:root {
    --primary-color: #301a4b; /* Deep Purple */
    --secondary-color: #4a00e0; /* Brighter Purple/Blue */
    --accent-color: #8e2de2; /* Lighter Purple Accent */
    --text-color-light: #ffffff;
    --text-color-dark: #333333;
    --text-color-medium: #555555; /* For less prominent text */
    --bg-light: #f4f4f9; /* Light grey-purple background */
    --card-bg: #ffffff;
    --separator-color: var(--accent-color);
    --link-color: var(--secondary-color);
    --link-hover-color: var(--accent-color);

    --header-height: 80px; /* Header height */

    /* Updated font stack to prioritize specified fonts */
    --font-body: 'Noto Sans SC', 'Open Sans', sans-serif;
    --font-heading: 'Exo 2', 'Noto Sans SC', sans-serif;

    --section-padding: 60px 0; /* Standard padding for sections */
    --container-padding: 0 15px; /* Standard padding within containers */
}

/* Apply Noto Sans SC to body for Chinese characters */
body {
    font-family: var(--font-body);
    color: var(--text-color-dark);
    line-height: 1.7; /* Slightly increased line-height for readability */
    margin: 0;
    padding: 0;
    background-color: #fff;
    font-size: 16px; /* Base font size */
    -webkit-font-smoothing: antialiased; /* Smoother fonts */
    -moz-osx-font-smoothing: grayscale;
}

.container {
    width: 90%;
    max-width: 1100px;
    margin: 0 auto;
    padding: var(--container-padding);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    margin-top: 0;
    margin-bottom: 0.8em; /* Consistent bottom margin */
    color: var(--primary-color); /* Default heading color */
    line-height: 1.3;
}

h1 { font-size: 2.8rem; } /* Example size */
h2 { font-size: 2.2rem; }
h3 { font-size: 1.8rem; }
h4 { font-size: 1.3rem; }

p {
    margin-top: 0;
    margin-bottom: 1.2em;
    color: var(--text-color-medium);
}

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

img {
    max-width: 100%;
    height: auto;
    display: block; /* Prevent bottom space */
}

/* --- Global Elements & Utilities --- */
section {
    padding: var(--section-padding);
}

.bg-light {
    background-color: var(--bg-light);
}

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

/* Separator style */
.separator {
    width: 80px;
    height: 3px;
    background-color: var(--separator-color);
    border: none;
    margin: 15px auto 30px auto; /* Center align in text-center */
}
/* Adjust margin if not in text-center */
.separator:not(:only-child) { /* Avoid extra margin if it's the only child */
     margin-left: 0;
     margin-right: 0;
     margin-top: 15px;
     margin-bottom: 30px;
}
.text-center .separator {
    margin-left: auto;
    margin-right: auto;
}

/* --- Header --- */
.site-header {
    position: absolute; /* Start transparent over the banner */
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: rgba(51, 51, 51, 0.3); /* Slightly transparent dark overlay initially */
    transition: background-color 0.4s ease, box-shadow 0.4s ease;
    height: var(--header-height);
    display: flex;
    align-items: center;
}

.site-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    padding: 0 15px; /* Ensure padding matches global container padding */
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo img {
    height: 55px; /* Adjusted for 80px header height */
    width: auto;
    /* Removed the comment, height seems reasonable */
}

.logo-text {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-color-light);
    text-shadow: 0 1px 2px rgba(0,0,0,0.5);
    transition: color 0.3s ease, text-shadow 0.3s ease;
}

.main-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
}

.main-nav li {
    margin-left: 30px; /* Increased spacing */
}

.main-nav a {
    font-weight: 500; /* Slightly less bold */
    font-size: 0.95rem;
    color: var(--text-color-light);
    text-shadow: 0 1px 2px rgba(0,0,0,0.5);
    text-decoration: none;
    padding: 5px 0;
    border-bottom: 2px solid transparent;
    transition: color 0.3s ease, border-color 0.3s ease;
}

.main-nav a:hover,
.main-nav a.active {
    color: #eee; /* Keep light on hover/active in transparent state */
    border-bottom-color: rgba(255, 255, 255, 0.7);
    text-decoration: none; /* Remove underline */
}

