/* =====================================================================
   TenRusl-Markdown-MD — header.css
   Shared header / toolbar utilities
   ===================================================================== */

:is(.app-header, .site-header) {
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    min-height: var(--topbar-h);
    padding: 12px 16px;
    background: color-mix(in srgb, var(--panel-3) 92%, transparent);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(12px) saturate(140%);
}

:is(.app-header, .site-header) a {
    color: inherit;
    text-decoration: none;
}

:is(.app-header, .site-header) .brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    min-width: 0;
    color: var(--heading);
}

:is(.app-header, .site-header) .brand-mark {
    width: 42px;
    height: 42px;
    flex: 0 0 auto;
    display: grid;
    place-items: center;
    border-radius: 14px;
    color: #ffffff;
    background: linear-gradient(135deg, var(--accent-strong), var(--accent));
    box-shadow: 0 10px 22px rgba(31, 111, 235, 0.28);
}

:is(.app-header, .site-header) .brand-copy {
    min-width: 0;
    display: grid;
    gap: 2px;
}

:is(.app-header, .site-header) .brand-name {
    margin: 0;
    font-size: 14px;
    line-height: 1.25;
    font-weight: 700;
    color: var(--heading);
    letter-spacing: 0.01em;
}

:is(.app-header, .site-header) .brand-tag {
    margin: 0;
    font-size: 12px;
    color: var(--muted);
    line-height: 1.3;
}

:is(.app-header, .site-header) .brand-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 8px;
    border-radius: var(--radius-pill);
    border: 1px solid var(--border);
    background: var(--surface-soft);
    color: var(--muted);
    font-size: 11px;
    white-space: nowrap;
}

:is(.app-header, .site-header) .toolbar,
:is(.app-header, .site-header) .controls,
:is(.app-header, .site-header) .nav {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    min-width: 0;
}

:is(.app-header, .site-header) .nav {
    position: relative;
}

:is(.app-header, .site-header) .nav a {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 11px;
    border-radius: 12px;
    color: var(--muted);
    white-space: nowrap;
    transition: color 0.18s ease, background 0.18s ease, border-color 0.18s ease;
}

:is(.app-header, .site-header) .nav a:hover,
:is(.app-header, .site-header) .nav a.active {
    color: var(--heading);
    background: var(--surface-soft);
}

.icon-btn {
    appearance: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-height: 38px;
    min-width: 38px;
    padding: 0 12px;
    border: 1px solid var(--border);
    border-radius: 12px;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.03), rgba(255, 255, 255, 0)), var(--panel);
    color: var(--text);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
    transition: transform 0.12s ease, border-color 0.16s ease, background 0.16s ease, color 0.16s ease,
        box-shadow 0.16s ease;
    white-space: nowrap;
}

.icon-btn:hover {
    color: var(--heading);
    border-color: var(--accent);
    box-shadow: 0 10px 24px rgba(31, 111, 235, 0.16);
}

.icon-btn:active {
    transform: translateY(1px);
}

.icon-btn.ghost {
    background: transparent;
}

.icon-btn.active,
.icon-btn[data-active="true"] {
    border-color: var(--accent);
    background: var(--accent-soft);
    box-shadow: 0 0 0 2px var(--accent-ring) inset;
}

.icon-btn.sm {
    min-height: 32px;
    min-width: 32px;
    padding-inline: 10px;
    border-radius: 10px;
}

.icon,
.icon-btn i {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    font-size: 16px;
    line-height: 1;
}

.icon-sun,
.icon-moon {
    transition: opacity 0.24s ease, transform 0.24s ease;
}

.icon-moon {
    position: absolute;
    opacity: 0;
    transform: scale(0.85) rotate(-8deg);
}

:root.light .icon-sun,
html[data-theme="light"] .icon-sun {
    opacity: 0;
    transform: scale(0.85) rotate(8deg);
}

:root.light .icon-moon,
html[data-theme="light"] .icon-moon {
    opacity: 1;
    transform: scale(1) rotate(0deg);
}

.nav-toggle {
    display: none;
}

@media (max-width: 980px) {
    :is(.app-header, .site-header) {
        padding-inline: 12px;
    }

    :is(.app-header, .site-header) .brand-mark {
        width: 38px;
        height: 38px;
        border-radius: 12px;
    }

    :is(.app-header, .site-header) .brand-tag {
        display: none;
    }

    .icon-btn {
        min-height: 38px;
        min-width: 38px;
        padding-inline: 10px;
    }

    .icon-btn .label {
        display: none;
    }
}

@media (max-width: 860px) {
    .nav-toggle {
        display: inline-grid;
        place-items: center;
    }

    :is(.app-header, .site-header) .nav.is-collapsible {
        position: absolute;
        right: 12px;
        top: calc(100% + 8px);
        display: none;
        flex-direction: column;
        align-items: stretch;
        width: min(320px, calc(100vw - 24px));
        padding: 8px;
        border: 1px solid var(--border);
        border-radius: 14px;
        background: var(--panel-2);
        box-shadow: var(--shadow-md);
        backdrop-filter: blur(12px);
    }

    :is(.app-header, .site-header) .nav.is-collapsible.open {
        display: flex;
    }

    :is(.app-header, .site-header) .nav.is-collapsible a {
        width: 100%;
    }
}