:root {
            --primary-color: #009ceb;
            --secondary-color: #0d3b66;
            --accent-color: #ffc107;
            --bg-light: #f5f8fc;
            --text-dark: #333333;
            --text-gray: #6c757d;
        }

        body { font-family: 'Kanit', sans-serif; background-color: var(--bg-light); color: var(--text-dark); overflow-x: hidden; }

        /* =================================================== */
        /* Header & 2-Tier Navbar (Transparent to Solid)       */
        /* =================================================== */
        #siteHeader { transition: background-color 0.4s ease, box-shadow 0.4s ease; background-color: transparent; }
        
        #topBar { background-color: rgba(108, 60, 146, 0.95); color: rgba(255,255,255,0.85); font-size: 0.85rem; transition: all 0.4s ease; height: 35px; display: flex; align-items: center; overflow: hidden; }
        #topBar a { color: rgba(255,255,255,0.85); text-decoration: none; transition: 0.2s; }
        #topBar a:hover { color: #ffffff; }

        #mainNavbar { padding-top: 15px; padding-bottom: 15px; transition: all 0.4s ease; }
        .navbar-brand-text .title { font-weight: 700; color: #ffffff; font-size: 1.2rem; transition: color 0.4s; }
        .navbar-brand-text .subtitle { font-size: 0.85rem; color: rgba(255,255,255,0.8); transition: color 0.4s; }
        .nav-link { font-weight: 500; color: rgba(255,255,255,0.9); margin: 0 10px; transition: color 0.4s; }
        .nav-link:hover, .nav-link.active { color: #ffffff !important; text-shadow: 0 0 10px rgba(255,255,255,0.5); }
        #mobileMenuIcon { color: #ffffff; transition: color 0.4s; font-size: 1.5rem; }

        /* Hover Dropdown */
        @media (min-width: 992px) {
            .navbar .dropdown:hover .dropdown-menu { display: block; margin-top: 0; opacity: 1; visibility: visible; transform: translateY(0); }
            .navbar .dropdown-menu { display: block; opacity: 0; visibility: hidden; transition: all 0.3s ease; transform: translateY(10px); border: none; box-shadow: 0 10px 30px rgba(0,0,0,0.1); border-radius: 15px; padding: 10px 0; background-color: #ffffff; }
        }
        .dropdown-item { font-weight: 500; color: var(--text-dark); padding: 8px 25px; transition: all 0.2s; }
        .dropdown-item:hover, .dropdown-item:focus { background-color: var(--bg-light); color: var(--primary-color); }

        /* Scrolled Mode */
        #siteHeader.scrolled { background-color: #ffffff; box-shadow: 0 5px 20px rgba(0,0,0,0.08); }
        #siteHeader.scrolled #topBar { height: 0; opacity: 0; padding: 0 !important; }
        #siteHeader.scrolled #mainNavbar { padding-top: 10px; padding-bottom: 10px; }
        #siteHeader.scrolled .navbar-brand-text .title { color: var(--secondary-color); }
        #siteHeader.scrolled .navbar-brand-text .subtitle { color: var(--primary-color); }
        #siteHeader.scrolled .nav-link { color: var(--text-dark); }
        #siteHeader.scrolled .nav-link:hover, #siteHeader.scrolled .nav-link.active { color: var(--primary-color) !important; text-shadow: none; }
        #siteHeader.scrolled #mobileMenuIcon { color: var(--text-dark); }

        .btn-apply { background-color: var(--primary-color); color: white; border-radius: 25px; padding: 10px 30px; font-weight: 600; box-shadow: 0 4px 10px rgba(0, 156, 235, 0.3); transition: all 0.3s; }
        .btn-apply:hover { background-color: #0082c3; color: white; transform: translateY(-2px); box-shadow: 0 6px 15px rgba(0, 156, 235, 0.4); }

/* =================================================== */
/* footer       */
/* =================================================== */
footer { background-color: rgba(108, 60, 146, 0.95); color: #ffffff; padding: 60px 0 20px 0; margin-top: 40px; }
footer a { color: #b0c4de; text-decoration: none; transition: color 0.3s; }
footer a:hover { color: white; }
.footer-divider { border-top: 1px solid rgba(255,255,255,0.1); margin: 40px 0 20px 0; }

@media (max-width: 992px) {
            #siteHeader.scrolled .navbar-collapse { background: white; padding: 15px; border-radius: 10px; box-shadow: 0 10px 30px rgba(0,0,0,0.1); margin-top: 10px; }
            .navbar-collapse { background: rgba(13, 59, 102, 0.5); padding: 15px; border-radius: 10px; margin-top: 10px; backdrop-filter: blur(10px); }
        }