/* Styles for header when scrolled */
.site-header.scrolled {
    position: fixed;
    background-color: rgba(255, 255, 255, 0.98); /* Almost opaque white */
    backdrop-filter: blur(5px); /* Optional: blur effect */
    -webkit-backdrop-filter: blur(5px);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.site-header.scrolled .logo-text {
    color: var(--primary-color);
    text-shadow: none;
}

.site-header.scrolled .main-nav a {
    color: var(--primary-color);
    text-shadow: none;
}

.site-header.scrolled .main-nav a:hover,
.site-header.scrolled .main-nav a.active {
    color: var(--secondary-color);
    border-bottom-color: var(--secondary-color);
}

/* --- Language Switcher Styles --- */
.language-switcher {
    margin-left: 20px; /* Space between nav and switcher */
    color: var(--text-color-light); /* Initial color */
    transition: color 0.3s ease;
}

.site-header.scrolled .language-switcher {
    color: var(--primary-color); /* Color when header is scrolled */
}

.language-switcher button {
    background: none;
    border: none;
    color: inherit; /* Inherit color from parent (.language-switcher) */
    cursor: pointer;
    padding: 0 5px;
    margin: 0 2px;
    font-size: inherit;
    vertical-align: middle; /* Align buttons nicely */
    text-shadow: inherit; /* Inherit text-shadow too */
    transition: opacity 0.3s ease, text-decoration 0.3s ease;
}

.language-switcher button.active-lang {
    font-weight: bold;
    text-decoration: underline;
    cursor: default; /* Indicate it's the current one */
    opacity: 1;
}

/* Optional: Style for non-active */
.language-switcher button:not(.active-lang) {
    font-weight: normal;
    text-decoration: none;
    opacity: 0.8; /* Example to de-emphasize */
}
.language-switcher button:not(.active-lang):hover {
    opacity: 1;
    text-decoration: underline;
}

/* --- Mobile Menu Toggle --- */
#mobile-menu-toggle {
   background: none;
   border: none;
   font-size: 1.8rem; /* Make it larger */
   cursor: pointer;
   display: none; /* Hide by default, show in media query */
   margin-left: 15px; /* Space from language switcher */
   color: var(--text-color-light); /* Initial color */
   transition: color 0.3s ease;
   padding: 0; /* Remove padding if it causes alignment issues */
   line-height: 1; /* Ensure tight bounding box */
}

.site-header.scrolled #mobile-menu-toggle {
    color: var(--primary-color); /* Color when scrolled */
}

/* --- Hero Section --- */
.hero {
    position: relative;
    min-height: 85vh; /* Slightly taller */
    background-size: cover;
    background-position: center center;
    color: var(--text-color-light);
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: calc(var(--header-height) + 40px); /* Ensure content below header */
    padding-bottom: 60px;

    /* Apply gradient overlay directly to background-image */
    /* The actual image URL comes from inline style in HTML */
    background-image: linear-gradient(rgba(30, 10, 50, 0.65), rgba(48, 26, 75, 0.75)), var(--bg-image, url('../images/banner.jpg'));
    background-repeat: no-repeat;
}

.hero-content {
    position: relative; /* Already relative */
    z-index: 2;
    max-width: 800px; /* Limit width of hero text */
}

.hero h1 {
    font-size: 3.5rem; /* Larger heading */
    margin-bottom: 25px;
    color: var(--text-color-light);
    font-weight: 700;
    text-shadow: 0 2px 5px rgba(0,0,0,0.6);
    line-height: 1.2;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 40px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    color: rgba(255, 255, 255, 0.9); /* Slightly less bright than pure white */
    text-shadow: 0 1px 3px rgba(0,0,0,0.5);
}

/* Primary CTA Button Style */
.cta-button {
    display: inline-block;
    background: linear-gradient(to right, var(--secondary-color), var(--accent-color));
    color: var(--text-color-light);
    padding: 14px 35px; /* Larger padding */
    border-radius: 30px; /* Rounded */
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    border: none;
}
.cta-button:hover {
    background: linear-gradient(to right, var(--accent-color), var(--secondary-color));
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
    transform: translateY(-2px);
    text-decoration: none; /* Keep no underline */
    color: var(--text-color-light);
}

/* --- Intro Section --- */
/* Styles restored */
.intro-section {
    padding: var(--section-padding);
}
.intro-section h2 {
    margin-bottom: 10px; /* Reduced margin before separator */
}
.intro-section p {
    max-width: 800px; /* Limit text width */
    margin-left: auto;
    margin-right: auto;
    font-size: 1.1rem;
    color: var(--text-color-medium);
}

