/* General Body & Typography */
body {
    font-family: 'Noto Sans SC', 'Montserrat', sans-serif;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    color: #333;
    line-height: 1.6;
    background-color: #f8fbfd;
    scroll-behavior: smooth; /* Smooth scrolling for anchor links */
}

h1, h2, h3, h4 {
    font-family: 'Montserrat', sans-serif;
    color: #2c3e50;
    font-weight: 700;
    line-height: 1.2;
}

h1 { font-size: 3.5rem; } /* 56px */
h2 { font-size: 2.8rem; } /* 44.8px */
h3 { font-size: 2.2rem; } /* 35.2px */
h4 { font-size: 1.8rem; } /* 28.8px */

p {
    font-size: 1.1rem; /* 17.6px */
    margin-bottom: 1rem;
}

a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s ease, background-color 0.3s ease;
}

a:hover {
    color: #2980b9;
}

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

/* Sections Padding */
.section-padding {
    padding: 80px 0;
}

.section-padding.bg-light {
    background-color: #f4f7fa;
}

.section-padding.bg-dark {
    background-color: #2c3e50;
    color: #fff;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.8rem;
    margin-bottom: 15px;
    position: relative;
    padding-bottom: 15px;
}

.section-header h2::after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: 0;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background-color: #3498db;
    border-radius: 2px;
}

.section-header p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    color: #666;
}

.section-padding.bg-dark .section-header h2,
.section-padding.bg-dark .section-header p {
    color: #fff;
}
.section-padding.bg-dark .section-header h2::after {
    background-color: #fff;
}


/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    text-align: center;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary {
    background-color: #3498db;
    color: #fff !important;
    box-shadow: 0 4px 8px rgba(52, 152, 219, 0.3);
}

.btn-primary:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(52, 152, 219, 0.4);
}

.btn-secondary {
    background-color: transparent;
    color: #fff !important;
    border: 2px solid #fff;
}

.btn-secondary:hover {
    background-color: rgba(255,255,255,0.1);
    transform: translateY(-2px);
}

.btn-accent { /* For CTA */
    background-color: #f39c12;
    color: #fff !important;
    box-shadow: 0 4px 8px rgba(243, 156, 18, 0.3);
}

.btn-accent:hover {
    background-color: #e67e22;
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(243, 156, 18, 0.4);
}

.btn-lg {
    padding: 15px 35px;
    font-size: 1.25rem;
}

/* Header & Navigation */
header {
    background-color: #fff;
    padding: 15px 0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    position: sticky;
    top: 0;
    z-index: 1000;
}

header nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap; /* Allows wrapping on smaller screens */
}

.logo {
    font-size: 2.2rem; /* 35.2px */
    font-weight: 700;
    color: #3498db;
    text-transform: uppercase;
}

.nav-menu {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 30px;
}

.nav-menu li a {
    font-weight: 600;
    color: #555;
    font-size: 1rem;
    padding: 5px 0;
    position: relative;
}

.nav-menu li a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 3px;
    background-color: #3498db;
    transition: width 0.3s ease;
}

.nav-menu li a:hover::after,
.nav-menu li a.active::after {
    width: 100%;
}

/* Hamburger Menu (Mobile) */
.hamburger {
    display: none; /* Hidden on desktop */
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 21px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
}

.hamburger .bar {
    width: 100%;
    height: 3px;
    background-color: #333;
    border-radius: 2px;
    transition: all 0.3s ease;
}

.hamburger.active .bar:nth-child(1) { transform: translateY(9px) rotate(45deg); }
.hamburger.active .bar:nth-child(2) { opacity: 0; }
.hamburger.active .bar:nth-child(3) { transform: translateY(-9px) rotate(-45deg); }


