:root {
    --primary: #1f6f8b;
    --accent: #38a3a5;
    --page-bg: #f6f8fb;
    --ink: #12313f;
    --line: rgba(31, 49, 63, 0.16);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    color: var(--ink);
    background: var(--page-bg);
    font-family: Arial, Helvetica, sans-serif;
}

header {
    padding: 18px 20px;
    color: #fff;
    background: var(--primary);
    text-align: center;
}

.eyebrow {
    margin: 0 0 6px;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 0;
    text-transform: uppercase;
}

header h1 {
    margin: 0;
    font-size: 30px;
    font-weight: 700;
}

header h3 {
    margin: 6px 0 0;
    font-size: 20px;
    font-style: italic;
    font-weight: 400;
}

.navbar {
    position: sticky;
    top: 0;
    z-index: 10;
    background: var(--accent);
    box-shadow: 0 2px 8px rgba(37, 49, 60, 0.16);
}

.navbar-toggle {
    display: none;
    width: 44px;
    height: 44px;
    border: 0;
    color: #fff;
    background: transparent;
    font-size: 26px;
    cursor: pointer;
}

.nav-links {
    display: flex;
    justify-content: center;
    gap: 2px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.nav-links a {
    display: block;
    min-width: 128px;
    padding: 14px 18px;
    color: #fff;
    text-align: center;
    text-decoration: none;
    font-size: 15px;
    font-weight: 700;
    text-transform: uppercase;
}

.nav-links a span {
    display: block;
    margin-top: 2px;
    font-size: 11px;
    font-weight: 400;
    text-transform: none;
}

.nav-links a:hover,
.nav-links a.active {
    background: var(--primary);
}

.nav-links a.disabled {
    cursor: not-allowed;
    opacity: 0.48;
}

.nav-links a.disabled:hover {
    background: transparent;
}

.grid-container {
    width: min(1200px, 100%);
    margin: 20px auto;
    padding: 0 16px;
}

.iframe-container {
    width: 100%;
    min-height: 740px;
    overflow: hidden;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(18, 49, 63, 0.1);
}

#responsive-iframe {
    display: block;
    width: 100%;
    height: 740px;
    border: 0;
    transition: height 0.2s ease;
}

.empty-state {
    display: grid;
    min-height: 320px;
    place-items: center;
    padding: 24px;
    color: var(--ink);
    font-size: 18px;
    text-align: center;
}

footer {
    padding: 18px 16px 24px;
    color: #fff;
    background: var(--ink);
    text-align: center;
}

footer p {
    margin: 4px 0;
}

@media (max-width: 720px) {
    .navbar-toggle {
        display: block;
    }

    .nav-links {
        display: none;
        flex-direction: column;
    }

    .nav-links.open {
        display: flex;
    }

    .nav-links a {
        min-width: 0;
        padding: 13px 16px;
    }

    .grid-container {
        margin: 10px auto;
        padding: 0 6px;
    }

    .iframe-container {
        min-height: 420px;
        border-radius: 8px;
    }

    #responsive-iframe {
        min-height: 420px;
    }
}