/* --- Feature Section --- */
/* Styles restored */
.feature-section {
    padding: var(--section-padding);
    overflow: hidden; /* Contain elements */
}
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 50px;
    align-items: center;
}
/* Order adjustment for image-left layout */
.feature-section.image-left .feature-image {
    order: 0; /* Image first */
}
.feature-section.image-left .feature-content {
    order: 1; /* Text second */
}
/* Styles for image-right layout (if you create one) */
/*
.feature-section.image-right .feature-image { order: 1; }
.feature-section.image-right .feature-content { order: 0; }
*/
.feature-image img {
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}
.feature-content {
    /* Padding might not be needed if gap is sufficient */
}
.feature-content h3 {
    margin-bottom: 15px;
    font-size: 1.9rem;
}
.feature-content p {
    margin-bottom: 25px;
    color: var(--text-color-medium);
}
/* Learn More link style (button-like) */
.learn-more {
    display: inline-block;
    font-weight: 600;
    color: var(--primary-color);
    padding: 10px 20px;
    border: 1px solid var(--primary-color);
    border-radius: 5px;
    transition: all 0.3s ease;
}
.learn-more:hover {
    background-color: var(--primary-color);
    color: var(--text-color-light);
    text-decoration: none;
}

/* Learn More Inline Style (for overview) */
.learn-more-inline {
    font-weight: 600;
    color: var(--link-color);
    text-decoration: none;
    transition: color 0.3s ease;
}
.learn-more-inline:hover {
    color: var(--link-hover-color);
    text-decoration: underline;
}


/* --- Overview Section --- */
/* Styles restored */
.overview-section {
    padding: var(--section-padding);
    background-color: var(--bg-light); /* Ensure light background */
}
.overview-section h2 {
    margin-bottom: 10px;
}
.overview-grid {
    display: grid;
    /* Responsive columns: 1 on small, 3 on large screens */
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px; /* Space after separator */
}
.overview-item {
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 3px 10px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center; /* Center content inside item */
}
.overview-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}
.overview-icon {
    width: 50px; /* Adjust icon size */
    height: 50px;
    margin: 0 auto 20px auto; /* Center icon horizontally */
    /* Add filter if icons are single color and need coloring */
    /* filter: invert(15%) sepia(21%) saturate(5877%) hue-rotate(248deg) brightness(90%) contrast(97%); */ /* Example filter to match --primary-color */
}
.overview-item h4 {
    margin-bottom: 15px;
    font-size: 1.25rem;
    color: var(--primary-color);
}
.overview-item p {
    font-size: 0.95rem;
    color: var(--text-color-medium);
    margin-bottom: 20px; /* Space before link */
}

/* --- Timeline Section --- */
.timeline-section {
    padding: var(--section-padding);
    background-color: #fff; /* Or keep transparent if desired */
}

.timeline-section h2 {
    margin-bottom: 10px;
}

.timeline {
    position: relative;
    max-width: 800px; /* Adjust max-width as needed */
    margin: 50px auto; /* Add vertical margin and center */
}

/* The vertical line */
.timeline::after {
    content: '';
    position: absolute;
    width: 4px; /* Thickness of the line */
    background-color: var(--primary-color); /* Color of the line */
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -2px; /* Center the line */
}

/* Container around content */
.timeline-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 50%;
    box-sizing: border-box; /* Ensure padding doesn't add to width */
}

/* The circles on the timeline */
.timeline-item::after {
    content: '';
    position: absolute;
    width: 16px; /* Size of the circle */
    height: 16px;
    right: -10px; /* Position circle slightly offset from center */
    background-color: #fff; /* Background of the circle */
    border: 4px solid var(--secondary-color); /* Border color of the circle */
    top: 15px; /* Align with top of content box */
    border-radius: 50%;
    z-index: 1;
}

/* Place the container to the left */
.timeline-item.left {
    left: 0;
    padding-right: 30px; /* Add space between text and line */
    text-align: right; /* Align text to the right */
}

/* Place the container to the right */
.timeline-item.right {
    left: 50%;
    padding-left: 30px; /* Add space between line and text */
    text-align: left; /* Align text to the left */
}

