:root {
    --topnav-height: 48px;
}

body.is-learning-page.has-topnav {
    padding-top: var(--topnav-height);
}

body.is-learning-page #appContent {
    min-height: calc(100vh - var(--topnav-height));
}

.has-topnav {
    padding-top: var(--topnav-height);
}

#appContent {
    min-height: calc(100vh - var(--topnav-height));
}

.site-topnav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 50;
    height: var(--topnav-height);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    background: rgba(255, 255, 255, 0.92);
}

.dark .site-topnav {
    background: rgba(22, 22, 23, 0.82);
}

.site-topnav-bar {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.site-topnav-logo {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    flex-shrink: 0;
    text-decoration: none;
    color: inherit;
}

.site-topnav-wordmark {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.02em;
    color: #1d1d1f;
    white-space: nowrap;
}

.site-topnav-wordmark-en {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.02em;
    color: #1d1d1f;
}

.dark .site-topnav-wordmark {
    color: #f5f5f7;
}

.dark .site-topnav-wordmark-en {
    color: #f5f5f7;
}

body.is-homepage.homepage-intro-active .site-topnav-wordmark {
    opacity: 0;
    transform: translateY(-6px);
}

body.is-homepage.homepage-intro-done:not(.homepage-intro-gsap) .site-topnav-wordmark {
    transition:
        opacity 0.75s cubic-bezier(0.22, 1, 0.36, 1),
        transform 0.75s cubic-bezier(0.22, 1, 0.36, 1);
}

.site-topnav-wordmark.is-revealed,
body.is-homepage.homepage-intro-done:not(.homepage-intro-gsap) .site-topnav-wordmark {
    opacity: 1;
    transform: translateY(0);
}

.site-topnav-links {
    display: none;
    align-items: center;
    justify-content: center;
    gap: 1.75rem;
    flex: 1;
    min-width: 0;
}

@media (min-width: 768px) {
    .site-topnav-links {
        display: flex;
    }
}

.site-topnav-link,
.site-topnav-link-btn {
    font-size: 12px;
    line-height: 1;
    font-weight: 400;
    letter-spacing: -0.01em;
    color: rgba(29, 29, 31, 0.88);
    text-decoration: none;
    background: none;
    border: 0;
    padding: 0;
    cursor: pointer;
    white-space: nowrap;
}

.dark .site-topnav-link,
.dark .site-topnav-link-btn {
    color: rgba(245, 245, 247, 0.88);
}

.site-topnav-link.is-active {
    color: #1d1d1f;
    font-weight: 500;
}

.dark .site-topnav-link.is-active {
    color: #f5f5f7;
}

.site-topnav-actions {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    flex-shrink: 0;
}

.site-topnav-icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.625rem;
    height: 1.625rem;
    border: 0;
    border-radius: 9999px;
    background: transparent;
    color: rgba(29, 29, 31, 0.8);
    text-decoration: none;
    cursor: pointer;
    transition: background-color 0.15s ease;
}

.site-topnav-icon-btn:hover {
    background: rgba(0, 0, 0, 0.06);
}

.dark .site-topnav-icon-btn {
    color: rgba(245, 245, 247, 0.8);
}

.dark .site-topnav-icon-btn:hover {
    background: rgba(255, 255, 255, 0.08);
}

.site-topnav-icon-btn i {
    font-size: 1.0625rem;
    line-height: 1;
}

.site-topnav-auth-actions {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    flex-shrink: 0;
}

@media (min-width: 768px) {
    .site-topnav-auth-actions {
        gap: 0.5rem;
    }
}

.site-topnav-login {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.625rem;
    height: 1.625rem;
    border: 0;
    border-radius: 9999px;
    background: transparent;
    padding: 0;
    text-decoration: none;
    transition: background-color 0.15s ease;
}

.site-topnav-login:hover {
    background: rgba(0, 0, 0, 0.06);
}

.dark .site-topnav-login:hover {
    background: rgba(255, 255, 255, 0.08);
}

.site-topnav-cta {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 600;
    line-height: 1;
    color: #fff;
    text-decoration: none;
    padding: 0.375rem 0.75rem;
    border-radius: 9999px;
    background: #f9671e;
    white-space: nowrap;
}

@media (min-width: 768px) {
    .site-topnav-cta {
        font-size: 12px;
        padding: 0.4375rem 0.875rem;
    }
}

