/* ========================================
   Design System — Tokens
   ======================================== */
:root {
    --bg: #f5f4ed;
    --surface: #ffffff;
    --fg: rgba(36, 41, 47, 0.9);
    --fg-heavy: #1c1b1a;
    --muted: #5c6469;
    --border: #e8e6dc;
    --accent: #c96442;
    --accent-ink: #faf9f5;
    --panel: #faf9f5;
    --soft: #e8e6dc;
    --link: #c96442;
    --code-bg: #f0efe8;
    --selection: #cfe6ff;

    --font-display:
        "TsangerJinKai02", "STKaiti", "KaiTi", -apple-system,
        BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
    --font-body:
        "TsangerJinKai02", -apple-system, BlinkMacSystemFont, "Segoe UI",
        "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    --font-content:
        "TsangerJinKai02", "STKaiti", "KaiTi", -apple-system,
        BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
    --font-mono:
        ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

    --header-h: 56px;
    --max-w: 720px;
    --article-max-w: 860px;
    --article-header-w: 900px;
    --radius: 8px;
}

/* Font face */
@font-face {
    font-family: "TsangerJinKai02";
    src: url("../fonts/TsangerJinKai02.woff2") format("woff2");
    font-weight: normal;
    font-style: normal;
    font-display: swap;
}

/* ========================================
   Reset & Base
   ======================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

::selection {
    background: var(--selection);
    color: inherit;
}

html {
    scroll-behavior: smooth;
    background: var(--bg);
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.7;
    color: var(--fg);
    letter-spacing: 0;
    -webkit-font-smoothing: subpixel-antialiased;
    background: var(--bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    color: var(--fg);
    text-decoration: none;
    transition: color 0.2s ease;
}
a:hover {
    color: var(--accent);
}

/* ========================================
   Header — sticky
   ======================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(245, 244, 237, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    height: var(--header-h);
}
.header-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 24px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}
.site-logo {
    font-family: var(--font-display);
    font-size: 20px;
    font-weight: 800;
    color: var(--fg);
    flex-shrink: 0;
    letter-spacing: -0.02em;
}
.site-logo:hover {
    color: var(--accent);
}

.header-nav {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-shrink: 0;
}
.header-menu {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* Category dropdown */
.cat-dropdown {
    position: relative;
}
.cat-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 6px 12px;
    font-size: 14px;
    font-family: var(--font-body);
    color: var(--muted);
    background: none;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition:
        color 0.15s,
        background 0.15s;
    letter-spacing: 0.5px;
}
.cat-btn:hover {
    color: var(--fg);
    background: rgba(0, 0, 0, 0.04);
}
.cat-btn svg {
    width: 14px;
    height: 14px;
    transition: transform 0.15s;
}
.cat-dropdown.open .cat-btn svg {
    transform: rotate(180deg);
}
.cat-menu {
    position: absolute;
    top: calc(100% + 6px);
    left: 0;
    min-width: 160px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
    padding: 6px 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition:
        opacity 0.15s,
        transform 0.15s,
        visibility 0.15s;
}
.cat-dropdown.open .cat-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.cat-menu a {
    display: block;
    padding: 8px 16px;
    font-size: 14px;
    color: var(--muted);
    transition:
        background 0.12s,
        color 0.12s;
}
.cat-menu a:hover {
    background: rgba(0, 0, 0, 0.03);
    color: var(--fg);
}
.cat-menu a.active {
    color: var(--accent);
    font-weight: 600;
}

.header-link {
    font-size: 14px;
    color: var(--muted);
    padding: 6px 8px;
    border-radius: 6px;
    transition:
        color 0.15s,
        background 0.15s;
}
.header-link:hover {
    color: var(--fg);
    background: rgba(0, 0, 0, 0.04);
}
.mobile-divider {
    display: none;
}

