/* --- 现代简约暗黑主题 --- */
:root {
    --dark-bg: #1a1d24;          /* 主背景色 */
    --light-bg: #272c36;         /* 卡片、表单等元素的背景色 */
    --text-color: #dbe1e8;       /* 主要文字颜色 */
    --text-muted-color: #a9b8c5; /* 次要文字颜色 (提升对比度以满足WCAG AA标准) */
    --accent-color: #88c0d0;      /* 链接、按钮等强调色 */
    --accent-hover-color: #a4d5e4;/* 链接、按钮悬停颜色 */
    --border-color: #3b4252;      /* 边框颜色 */
    /* --- ENHANCEMENT: New Variables --- */
    --shadow-color-soft: rgba(0, 0, 0, 0.2);
    --shadow-color-glow: rgba(136, 192, 208, 0.15);
}

/* --- 全局样式 --- */
body {
    background-color: var(--dark-bg);
    color: var(--text-color);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

h1, h2, h3, h4, h5, h6 {
    color: var(--text-color);
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

a:hover {
    color: var(--accent-hover-color);
    text-decoration: underline;
    /* --- ENHANCEMENT: Glow effect --- */
    box-shadow: 0 0 15px var(--shadow-color-glow);
}

/* --- Bootstrap 组件颜色覆盖 --- */

/* --- ENHANCEMENT: Sticky Navbar --- */
.navbar.sticky-top {
    border-bottom: 1px solid var(--border-color);
    background-color: rgba(26, 29, 36, 0.85); /* Semi-transparent background */
    backdrop-filter: blur(10px); /* Frosted glass effect */
    box-shadow: 0 2px 10px var(--shadow-color-soft);
    transition: background-color 0.3s ease;
}

/* 卡片 (用于文章列表) */
.card {
    background-color: var(--light-bg);
    border: 1px solid var(--border-color);
    /* --- ENHANCEMENT: Soft shadow for depth --- */
    box-shadow: 0 1px 3px var(--shadow-color-soft);
}

.card-body {
    color: var(--text-color);
}

.card-title {
    color: var(--text-color);
    transition: color 0.2s ease-in-out;
}

.card-subtitle {
    color: var(--text-muted-color) !important;
}

/* 表单 */
.form-control {
    background-color: var(--light-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    transition: border-color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

.form-control:focus {
    background-color: var(--light-bg);
    color: var(--text-color);
    border-color: var(--accent-color);
    /* --- ENHANCEMENT: Brighter glow effect on focus --- */
    box-shadow: 0 0 0 0.25rem var(--shadow-color-glow), 0 0 15px var(--shadow-color-glow);
}

.form-control::placeholder {
    color: var(--text-muted-color);
}

/* 按钮 */
.btn {
    transition: all 0.2s ease-in-out;
}
.btn:active {
    /* --- ENHANCEMENT: Click feedback --- */
    transform: translateY(1px);
}

.btn-outline-success {
    --bs-btn-color: var(--accent-color);
    --bs-btn-border-color: var(--accent-color);
    --bs-btn-hover-color: var(--dark-bg);
    --bs-btn-hover-bg: var(--accent-color);
    --bs-btn-hover-border-color: var(--accent-color);
    --bs-btn-active-color: var(--dark-bg);
    --bs-btn-active-bg: var(--accent-hover-color);
    --bs-btn-active-border-color: var(--accent-hover-color);
}
.btn-outline-success:hover {
    box-shadow: 0 0 15px var(--shadow-color-glow);
}

.btn-primary {
    --bs-btn-color: #fff;
    --bs-btn-bg: var(--accent-color);
    --bs-btn-border-color: var(--accent-color);
    --bs-btn-hover-color: #fff;
    --bs-btn-hover-bg: var(--accent-hover-color);
    --bs-btn-hover-border-color: var(--accent-hover-color);
    --bs-btn-focus-shadow-rgb: 136, 192, 208;
    --bs-btn-active-color: #fff;
    --bs-btn-active-bg: var(--accent-hover-color);
    --bs-btn-active-border-color: var(--accent-hover-color);
}


