/* Header CSS - Optimized for LCP & CLS */

:root {
    --header-height: 72px;
    /* Increased for safety */
    --nav-width: 280px;
    --z-header: 1000;
    --z-overlay: 1001;
    --z-sidenav: 1002;
    --header-bg: #ffffff;
    --header-text: #202124;
    --nav-bg: #ffffff;
    --overlay-bg: rgba(0, 0, 0, 0.5);
    --border-color: #dadce0;
    --primary-color: #4285f4;
}

/* Base Reset */
.global-header *,
.side-nav * {
    box-sizing: border-box;
}

/* Critical LCP: Fixed Header */
.global-header {
    position: fixed;
    /* Fixed as per requirement */
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background: var(--header-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 1rem;
    z-index: var(--z-header);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    contain: layout size;
    /* Performance optimization */
}

/* Prevent content from hiding behind fixed header */
body {
    padding-top: var(--header-height);
}

.brand-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--header-text);
    text-decoration: none;
    font-family: inherit;
}

.menu-toggle {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--header-text);
    transition: background 0.2s;
}

.menu-toggle:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

/* SVG Handling */
.menu-toggle svg,
.close-menu svg {
    fill: currentColor;
    width: 24px;
    height: 24px;
}

/* Navigation Overlay */
.nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--overlay-bg);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease;
    z-index: var(--z-overlay);
    pointer-events: none;
}

.nav-overlay.active {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

/* Side Navigation */
.side-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--nav-width);
    height: 100%;
    background: var(--nav-bg);
    z-index: var(--z-sidenav);
    transform: translateX(-100%);
    transition: transform 0.3s cubic-bezier(0.4, 0.0, 0.2, 1);
    display: flex;
    flex-direction: column;
    box-shadow: 2px 0 8px rgba(0, 0, 0, 0.1);
    visibility: hidden;
    /* Hide when closed to prevent focus */
}

.side-nav.active {
    transform: translateX(0);
    visibility: visible;
}

.nav-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1rem;
    border-bottom: 1px solid var(--border-color);
}

.brand-name-nav {
    font-weight: 700;
    font-size: 1.2rem;
}

.close-menu {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--header-text);
}

.close-menu:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

/* Navigation List */
.nav-list {
    list-style: none;
    padding: 1rem 0;
    margin: 0;
    overflow-y: auto;
}

.nav-item,
.nav-item-accordion {
    display: flex;
    align-items: center;
    width: 100%;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    color: var(--header-text);
    font-size: 1rem;
    background: none;
    border: none;
    text-align: left;
    cursor: pointer;
    transition: background 0.2s;
}

.nav-item:hover,
.nav-item-accordion:hover {
    background-color: rgba(0, 0, 0, 0.03);
}

.nav-item.active {
    background-color: rgba(66, 133, 244, 0.1);
    color: var(--primary-color);
    font-weight: 500;
}

.nav-item.disabled {
    color: #9aa0a6;
    cursor: default;
    pointer-events: none;
}

/* Accordion */
.nav-item-group {
    display: flex;
    flex-direction: column;
}

.nav-item-accordion {
    justify-content: space-between;
}

.icon-arrow {
    transition: transform 0.2s;
    fill: currentColor;
    width: 24px;
    height: 24px;
}

.nav-item-group.expanded .icon-arrow {
    transform: rotate(180deg);
}

.nav-accordion-content {
    list-style: none;
    padding: 0;
    margin: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    background-color: #fafafa;
}

.nav-item-group.expanded .nav-accordion-content {
    max-height: 500px;
}

.nav-accordion-content li a {
    display: block;
    padding: 0.75rem 1.5rem 0.75rem 2.5rem;
    text-decoration: none;
    color: #5f6368;
    font-size: 0.95rem;
}

.nav-accordion-content li a:hover {
    color: var(--header-text);
}

.nav-accordion-content li a.active {
    color: var(--primary-color);
    font-weight: 500;
}