/* Mobile menu */
.mobile-menu-btn {
    display: none;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: none;
    background: none;
    color: var(--muted);
    border-radius: 6px;
    cursor: pointer;
}
.mobile-menu-btn svg {
    width: 20px;
    height: 20px;
}

@media (max-width: 640px) {
    .mobile-menu-btn {
        display: flex;
    }
    .header-menu {
        display: none;
        flex-direction: column;
        align-items: stretch;
        position: absolute;
        top: var(--header-h);
        left: 0;
        right: 0;
        background: var(--bg);
        border-bottom: 1px solid var(--border);
        padding: 8px 0;
        z-index: 99;
        gap: 0;
        box-shadow: 0 10px 24px rgba(0, 0, 0, 0.06);
    }
    .header-menu.open {
        display: flex;
    }
    .header-menu .cat-dropdown {
        display: block;
        position: static;
    }
    .header-menu .cat-btn {
        display: none;
    }
    .header-menu .cat-menu {
        position: static;
        box-shadow: none;
        border: none;
        border-radius: 0;
        background: transparent;
        opacity: 1;
        visibility: visible;
        transform: none;
        padding: 0;
    }
    .header-menu .cat-menu a {
        display: block;
        padding: 10px 28px;
        font-size: 15px;
        color: var(--muted);
    }
    .header-menu .cat-menu a:hover {
        background: rgba(0, 0, 0, 0.03);
        color: var(--fg);
    }
    .header-menu .mobile-divider {
        display: block;
        border: none;
        border-top: 1px solid var(--border);
        margin: 8px 24px;
        width: auto;
    }
    .header-menu .header-link {
        display: block;
        padding: 10px 28px;
        font-size: 15px;
        border-radius: 0;
        color: var(--muted);
    }
    .header-menu .header-link:hover {
        color: var(--fg);
        background: rgba(0, 0, 0, 0.03);
    }
}

/* ========================================
   Main content
   ======================================== */
.main {
    flex: 1;
    max-width: var(--max-w);
    width: 100%;
    margin: 0 auto;
    padding: 32px 24px 60px;
}

/* ========================================
   Article list — homepage / archive / category / tag
   ======================================== */
.article-list {
    display: flex;
    flex-direction: column;
    gap: 0;
}
.article-card {
    display: block;
    padding: 24px 0;
    border-bottom: 1px solid var(--border);
    transition: background 0.15s;
}
.article-card:first-child {
    padding-top: 0;
}
.article-card:hover {
    background: transparent;
}
.article-card h2 {
    font-family: var(--font-display);
    font-size: 20px;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 8px;
    color: var(--fg);
    transition: color 0.15s;
}
@media (min-width: 640px) {
    .article-card h2 {
        font-size: 22px;
    }
}
.article-card:hover h2 {
    color: var(--accent);
}
.article-card .excerpt {
    font-size: 15px;
    color: var(--muted);
    line-height: 1.65;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.article-card .tags {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
}
.article-card .tag {
    font-size: 12px;
    color: var(--muted);
    letter-spacing: 0.3px;
    line-height: 1;
}
.article-card .tag.cat {
    display: inline-flex;
    align-items: center;
    gap: 3px;
    color: var(--accent);
    background: rgba(201, 100, 66, 0.08);
    padding: 3px 10px;
    border-radius: 4px;
    line-height: 1;
}

/* ========================================
   Pagination
   ======================================== */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 4px;
    margin-top: 48px;
    font-size: 15px;
}
.pagination a,
.pagination span {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 10px;
    border-radius: 6px;
    color: var(--muted);
    transition: all 0.15s;
}
.pagination a:hover {
    background: rgba(0, 0, 0, 0.04);
    color: var(--fg);
}
.pagination .current {
    font-weight: 700;
    color: var(--accent);
}
.pagination .prev,
.pagination .next {
    font-size: 18px;
    padding: 0 12px;
}

/* ========================================
   Article page — layout override
   ======================================== */
.page-post .main {
    max-width: var(--article-max-w);
    padding: 0 24px 60px;
}
.page-post .header-inner {
    max-width: var(--article-header-w);
}