/* --- 文章内容样式优化 --- */
article {
    /* --- ENHANCEMENT: Constrain article width for readability on large screens --- */
    max-width: 820px;
    margin-left: auto;
    margin-right: auto;
}
article section {
    line-height: 1.8;
}

article section img {
    max-width: 100%;
    height: auto;
    border-radius: 5px;
    margin: 1rem 0;
}

article section a {
    text-decoration: underline;
}

article section h1, article section h2, article section h3, article section h4 {
    margin-top: 2.5rem;
    margin-bottom: 1.25rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

article section blockquote {
    border-left: 4px solid var(--border-color);
    padding-left: 1rem;
    color: var(--text-muted-color);
    font-style: italic;
    margin: 1.5rem 0;
}


/* ========== CORRECTED CODE BLOCK STYLES START ========== */
article section :not(pre) > code {
    background-color: #3b4252;
    color: #d8dee9;
    padding: 0.2em 0.4em;
    margin: 0 0.1em;
    font-size: 95%;
    border-radius: 6px;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}
article section .highlight {
    position: relative;
    background-color: #2E3440;
    border-radius: 8px;
    padding-top: 3rem;
    margin: 1.2rem 0;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
    font-size: 14px; /* 确保代码块字体在移动端的可读性 (大于12px) */
    box-shadow: 0 2px 8px var(--shadow-color-soft);
}
article section .highlight > pre {
    margin: 0;
    padding: 0 1.2rem 1.2rem;
    border-radius: 0;
    background-color: transparent;
    overflow-x: auto;
    position: static;
}
article section .highlight pre > code {
    background: none;
    padding: 0;
    margin: 0;
    font-family: inherit;
}
/* ========== CORRECTED CODE BLOCK STYLES END ========== */


/* ========== ADDITION START: Terminal Window Effect ========== */
article section .highlight::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2.2rem;
    background-color: #3b4252;
    border-top-left-radius: 8px;
    border-top-right-radius: 8px;
    border-bottom: 1px solid var(--border-color);
}
article section .highlight::after {
    content: ' ';
    position: absolute;
    top: 0.7rem;
    left: 0.8rem;
    width: 0.8rem;
    height: 0.8rem;
    border-radius: 50%;
    background-color: #ff5f56;
    box-shadow: 1.2rem 0 0 #ffbd2e,
                2.4rem 0 0 #27c93f;
}
/* ========== ADDITION END: Terminal Window Effect ========== */


