/* navigation header */
header {
    position: sticky;
    top: 0;
    background: var(--nav-bg);
    box-shadow: 0 1px 4px var(--shadow-strong);
    z-index: 1000;
}

.nav-header {
    max-width: 100%;
    margin: 0 auto;
    padding: 0.75rem 1rem;
    font-family: 'Noto Sans', Helvetica, sans-serif;
    font-weight: 600;
    position: sticky;
    z-index: 1000;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.hamburger {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--text);
    position: relative;
    transition: all 0.25s ease;
}

.hamburger::before,
.hamburger::after {
    content: "";
    position: absolute;
    width: 25px;
    height: 3px;
    background: var(--text);
    left: 0;
    transition: all 0.25s ease;
}

.hamburger::before {
    top: -8px;
}

.hamburger::after {
    top: 8px;
}

.nav-toggle.active .hamburger {
    background: transparent;
}

.nav-toggle.active .hamburger::before {
    top: 0;
    transform: rotate(45deg);
}

.nav-toggle.active .hamburger::after {
    top: 0;
    transform: rotate(-45deg);
}

.nav-links {
    list-style: none;
    display: flex;
    flex-wrap: nowrap;
    justify-content: flex-start;
    gap: 2rem;
    margin: 0;
    padding: 0;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text);
    padding: 0.5rem 1rem;
    transition: background 0.3s, color 0.3s;
    white-space: nowrap;
}

.nav-links a:hover, .nav-links a:focus-visible {
    background-color: color-mix(in srgb, var(--accent) 15%, transparent);
    border-radius: 5px;
}

.nav-links a.active {
    background-color: var(--accent);
    color: #ffffff;
    border-radius: 5px;
}

.nav-actions {
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    margin-left: auto;
    flex-shrink: 0;
}

/* light/dark mode */
#theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    cursor: pointer;
}

#theme-icon {
    width: 24px;
    height: 24px;
    transition: transform 0.3s ease;
}

.dark-mode #theme-icon{
    transform: rotate(180deg);
}