/* 主题变量 */
:root {
    color-scheme: light;
    --bg-page: #fafafa;
    --bg-surface: #ffffff;
    --text-primary: #333333;
    --text-heading: #1a1a1a;
    --text-secondary: #555555;
    --text-subtle: #666666;
    --text-muted: #888888;
    --border-color: #e0e0e0;
    --border-strong: #dfe2e5;
    --accent: #0066cc;
    --accent-hover: #0052a3;
    --accent-soft-bg: #e6f2ff;
    --accent-soft-border: #0066cc;
    --search-indicator-bg: #e6f2ff;
    --search-indicator-color: #0066cc;
    --search-info-bg: #f0f8ff;
    --search-info-text: #333333;
    --search-info-strong: #0066cc;
    --search-info-alt-bg: #fffbea;
    --search-info-alt-border: #f5e6b3;
    --search-info-alt-text: #856404;
    --tag-bg: #f0f0f0;
    --tag-color: #555555;
    --tag-hover-bg: #0066cc;
    --tag-hover-color: #ffffff;
    --inline-code-bg: rgba(27, 31, 35, 0.05);
    --inline-code-border: rgba(27, 31, 35, 0.06);
    --inline-code-color: #b33a0b;
    --code-border: #e1e4e8;
    --code-bg: #f6f8fa;
    --code-header-bg: #eef3fb;
    --code-header-color: #245b96;
    --code-copy-bg: rgba(36, 91, 150, 0.12);
    --code-copy-bg-hover: rgba(36, 91, 150, 0.2);
    --code-copy-bg-active: #245b96;
    --code-copy-color-active: #ffffff;
    --code-text: #1f2933;
    --blockquote-bg: #f4f8ff;
    --blockquote-border: #0a66c2;
    --blockquote-text: #3b3b3b;
    --empty-state-color: #888888;
    --footer-text: #888888;
    --error-number: #dddddd;
    --input-placeholder: #999999;
    --container-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --container-shadow-hover: 0 4px 12px rgba(0, 0, 0, 0.15);
    --focus-outline: rgba(0, 102, 204, 0.35);
}

:root[data-theme='dark'] {
    color-scheme: dark;
    --bg-page: #0f172a;
    --bg-surface: #1e293b;
    --text-primary: #e2e8f0;
    --text-heading: #f8fafc;
    --text-secondary: #cbd5f5;
    --text-subtle: #94a3b8;
    --text-muted: #94a3b8;
    --border-color: rgba(148, 163, 184, 0.35);
    --border-strong: rgba(148, 163, 184, 0.5);
    --accent: #60a5fa;
    --accent-hover: #93c5fd;
    --accent-soft-bg: rgba(96, 165, 250, 0.18);
    --accent-soft-border: rgba(96, 165, 250, 0.6);
    --search-indicator-bg: rgba(96, 165, 250, 0.18);
    --search-indicator-color: #93c5fd;
    --search-info-bg: rgba(59, 130, 246, 0.15);
    --search-info-text: #e2e8f0;
    --search-info-strong: #93c5fd;
    --search-info-alt-bg: rgba(217, 119, 6, 0.16);
    --search-info-alt-border: rgba(217, 119, 6, 0.4);
    --search-info-alt-text: #fcd34d;
    --tag-bg: rgba(148, 163, 184, 0.2);
    --tag-color: #e2e8f0;
    --tag-hover-bg: #60a5fa;
    --tag-hover-color: #0f172a;
    --inline-code-bg: rgba(148, 163, 184, 0.2);
    --inline-code-border: rgba(148, 163, 184, 0.35);
    --inline-code-color: #fca5a5;
    --code-border: rgba(148, 163, 184, 0.45);
    --code-bg: #0c182e;
    --code-header-bg: rgba(30, 41, 59, 0.88);
    --code-header-color: #e0f2fe;
    --code-copy-bg: rgba(96, 165, 250, 0.28);
    --code-copy-bg-hover: rgba(96, 165, 250, 0.45);
    --code-copy-bg-active: #93c5fd;
    --code-copy-color-active: #0b1120;
    --code-text: #e8f1ff;
    --blockquote-bg: rgba(37, 99, 235, 0.15);
    --blockquote-border: rgba(96, 165, 250, 0.6);
    --blockquote-text: #e2e8f0;
    --empty-state-color: #94a3b8;
    --footer-text: #64748b;
    --error-number: rgba(148, 163, 184, 0.4);
    --input-placeholder: #94a3b8;
    --container-shadow: 0 1px 3px rgba(15, 23, 42, 0.6);
    --container-shadow-hover: 0 6px 16px rgba(15, 23, 42, 0.5);
    --focus-outline: rgba(96, 165, 250, 0.45);
}

