/* Top-left hamburger navigation + Night Tube dark mode */

.site-nav {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
}

/* Hamburger button */
.nav-toggle {
    position: fixed;
    top: 1rem;
    left: 1rem;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #003688;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.25);
    z-index: 1002;
}

.nav-bars,
.nav-bars::before,
.nav-bars::after {
    content: "";
    display: block;
    width: 22px;
    height: 2.5px;
    background: #fff;
    border-radius: 2px;
    transition: transform 0.25s ease, opacity 0.2s ease;
}

.nav-bars::before { transform: translateY(-7px); }
.nav-bars::after  { transform: translateY(4.5px); }

/* Animate into an X when open */
.nav-toggle[aria-expanded="true"] .nav-bars {
    background: transparent;
}
.nav-toggle[aria-expanded="true"] .nav-bars::before {
    transform: translateY(0) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-bars::after {
    transform: translateY(-2.5px) rotate(-45deg);
}

/* Backdrop */
.nav-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.25s ease;
}
.nav-backdrop.is-visible { opacity: 1; }

/* Slide-out panel */
.nav-panel {
    position: fixed;
    top: 0;
    left: 0;
    height: 100%;
    width: min(78vw, 280px);
    background: #003688;
    color: #fff;
    padding: 4.5rem 1.5rem 1.5rem;
    box-shadow: 2px 0 16px rgba(0, 0, 0, 0.35);
    transform: translateX(-100%);
    transition: transform 0.28s ease;
    z-index: 1001;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}
.nav-panel.is-open { transform: translateX(0); }

.nav-heading {
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, sans-serif;
    font-weight: bold;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    font-size: 0.9rem;
    opacity: 0.7;
}

.nav-links {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.nav-links a {
    display: block;
    padding: 0.7rem 0.85rem;
    color: #fff;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    transition: background 0.15s ease;
}
.nav-links a:hover { background: rgba(255, 255, 255, 0.12); }
.nav-links a.active {
    background: #E32017;          /* Central-line red accent */
    font-weight: bold;
}

/* Theme toggle */
.nav-theme-toggle {
    margin-top: auto;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 999px;
    padding: 0.6rem 0.9rem;
    cursor: pointer;
    font: inherit;
}
.nav-theme-toggle .theme-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: #ffd400;          /* "day" sun */
    box-shadow: inset -4px -4px 0 0 rgba(0, 0, 0, 0); /* full circle */
    transition: background 0.2s ease, box-shadow 0.2s ease;
}

/* Avoid layout flash before nav.js runs: panels stay hidden via [hidden] */
[hidden] { display: none !important; }

/* ---------- Night Tube dark theme ---------- */
[data-theme="dark"] body {
    background-color: #0e1320;
    color: #c7d2e6;
}
[data-theme="dark"] .station-info {
    background-color: transparent;
    color: #c7d2e6;
}
[data-theme="dark"] .station-info .welcome { color: #eaf0fb; }
[data-theme="dark"] .roundel,
[data-theme="dark"] .station-info { background-color: transparent; }
[data-theme="dark"] .roundel { background-color: #0e1320; }

[data-theme="dark"] .nav-toggle { background: #1b2740; }
[data-theme="dark"] .nav-panel { background: #131c30; }

/* Crescent moon when dark mode is active */
[data-theme="dark"] .nav-theme-toggle .theme-dot {
    background: #eaf0fb;
    box-shadow: inset -5px -2px 0 0 #131c30;
}

@media (prefers-reduced-motion: reduce) {
    .nav-bars, .nav-bars::before, .nav-bars::after,
    .nav-backdrop, .nav-panel { transition: none; }
}