.article-wrap {
    display: grid;
    grid-template-columns: 1fr 200px;
    gap: 40px;
    align-items: start;
}

.article-main {
    padding: 40px 0 60px;
    min-width: 0;
}

/* ========================================
   Article header
   ======================================== */
.article-header {
    margin-bottom: 32px;
}
.article-header .breadcrumb {
    font-size: 13px;
    color: var(--muted);
    margin-bottom: 10px;
}
.article-header .breadcrumb a {
    color: var(--muted);
}
.article-header .breadcrumb a:hover {
    color: var(--accent);
}
.article-header .breadcrumb span {
    color: var(--border);
    margin: 0 6px;
}

.article-header h1 {
    font-family: var(--font-display);
    font-size: 28px;
    font-weight: 800;
    line-height: 1.35;
    color: var(--fg-heavy);
    margin-bottom: 16px;
    letter-spacing: 0;
}
@media (min-width: 640px) {
    .article-header h1 {
        font-size: 32px;
    }
}

.article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
}
.article-meta .tag {
    font-size: 12px;
    color: var(--accent);
    background: rgba(201, 100, 66, 0.08);
    padding: 3px 12px;
    border-radius: 4px;
    letter-spacing: 0.3px;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

/* ========================================
   Article body — typography
   ======================================== */
.article-body {
    font-family: var(--font-content);
    font-size: 16px;
    line-height: 1.8;
}

.article-body h2 {
    font-size: 22px;
    font-weight: 700;
    line-height: 1.4;
    color: var(--fg-heavy);
    margin: 40px 0 14px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}
@media (min-width: 640px) {
    .article-body h2 {
        font-size: 24px;
    }
}

.article-body h3 {
    font-size: 18px;
    font-weight: 700;
    line-height: 1.4;
    color: var(--fg-heavy);
    margin: 28px 0 10px;
}
@media (min-width: 640px) {
    .article-body h3 {
        font-size: 20px;
    }
}

.article-body p {
    margin-bottom: 16px;
    color: var(--fg);
}

.article-body blockquote {
    margin: 24px 0;
    padding: 16px 20px;
    background: var(--panel);
    border-left: 3px solid var(--accent);
    border-radius: 0 var(--radius) var(--radius) 0;
    font-style: italic;
    color: var(--fg-heavy);
}
.article-body blockquote p:last-child {
    margin-bottom: 0;
}

.article-body strong {
    color: var(--fg-heavy);
}

.article-body img {
    max-width: 100%;
    border-radius: var(--radius);
    margin: 24px 0;
    display: block;
    background: var(--panel);
}

.article-body hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 32px 0;
}

.article-body ul,
.article-body ol {
    margin: 0 0 16px 20px;
}
.article-body li {
    margin-bottom: 8px;
}

.article-body code {
    font-family: var(--font-mono);
    font-size: 14px;
    background: rgba(0, 0, 0, 0.05);
    padding: 2px 6px;
    border-radius: 4px;
}
.article-body pre {
    margin: 24px 0;
    padding: 16px;
    background: var(--code-bg);
    border-radius: var(--radius);
    overflow-x: auto;
    font-size: 14px;
    line-height: 1.6;
}
.article-body pre code {
    background: none;
    padding: 0;
    border-radius: 0;
    color: var(--fg);
}
.article-body figure.highlight {
    margin: 24px 0;
    border-radius: var(--radius);
    overflow: hidden;
    background: var(--code-bg);
}
.article-body figure.highlight table {
    width: 100%;
    border-collapse: collapse;
}
.article-body figure.highlight .gutter {
    padding: 12px 0;
    text-align: right;
    user-select: none;
    color: var(--muted);
    font-size: 13px;
}
.article-body figure.highlight .gutter pre {
    margin: 0;
    padding: 0 12px;
    background: none;
}
.article-body figure.highlight .code {
    padding: 12px 16px;
    width: 100%;
}
.article-body figure.highlight .code pre {
    margin: 0;
    padding: 0;
    background: none;
    border-radius: 0;
    color: var(--fg);
}