/* ========== PYGMENTS THEME START ========== */
.highlight { background: transparent; color: #D8DEE9 }
.highlight .hll { background-color: #434C5E }
.highlight .c { color: #4C566A } .highlight .err { color: #BF616A } .highlight .k { color: #81A1C1 } .highlight .l { color: #B48EAD } .highlight .n { color: #D8DEE9 } .highlight .o { color: #81A1C1 } .highlight .p { color: #ECEFF4 } .highlight .ch { color: #4C566A } .highlight .cm { color: #4C566A } .highlight .cp { color: #5E81AC } .highlight .cpf { color: #4C566A } .highlight .c1 { color: #4C566A } .highlight .cs { color: #4C566A } .highlight .kc { color: #81A1C1 } .highlight .kd { color: #81A1C1 } .highlight .kn { color: #81A1C1 } .highlight .kp { color: #81A1C1 } .highlight .kr { color: #81A1C1 } .highlight .kt { color: #8FBCBB } .highlight .ld { color: #A3BE8C } .highlight .m { color: #B48EAD } .highlight .s { color: #A3BE8C } .highlight .na { color: #88C0D0 } .highlight .nb { color: #81A1C1 } .highlight .nc { color: #8FBCBB } .highlight .no { color: #D8DEE9 } .highlight .nd { color: #88C0D0 } .highlight .ni { color: #D8DEE9 } .highlight .ne { color: #BF616A } .highlight .nf { color: #88C0D0 } .highlight .nl { color: #D8DEE9 } .highlight .nn { color: #8FBCBB } .highlight .nx { color: #ECEFF4 } .highlight .py { color: #8FBCBB } .highlight .nt { color: #81A1C1 } .highlight .nv { color: #D8DEE9 } .highlight .ow { color: #81A1C1 } .highlight .w { color: #D8DEE9 } .highlight .mb { color: #B48EAD } .highlight .mf { color: #B48EAD } .highlight .mh { color: #B48EAD } .highlight .mi { color: #B48EAD } .highlight .mo { color: #B48EAD } .highlight .sa { color: #A3BE8C } .highlight .sb { color: #A3BE8C } .highlight .sc { color: #A3BE8C } .highlight .dl { color: #A3BE8C } .highlight .sd { color: #4C566A } .highlight .s2 { color: #A3BE8C } .highlight .se { color: #EBCB8B } .highlight .sh { color: #A3BE8C } .highlight .si { color: #EBCB8B } .highlight .sx { color: #A3BE8C } .highlight .sr { color: #A3BE8C } .highlight .s1 { color: #A3BE8C } .highlight .ss { color: #A3BE8C } .highlight .bp { color: #81A1C1 } .highlight .fm { color: #88C0D0 } .highlight .vc { color: #D8DEE9 } .highlight .vg { color: #D8DEE9 } .highlight .vi { color: #D8DEE9 } .highlight .vm { color: #88C0D0 } .highlight .il { color: #B48EAD }
/* ========== PYGMENTS THEME END ========== */


/* ========== FIX START: 侧边栏分类列表暗黑主题适配 ========== */
.card-header {
    background-color: var(--dark-bg);
    border-bottom: 1px solid var(--border-color);
}
.list-group-item {
    background-color: var(--light-bg);
    color: var(--text-color);
    border-color: var(--border-color);
    /* --- ENHANCEMENT: Smooth Transition & Active Indicator Space --- */
    transition: background-color 0.2s ease-in-out, border-left-color 0.2s ease-in-out, color 0.2s ease-in-out;
    border-left: 3px solid transparent;
}
/* --- ENHANCEMENT: Sidebar Item Hover/Focus/Active states --- */
.list-group-item-action:hover, .list-group-item-action:focus {
    background-color: #3b4252;
    color: var(--accent-hover-color);
    border-left-color: var(--accent-color);
}
.list-group-item.active {
    background-color: rgba(136, 192, 208, 0.1);
    color: var(--accent-hover-color);
    border-color: var(--border-color);
    border-left-color: var(--accent-hover-color);
}

.badge.bg-secondary {
    background-color: var(--border-color) !important;
    color: var(--text-color);
}
.btn-outline-primary {
    --bs-btn-color: var(--accent-color);
    --bs-btn-border-color: var(--accent-color);
    --bs-btn-hover-color: var(--dark-bg);
    --bs-btn-hover-bg: var(--accent-color);
    --bs-btn-hover-border-color: var(--accent-color);
    --bs-btn-focus-shadow-rgb: 136, 192, 208;
    --bs-btn-active-color: var(--dark-bg);
    --bs-btn-active-bg: var(--accent-hover-color);
    --bs-btn-active-border-color: var(--accent-hover-color);
    --bs-btn-disabled-color: var(--accent-color);
    --bs-btn-disabled-bg: transparent;
    --bs-btn-disabled-border-color: var(--accent-color);
    --bs-gradient: none;
}
/* ========== FIX END ========== */

