/*
 * Shared site header. Markup lives in partials/site-nav.html and is copied into
 * every page by `npm run sync:nav`. Colours are literal (not page variables) so
 * the header looks the same on every page.
 */

.site-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: #FFFFFF;
    border-bottom: 1px solid #E5E5E5;
    z-index: 1000;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', sans-serif;
    line-height: 1.6;
    text-align: left;
    letter-spacing: normal;
}

/*
 * Neutralise page-wide element styles (e.g. a page's global `a { ... }` button
 * style) inside the header. `.site-nav :where(...)` has one-class specificity:
 * enough to beat a page's element selectors, low enough that every header rule
 * below (same or higher specificity, later in this file) still wins.
 */
.site-nav :where(a, button, ul, li, img, span) {
    margin: 0;
    padding: 0;
    border: 0;
    border-radius: 0;
    background: none;
    box-shadow: none;
    text-transform: none;
    letter-spacing: inherit;
    line-height: inherit;
    font: inherit;
    color: inherit;
}

.site-nav :where(a) {
    display: inline;
}

.site-nav *,
.site-nav *::before,
.site-nav *::after {
    box-sizing: border-box;
}

.site-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.site-nav__inner {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 3rem;
}

.site-nav__logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
}

.site-nav__logo img {
    height: 50px;
    width: auto;
    display: block;
}

.site-nav__logo-text {
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: #000000;
    line-height: 1;
}

.site-nav__links {
    display: flex;
    gap: 3rem;
}

.site-nav__links a {
    color: #404040;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s;
}

.site-nav a:focus-visible,
.site-nav button:focus-visible {
    outline: 2px solid #000000;
    outline-offset: 2px;
}

/* Resources dropdown (desktop) */
.site-nav__item--has-dropdown {
    position: relative;
}

.site-nav__dropdown-head {
    display: flex;
    align-items: center;
}

.site-nav__dropdown-link {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.site-nav__dropdown-link::after {
    content: '';
    width: 0;
    height: 0;
    border-left: 4px solid transparent;
    border-right: 4px solid transparent;
    border-top: 4px solid currentColor;
    transition: transform 0.2s;
}

.site-nav__subtoggle,
.site-nav__toggle {
    display: none;
}

.site-nav__dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    margin-top: 0.5rem;
    background: #FFFFFF;
    border: 1px solid #E5E5E5;
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    min-width: 220px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    /* Visibility flips instantly on open (so keyboard focus can enter at once) and only after the fade on close. */
    transition: opacity 0.2s ease, transform 0.2s ease, visibility 0s linear 0.2s;
    z-index: 1000;
    padding: 0.5rem 0;
}

.site-nav__dropdown a {
    display: block;
    padding: 0.75rem 1.5rem;
    color: #404040;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    /* Not `all`: a transition on the inherited `visibility` would keep the links unfocusable while the list opens. */
    transition: background-color 0.15s, color 0.15s, border-color 0.15s;
    border-left: 3px solid transparent;
}

.site-nav__dropdown a.site-nav__highlight {
    background: rgba(59, 130, 246, 0.05);
    color: #3B82F6;
    font-weight: 600;
    border-left-color: #3B82F6;
}

.site-nav a.site-nav__blog {
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.site-nav a.site-nav__blog::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    background: #FF0000;
    border-radius: 2px;
    animation: site-nav-pulse 2s ease-in-out infinite;
}

@keyframes site-nav-pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.6; }
}

@media (min-width: 1024px) {
    .site-nav__links a:hover {
        color: #000000;
    }

    .site-nav__dropdown a:hover {
        background: #F5F5F5;
        color: #000000;
        border-left-color: #000000;
    }

    .site-nav__dropdown a.site-nav__highlight:hover {
        background: rgba(59, 130, 246, 0.1);
        color: #2563EB;
    }

    .site-nav__item--has-dropdown:hover .site-nav__dropdown,
    .site-nav__item--has-dropdown:focus-within .site-nav__dropdown,
    .site-nav__item--has-dropdown.is-open .site-nav__dropdown {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
        transition: opacity 0.2s ease, transform 0.2s ease, visibility 0s;
    }

    .site-nav__item--has-dropdown.is-open .site-nav__dropdown-link::after {
        transform: rotate(180deg);
    }

    /* Escape closes a dropdown opened by hover or focus until the pointer or focus leaves. */
    .site-nav__item--has-dropdown.is-dismissed .site-nav__dropdown {
        opacity: 0;
        visibility: hidden;
        transform: translateY(-10px);
    }
}

