.site-header {
    background-color: var(--theme-palette-color-8);
    position: relative;
    z-index: 50;
}

.header-top-row {
    padding: 20px 0;
    border-bottom: 1px solid var(--theme-palette-color-6);
}

.header-top-row__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    gap: 20px;
}
.header-group {
    display: flex;
    align-items: center;
    gap: 15px;
}
.header-group--left, .header-group--right {
    flex: 1 1 0;
}
.header-group--center {
    flex-shrink: 0;
}
.header-group--right {
    justify-content: flex-end;
}
.site-logo-container {
    height: 25px;
    display: block;
}
.site-logo-container img {
    height: 100%;
    width: auto;
}
.site-description {
    display: flex;
    flex-direction: column;
    line-height: 1.3;
    color: var(--theme-palette-color-4);
}
.site-description span {
    font-weight: 600;
    font-size: 0.9rem;
}
.site-description small {
    font-size: 0.8rem;
    font-weight: 400;
    color: var(--theme-palette-color-3);
}
.header-search {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    text-decoration: none;
    color: var(--theme-palette-color-4);
}
.header-search .material-symbols-rounded {
    font-size: 26px;
}
.header-search__text {
    font-weight: 600;
    font-size: 1.1rem;
}
.mobile-menu-trigger {
    display: none;
    cursor: pointer;
}
.mobile-menu-trigger .material-symbols-rounded {
    font-size: 28px;
}

/* Logo Görünürlük Kuralları */
body:not([data-color-mode="dark"]) .default-logo {
    display: block;
}
body:not([data-color-mode="dark"]) .dark-mode-logo {
    display: none;
}
body[data-color-mode="dark"] .default-logo {
    display: none;
}
body[data-color-mode="dark"] .dark-mode-logo {
    display: block;
}
@media (prefers-color-scheme: dark) {
    body[data-color-mode*="os-default"] .dark-mode-logo {
        display: initial;
    }
    body[data-color-mode*="os-default"] .default-logo {
        display: none;
    }
}

.offcanvas-panel {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    z-index: 100000; background-color: rgba(18, 21, 25, 0.85);
    backdrop-filter: blur(5px); -webkit-backdrop-filter: blur(5px);
    opacity: 0; visibility: hidden; transition: opacity 0.3s ease;
}
.offcanvas-panel-inner {
    width: 100%; max-width: 350px; height: 100%;
    background-color: var(--theme-palette-color-7);
    box-shadow: 0 0 70px rgba(0,0,0,0.35);
    transform: translateX(-100%); transition: transform 0.3s ease-in-out;
    display: flex; flex-direction: column;
    overflow-y: auto;
}
body.is-mobile-menu-active .offcanvas-panel {
    opacity: 1; visibility: visible;
}
body.is-mobile-menu-active .offcanvas-panel-inner {
    transform: translateX(0);
}
body.is-mobile-menu-active {
    overflow: hidden;
}
.offcanvas-header {
    display: flex; justify-content: space-between; align-items: center;
    padding: 15px 20px; border-bottom: 1px solid var(--theme-palette-color-6);
    flex-shrink: 0;
}
.offcanvas-logo-container img {
    height: 32px;
    width: auto;
    display: block;
}
.offcanvas-close {
    cursor: pointer;
    padding: 5px;
    margin: -5px;
    display: flex;
    align-items: center;
}
.offcanvas-close .material-symbols-rounded {
    font-size: 30px;
}
.offcanvas-content {
    padding: 20px;
}
.offcanvas-footer {
    padding: 15px 20px; border-top: 1px solid var(--theme-palette-color-6); flex-shrink: 0;
    margin-top: auto;
}
.bf-dark-mode-switch {
    display: flex; align-items: center; gap: 15px; cursor: pointer; user-select: none;
}
.bf-dark-mode-switch input {
    display: none;
}
.bf-dark-mode-switch__slider {
    width: 44px; height: 24px; background-color: var(--theme-palette-color-6); border-radius: 12px; position: relative; transition: background-color 0.3s ease;
}
.bf-dark-mode-switch__slider::before {
    content: ''; position: absolute; top: 2px; left: 2px; width: 20px; height: 20px; background-color: white; border-radius: 50%; transition: transform 0.3s ease;
}
.bf-dark-mode-switch input:checked + .bf-dark-mode-switch__slider {
    background-color: var(--theme-palette-color-1);
}
.bf-dark-mode-switch input:checked + .bf-dark-mode-switch__slider::before {
    transform: translateX(20px);
}