/* ========== ADDITION START: Pagination Dark Theme Styles ========== */
.pagination .page-link {
    background-color: var(--light-bg);
    color: var(--text-color);
    border-color: var(--border-color);
    transition: all 0.2s ease-in-out;
}
.pagination .page-link:hover {
    background-color: #3b4252;
    color: var(--accent-hover-color);
    border-color: var(--border-color);
}
.pagination .page-link:focus {
    box-shadow: 0 0 0 0.25rem var(--shadow-color-glow);
}
.pagination .page-item.active .page-link {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: var(--dark-bg);
}
.pagination .page-item.disabled .page-link {
    background-color: var(--light-bg);
    color: var(--text-muted-color);
    border-color: var(--border-color);
}
/* ========== ADDITION END: Pagination Dark Theme Styles ========== */


/* ========== MODIFICATION START: New card styles for multi-line excerpt ========== */
.card.h-100 {
    display: flex;
    flex-direction: column;
}
@media (min-width: 768px) {
    .card.h-100 {
        min-height: 250px;
    }
}
.card-link-wrapper {
    display: block;
    text-decoration: none;
    color: inherit;
    height: 100%;
    border-radius: var(--bs-card-border-radius);
}
.card-link-wrapper:hover {
    text-decoration: none;
    box-shadow: none; /* Remove glow from the link wrapper itself */
}
.card.h-100 .card-body {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}
.card-link-wrapper .card {
    transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out, border-color 0.2s ease-in-out;
}
.card-link-wrapper:hover .card {
    transform: translateY(-5px);
    box-shadow: 0 4px 15px var(--shadow-color-soft), 0 0 20px var(--shadow-color-glow);
    border-color: var(--accent-color);
}
.card-link-wrapper:hover .card-title {
    color: var(--accent-color);
}
.card-excerpt {
    flex-grow: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 4;
    line-height: 1.5;
}
/* ========== MODIFICATION END ========== */

/* 响应式调整 */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }
}

/* ========== MODIFICATION START: Mobile beautification for cards ========== */
@media (max-width: 767.98px) {
    .card.h-100 {
        height: auto;
        min-height: 0;
    }
    .card-excerpt {
        -webkit-line-clamp: 2;
        line-height: 1.4;
        flex-grow: 0;
    }
}
/* ========== MODIFICATION END ========== */

/* ========== MODIFICATION START: Styles for Fixed Sidebar Layout ========== */
@media (min-width: 768px) {
    .sidebar-fixed {
        flex: 0 0 280px;
    }
    .sidebar-sticky {
        position: sticky;
        top: 6rem; /* Adjust based on navbar height + desired spacing */
        max-height: calc(100vh - 7rem);
        overflow-y: auto;
    }
}
@media (max-width: 767.98px) {
    .sidebar-fixed {
        margin-bottom: 1.5rem;
    }
}
/* ========== MODIFICATION END ========== */


/* ========== ADDITION START: Infinite Scroll Loading Indicator ========== */
.loading-indicator {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    text-align: center;
    color: var(--text-muted-color);
}
.spinner {
    width: 2rem;
    height: 2rem;
    border: 3px solid var(--border-color);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-right: 1rem;
}
@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}
/* ========== ADDITION END: Infinite Scroll Loading Indicator ========== */

/* ========== ADDITION START: Series Box Styles ========== */
.series-box .card-header {
    font-weight: bold;
}
.series-box .list-group-item {
    border-left: 0;
    border-right: 0;
}
.series-box .list-group-item.active {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: var(--dark-bg);
    border-left: 3px solid var(--accent-color);
}
.series-box a.list-group-item-action:hover, 
.series-box a.list-group-item-action:focus {
    background-color: #3b4252;
    color: var(--accent-hover-color);
}
/* ========== ADDITION END: Series Box Styles ========== */

