:root {
    --blue-50: #f1f5f9; /* ฟ้าอ่อนมาก */
    --blue-100: #e2e8f0; /* body */
    --blue-200: #cbd5e1;
    --blue-700: #1e293b; /* container */
    --blue-800: #0f172a; /* navbar */
    --blue-900: #020617;
    --text-muted: #94a3b8;
    --accent: #38bdf8; /* ฟ้าเน้น */

    --bg-body: linear-gradient(180deg, #e2e8f0, #f8fafc);
    --bg-container: rgba(245, 248, 255, 0.85);
    --bg-navbar: #1e293b;
    --text-main: #0f172a;
    --text-invert: #e5e7eb;
    --card-shadow: 0 10px 30px rgba(2,6,23,.15);
    --text-hover: #facc15;
}
body {
    padding-top: 50px;
    /*background: linear-gradient( 180deg, var(--blue-100), var(--blue-50) );
    color: #0f172a;*/
    font-family: 'Segoe UI', 'Prompt', sans-serif;

    background: var(--bg-body);
    color: var(--text-main);
    transition: background .4s ease, color .4s ease;
}
    body.dark {
        --bg-body: linear-gradient(180deg, #020617, #0f172a);
        --bg-container: rgba(30, 41, 59, 0.85);
        --bg-navbar: #020617;
        --text-main: #e5e7eb;
        --text-invert: #e5e7eb;
        --card-shadow: 0 10px 30px rgba(0,0,0,.6);
        --text-hover: #38bdf8;
    }
main.container {
    /*background: var(--blue-700);*/
    color: var(--text-main);
    border-radius: 8px;
    padding: 24px;
    margin-top: 16px;
    box-shadow: 0 10px 30px rgba(2, 6, 23, 0.35);

    background: var(--bg-container);
    box-shadow: var(--card-shadow);
    transition: background .4s ease;
}
a{
    text-decoration:none;
}
    a:hover {
        text-decoration: none;
        color:inherit;
    }

.logo {
    width: 150px;
}
    .logo:hover {
        transform: scale(1.08); /* ⭐ ซูมพอดี ไม่เวอร์ */
    }
/* ===== Navbar ===== */
#navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 60px;
    background: var(--bg-navbar);
    /*background: #f8fafc; /* สีอ่อน */
    border-bottom: 1px solid #e5e7eb;
    z-index: 999;
    transition: top 0.3s ease, box-shadow 0.3s ease;
    background: var(--blue-800);
    box-shadow: 0 4px 12px rgba(2, 6, 23, 0.4);
}
    #navbar.scrolled {
        box-shadow: 0 4px 12px rgba(0,0,0,0.06);
    }
    #navbar .logo {
        color: #e5e7eb;
        font-weight: 700;
    }

.nav-inner {
    max-width: 1200px;
    height: 100%;
    margin: auto;
    padding: 0 16px;
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
}
.nav-center {
    display: flex;
    justify-content: center;
}
/* ซ้าย */
.nav-left {
    display: flex;
    align-items: center;
    gap: 20px;
    width:150px;
}

/* ขวา */
.nav-right {
    display: flex;
    align-items: center;
    gap: 20px;
    width: 150px;
}


/* link ปกติ */
.nav-link {
    position: relative;
    font-size: 15px;
    color: #334155;
    text-decoration: none;
    padding: 6px 0;
}

    .nav-link::after {
        content: "";
        position: absolute;
        left: 0;
        bottom: -2px;
        width: 0;
        height: 2px;
        background: #2563eb;
        transition: width 0.25s ease;
    }

    .nav-link:hover {
        color: #2563eb;
    }

        .nav-link:hover::after {
            width: 100%;
        }
.btn-login {
    text-align:center;
    background: linear-gradient(135deg, #ef4444, #f97316);
    color: #fff;
    padding: 8px 16px;
    border-radius: 10px;
    font-size: 20px;
    text-decoration: none;
    transition: all 0.25s ease;
    box-shadow: 0 6px 16px rgba(239, 68, 68, 0.35);
}

    .btn-login:hover {
        filter: brightness(1.1);
        transform: translateY(-1px);
    }

.hero {
    margin-top: 0px;
}