.offcanvas-header {
    align-items: center;
}
.offcanvas-site-icon img {
    height: 32px;
    width: auto;
    display: block;
}

/* TABLET VE MOBİL GÖRÜNÜM */
@media (max-width: 999.98px) {
    .site-description, .header-main-row, .header-search__text {
        display: none;
    }
    .header-top-row {
        padding: 10px 0;
        border-bottom: 1px solid var(--theme-palette-color-6);
    }
    .mobile-menu-trigger {
        display: block;
        padding: 10px;
        margin: -10px;
    }
    .header-group--right .header-search {
        padding: 10px;
        margin: -10px;
    }
    .header-search .material-symbols-rounded {
        font-size: 28px;
    }
}

/* Masaüstü Dark Mode Butonu Stilleri */
.bf-theme-switcher {
    display: none;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: var(--theme-palette-color-7);
    border: 1px solid var(--theme-palette-color-6);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
}
.bf-theme-switcher:hover {
    border-color: var(--theme-palette-color-1);
    color: var(--theme-palette-color-1);
}

.bf-theme-switcher .material-symbols-rounded {
    font-size: 22px;
}

.bf-theme-switcher .icon-light { display: none; }
.bf-theme-switcher .icon-dark { display: block; }

body[data-color-mode="dark"] .bf-theme-switcher .icon-light { display: block; }
body[data-color-mode="dark"] .bf-theme-switcher .icon-dark { display: none; }

@media (min-width: 999.98px) {
    .bf-theme-switcher {
        display: flex;
    }
}

/* ===== YENİ: Sticky Header Stilleri ===== */

.header-main-row,
.header-top-row {
    position: -webkit-sticky;
    position: sticky;
    top: 0;
    z-index: 999;
}

/* Masaüstünde sadece ana menü yapışkan olsun ve gölgesi olsun */
@media (min-width: 1000px) {
    .header-top-row {
        position: static; /* Yapışkanlığı iptal et */
    }
    .header-main-row {
        background-color: var(--theme-palette-color-8);
        box-shadow: 0 2px 10px rgba(18, 18, 18, 0.08);
    }
}

/* Mobilde sadece üst bar yapışkan olsun ve gölgesi olsun */
@media (max-width: 999.98px) {
    .header-main-row {
        position: static; /* Yapışkanlığı iptal et */
    }
    .header-top-row {
        background-color: var(--theme-palette-color-8);
        box-shadow: 0 2px 10px rgba(18, 18, 18, 0.08);
    }
}

/* ===== YENİ: JS Tabanlı Sticky Header Stilleri ===== */

/* Yapışkan başlık aktif olduğunda içeriğin zıplamasını önlemek için body'e padding ekler */
body.is-sticky-active {
    padding-top: var(--sticky-header-height, 70px); /* JS ile hesaplanan yükseklik, 70px yedek değer */
}

@keyframes slideDown {
    from { transform: translateY(-100%); }
    to { transform: translateY(0); }
}

/* Masaüstü için Yapışkan Navigasyon Menüsü */
@media (min-width: 1000px) {
    body.is-sticky-active .site-header .header-main-row {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        width: 100%;
        background-color: var(--theme-palette-color-8);
        box-shadow: 0 2px 10px rgba(18, 18, 18, 0.08);
        animation: slideDown 0.3s ease-in-out;
    }
}

/* Mobil için Yapışkan Üst Bar */
@media (max-width: 999.98px) {
    body.is-sticky-active .site-header .header-top-row {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        width: 100%;
        background-color: var(--theme-palette-color-8);
        box-shadow: 0 2px 10px rgba(18, 18, 18, 0.08);
        animation: slideDown 0.3s ease-in-out;
    }
}