.article-body a {
    color: var(--accent);
    text-decoration: underline;
    text-underline-offset: 2px;
}
.article-body a:hover {
    opacity: 0.8;
}

/* ========================================
   Article tags footer
   ======================================== */
.article-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.article-tags .tag {
    font-size: 13px;
    color: var(--muted);
    letter-spacing: 0.3px;
    display: inline-flex;
    align-items: center;
    line-height: 1;
}
.article-tags .tag.cat {
    color: var(--accent);
    background: rgba(201, 100, 66, 0.08);
    padding: 5px 10px;
    border-radius: 4px;
}

/* ========================================
   TOC sidebar — desktop
   ======================================== */
.toc-sidebar {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    padding-top: 40px;
}
.toc-sidebar .toc-label {
    font-size: 12px;
    font-weight: 700;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.12em;
    margin-bottom: 12px;
}
.toc-sidebar nav {
    max-height: calc(100vh - var(--header-h) - 120px);
    overflow-y: auto;
    overscroll-behavior: contain;
    padding-right: 6px;
    scrollbar-width: none;
    -ms-overflow-style: none;
}
.toc-sidebar nav::-webkit-scrollbar {
    display: none;
}
.toc-sidebar nav a {
    display: block;
    font-size: 13px;
    line-height: 1.5;
    color: var(--muted);
    padding: 5px 0 5px 12px;
    border-left: 2px solid var(--border);
    transition:
        color 0.15s,
        border-color 0.15s;
}
.toc-sidebar nav a:hover {
    color: var(--fg);
    border-left-color: var(--accent);
}
.toc-sidebar nav a.active {
    color: var(--accent);
    border-left-color: var(--accent);
    font-weight: 600;
}
.toc-sidebar nav a.toc-h3 {
    padding-left: 24px;
    font-size: 12px;
}

/* TOC sidebar — mobile */
@media (max-width: 768px) {
    .article-wrap {
        grid-template-columns: 1fr;
        gap: 0;
    }
    .toc-sidebar {
        position: static;
        padding-top: 0;
        margin-top: 0;
        border-bottom: 1px solid var(--border);
        margin-bottom: 24px;
    }
    .toc-sidebar .toc-label {
        cursor: pointer;
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 14px 0;
        margin-bottom: 0;
    }
    .toc-sidebar .toc-label::after {
        content: "";
        display: inline-block;
        width: 12px;
        height: 12px;
        border-right: 2px solid var(--muted);
        border-bottom: 2px solid var(--muted);
        transform: rotate(45deg);
        transition: transform 0.2s;
        margin-top: -4px;
    }
    .toc-sidebar.collapsed .toc-label::after {
        transform: rotate(-45deg);
        margin-top: 4px;
    }
    .toc-sidebar.collapsed nav {
        display: none;
    }
    .toc-sidebar nav {
        padding-bottom: 12px;
    }
}

/* ========================================
   Footer
   ======================================== */
.site-footer {
    text-align: center;
    padding: 24px;
    font-size: 14px;
    color: var(--muted);
    border-top: 1px solid var(--border);
}
.busuanzi-hidden {
    display: none;
}

/* ========================================
   Lightbox
   ======================================== */
.article-body img {
    cursor: zoom-in;
}
.lightbox-overlay {
    position: fixed;
    inset: 0;
    z-index: 999;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
    cursor: zoom-out;
}
.lightbox-overlay.active {
    opacity: 1;
    pointer-events: auto;
}
.lightbox-overlay img {
    max-width: 90vw;
    max-height: 90vh;
    border-radius: var(--radius);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

/* ========================================
   Transitions
   ======================================== */
.fade-in {
    animation: fadeIn 0.3s ease;
}
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}