.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--header-border);
}

.nav-shell {
    width: min(100% - 2rem, var(--max-width));
    margin-inline: auto;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
    padding: 0.85rem 0;
}

.brand {
    text-decoration: none;
    font-family: "Fraunces", "Georgia", serif;
    font-size: 1.15rem;
    color: var(--header-control-text);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-left: auto;
}

.header-select,
.theme-toggle,
.nav-toggle {
    border: 1px solid var(--header-control-border);
    background: var(--header-control-bg);
    color: var(--header-control-text);
    border-radius: 999px;
    padding: 0.5rem 0.8rem;
    font: inherit;
    font-weight: 700;
    transition: background-color 200ms var(--ease-artful), border-color 200ms var(--ease-artful),
        transform 200ms var(--ease-artful);
}

.header-select {
    min-width: 6.75rem;
    appearance: none;
}

.nav-toggle {
    border-radius: var(--radius-sm);
    padding: 0.45rem 0.7rem;
}

.header-select:hover,
.theme-toggle:hover,
.nav-toggle:hover {
    background: var(--header-control-hover);
    transform: translateY(-1px);
}

.nav-links {
    list-style: none;
    margin: 0;
    padding: 0;
    display: none;
    flex-direction: column;
    gap: 0.5rem;
    position: absolute;
    right: 1rem;
    top: calc(100% + 0.45rem);
    width: min(16rem, calc(100% - 2rem));
    background: var(--surface-1);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: var(--space-3);
    overflow: hidden;
}

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

.nav-links a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    padding: 0.3rem 0.1rem;
    position: relative;
    border-bottom: 2px solid transparent;
    transition: border-color 250ms var(--ease-artful), color 250ms var(--ease-artful);
}

.nav-links a::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: -0.12rem;
    height: 2px;
    background: var(--terracotta-500);
    transform: scaleX(0);
    transform-origin: left center;
    transition: transform 260ms var(--ease-artful);
}

.nav-links a[aria-current="true"] {
    color: var(--header-control-text);
    border-color: transparent;
}

.nav-links a[aria-current="true"]::after {
    transform: scaleX(1);
}

.nav-links a.sandbox-link {
    background: var(--btn-sandbox-bg);
    color: var(--btn-sandbox-text);
    border: 1px solid var(--btn-sandbox-bg);
    border-bottom-color: var(--btn-sandbox-bg);
    border-radius: 999px;
    padding: 0.35rem 0.75rem;
}

.nav-links a.sandbox-link[aria-current="true"] {
    color: var(--btn-sandbox-text);
    border-color: var(--btn-sandbox-bg);
}

.nav-links a.sandbox-link:hover {
    color: var(--btn-sandbox-text);
    border-color: var(--btn-sandbox-hover);
    background: var(--btn-sandbox-hover);
}

.site-main {
    overflow: clip;
}

.nav-indicator {
    display: none;
}

.site-footer {
    padding: var(--space-5) 0;
    background: var(--footer-bg);
    color: var(--footer-text);
    margin-top: var(--space-6);
}

.site-footer p {
    margin: 0;
    text-align: center;
}

@media (min-width: 48rem) {
    .nav-toggle {
        display: none;
    }

    .nav-links {
        position: static;
        width: auto;
        padding: 0;
        box-shadow: none;
        border: 0;
        background: transparent;
        display: flex;
        flex-direction: row;
        align-items: center;
        gap: var(--space-3);
        position: relative;
    }

    .nav-shell {
        gap: var(--space-3);
    }

    .nav-actions {
        margin-left: 0;
        order: 3;
    }

    .nav-indicator {
        display: block;
        position: absolute;
        bottom: -0.18rem;
        left: 0;
        height: 3px;
        width: 2rem;
        border-radius: 999px;
        background: linear-gradient(90deg, var(--terracotta-500), var(--deep-green-600));
        transform: translateX(0);
        opacity: 0;
        transition: transform 280ms var(--ease-artful), width 280ms var(--ease-artful), opacity 180ms linear;
    }

    .nav-indicator.is-active {
        opacity: 1;
    }
}

@media (max-width: 47.99rem) {
    .nav-shell {
        flex-wrap: wrap;
    }

    .brand {
        max-width: calc(100% - 12rem);
    }

    .nav-actions {
        flex-wrap: wrap;
        justify-content: flex-end;
    }
}