/* Header — minimal, single-row chrome */
header {
    background-color: var(--color-surface);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    padding: 0;
    border-bottom: 1px solid var(--color-outline);
    box-shadow: none;
    backdrop-filter: none;
}

nav {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0.5rem;
    width: 100%;
    min-height: 3.25rem;
    padding: 0 var(--space-grid-margin);
    max-width: var(--container-max);
    margin: 0 auto;
}

.logo {
    flex: 0 0 auto;
    margin: 0;
    display: flex;
    align-items: center;
    min-width: 0;
}

.logo a {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    border-radius: var(--radius-default);
}

.brand {
    text-decoration: none;
    color: var(--color-on-surface);
    padding: 0;
}

.brand__title {
    font-family: var(--font-heading);
    font-weight: 400;
    letter-spacing: -0.01em;
    font-size: 1.05rem;
    line-height: 1.2;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.logo img {
    height: 36px;
    width: auto;
    display: block;
}

.nav-container {
    display: flex;
    align-items: center;
    margin-left: auto;
    margin-right: 0.25rem;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 0.15rem;
    flex: 0 0 auto;
}

.nav-links {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 0.85rem;
}

.nav-links li {
    position: relative;
}

.nav-links a {
    text-decoration: none;
    color: var(--color-on-surface);
    font-family: var(--font-ui);
    font-size: 0.875rem;
    font-weight: 400;
    line-height: 1.2;
    letter-spacing: 0;
    text-transform: none;
    transition: opacity var(--duration-normal) var(--ease-premium);
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    padding: 0;
    opacity: 0.78;
}

.nav-links a:hover,
.nav-links a:focus-visible {
    opacity: 1;
    color: var(--color-on-surface);
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--color-on-surface);
    font-size: 0.9rem;
    cursor: pointer;
    padding: 0;
    transition: opacity var(--duration-normal) var(--ease-premium);
    border-radius: var(--radius-default);
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0.7;
}

.theme-toggle:hover,
.theme-toggle:focus-visible {
    opacity: 1;
    color: var(--color-on-surface);
    background: none;
}

.hamburger {
    display: none;
    position: relative;
    cursor: pointer;
    background: none;
    border: none;
    padding: 0;
    z-index: 1006;
    width: 44px;
    height: 44px;
    flex: 0 0 auto;
    align-items: center;
    justify-content: center;
}

.hamburger span {
    position: absolute;
    left: 50%;
    top: 50%;
    display: block;
    width: 16px;
    height: 1.5px;
    margin: 0;
    background-color: var(--color-on-surface);
    border-radius: 1px;
    transform-origin: center;
    transition: transform var(--duration-normal) var(--ease-premium),
        opacity var(--duration-normal) var(--ease-premium);
}

.hamburger span:nth-child(1) {
    transform: translate(-50%, calc(-50% - 5px));
}

.hamburger span:nth-child(2) {
    transform: translate(-50%, -50%);
}

.hamburger span:nth-child(3) {
    transform: translate(-50%, calc(-50% + 5px));
}

.hamburger.active span:nth-child(1) {
    transform: translate(-50%, -50%) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: translate(-50%, -50%) rotate(-45deg);
}

@media screen and (min-width: 1024px) {
    nav {
        min-height: 3.75rem;
        gap: 1rem;
        padding: 0 clamp(1.5rem, 3vw, 2.5rem);
    }

    .brand__title {
        font-size: 1.2rem;
        letter-spacing: -0.015em;
    }

    .nav-container {
        margin-right: 0.5rem;
    }

    .nav-links {
        gap: 1.35rem;
    }

    .nav-links a {
        font-size: 0.9375rem;
        opacity: 0.82;
    }

    .nav-actions {
        gap: 0.35rem;
    }
}

@media screen and (min-width: 1280px) {
    nav {
        min-height: 4rem;
        padding: 0 var(--space-grid-margin);
    }

    .brand__title {
        font-size: 1.28rem;
    }

    .nav-links {
        gap: 1.6rem;
    }
}

@media screen and (max-width: 1023px) {
    nav {
        padding: 0 var(--space-md);
    }

    .nav-links {
        gap: 0.7rem;
    }

    .nav-links a {
        font-size: 0.8125rem;
    }
}

@media screen and (max-width: 768px) {
    nav {
        position: relative;
        min-height: 3.25rem;
        padding: 0 0.65rem;
        gap: 0.1rem;
    }

    .brand__title {
        font-size: 0.95rem;
        max-width: calc(100vw - 9rem);
    }

    .nav-container {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        width: auto;
        max-width: none;
        margin: 0;
        background-color: var(--color-surface);
        border-bottom: 1px solid var(--color-outline);
        visibility: hidden;
        opacity: 0;
        pointer-events: none;
        transform: translateY(-0.2rem);
        transition: opacity var(--duration-normal) var(--ease-premium),
            transform var(--duration-normal) var(--ease-premium),
            visibility var(--duration-normal) var(--ease-premium);
    }

    .nav-container.active {
        visibility: visible;
        opacity: 1;
        pointer-events: auto;
        transform: translateY(0);
    }

    .nav-links {
        flex-direction: column;
        width: 100%;
        gap: 0;
        padding: 0.25rem 0.85rem 0.5rem;
    }

    .nav-links a {
        display: flex;
        width: 100%;
        min-height: 44px;
        font-size: 1rem;
        font-weight: 400;
        opacity: 1;
    }

    .hamburger {
        display: flex;
        order: 3;
    }

    .nav-actions {
        order: 2;
        margin-left: auto;
        gap: 0;
    }

    .theme-toggle {
        width: 44px;
        height: 44px;
        font-size: 0.85rem;
    }

    .lang-toggle__link {
        min-width: 36px;
        min-height: 44px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        padding: 0 0.15rem;
        font-size: 0.75rem;
        font-weight: 500;
    }
}