/* Base Reset & Fonts */
:root {
    --primary-blue: #1E4FD6;
    --secondary-teal: #1F7A7A;
    --text-dark: #0f172a;
    --bg-light: #f8fafc;
    --bg-white: #ffffff;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    color: var(--text-dark);
    background-color: var(--bg-white);
    -webkit-font-smoothing: antialiased;
    line-height: 1.6;
}

/* Language Visibility Logic */
.lang-cn { display: none; }
body.show-cn .lang-en { display: none !important; }
body.show-cn .lang-cn { display: inline !important; }
body.show-cn div.lang-cn, 
body.show-cn p.lang-cn, 
body.show-cn span.lang-cn,
body.show-cn li.lang-cn { display: block !important; }
body.show-cn span.lang-cn { display: inline !important; }

/* Custom Theme Utilities */
.text-brand-blue { color: var(--primary-blue); }
.text-brand-teal { color: var(--secondary-teal); }
.bg-brand-blue { background-color: var(--primary-blue); }
.bg-brand-teal { background-color: var(--secondary-teal); }

/* Navigation Active States */
.nav-link.active {
    color: var(--primary-blue);
    font-weight: 900;
    position: relative;
}
.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 0;
    width: 100%;
    height: 4px;
    background-color: var(--primary-blue);
    border-radius: 99px;
}

/* Header & Menu Z-Index Management */
#site-header {
    pointer-events: auto;
}

/* Mobile Menu Panel */
#mobile-menu-panel {
    transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: -15px 0 60px rgba(0,0,0,0.2);
}

#mobile-menu-overlay.hidden {
    pointer-events: none;
    opacity: 0;
}
#mobile-menu-overlay {
    transition: opacity 0.3s ease;
    pointer-events: auto;
    opacity: 1;
}

/* Hero Section */
.hero-overlay {
    background: linear-gradient(90deg, rgba(255,255,255,1) 0%, rgba(255,255,255,0.9) 30%, rgba(255,255,255,0.2) 100%);
}

/* Contact Cards */
.contact-card {
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
.contact-card:hover {
    transform: translateY(-12px);
    box-shadow: 0 40px 80px -15px rgba(50,50,93,0.2);
}

/* Buttons */
.btn-primary {
    background-color: var(--primary-blue);
    color: white;
    font-weight: 900;
    padding: 1.25rem 2.5rem;
    border-radius: 1rem;
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}
.btn-primary:hover {
    background-color: #163ba3;
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 15px 30px rgba(30,79,214,0.4);
}

/* Form Styling Override */
input:focus, textarea:focus {
    outline: none !important;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}
::-webkit-scrollbar-track {
    background: #f1f5f9;
}
::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 5px;
    border: 2px solid #f1f5f9;
}
::-webkit-scrollbar-thumb:hover {
    background: #94a3b8;
}