.site-topnav-profile {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.625rem;
    height: 1.625rem;
    border: 0;
    border-radius: 9999px;
    background: transparent;
    padding: 0;
    cursor: pointer;
    transition: background-color 0.15s ease;
}

.site-topnav-profile:hover {
    background: rgba(0, 0, 0, 0.06);
}

.dark .site-topnav-profile:hover {
    background: rgba(255, 255, 255, 0.08);
}

.site-topnav-avatar {
    width: 1.625rem;
    height: 1.625rem;
    border-radius: 9999px;
    object-fit: cover;
}

.site-topnav-avatar-fallback {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.06);
    color: rgba(29, 29, 31, 0.65);
    font-size: 0.875rem;
}

.dark .site-topnav-avatar-fallback {
    background: rgba(255, 255, 255, 0.1);
    color: rgba(245, 245, 247, 0.65);
}

.site-topnav-menu-btn {
    display: inline-flex;
}

@media (min-width: 768px) {
    .site-topnav-menu-btn {
        display: none;
    }
}

.topnav-menu-icon-close {
    display: none;
}

body.topnav-menu-open .topnav-menu-icon-open {
    display: none;
}

body.topnav-menu-open .topnav-menu-icon-close {
    display: inline;
}

.site-topnav-mobile {
    position: fixed;
    inset: 0;
    z-index: 49;
    overflow-x: hidden;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.32s cubic-bezier(0.22, 1, 0.36, 1), visibility 0.32s cubic-bezier(0.22, 1, 0.36, 1);
    background: #ffffff;
}

.dark .site-topnav-mobile {
    background: #000000;
}

.site-topnav-mobile.is-open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.site-topnav-mobile-nav {
    min-height: 100%;
    padding-top: calc(var(--topnav-height) + 2rem);
    padding-bottom: 2.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.site-topnav-mobile-nav > * {
    opacity: 0;
    transform: translateY(1.5rem);
}

.site-topnav-mobile.is-open .site-topnav-mobile-nav > * {
    animation: topnavMobileItemIn 0.52s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(1) { animation-delay: 0.06s; }
.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(2) { animation-delay: 0.12s; }
.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(3) { animation-delay: 0.18s; }
.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(4) { animation-delay: 0.24s; }
.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(5) { animation-delay: 0.30s; }
.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(6) { animation-delay: 0.36s; }
.site-topnav-mobile.is-open .site-topnav-mobile-nav > *:nth-child(7) { animation-delay: 0.42s; }

@keyframes topnavMobileItemIn {
    from {
        opacity: 0;
        transform: translateY(1.5rem);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.site-topnav-mobile-nav a,
.site-topnav-mobile-nav button {
    display: flex;
    align-items: center;
    width: 100%;
    padding: 0.875rem 0.25rem;
    font-size: 1.75rem;
    line-height: 1.1;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: #1d1d1f;
    text-decoration: none;
    background: none;
    border: 0;
    text-align: left;
    cursor: pointer;
}

.dark .site-topnav-mobile-nav a,
.dark .site-topnav-mobile-nav button {
    color: #f5f5f7;
}

.site-topnav-overlay {
    display: none !important;
}

.app-page-meta {
    flex-shrink: 0;
    padding-top: 0.625rem;
    padding-bottom: 0.625rem;
}

.app-breadcrumb-text {
    display: block;
    max-width: 100%;
    color: #6b7280;
    font-size: var(--site-meta-font-size);
    line-height: var(--site-meta-line-height);
}

.dark .app-breadcrumb-text {
    color: #9ca3af;
}

.app-breadcrumb-text:hover {
    color: #4b5563;
}

.dark .app-breadcrumb-text:hover {
    color: #d1d5db;
}

.app-breadcrumb-sep i {
    color: #d1d5db;
}

.dark .app-breadcrumb-sep i {
    color: #4b5563;
}

body.topnav-menu-open {
    overflow: hidden;
}

body.topnav-menu-open .site-topnav {
    z-index: 51;
}

.app-breadcrumb-list {
    min-width: 0;
    gap: 0.25rem;
    flex-wrap: nowrap;
    overflow: hidden;
    font-size: var(--site-meta-font-size);
    line-height: var(--site-meta-line-height);
}

.app-breadcrumb-sep {
    width: 1rem;
    justify-content: center;
}

.app-breadcrumb-item--current {
    overflow: hidden;
}

@media (max-width: 767px) {
    .app-breadcrumb-item:not(.app-breadcrumb-item--current) .app-breadcrumb-text {
        max-width: 5.5rem;
    }