/* 重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-page);
    font-size: 16px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

a {
    color: inherit;
}

/* 容器 */
.container {
    width: 90%;
    margin: 0 auto;
    padding: 40px 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* 头部 */
header {
    text-align: left;
    margin-bottom: 60px;
    padding-bottom: 30px;
    border-bottom: 1px solid var(--border-color);
    transition: border-color 0.3s ease;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 40px;
}

.header-left {
    flex: 1;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

header h1 {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-heading);
    margin-bottom: 0;
    transition: color 0.12s ease;
}

header h1 a {
    color: inherit;
    text-decoration: none;
    transition: color 0.12s cubic-bezier(0.3, 0, 0.2, 1);
}

header h1 a:hover {
    color: var(--accent);
}

.subtitle {
    font-size: 1.8rem;
    color: var(--text-subtle);
    font-weight: 300;
    transition: color 0.3s ease;
}

/* 主题切换按钮 */
.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.4rem;
    min-width: 2.4rem;
    height: 2.4rem;
    padding: 0;
    border-radius: 999px;
    border: 1px solid transparent;
    background: var(--tag-bg);
    color: var(--text-secondary);
    font-size: 1.05rem;
    cursor: pointer;
    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
    flex-shrink: 0;
    aspect-ratio: 1 / 1;
}

.theme-toggle:hover {
    background: var(--accent-soft-bg);
    color: var(--accent);
}

.theme-toggle:active {
    transform: translateY(1px);
}

.theme-toggle:focus-visible {
    outline: 3px solid var(--focus-outline);
    outline-offset: 2px;
}

.theme-toggle__icon {
    font-size: 1.1rem;
    line-height: 1;
}

:root[data-theme='dark'] .theme-toggle__icon--moon {
    display: none;
}

:root:not([data-theme='dark']) .theme-toggle__icon--sun {
    display: none;
}

/* 搜索容器 */
.search-container {
    display: flex;
    align-items: center;
    min-width: 200px;
}

.search-form {
    width: 100%;
}

.search-input-wrapper {
    position: relative;
    width: 100%;
}

.search-input {
    width: 100%;
    padding: 8px 0;
    font-size: 1rem;
    border: none;
    border-bottom: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-primary);
    transition: border-color 0.3s ease, color 0.3s ease;
    font-family: inherit;
}

.search-input::placeholder {
    color: var(--input-placeholder);
    transition: color 0.3s ease;
}

.search-input:focus {
    outline: none;
    border-bottom-color: var(--accent);
}

.search-type-indicator {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.75rem;
    color: var(--search-indicator-color);
    background: var(--search-indicator-bg);
    padding: 2px 8px;
    border-radius: 10px;
    pointer-events: none;
    transition: background 0.3s ease, color 0.3s ease;
}

/* 搜索信息 */
.search-info {
    margin-bottom: 30px;
    padding: 20px;
    background: var(--search-info-bg);
    border-radius: 6px;
    border-left: 4px solid var(--accent-soft-border);
    transition: background 0.8s cubic-bezier(0.3, 0, 0.2, 1),
                border-left-color 0.8s cubic-bezier(0.3, 0, 0.2, 1);
}

.search-info.no-results {
    background: var(--search-info-alt-bg);
    border-left-color: var(--search-info-alt-border);
}

.search-info p {
    margin: 0;
    color: var(--search-info-text);
    line-height: 1.6;
    transition: color 0.8s cubic-bezier(0.3, 0, 0.2, 1);
}

