:root {
    --primary-color: #0056a7;
    --secondary-color: #004a91;
    --accent-color: #007bff;
    --text-color: #2b2d42;
    --light-text: #555b6e;
    --background: #f8f9fa;
    --card-bg: #ffffff;
    --border-radius: 12px;
    --box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Poppins', sans-serif;
    line-height: 1.8;
    color: var(--text-color);
    background-color: var(--background);
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

body.vi {
    font-family: 'Roboto', sans-serif;
}

header {
    margin-bottom: 40px;
    text-align: center;
    animation: fadeIn 1s ease-in-out;
    position: relative;
}

.logo {
    max-width: 200px;
    position: relative;
    display: block;
    margin: 0 auto 30px;
}

h1 {
    font-size: 2.8rem;
    margin-bottom: 15px;
    color: var(--primary-color);
    font-weight: 700;
    position: relative;
    display: inline-block;
}

h1::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 70px;
    height: 4px;
    background: var(--secondary-color);
    border-radius: 2px;
}

h2 {
    font-size: 1.9rem;
    margin-top: 35px;
    margin-bottom: 20px;
    color: var(--secondary-color);
    font-weight: 600;
    display: flex;
    align-items: center;
}

h2 i {
    margin-right: 10px;
    font-size: 1.5rem;
}

p {
    margin-bottom: 0;
    color: var(--light-text);
    text-align: justify;
}

ul {
    margin-left: 25px;
    margin-bottom: 10px;
}

li {
    margin-bottom: 0;
    position: relative;
    padding-left: 5px;
    color: var(--light-text);
}

.container {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(to right, var(--primary-color), var(--accent-color));
}

section {
    margin-bottom: 0;
    padding: 5px;
    border-radius: var(--border-radius);
    background-color: rgba(255, 255, 255, 0.7);
    box-shadow: 0 4px 15px rgba(0,0,0,0.03);
    transition: var(--transition);
}

section:hover {
    box-shadow: 0 6px 20px rgba(0,0,0,0.06);
    transform: translateY(-2px);
}

.last-updated {
    font-size: 0.9rem;
    color: #6c757d;
    text-align: center;
    margin-bottom: 30px;
    font-style: italic;
}

.company-name {
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--primary-color);
    text-align: center;
}

.contact-info {
    background-color: transparent;
    padding: 5px;
    border-radius: var(--border-radius);
    margin-top: 35px;
}

.contact-info h3 {
    color: var(--secondary-color);
    margin-bottom: 15px;
    font-size: 1.5rem;
    display: flex;
    align-items: center;
}

.contact-info h3 i {
    margin-right: 10px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 10px;
}

.contact-item i {
    margin-right: 10px;
    color: var(--primary-color);
    margin-top: 5px;
}

.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

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

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 768px) {
    h1 {
        font-size: 2.2rem;
    }
    h2 {
        font-size: 1.6rem;
    }
    .container {
        padding: 25px 15px;
    }
    section {
        padding: 5px;
    }
    body {
        padding: 15px;
    }
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
    }
    .logo {
        max-width: 180px;
        margin-bottom: 25px;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.9rem;
    }
    h2 {
        font-size: 1.4rem;
    }
    body {
        padding: 10px;
    }
    .container {
        padding: 15px 12px;
    }
    section {
        padding: 5px;
    }
    .logo {
        max-width: 150px;
        margin-bottom: 20px;
    }
}