/* Hero Section */
.hero {
    background: linear-gradient(rgba(0,0,0,0.65), rgba(0,0,0,0.65)), url('https://via.placeholder.com/1920x800/3a4750/ffffff?text=PCDN+Hero+Background') no-repeat center center/cover;
    color: #fff;
    text-align: center;
    padding: 120px 20px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 600px;
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 4.2rem; /* 67.2px */
    margin-bottom: 25px;
    color: #fff;
    line-height: 1.1;
}

.hero p {
    font-size: 1.5rem; /* 24px */
    max-width: 800px;
    margin-bottom: 50px;
    color: #eee;
}

.hero-actions .btn {
    margin: 0 15px;
}


/* About PCDN Section */
.about-pcdn .about-content {
    display: flex;
    align-items: center;
    gap: 40px;
    flex-wrap: wrap;
}

.about-pcdn .about-text {
    flex: 2;
    min-width: 300px;
}

.about-pcdn .about-image {
    flex: 1;
    min-width: 300px;
    text-align: center;
}

.about-pcdn .about-image img {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

.about-pcdn .benefit-list {
    list-style: none;
    padding: 0;
    margin-top: 20px;
}

.about-pcdn .benefit-list li {
    font-size: 1.1rem;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
}

.about-pcdn .benefit-list li i {
    color: #27ae60;
    margin-right: 10px;
    font-size: 1.3rem;
}


/* Features Section */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.feature-item {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.12);
}

.feature-item .icon-large {
    font-size: 4.5rem; /* 72px */
    color: #3498db;
    margin-bottom: 20px;
    line-height: 1;
}

.feature-item h3 {
    font-size: 1.8rem; /* 28.8px */
    margin-bottom: 15px;
}

.feature-item p {
    font-size: 1rem;
    color: #666;
}


/* Solutions Section */
.solution-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.solution-item {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    text-align: left;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.solution-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.12);
}

.solution-item .solution-icon {
    font-size: 3rem; /* 48px */
    color: #3498db;
    margin-bottom: 15px;
}

.solution-item h3 {
    font-size: 1.8rem;
    margin-bottom: 15px;
    color: #2c3e50;
}

.solution-item p {
    font-size: 1rem;
    color: #666;
}

/* Technology Section */
.tech-overview {
    display: flex;
    align-items: center;
    gap: 40px;
    margin-bottom: 80px;
    flex-wrap: wrap;
}

.tech-overview .tech-text {
    flex: 2;
    min-width: 300px;
}

.tech-overview .tech-image {
    flex: 1;
    min-width: 300px;
    text-align: center;
}

.tech-overview .tech-image img {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.tech-item {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.tech-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.12);
}

.tech-item .tech-icon {
    font-size: 3.5rem; /* 56px */
    color: #3498db;
    margin-bottom: 15px;
}

.tech-item h3 {
    font-size: 1.6rem; /* 25.6px */
    margin-bottom: 10px;
}

.tech-item p {
    font-size: 0.95rem;
    color: #666;
}

.performance-metrics {
    margin-top: 80px;
    text-align: center;
}

.performance-metrics h3 {
    font-size: 2.2rem;
    margin-bottom: 40px;
}

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

.metric-item {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s ease;
}

.metric-item:hover {
    transform: translateY(-5px);
}

.metric-item h4 {
    font-size: 1.8rem;
    color: #3498db;
    margin-bottom: 10px;
}

.metric-item p {
    font-size: 2.5rem; /* 40px */
    font-weight: 700;
    color: #2c3e50;
    line-height: 1;
    margin-bottom: 10px;
}

.metric-item span {
    font-size: 1rem;
    color: #777;
    display: block;
}


/* Case Studies Section */
.case-study-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.case-item {
    background-color: #fff;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: left;
}

.case-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.12);
}

.case-item img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin-bottom: 20px;
}

