.header {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    display: flex;
    align-items: center;
    padding: 0 24px;
    gap: 16px;
    transition: background var(--transition), border-color var(--transition);
    contain: layout style;
}

[data-theme="dark"] .header {
    background: rgba(26, 18, 37, 0.85);
}

.header-left {
    display: flex;
    align-items: center;
    flex-shrink: 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
}

.logo-icon {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    object-fit: contain;
    flex-shrink: 0;
    transition: transform var(--transition);
}

.logo:hover .logo-icon {
    transform: rotate(-10deg) scale(1.1);
}

.site-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    transition: color var(--transition);
}

.logo:hover .site-name {
    color: var(--accent);
}

.header-center {
    flex: 1;
    display: flex;
    justify-content: center;
    overflow-x: auto;
    scrollbar-width: none;
}

.header-center::-webkit-scrollbar {
    display: none;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.header-right-end {
    display: flex;
    align-items: center;
    gap: 4px;
    margin-left: auto;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
    flex: 1;
    max-width: 280px;
    min-width: 120px;
}

.search-icon {
    position: absolute;
    left: 10px;
    width: 16px;
    height: 16px;
    color: var(--text-tertiary);
    pointer-events: none;
    z-index: 1;
}

.search-box input {
    padding: 7px 12px 7px 34px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 0.85rem;
    width: 100%;
    transition: border-color var(--transition), background var(--transition), box-shadow var(--transition);
    font-family: var(--font-sans);
    outline: none;
}

.search-box input:focus {
    border-color: var(--accent);
    background: var(--bg-secondary);
    box-shadow: 0 0 0 3px rgba(232, 102, 138, 0.15);
}

.search-box input::placeholder {
    color: var(--text-tertiary);
}

.view-toggle {
    display: flex;
    align-items: center;
    gap: 2px;
    padding: 4px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
}

.view-btn,
.theme-toggle,
.lang-toggle,
.login-btn {
    padding: 6px;
    border: none;
    background: transparent;
    color: var(--text-tertiary);
    border-radius: 6px;
    cursor: pointer;
    transition: color var(--transition), background var(--transition), transform var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    will-change: transform;
    -webkit-user-select: none;
    user-select: none;
    touch-action: manipulation;
}

.view-btn svg,
.theme-toggle svg,
.lang-toggle svg,
.login-btn svg {
    width: 18px;
    height: 18px;
}

.view-btn:hover,
.theme-toggle:hover,
.lang-toggle:hover,
.login-btn:hover {
    color: var(--text-primary);
    background: var(--bg-secondary);
}

.view-btn:active,
.theme-toggle:active,
.lang-toggle:active,
.login-btn:active {
    transform: scale(0.9);
}

.view-btn.active {
    background: var(--accent);
    color: var(--text-inverse);
}

.login-btn {
    text-decoration: none;
}

.theme-toggle .moon-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .sun-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
    display: block;
}

body.has-custom-background .header {
    background: rgba(var(--bg-card-rgb), var(--custom-card-alpha, 0.7));
    border-color: rgba(var(--border-color-rgb), 0.4);
}

body.has-custom-background .search-box input {
    background: rgba(var(--bg-card-rgb), 0.7);
    border-color: rgba(var(--border-color-rgb), 0.4);
}

body.has-custom-background .search-box input:focus {
    background: rgba(var(--bg-card-rgb), 0.88);
}

body.has-custom-background .view-toggle {
    background: rgba(var(--bg-card-rgb), 0.65);
}

body.has-custom-background .view-btn:hover,
body.has-custom-background .theme-toggle:hover,
body.has-custom-background .lang-toggle:hover,
body.has-custom-background .login-btn:hover {
    background: rgba(var(--bg-card-rgb), 0.8);
}

@media (max-width: 768px) {
    .header {
        height: auto;
        padding: 10px 12px;
        flex-wrap: wrap;
        gap: 8px;
    }

    .header-center {
        display: none;
    }

    .header-right {
        gap: 4px;
        flex-wrap: wrap;
        flex: 1;
    }

    .header-right > *:not(.search-box):not(.header-right-end) {
        order: 0;
    }

    .header-right-end {
        order: 1;
        margin-left: auto;
        flex-shrink: 0;
    }

    .search-box {
        order: 10;
        max-width: none;
        min-width: 0;
        width: 100%;
        margin-top: 4px;
    }

    .search-box input {
        width: 100%;
    }

    .search-box input:focus {
        width: 100%;
    }

    .site-name {
        font-size: 1rem;
    }

    .logo-icon {
        width: 28px;
        height: 28px;
    }

    .view-toggle, .lang-toggle {
        display: none;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 8px 10px;
    }

    .header-right {
        flex: 1;
    }

    .header-right-end {
        margin-left: auto;
    }

    .search-box {
        display: none;
    }

    .login-btn svg {
        width: 18px;
        height: 18px;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .search-box {
        max-width: 200px;
        min-width: 100px;
    }
}

@media (hover: none) {
    .view-btn:hover,
    .theme-toggle:hover,
    .lang-toggle:hover,
    .login-btn:hover {
        transform: none;
        background: transparent;
        color: var(--text-tertiary);
    }

    .logo:hover .logo-icon {
        transform: none;
    }

    .logo:hover .site-name {
        color: var(--text-primary);
    }
}