.header {
    background-color: var(--color-header);
    color: var(--color-text);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 1100;
    transition: background-color 0.25s ease, border-color 0.25s ease;
}
.header__container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.55rem 0;
    gap: 1rem;
    transition: padding 0.25s ease;
}
.header__logo {
    font-size: 1.5rem;
    font-weight: bold;
    display: flex;
    align-items: center;
    line-height: 1;
}
.header__logo-link {
    color: var(--color-text);
    transition: color 0.3s;
    display: flex;
    align-items: center;
}
.header__logo-link:hover {
    opacity: 0.8;
}
.header__logo-img {
    max-height: 56px;
    width: auto;
    display: block;
    transition: max-height 0.25s ease;
}
.header__nav {
    list-style: none;
    display: flex;
    align-items: center;
    margin: 0;
    padding: 0;
}
.header__nav-item {
    margin-left: 1rem;
}
.header__nav-link {
    color: var(--color-text);
    padding: 0.42rem 0.65rem;
    transition: background 0.3s;
}
.header__nav-link:hover {
    background-color: var(--color-surface-2);
}

.header__theme-toggle {
    color: var(--color-text);
    background-color: transparent;
    border: 1px solid var(--color-border);
    width: 34px;
    height: 34px;
    padding: 0;
    cursor: pointer;
    border-radius: 50%;
    font-size: 1.1rem;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    position: relative;
    transition: background-color 0.3s, color 0.3s, border-color 0.3s;
}

.header__theme-toggle::after {
    content: attr(title);
    position: absolute;
    top: calc(100% + 0.35rem);
    left: 50%;
    transform: translateX(-50%);
    font-size: 0.75rem;
    line-height: 1.2;
    color: var(--color-text-muted);
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    padding: 0.18rem 0.5rem;
    white-space: nowrap;
    display: none;
}

.header__theme-toggle:hover {
    background-color: var(--color-surface-2);
}

.header__menu-toggle {
    display: none;
    color: var(--color-accent);
    background-color: var(--color-surface);
    border: 1px solid var(--color-accent);
    width: 38px;
    height: 38px;
    border-radius: 50%;
    font-size: 1.4rem;
    line-height: 1;
    cursor: pointer;
    align-items: center;
    justify-content: center;
}

.header__menu-toggle:hover {
    background-color: var(--color-surface-2);
}

.header__nav-wrapper {
    display: flex;
    align-items: center;
}

.header--scrolled {
    background-color: rgba(22, 27, 34, 0.68);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    border-bottom-color: rgba(52, 61, 72, 0.65);
}

:root[data-theme="light"] .header--scrolled {
    background-color: rgba(233, 238, 246, 0.75);
    border-bottom-color: rgba(198, 209, 224, 0.8);
}

.header--scrolled .header__container {
    padding: 0.35rem 0;
}

.header--scrolled .header__logo-img {
    max-height: 44px;
}

@media (max-width: 900px) {
    .menu-backdrop {
        position: fixed;
        inset: 0;
        z-index: 1090;
        background: rgba(0, 0, 0, 0.21);
        backdrop-filter: blur(4.5px);
        -webkit-backdrop-filter: blur(4.5px);
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transition: opacity 0.25s ease, visibility 0s linear 0.25s;
    }

    :root[data-theme="light"] .menu-backdrop {
        background: rgba(31, 45, 63, 0.15);
    }

    .menu-backdrop.menu-backdrop--visible {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transition: opacity 0.25s ease;
    }

    .header__container {
        flex-wrap: wrap;
        gap: 0.75rem;
        padding: 0.5rem 0;
    }

    .header__logo-img {
        max-height: 50px;
    }

    .header--scrolled .header__logo-img {
        max-height: 40px;
    }

    .header__menu-toggle {
        display: inline-flex;
        margin-left: auto;
    }

    .header__nav-wrapper {
        width: min(320px, calc(100vw - 1.8rem));
        display: block;
        position: absolute;
        top: calc(100% - 1px);
        right: 0.9rem;
        z-index: 1250;
        background-color: rgba(20, 26, 35, 0.72);
        backdrop-filter: blur(7px);
        -webkit-backdrop-filter: blur(7px);
        border: 1px solid var(--color-border);
        border-radius: 12px;
        padding: 0.7rem;
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transform: translateY(-10px) scale(0.98);
        transform-origin: top right;
        will-change: opacity, transform;
        transition: opacity 0.25s ease, transform 0.25s ease, visibility 0s linear 0.25s;
    }

    :root[data-theme="light"] .header__nav-wrapper {
        background-color: rgba(233, 238, 246, 0.72);
    }

    .header--menu-open .header__nav-wrapper {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transform: translateY(0) scale(1);
        transition: opacity 0.25s ease, transform 0.25s ease;
    }

    .header__nav {
        flex-direction: column;
        align-items: stretch;
        border-top: 0;
        padding-top: 0;
        gap: 0.25rem;
    }

    .header__nav-item {
        margin-left: 0;
    }

    .header__nav-link {
        display: block;
        width: 100%;
        border-radius: 6px;
        padding: 0.7rem 0.8rem;
    }

    .header__theme-toggle {
        width: 38px;
        height: 38px;
        border-radius: 50%;
        justify-content: center;
        padding-left: 0;
        margin-top: 0.25rem;
    }

    .header__theme-toggle::after {
        display: inline-block;
        top: 50%;
        left: calc(100% + 0.45rem);
        transform: translateY(-50%);
    }
}

@media (min-width: 901px) {
    .header__nav-wrapper {
        display: flex !important;
    }
}

@media (max-width: 768px) {
    .header {
        position: sticky;
    }

    .header__container {
        justify-content: flex-end;
    }

    .header__logo {
        margin-left: auto;
    }

    .header__logo-link {
        display: flex;
        justify-content: flex-end;
    }

    .header__menu-toggle {
        position: absolute;
        top: 50%;
        transform: translateY(-50%);
        left: 0.9rem;
        z-index: 1300;
        margin-left: 0;
        border-radius: 50%;
        background-color: var(--color-header);
    }

    .header__nav-wrapper {
        left: 0.9rem;
        right: auto;
        transform-origin: top left;
    }
}