@font-face {
        font-family: 'Sarabun', sans-serif;
    }

    body,
    div,
    p {
        font-family: 'Sarabun', sans-serif;
        font-size: 16px;
    }

    .bd-placeholder-img {
        font-size: 1.125rem;
        text-anchor: middle;
        -webkit-user-select: none;
        -moz-user-select: none;
        user-select: none;
    }

    /* unvisited link */
    a:link {
        color: #19BBAF;
        text-decoration: none;
    }

    /* visited link */
    a:visited {
        color: #19BBAF;
        text-decoration: none;
    }

    /* mouse over link */
    a:hover {
        color: #19BBAF;
        text-decoration: none;
    }

    /* selected link */
    a:active {
        color: #19BBAF;
        text-decoration: none;
    }

    .btn {
        border: 2px solid black;
        background-color: white;
        color: #19BBAF;
        border-color: #19BBAF;
        padding: 8px 8px;
        font-size: 14px;
        cursor: pointer;
        border-radius: 5px;
    }

    .btn:hover {
        background: #19BBAF;
        color: white;
        border-color: #19BBAF;
    }

    @media (min-width: 768px) {
        .bd-placeholder-img-lg {
            font-size: 3.5rem;
        }
    }
    
    /* ===== Modern Responsive + Green Gradient Theme ===== */
    :root{
        --brand-1:#16a34a; /* emerald-600 */
        --brand-2:#22c55e; /* emerald-500 */
        --brand-3:#86efac; /* emerald-300 */
        --ink:#0f172a;
    }
    body{
        min-height:100vh;
        background: 
                     radial-gradient(1200px 600px at 20% 10%, rgba(221, 231, 225, 0.55), transparent 100%), 
                     radial-gradient(900px 500px at 80% 20%, rgba(224, 224, 224, 0.35), transparent 100%), 
                      linear-gradient(135deg,  rgba(224, 224, 224, 0.55),  rgba(233, 239, 236, 0.55)); 
        color: var(--ink);
    }
    header .navbar{
         background: linear-gradient(135deg, rgba(6,78,59,.92),rgba(6,78,59,.92));
        backdrop-filter: blur(6px);
        -webkit-backdrop-filter: blur(6px);
        border-bottom: 1px solid rgba(255,255,255,.25);
    }
    .page-shell{
        background: rgba(255,255,255,.86);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        border: 1px solid rgba(255,255,255,.35);
        border-radius: 1.25rem;
        box-shadow: 0 1.25rem 2.5rem rgba(2,6,23,.18);
        padding: 1.25rem;
    }
    @media (min-width: 992px){
        .page-shell{ padding: 2rem; }
    }
    .card{
        border: 0;
        border-radius: 1.25rem;
        overflow: hidden;
        box-shadow: 0 .75rem 1.5rem rgba(2,6,23,.10);
        transition: transform .18s ease, box-shadow .18s ease;
        height: 100%;
    }
    .card:hover{
        transform: translateY(-4px);
        box-shadow: 0 1.25rem 2.5rem rgba(2,6,23,.16);
    }
    .card img{ object-fit: cover; }
    .card-text a{ font-weight: 700; }
    .btn{
        border-radius: .9rem;
        font-weight: 600;
    }
    .btn-outline-secondary{
        border-color: rgba(15,23,42,.25);
        color: rgba(15,23,42,.85);
    }
    .btn-outline-secondary:hover{
        background: rgba(22,163,74,.12);
        border-color: rgba(22,163,74,.35);
        color: rgba(15,23,42,.95);
    }
    a:link, a:visited, a:hover, a:active { color: #0f766e; }
    .section-title{
        font-weight: 800;
        letter-spacing: -.02em;
    }
    /* Make grid cards truly responsive */
    .row-cols-1 > *{ display:flex; }
    /* Footer */
    footer{
        background: rgba(255,255,255,.75);
        border: 1px solid rgba(255,255,255,.35);
        border-radius: 1.25rem;
        padding-inline: 1rem;
    }