/* Adjust circle position for left items */
.timeline-item.left::after {
    left: -8px; /* Adjust position for left side */
    right: auto;
}

/* Fix the circle for right items (already correct) */
/* .timeline-item.right::after { right: -8px; } */


/* Content box */
.timeline-content {
    padding: 20px 30px;
    background-color: var(--bg-light); /* Background for content */
    position: relative;
    border-radius: 6px;
    box-shadow: 0 3px 8px rgba(0,0,0,0.05);
    display: inline-block; /* Fit content */
    text-align: left; /* Ensure text inside is left aligned */
    width: auto; /* Let content determine width */
    max-width: 100%; /* Prevent overflow */
}

/* Timeline date/year styling */
.timeline-date {
    font-size: 0.9rem;
    font-weight: bold;
    color: var(--secondary-color);
    margin-bottom: 5px;
    display: block; /* Ensure it's on its own line */
}

/* Timeline title */
.timeline-content h4 {
    margin-top: 0;
    margin-bottom: 10px;
    font-size: 1.2rem;
    color: var(--primary-color);
}

/* Timeline description */
.timeline-content p {
    margin: 0;
    font-size: 0.95rem;
    color: var(--text-color-medium);
    line-height: 1.6;
    white-space: normal; /* Allow text wrapping */
}

/* --- CTA Section --- */
/* Styles restored */
.cta-section {
    position: relative; /* For overlay positioning */
    padding: 80px 0; /* More vertical padding */
    background-size: cover;
    background-position: center;
    color: var(--text-color-light);
    /* background-image URL is set inline in HTML */
}
.cta-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(30, 10, 50, 0.8); /* Darker overlay */
    z-index: 1;
}
.cta-content {
    position: relative; /* To stay above overlay */
    z-index: 2;
    max-width: 700px; /* Limit width */
    margin: 0 auto; /* Center content */
}
.cta-content h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--text-color-light); /* Ensure heading is light */
    text-shadow: 0 1px 3px rgba(0,0,0,0.4);
}
.cta-content p {
    font-size: 1.1rem;
    margin-bottom: 30px;
    color: rgba(255, 255, 255, 0.9);
    text-shadow: 0 1px 2px rgba(0,0,0,0.4);
}
/* Secondary CTA Button Style */
.cta-button-secondary {
    display: inline-block;
    background-color: transparent;
    color: var(--text-color-light);
    padding: 12px 30px;
    border-radius: 30px; /* Match primary button */
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    border: 2px solid var(--text-color-light);
    transition: all 0.3s ease;
}
.cta-button-secondary:hover {
    background-color: var(--text-color-light);
    color: var(--primary-color);
    text-decoration: none;
    transform: translateY(-2px);
}


/* --- Placeholder Styles (Keep these as you build out pages) --- */
/* --- Page Header (for inner pages) --- */
.page-header { /* ... */ }
.page-header h1 { /* ... */ }
.page-header p { /* ... */ }
/* --- Guiding Principle / Quote --- */
.guiding-principle p { /* ... */ }
.inspirational-quote { /* ... */ }
.inspirational-quote p { /* ... */ }
.inspirational-quote cite { /* ... */ }
/* --- Research / Product Cards --- */
.card { /* ... */ }
.card-image { /* ... */ }
.placeholder-image { /* ... */ }
.card-content { /* ... */ }
.card-content h3 { /* ... */ }
.product-status { /* ... */ }
.product-status.future { /* ... */ }
.product-status.completed, .product-status { /* ... */ }
.research-grid, .product-grid { /* ... */ }
/* --- Collaboration Section --- */
.offerings-grid { /* ... */ }
.offering-icon { /* ... */ }
.target-audience p { /* ... */ }
.audience-tags span { /* ... */ }
.final-cta .contact-email { /* ... */ }
.final-cta .contact-email a { /* ... */ }
.final-cta .contact-email a:hover { /* ... */ }