.search-info.no-results p {
    color: var(--search-info-alt-text);
}

.search-info p + p {
    margin-top: 8px;
}

.search-info strong {
    color: var(--search-info-strong);
    transition: color 0.8s cubic-bezier(0.3, 0, 0.2, 1);
}

.search-info.no-results strong {
    color: var(--search-info-alt-text);
}

/* 主内容 */
main {
    flex: 1;
}

/* 文章列表 */
.posts-list {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.post-preview {
    padding: 30px;
    background: var(--bg-surface);
    border-radius: 8px;
    box-shadow: var(--container-shadow);
    transition: box-shadow 0.2s ease, background 0.3s ease, color 0.3s ease;
}

.post-preview:hover {
    box-shadow: var(--container-shadow-hover);
}

.post-title {
    font-size: 1.75rem;
    margin-bottom: 10px;
    line-height: 1.3;
    color: var(--text-heading);
    transition: color 0.12s ease;
}

.post-title a {
    color: inherit;
    text-decoration: none;
    transition: color 0.12s cubic-bezier(0.3, 0, 0.2, 1);
}

.post-title a:hover {
    color: var(--accent);
}

.post-date {
    display: inline-block;
    font-size: 0.9rem;
    color: var(--text-muted);
    transition: color 0.3s ease;
}

.post-description {
    color: var(--text-secondary);
    margin-bottom: 15px;
    line-height: 1.7;
    transition: color 0.3s ease;
}

.post-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 15px;
}

.tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--tag-bg);
    border-radius: 4px;
    font-size: 0.85rem;
    color: var(--tag-color);
    transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;
}

.clickable-tag {
    cursor: pointer;
}

.clickable-tag:hover {
    background: var(--tag-hover-bg);
    color: var(--tag-hover-color);
    transform: translateY(-1px);
}

/* 文章详情页 */
.post-content {
    background: var(--bg-surface);
    padding: 40px;
    border-radius: 8px;
    box-shadow: var(--container-shadow);
    transition: box-shadow 0.2s ease, background 0.3s ease, color 0.3s ease;
}

.post-content .post-title {
    font-size: 2.25rem;
    margin-bottom: 0;
    color: var(--text-heading);
    transition: color 0.12s ease;
}

.post-meta {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
    transition: border-color 0.3s ease;
}

/* Markdown 内容样式 */
.markdown-content {
    line-height: 1.8;
    color: var(--text-primary);
    font-size: 1rem;
}

.markdown-content h1,
.markdown-content h2,
.markdown-content h3,
.markdown-content h4,
.markdown-content h5,
.markdown-content h6 {
    margin: 2.2rem 0 1rem;
    font-weight: 600;
    line-height: 1.25;
    color: var(--text-heading);
    transition: color 0.3s ease;
}

.markdown-content h1 { font-size: 2.2rem; }
.markdown-content h2 { font-size: 1.9rem; }
.markdown-content h3 { font-size: 1.6rem; }
.markdown-content h4 { font-size: 1.35rem; }
.markdown-content h5 { font-size: 1.15rem; }
.markdown-content h6 { font-size: 1rem; }

.markdown-content p {
    margin: 1rem 0;
}

.markdown-content a {
    color: var(--accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

.markdown-content a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

.markdown-content ul,
.markdown-content ol {
    margin: 1rem 0 1rem 1.5rem;
    padding-left: 1rem;
}

.markdown-content li {
    margin: 0.4rem 0;
}

.markdown-content blockquote {
    margin: 1.6rem 0;
    padding: 1rem 1.5rem;
    border-left: 4px solid var(--blockquote-border);
    background: var(--blockquote-bg);
    color: var(--blockquote-text);
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.markdown-content blockquote p {
    margin: 0.8rem 0;
}

.markdown-content code {
    font-family: "Fira Code", "JetBrains Mono", SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.95rem;
}

.markdown-content p code,
.markdown-content li code,
.markdown-content table code {
    padding: 0.15rem 0.35rem;
    border-radius: 6px;
    background: var(--inline-code-bg);
    border: 1px solid var(--inline-code-border);
    color: var(--inline-code-color);
    transition: background 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}