/* Phones and tablets */
@media (max-width: 1023.98px) {
    .site-nav__inner {
        padding: 0.75rem 1.25rem;
        gap: 1rem;
    }

    .site-nav__logo img {
        height: 40px;
    }

    .site-nav__logo-text {
        font-size: 1rem;
        line-height: 1.15;
    }

    .site-nav__links a {
        font-size: 1rem;
    }

    .site-nav__dropdown-link::after {
        display: none;
    }

    /* With JavaScript: logo + menu button; the menu opens as a panel below the bar. */
    .site-nav.js .site-nav__toggle {
        display: inline-flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 5px;
        flex-shrink: 0;
        width: 44px;
        height: 44px;
        padding: 0;
        margin-left: auto;
        background: none;
        border: 1px solid #E5E5E5;
        border-radius: 8px;
        cursor: pointer;
    }

    .site-nav__toggle-bar {
        display: block;
        width: 20px;
        height: 2px;
        background: #000000;
        transition: transform 0.2s, opacity 0.2s;
    }

    .site-nav.is-open .site-nav__toggle-bar:nth-child(1) {
        transform: translateY(7px) rotate(45deg);
    }

    .site-nav.is-open .site-nav__toggle-bar:nth-child(2) {
        opacity: 0;
    }

    .site-nav.is-open .site-nav__toggle-bar:nth-child(3) {
        transform: translateY(-7px) rotate(-45deg);
    }

    .site-nav.js .site-nav__links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        gap: 0;
        padding: 0.5rem 1.25rem 1rem;
        background: #FFFFFF;
        border-bottom: 1px solid #E5E5E5;
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
        max-height: calc(100vh - 70px);
        max-height: calc(100dvh - 70px);
        overflow-y: auto;
    }

    .site-nav.js.is-open .site-nav__links {
        display: flex;
    }

    .site-nav.js .site-nav__links > li > a,
    .site-nav.js .site-nav__dropdown-link {
        display: flex;
        align-items: center;
        min-height: 44px;
    }

    .site-nav.js .site-nav__links > li {
        border-bottom: 1px solid #F5F5F5;
    }

    .site-nav.js .site-nav__links > li:last-child {
        border-bottom: none;
    }

    .site-nav.js .site-nav__dropdown-head {
        justify-content: space-between;
    }

    .site-nav.js .site-nav__subtoggle {
        display: inline-flex;
        justify-content: center;
        align-items: center;
        width: 44px;
        height: 44px;
        padding: 0;
        background: none;
        border: none;
        cursor: pointer;
    }

    .site-nav.js .site-nav__subtoggle::after {
        content: '';
        width: 0;
        height: 0;
        border-left: 5px solid transparent;
        border-right: 5px solid transparent;
        border-top: 5px solid #404040;
        transition: transform 0.2s;
    }

    .site-nav.js .site-nav__item--has-dropdown.is-open .site-nav__subtoggle::after {
        transform: rotate(180deg);
    }

    .site-nav.js .site-nav__dropdown {
        display: none;
        position: static;
        margin: 0 0 0.5rem;
        padding: 0 0 0 1rem;
        min-width: 0;
        opacity: 1;
        visibility: visible;
        transform: none;
        border: none;
        border-radius: 0;
        box-shadow: none;
    }

    .site-nav.js .site-nav__item--has-dropdown.is-open .site-nav__dropdown {
        display: block;
    }

    .site-nav.js .site-nav__dropdown a {
        display: flex;
        align-items: center;
        min-height: 44px;
        padding: 0.5rem 1rem;
        font-size: 0.95rem;
    }

    /* Without JavaScript: every link stays visible as a wrapped list. */
    .site-nav:not(.js) {
        position: static;
    }

    .site-nav:not(.js) .site-nav__inner {
        flex-wrap: wrap;
    }

    .site-nav:not(.js) .site-nav__links {
        flex-wrap: wrap;
        gap: 0.5rem 1.25rem;
        width: 100%;
    }

    .site-nav:not(.js) .site-nav__dropdown {
        position: static;
        display: flex;
        flex-wrap: wrap;
        gap: 0.5rem 1.25rem;
        margin: 0.5rem 0 0;
        padding: 0;
        min-width: 0;
        opacity: 1;
        visibility: visible;
        transform: none;
        border: none;
        box-shadow: none;
    }

    .site-nav:not(.js) .site-nav__dropdown a {
        padding: 0;
        border-left: none;
    }
}

@media (prefers-reduced-motion: reduce) {
    .site-nav *,
    .site-nav *::before,
    .site-nav *::after {
        transition: none !important;
        animation: none !important;
    }
}