.case-item h3 {
    font-size: 1.8rem;
    margin-bottom: 10px;
}

.case-item p {
    font-size: 1rem;
    color: #666;
    margin-bottom: 5px;
}

.case-item p strong {
    color: #3498db;
}

/* Call to Action Section */
.cta {
    text-align: center;
}

.cta h2 {
    color: #fff;
    font-size: 2.8rem;
    margin-bottom: 30px;
}

.cta p {
    font-size: 1.3rem;
    max-width: 900px;
    margin: 0 auto 50px auto;
    color: #eee;
}


/* Footer */
footer {
    background-color: #2c3e50;
    color: #eee;
    padding: 60px 0 20px 0;
    font-size: 0.95rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.footer-col h3 {
    color: #fff;
    font-size: 1.4rem;
    margin-bottom: 20px;
}

.footer-col p, .footer-col ul li {
    color: #bbb;
    margin-bottom: 10px;
}

.footer-col ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-col ul li a {
    color: #bbb;
}

.footer-col ul li a:hover {
    color: #fff;
}

.footer-col .social-links a {
    color: #fff;
    font-size: 1.8rem;
    margin-right: 15px;
    transition: color 0.3s ease;
}

.footer-col .social-links a:hover {
    color: #3498db;
}

.footer-bottom {
    border-top: 1px solid #444;
    padding-top: 20px;
    text-align: center;
    color: #bbb;
}

.footer-bottom p {
    margin-bottom: 5px;
}

.footer-bottom a {
    color: #bbb;
}

.footer-bottom a:hover {
    color: #fff;
}

/* Responsive Design */
@media (max-width: 992px) {
    .hero h1 { font-size: 3.5rem; }
    .hero p { font-size: 1.3rem; }
    .section-header h2 { font-size: 2.5rem; }
    h1 { font-size: 3rem; }
    h2 { font-size: 2.4rem; }
    h3 { font-size: 2rem; }

    .nav-menu {
        display: none; /* Hide on smaller screens by default */
        flex-direction: column;
        width: 100%;
        background-color: #fff;
        position: absolute;
        top: 80px; /* Adjust based on header height */
        left: 0;
        box-shadow: 0 8px 16px rgba(0,0,0,0.1);
        padding: 20px 0;
        border-top: 1px solid #eee;
    }

    .nav-menu.active {
        display: flex; /* Show when active */
    }

    .nav-menu li {
        margin: 10px 0;
        text-align: center;
    }

    .nav-menu li a {
        padding: 10px 0;
        display: block;
        color: #333;
    }

    .nav-menu li a::after {
        display: none; /* Hide underline on mobile menu */
    }

    .hamburger {
        display: flex; /* Show hamburger icon */
    }

    header nav .btn-primary {
        display: none; /* Hide desktop CTA button on mobile */
    }

    .about-pcdn .about-content,
    .tech-overview {
        flex-direction: column;
        text-align: center;
    }
    .about-pcdn .about-image,
    .tech-overview .tech-image {
        order: -1; /* Image appears above text on mobile */
        margin-bottom: 30px;
    }
    .about-pcdn .benefit-list {
        text-align: left; /* Keep bullet points aligned left */
    }
}

@media (max-width: 768px) {
    .hero h1 { font-size: 2.8rem; }
    .hero p { font-size: 1.2rem; }
    .section-padding { padding: 60px 0; }
    .section-header h2 { font-size: 2.2rem; }
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    h3 { font-size: 1.7rem; }
    p { font-size: 1rem; }

    .hero-actions {
        flex-direction: column;
        gap: 15px;
    }
    .hero-actions .btn {
        margin: 0; /* Reset margins for stacked buttons */
        width: 80%; /* Make buttons wider */
        max-width: 300px;
    }

    .metric-item p { font-size: 2rem; }

    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .footer-col ul {
        margin-bottom: 20px;
    }
    .footer-col .social-links {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero h1 { font-size: 2.2rem; }
    .hero p { font-size: 1rem; }
    .section-header h2 { font-size: 1.8rem; }
    .btn-lg { padding: 12px 25px; font-size: 1.1rem; }
}