    .app-breadcrumb-item--current .app-breadcrumb-text {
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }
}

@media (min-width: 768px) {
    .app-breadcrumb-list {
        flex-wrap: wrap;
        overflow: visible;
    }

    .app-breadcrumb-item--current {
        flex: 0 1 auto;
        max-width: 100%;
    }
}

@media (min-width: 768px) {
    .site-topnav-mobile {
        display: none !important;
    }
}

/* 学习页顶栏：默认仅词库名，hover/点击展开左右操作 */
.site-topnav.is-learning .site-topnav-bar {
    position: relative;
}

.site-topnav.is-learning .site-topnav-actions--learning {
    display: flex;
    flex-shrink: 0;
    z-index: 3;
    gap: 0.25rem;
}

.site-topnav-actions.site-topnav-learning-collapsible {
    --learning-collapsible-max: 8rem;
}

.site-topnav-learning-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex: 1;
    min-width: 0;
}

.site-topnav-learning-start,
.site-topnav-learning-end {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    flex-shrink: 0;
    z-index: 2;
}

.site-topnav-learning-end {
    justify-content: flex-end;
}

.site-topnav-learning-collapsible {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    max-width: 0;
    overflow: hidden;
    transition:
        opacity 0.36s cubic-bezier(0.22, 1, 0.36, 1),
        max-width 0s linear 0.36s,
        visibility 0s linear 0.36s;
}

.site-topnav-learning-start.site-topnav-learning-collapsible {
    --learning-collapsible-max: 6.5rem;
}

.site-topnav-learning-end.site-topnav-learning-collapsible {
    --learning-collapsible-max: 4.5rem;
}

body.is-learning-page .site-topnav.is-learning:hover .site-topnav-learning-collapsible,
body.is-learning-page .site-topnav.is-learning:hover .site-topnav-actions.site-topnav-learning-collapsible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    max-width: var(--learning-collapsible-max);
    transition:
        opacity 0.36s cubic-bezier(0.22, 1, 0.36, 1),
        max-width 0s linear 0s,
        visibility 0s linear 0s;
}

@media (max-width: 767px) {
    body.is-learning-page.learning-topnav-visible .site-topnav-learning-collapsible,
    body.is-learning-page.learning-topnav-visible .site-topnav-actions.site-topnav-learning-collapsible {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        max-width: var(--learning-collapsible-max);
    }
}

/* 学习页顶栏细节 */
.site-topnav-learning-close {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.625rem;
    height: 1.625rem;
    flex-shrink: 0;
    border: 0;
    border-radius: 9999px;
    background: transparent;
    text-decoration: none;
    cursor: pointer;
    transition: background-color 0.15s ease;
}

.site-topnav-learning-close:hover {
    background: rgba(0, 0, 0, 0.06);
}

.dark .site-topnav-learning-close:hover {
    background: rgba(255, 255, 255, 0.08);
}

.site-topnav-learning-close-dot {
    display: block;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #ff5f57;
    box-shadow: inset 0 0 0 0.5px rgba(0, 0, 0, 0.12);
    position: relative;
}

.site-topnav-learning-close-dot::before,
.site-topnav-learning-close-dot::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 6px;
    height: 1px;
    background: rgba(76, 0, 0, 0.55);
    border-radius: 1px;
}

.site-topnav-learning-close-dot::before {
    transform: translate(-50%, -50%) rotate(45deg);
}

.site-topnav-learning-close-dot::after {
    transform: translate(-50%, -50%) rotate(-45deg);
}

.site-topnav-learning-close:hover .site-topnav-learning-close-dot {
    background: #ff3b30;
}

.site-topnav-learning-center {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    max-width: min(14rem, calc(100vw - 4rem));
    min-width: 0;
    z-index: 1;
    text-align: center;
}

.site-topnav-learning-library {
    display: block;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-weight: 600;
    font-size: 0.875rem;
    line-height: 1.2;
}

@media (max-width: 767px) {
    .site-topnav-learning-center {
        pointer-events: auto;
        cursor: pointer;
    }
}

@media (min-width: 768px) {
    .site-topnav-learning-center {
        pointer-events: none;
        cursor: default;
    }

    .site-topnav-learning-library {
        font-size: 0.9375rem;
    }
}