/* --- General Styles --- */
:root {
    --primary-color: #003366; /* A professional dark blue */
    --secondary-color: #f4f4f4; /* Light grey background */
    --text-color: #333;
    --border-color: #ddd;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #fff;
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- Header --- */
.site-header {
    background-color: #fff;
    border-bottom: 1px solid var(--border-color);
    padding: 10px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    max-height: 50px; /* Adjust as needed */
}

.main-nav a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: bold;
    margin-left: 25px;
    transition: color 0.3s;
}

.main-nav a:hover {
    color: #0055a5;
}

/* --- Hero Section --- */
.hero {
    background-color: var(--secondary-color);
    padding: 60px 0;
    text-align: center;
}

.hero h1 {
    margin: 0;
    font-size: 2.5em;
    color: var(--primary-color);
}

.hero p {
    margin: 5px 0 0;
    font-size: 1.2em;
    color: #555;
}

/* --- Main Content & Product Sections --- */
section {
    padding: 60px 0;
    border-bottom: 1px solid var(--border-color);
}

section:last-of-type {
    border-bottom: none;
}

.product-grade {
    margin-bottom: 50px;
}

.product-grade:last-child {
    margin-bottom: 0;
}

h2 {
    font-size: 2em;
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 10px;
    margin-top: 0;
}

h3 {
    font-size: 1.4em;
    margin-top: 30px;
}

/* --- Table Styles --- */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th, td {
    border: 1px solid var(--border-color);
    padding: 12px;
    text-align: left;
}

th {
    background-color: var(--secondary-color);
    font-weight: bold;
}

tr:nth-child(even) {
    background-color: #fafafa;
}

.download-link {
    display: inline-block;
    text-decoration: none;
    color: var(--primary-color);
    font-weight: bold;
    transition: color 0.3s;
}

.download-link:hover {
    color: #0055a5;
}

/* --- Contact & Footer --- */
.contact-info {
    list-style: none;
    padding: 0;
}

.contact-info li {
    margin-bottom: 10px;
}

.site-footer {
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 20px 0;
}

/* --- Responsive Design --- */
@media (max-width: 768px) {
    .site-header .container {
        flex-direction: column;
    }
    .main-nav {
        margin-top: 10px;
    }
    .hero h1 {
        font-size: 2em;
    }
    /* Makes tables scroll horizontally on small screens */
    .table-wrapper {
        overflow-x: auto;
    }
}