.code-block {
    margin: 1.75rem 0;
    border: 1px solid var(--code-border);
    border-radius: 12px;
    background: var(--code-bg);
    overflow: hidden;
    color: var(--code-text);
    transition: background 0.3s ease, border-color 0.3s ease;
}

.code-block__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.6rem 1rem;
    background: var(--code-header-bg);
    border-bottom: 1px solid var(--code-border);
    font-family: "Fira Code", "JetBrains Mono", SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.8rem;
    letter-spacing: 0.04em;
    color: var(--code-header-color);
    text-transform: uppercase;
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.code-block__language {
    opacity: 0.8;
}

.code-block__copy {
    border: none;
    background: var(--code-copy-bg);
    color: var(--code-header-color);
    font-size: 0.75rem;
    padding: 0.3rem 0.75rem;
    border-radius: 999px;
    cursor: pointer;
    transition: background 0.2s ease, color 0.2s ease;
}

.code-block__copy:hover {
    background: var(--code-copy-bg-hover);
}

.code-block__copy.is-copied {
    background: var(--code-copy-bg-active);
    color: var(--code-copy-color-active);
}

.code-block pre {
    margin: 0;
    padding: 1.25rem;
    overflow: auto;
    background: transparent;
    color: inherit;
}

.code-block pre code {
    background: none;
    color: inherit;
    padding: 0;
}

.markdown-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.75rem 0;
    font-size: 0.95rem;
}

.markdown-content table th,
.markdown-content table td {
    padding: 0.85rem 1rem;
    border: 1px solid var(--border-strong);
    text-align: left;
    transition: border-color 0.3s ease;
}

.markdown-content table th {
    background: var(--code-bg);
    font-weight: 600;
}

.markdown-content img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.markdown-content hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 2rem 0;
    transition: border-color 0.3s ease;
}

.markdown-content .katex-display {
    margin: 2rem 0;
    width: 100%;
}

.markdown-content .katex-display > .katex {
    display: block;
    font-size: 1.2rem;
    overflow: visible;
    max-width: none;
}

.markdown-content .arithmatex {
    font-size: inherit;
}

/* 文章底部 */
.post-footer {
    margin-top: 40px;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
    transition: border-color 0.3s ease;
}

.back-link {
    color: var(--accent);
    text-decoration: none;
    font-size: 1rem;
    transition: color 0.2s ease;
}

.back-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 80px 20px;
    color: var(--empty-state-color);
    transition: color 0.3s ease;
}

.empty-state.search-empty {
    background: var(--search-info-alt-bg);
    border-radius: 8px;
    border: 1px solid var(--search-info-alt-border);
    color: var(--search-info-alt-text);
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

/* 404 错误页 */
.error-page {
    text-align: center;
    padding: 80px 20px;
}

.error-page h1 {
    font-size: 6rem;
    color: var(--error-number);
    margin-bottom: 20px;
    transition: color 0.3s ease;
}

.error-page p {
    font-size: 1.2rem;
    color: var(--text-subtle);
    margin-bottom: 30px;
    transition: color 0.3s ease;
}

/* 页脚 */
footer {
    margin-top: 60px;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--footer-text);
    font-size: 0.9rem;
    transition: color 0.3s ease, border-color 0.3s ease;
}

/* 无障碍：键盘焦点 */
.clickable-tag:focus-visible,
.back-link:focus-visible,
header h1 a:focus-visible {
    outline: 3px solid var(--focus-outline);
    outline-offset: 2px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 20px 15px;
    }

    .header-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 20px;
    }

    .header-actions {
        width: 100%;
        justify-content: space-between;
    }

    header h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1.2rem;
    }

    .search-container {
        width: 100%;
        min-width: unset;
    }

    .post-preview,
    .post-content {
        padding: 20px;
    }

    .post-title {
        font-size: 1.5rem;
    }

    .post-content .post-title {
        font-size: 1.75rem;
    }

    .post-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }

    .error-page h1 {
        font-size: 4rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        transition: none !important;
    }
}