:root {
    --header-height: 70px;
    --header-height-sticky: 65px;
    --header-bg: var(--bg-primary);
    --header-text-color: var(--text-secondary);
    --header-link-hover-color: var(--accent-primary);
    --header-border-color: var(--border-color-light);
}

.site-header-arh24 {
    background-color: var(--header-bg);
    height: var(--header-height);
    padding: 0;
    border-bottom: 1px solid var(--header-border-color);
    position: sticky;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: height 0.3s ease, background-color 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    align-items: center;
}

/* --- Sticky Header "Glass" Effect --- */
.site-header-arh24.is-sticky {
    height: var(--header-height-sticky);
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom-color: transparent;
    box-shadow: var(--shadow-lg);
}

.header-arh24-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

/* --- Professional Gradient Logo --- */
.site-logo-arh24 {
    font-size: 1.8rem;
    font-weight: 800;
    text-decoration: none;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
}
.logo-text-gradient {
    background: linear-gradient(90deg, var(--accent-primary-hover), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block; /* Crucial for gradient to apply */
}

/* --- Desktop Navigation --- */
.main-nav-arh24 {
    margin: 0 auto;
}
.nav-links-arh24 {
    list-style: none; padding: 0; margin: 0;
    display: flex; align-items: center;
    gap: 0.5rem;
}
.nav-links-arh24 li { margin: 0; }
.nav-link-arh24 {
    display: flex; align-items: center;
    padding: 0.6rem 1rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    color: var(--header-text-color);
    text-decoration: none;
    border-radius: var(--border-radius-sm);
    transition: color 0.2s ease, background-color 0.2s ease;
    position: relative;
}
.nav-link-arh24:hover {
    color: var(--header-link-hover-color);
    background-color: var(--accent-primary-soft);
}
.nav-link-arh24.active {
    color: var(--accent-primary);
    font-weight: 600;
}

/* Elegant Underline for Active/Hover State */
.nav-link-arh24::after {
    content: '';
    position: absolute;
    bottom: 5px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background-color: var(--accent-primary);
    transition: width 0.3s ease;
    border-radius: 2px;
}
.nav-link-arh24:hover::after,
.nav-link-arh24.active::after {
    width: 25px;
}
.nav-link-arh24 i.link-icon {
    margin-right: 0.4em;
    font-size: 0.9em;
    color: var(--text-muted);
    transition: color 0.2s ease;
}
.nav-link-arh24:hover i.link-icon,
.nav-link-arh24.active i.link-icon {
    color: var(--accent-primary);
}

/* --- Header Action Buttons --- */
.header-actions-arh24 {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}
.header-actions-arh24 .btn-sm {
    padding: 0.5rem 1.1rem;
    transition: all 0.2s ease;
}
.header-actions-arh24 .btn-sm:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}


/* --- Mobile Menu --- */
.menu-toggle-btn-arh24 {
    display: none;
    background: none; border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    padding: 0.5rem;
    cursor: pointer;
    z-index: 1200; /* Highest z-index */
    border-radius: var(--border-radius-sm);
    transition: background-color 0.2s ease, color 0.2s ease;
    line-height: 1;
}
.menu-toggle-btn-arh24:hover {
    background-color: var(--accent-primary-soft);
    color: var(--accent-primary);
}

/* This is the dark overlay */
.mobile-nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    z-index: 1090;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0s 0.3s;
}
body.mobile-menu-open .mobile-nav-overlay {
    opacity: 1;
    visibility: visible;
    transition: opacity 0.3s ease, visibility 0s;
}

/* This is the actual menu panel */
.mobile-nav-panel-arh24 {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    max-width: 320px;
    height: 100%;
    background-color: var(--bg-primary);
    z-index: 1100; /* Higher than overlay */
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    box-shadow: var(--shadow-xl);
    transform: translateX(-100%);
    transition: transform 0.35s cubic-bezier(0.25, 1, 0.5, 1);
}
body.mobile-menu-open .mobile-nav-panel-arh24 {
    transform: translateX(0);
}

.mobile-nav-header-arh24 {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color-light);
}
.mobile-nav-logo-arh24 {
    font-size: 1.6rem; font-weight: 800; text-decoration: none;
}
.mobile-menu-close-btn-arh24 {
    background: none; border: none; font-size: 1.8rem;
    color: var(--text-primary); cursor: pointer; padding: 0.5rem;
    line-height: 1;
    transition: transform 0.2s ease;
}
.mobile-menu-close-btn-arh24:hover { 
    color: var(--accent-primary); 
    transform: rotate(90deg);
}
.mobile-nav-links-arh24 {
    list-style: none; padding: 0; margin: 0;
    flex-grow: 1;
}
.mobile-nav-links-arh24 li {
    margin-bottom: 0.5rem;
}
.mobile-nav-link-arh24 {
    display: flex;
    align-items: center;
    padding: 1rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    color: var(--text-primary);
    text-decoration: none;
    border-radius: var(--border-radius-md);
    transition: background-color 0.2s ease, color 0.2s ease;
}
.mobile-nav-link-arh24:hover,
.mobile-nav-link-arh24.active {
    background-color: var(--accent-primary-soft);
    color: var(--accent-primary);
}
.mobile-nav-link-arh24 i.link-icon {
    margin-right: 0.8em;
    font-size: 1.1em;
    width: 24px;
    text-align: center;
    color: var(--accent-primary);
}
.mobile-nav-actions-arh24 {
    margin-top: auto;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}
.mobile-nav-actions-arh24 .btn {
    display: block;
    width: 100%;
    text-align: center;
    margin-bottom: 0.75rem;
}
.mobile-nav-actions-arh24 .btn:last-child {
    margin-bottom: 0;
}
body.mobile-menu-open {
    overflow: hidden;
}

/* Media Query to show mobile menu toggle */
@media (max-width: 992px) {
    .main-nav-arh24 { display: none; }
    .header-actions-arh24 .btn { display: none; }
    .menu-toggle-btn-arh24 { display: block; }
}