/* --- Footer --- */
.site-footer {
    background-color: var(--primary-color); /* Use primary dark color */
    color: rgba(255, 255, 255, 0.7); /* Light text, slightly transparent */
    padding: 50px 0 0 0; /* Padding top, no padding bottom initially */
}
.footer-content {
    display: grid;
    /* grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); */
    grid-template-columns: 1.5fr 1fr 1fr; /* Logo column wider */
    gap: 30px;
    padding-bottom: 40px; /* Space before copyright */
    border-bottom: 1px solid rgba(255, 255, 255, 0.1); /* Subtle separator */
    margin-bottom: 20px; /* Space between content and copyright */
}
.footer-logo {
    display: flex;
    align-items: flex-start; /* Align logo to top */
    gap: 10px;
    /* No extra margin needed if grid handles spacing */
}
.footer-logo img {
    height: 40px; /* Footer logo size */
    opacity: 0.9;
}
/* Optional footer logo text style */
/* .footer-logo-text { font-size: 1.2rem; color: #fff; font-weight: 600; } */

.footer-contact h4, .footer-nav h4 {
    color: var(--text-color-light);
    font-size: 1.1rem;
    margin-bottom: 15px;
    font-weight: 600;
}
.footer-contact p {
    margin-bottom: 8px;
    font-size: 0.9rem;
    line-height: 1.6;
    /* Handle new lines in address */
    white-space: pre-line;
}
.footer-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}
.footer-nav li {
    margin-bottom: 8px;
}
.footer-nav a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}
.footer-nav a:hover {
    color: var(--text-color-light);
    text-decoration: underline;
}
.copyright {
    padding-bottom: 20px; /* Final padding at the bottom */
}
.copyright p {
    margin: 0;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.5);
}
.copyright a { /* Style for potential Beian link */
    color: rgba(255, 255, 255, 0.5);
}
.copyright a:hover {
    color: rgba(255, 255, 255, 0.8);
}

/* --- Responsive Adjustments --- */
@media (max-width: 992px) {
     /* Adjust grid for feature section */
    .grid-2 {
        grid-template-columns: 1fr; /* Stack on medium screens */
        gap: 30px;
    }
     /* Reset order if needed or keep image first */
    .feature-section.image-left .feature-image,
    .feature-section.image-left .feature-content {
        order: 0; /* Reset order */
        text-align: center; /* Center text when stacked */
    }
     .feature-section.image-left .feature-image img {
         margin: 0 auto; /* Center image */
     }
     .feature-content h3 {
         text-align: center; /* Center heading */
     }

     .hero h1 { font-size: 3rem; }
     h1 { font-size: 2.5rem; }
     h2 { font-size: 2rem; }
}

@media (max-width: 768px) { /* Adjust breakpoint as needed */
    :root {
        --header-height: 70px; /* Slightly smaller header on mobile */
    }

    .logo img { height: 45px; }
    .logo-text { font-size: 1.3rem; }

    h1 { font-size: 2.2rem; }
    .hero h1 { font-size: 2.5rem; }
    h2 { font-size: 1.8rem; }
    h3 { font-size: 1.6rem; }

    /* Mobile Nav adjustments */
    .main-nav {
        /* The JS toggles the .active class on the parent .main-nav element */
        /* position: absolute; top: var(--header-height); left: 0; width: 100%; background: #fff; */
    }
    .main-nav ul {
        display: none; /* Hide by default */
        flex-direction: column; /* Stack links vertically */
        align-items: center; /* Center links */
        width: 100%;
        background-color: rgba(255, 255, 255, 0.98); /* Background for mobile dropdown */
        position: absolute;
        top: var(--header-height); /* Position below header */
        left: 0;
        padding: 15px 0;
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        border-top: 1px solid #eee; /* Add a subtle top border */
    }
     .main-nav.active ul { /* Class added by JS to show */
        display: flex;
     }

    .main-nav li {
        margin: 10px 0; /* Vertical spacing */
        margin-left: 0; /* Remove left margin */
    }
    .main-nav a {
        color: var(--primary-color); /* Dark links on mobile dropdown */
        text-shadow: none;
        padding: 10px 20px;
        border-bottom: none; /* Remove bottom border */
        display: block; /* Make links take full width */
        width: 100%; /* Ensure full width for centering */
        text-align: center;
    }
     .main-nav a:hover, .main-nav a.active {
         color: var(--secondary-color);
         background-color: rgba(0,0,0,0.03); /* Slight background on hover/active */
         border-bottom-color: transparent; /* Ensure no border */
     }

    /* Show Mobile Toggle Button */
    #mobile-menu-toggle {
        display: block;
    }

    /* Responsive adjustments for timeline */
    .timeline::after {
        left: 31px; /* Position line to the left */
    }
    .timeline-item {
        width: 100%;
        padding-left: 70