/* =========================================
   20 - Header / Nav (Brand v2)
   - Unified glass system (surface/border/shadow from tokens)
========================================= */

/* Header shell */
.s-header {
    position: sticky;
    top: 0;
    z-index: 20;

    background: var(--header-surface);
    border: none;
    border-bottom: 1px solid var(--header-border);

    -webkit-backdrop-filter: blur(var(--header-blur));
    backdrop-filter: blur(var(--header-blur));

    box-shadow: var(--header-shadow);
}

/* Desktop nav row */
.c-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;

    padding: var(--header-pad-y) 0;
    gap: 16px;
}

/* Brand */
.c-brand {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
    color: inherit;
}

.c-brand__logo {
    height: 34px;
    width: auto;
    display: block;
    transform: translateY(1px);
}

/* Right area */
.c-nav__right {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Menu links */
.c-menu {
    display: flex;
    align-items: center;
    gap: 16px;

    font-size: var(--fs-nav);
    color: var(--stone-700);
}

.c-menu a {
    opacity: .78;
    transition: opacity 180ms ease;
    text-decoration: none;
    color: inherit;
}

.c-menu a:hover,
.c-menu a.is-active {
    opacity: 1;
}

/* Burger button */
.c-menuBtn {
    width: 42px;
    height: 42px;
    border-radius: 12px;

    display: none;
    /* shown in RWD */
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 4px;

    cursor: pointer;

    border: 1px solid var(--btn-border);
    background: var(--btn-bg);
}

.c-menuBtn span {
    width: 18px;
    height: 1.4px;
    background: var(--text);
    opacity: .65;
}

/* Overlay */
.c-overlay {
    position: fixed;
    inset: 0;
    z-index: 90;

    background: var(--overlay-bg);

    -webkit-backdrop-filter: blur(var(--overlay-blur));
    backdrop-filter: blur(var(--overlay-blur));
}

/* Drawer */
.c-drawer {
    position: fixed;
    top: 0;
    right: 0;

    height: 100svh;
    width: min(360px, 86vw);

    z-index: 100;

    background: var(--drawer-surface);
    border-left: 1px solid var(--drawer-border);
    box-shadow: var(--drawer-shadow);

    -webkit-backdrop-filter: blur(var(--drawer-blur));
    backdrop-filter: blur(var(--drawer-blur));

    transform: translateX(100%);
    transition: transform 260ms ease;
}

.c-drawer__inner {
    padding: 18px 18px 26px;
}

.c-drawer__top {
    display: flex;
    align-items: center;
    justify-content: space-between;

    padding: 6px 2px 18px;
}

.c-drawer__title {
    font-size: var(--fs-drawer-title);
    letter-spacing: var(--ls-drawer-title);
    opacity: .75;
    color: var(--stone-700);
}

.c-drawer__close {
    width: 40px;
    height: 40px;
    border-radius: 12px;
}

.c-drawer__link {
    display: block;
    padding: 14px 10px;
    border-radius: 14px;

    color: var(--text);
    opacity: .92;
    text-decoration: none;
}

.c-drawer__link:hover {
    background: var(--drawer-link-hover-bg);
}

.c-drawer__cta {
    margin-top: 18px;
}

/* Open state (配合 JS：html.menu-open) */
html.menu-open .c-drawer {
    transform: translateX(0);
}

/* [hidden] 保底（確保 overlay 真隱藏） */
[hidden] {
    display: none !important;
}

/* Responsive */
@media (max-width: 900px) {
    .c-menu {
        display: none;
    }

    .c-menuBtn {
        display: inline-flex;
    }
}