translateY(-2px);
}

.cta-button i {
    margin-right: 8px;
}

.secondary-cta {
    background: var(--primary-color);
    border: 2px solid var(--text-light);
}

.secondary-cta:hover {
    background: #0056b3; /* Darker blue */
}

/* Services Section */
.services {
    padding: 60px 0;
    text-align: center;
    background-color: var(--card-bg);
}

.services h3 {
    font-size: 2.2rem;
    margin-bottom: 40px;
    color: var(--primary-color);
}

.service-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.service-card {
    background: var(--bg-light);
    border: 1px solid var(--border-light);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: left;
}

.service-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.service-card i {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 15px;
    display: block;
}

.service-card h4 {
    font-size: 1.5rem;
    color: var(--text-dark);
    margin-bottom: 10px;
}

.service-card p {
    font-size: 0.95rem;
    color: #666;
}

/* Why Us Section */
.why-us {
    background-color: var(--primary-color);
    color: var(--text-light);
    padding: 60px 0;
    text-align: center;
}

.why-us h3 {
    color: var(--text-light);
    font-size: 2.2rem;
    margin-bottom: 40px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.feature-item {
    background: rgba(255, 255, 255, 0.1);
    padding: 30px;
    border-radius: 10px;
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.feature-item:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-5px);
}

.feature-item i {
    font-size: 2.8rem;
    color: var(--secondary-color);
    margin-bottom: 15px;
}

.feature-item h4 {
    font-size: 1.4rem;
    color: var(--text-light);
    margin-bottom: 10px;
}

.feature-item p {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.8);
}

/* Testimonials Section */
.testimonials {
    padding: 60px 0;
    background-color: var(--bg-light);
    text-align: center;
}

.testimonials h3 {
    font-size: 2.2rem;
    color: var(--primary-color);
    margin-bottom: 40px;
}

.testimonial-slider {
    display: flex;
    overflow: hidden; /* Only show one card at a time */
    width: 100%;
    margin: 0 auto 20px auto;
    position: relative;
    justify-content: center; /* Center current card */
}

.testimonial-card {
    background: var(--card-bg);
    border: 1px solid var(--border-light);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    flex: 0 0 80%; /* Takes 80% width */
    max-width: 600px;
    margin: 0 10px;
    text-align: center;
    display: none; /* Hidden by default, JS will show one */
}

.testimonial-card.active {
    display: block;
}

.testimonial-card p {
    font-style: italic;
    font-size: 1.1rem;
    color: #555;
    margin-bottom: 15px;
}

.testimonial-card span {
    font-weight: 700;
    color: var(--primary-color);
}

.slider-nav {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-top: 20px;
}

.dot {
    height: 12px;
    width: 12px;
    background-color: #bbb;
    border-radius: 50%;
    display: inline-block;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.dot.active, .dot:hover {
    background-color: var(--primary-color);
}


/* Footer */
.footer {
    background: var(--bg-dark);
    color: var(--text-light);
    padding: 50px 0 20px 0;
    font-size: 0.95rem;
}

.footer .footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.footer-col h4 {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-bottom: 20px;
}

.footer-col p, .footer-col ul li {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 10px;
}

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

.footer-col ul li a:hover {
    color: var(--secondary-color);
}

.footer-col i {
    margin-right: 10px;
    color: var(--secondary-color);
}

.social-links a {
    display: inline-block;
    margin-right: 15px;
    color: var(--text-light);
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: var(--secondary-color);
}

.copyright {
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 20px;
    margin-top: 20px;
    color: rgba(255, 255, 255, 0.5);
}

.logo-image {
    /* Đặt lớp (class) thay vì inline style để dễ quản lý */
    width: 40px; 
    height: 40px; 
    margin-right: 10px; /* Tạo khoảng cách giữa logo và chữ */
}

/* Responsive Design */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        text-align: center;
    }

    .header .logo {
        margin-bottom: 15px;
    }

    .header nav ul {
        flex-direction: column;
        gap: 10px;
        margin-bottom: 15px;
    }

    .hero h2 {
        font-size: 2.2rem;
    }

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

    .cta-button {
        display: block;
        margin: 10px auto;
        width: 80%;
    }

    .service-list, .features-grid, .footer-grid {
        grid-template-columns: 1fr;
    }

    .testimonial-card {
        flex: 0 0 95%; /* Make card wider on smaller screens */
    }

    .footer-col {
        text-align: center;
    }

    .footer-col i {
        margin-right: 5px;
    }

    .social-links {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .header .logo h1 {
        font-size: 1.5rem;
    }
    .contact-header {
        font-size: 1rem;
    }
    .hero h2 {
        font-size: 1.8rem;
    }
    .hero p {
        font-size: 0.9rem;
    }
    .services h3, .why-us h3, .testimonials h3 {
        font-size: 1.8rem;
    }
}