/* ========== ADDITION START: Post Navigation & Back to Top Styles ========== */
.post-navigation {
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1.5rem 0;
}
.post-navigation .prev-post,
.post-navigation .next-post {
    flex-basis: 48%;
}
.post-nav-link {
    display: block;
    padding: 1rem;
    border: 1px solid transparent;
    border-radius: 8px;
    transition: background-color 0.2s ease-in-out, border-color 0.2s ease-in-out;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.next-post .post-nav-link {
    flex-direction: row-reverse;
}
.post-nav-link:hover {
    background-color: var(--light-bg);
    border-color: var(--border-color);
    text-decoration: none;
}
.post-nav-link small {
    color: var(--text-muted-color);
    font-size: 0.9em;
    flex-shrink: 0;
}
.post-nav-link .post-nav-title {
    color: var(--text-color);
    font-weight: 500;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.post-nav-link:hover .post-nav-title {
    color: var(--accent-hover-color);
}
.back-to-top {
    position: fixed;
    bottom: 25px;
    right: 25px;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: var(--light-bg);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    text-decoration: none;
    font-size: 20px;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    /* --- ENHANCEMENT: Smooth fade and slide animation --- */
    transform: translateY(10px);
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease, background-color 0.2s, color 0.2s, border-color 0.2s, box-shadow 0.2s;
    cursor: pointer;
    box-shadow: 0 2px 8px var(--shadow-color-soft);
}
.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.back-to-top:hover {
    background-color: var(--accent-color);
    color: var(--dark-bg);
    border-color: var(--accent-color);
    text-decoration: none;
    box-shadow: 0 0 15px var(--shadow-color-glow);
}
/* ========== ADDITION END ========== */

@media (max-width: 767.98px) {
    .post-navigation {
        flex-direction: column;
    }
    .post-navigation .prev-post,
    .post-navigation .next-post {
        flex-basis: 100%;
        text-align: left;
    }
    .post-navigation .prev-post {
        margin-bottom: 1rem;
    }
}

/* ========== ADDITION START: Social Share Buttons ========== */
.social-share-container {
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1.5rem 0;
}
.social-share-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    background-color: var(--light-bg);
    color: var(--text-muted-color);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s ease-in-out;
    cursor: pointer;
}
.social-share-btn svg {
    width: 16px;
    height: 16px;
}
.social-share-btn:hover {
    color: #fff;
    transform: translateY(-2px);
    border-color: transparent;
    box-shadow: 0 2px 8px var(--shadow-color-soft);
}
.social-share-btn.btn-twitter:hover { background-color: #1DA1F2; }
.social-share-btn.btn-facebook:hover { background-color: #1877F2; }
.social-share-btn.btn-weibo:hover { background-color: #E6162D; }
.social-share-btn.btn-linkedin:hover { background-color: #0A66C2; }
.social-share-btn.btn-copy:hover { 
    background-color: var(--accent-color);
    color: var(--dark-bg);
}
.social-share-btn.btn-copy.copied {
    background-color: #27c93f;
    color: #fff;
    border-color: #27c93f;
    pointer-events: none;
}
/* ========== ADDITION END: Social Share Buttons ========== */


/* ========== FINAL FIX START: Diagram Styles ========== */
 article section > svg {
    display: block;
    max-width: 100%;
    height: auto !important;
    margin: 1.5rem auto;
}
.mermaid,
div.diagram-container {
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--light-bg);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
    overflow-x: auto;
}
.mermaid svg,
div.diagram-container svg {
    width: 100%;
    max-width: none;
    height: auto !important;
}
div.diagram-container svg text {
    fill: var(--text-color);
}
div.diagram-container svg path,
div.diagram-container svg line,
div.diagram-container svg rect,
div.diagram-container svg circle,
div.diagram-container svg polygon {
    stroke: var(--text-muted-color);
    fill: none;
}
/* ========== FINAL FIX END: Diagram Styles ========== */

/* --- ENHANCEMENT: Footer --- */
.site-footer {
    background-color: var(--dark-bg);
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
}
.site-footer a {
    text-decoration: underline;
}
.site-footer a:hover {
    box-shadow: none; /* Remove glow from footer links */
}