/* ============================================================
   LaTeX Blog — Minimal Academic Theme
   ============================================================ */

:root {
    --font-serif: "Latin Modern Roman", "Noto Serif", "Georgia", serif;
    --font-sans: "Noto Sans CJK SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", "Noto Sans Mono CJK SC", "Consolas", monospace;
    --color-text: #262626;
    --color-text-secondary: #7f7f7f;
    --color-link: #0066cc;
    --color-link-hover: #004999;
    --color-border: #d9d9d9;
    --color-bg: #fafaf8;
    --color-bg-code: #f3f3f0;
    --color-bg-inline-code: #ede9e1;
    --color-tag-bg: #ede9e1;
    --color-tag-text: #5a5a5a;
    --max-width: 45rem;
}

/* Reset */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* Base */
html {
    font-size: 17px;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: var(--font-serif);
    color: var(--color-text);
    background: var(--color-bg);
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.25rem;
}

/* CJK override */
:lang(zh),
:lang(ja),
:lang(ko) {
    font-family: var(--font-sans);
}

/* Header */
.site-header {
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 1.2rem;
}

.site-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    font-family: var(--font-serif);
    letter-spacing: 0.05em;
}

.site-title:hover {
    color: var(--color-link);
}

/* Footer */
.site-footer {
    margin-top: 2.5rem;
    padding: 1rem 0;
    border-top: 1px solid var(--color-border);
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    text-align: center;
}

.site-footer a {
    color: var(--color-text-secondary);
}

/* Links */
a {
    color: var(--color-link);
    text-decoration: none;
}

a:hover {
    color: var(--color-link-hover);
    text-decoration: underline;
}

/* Headings */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-serif);
    font-weight: 700;
    line-height: 1.25;
    margin-top: 1.4em;
    margin-bottom: 0.4em;
}

h1 {
    font-size: 1.65rem;
    margin-top: 1.2em;
}

h2 {
    font-size: 1.25rem;
    margin-top: 1.2em;
}

h3 {
    font-size: 1.05rem;
}

h4 {
    font-size: 1rem;
}

/* Post Header */
.post-header {
    margin-bottom: 1.2rem;
}

.post-title {
    margin-top: 0;
    margin-bottom: 0.25em;
    font-size: 2rem;
}

.post-meta {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    display: flex;
    align-items: center;
    gap: 0.8rem;
    flex-wrap: wrap;
    margin-bottom: 0.5rem;
}

.post-tags {
    display: flex;
    gap: 0.4rem;
}

.tag {
    background: var(--color-tag-bg);
    color: var(--color-tag-text);
    padding: 0.2em 0.6em;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    display: inline-block;
    border: 1px solid var(--color-border);
    transition: all 0.2s ease;
}

.tag:hover {
    background: var(--color-link);
    color: #ffffff;
    border-color: var(--color-link);
    text-decoration: none;
}

.pdf-download {
    font-size: 0.8rem;
    padding: 0.2em 0.6em;
    border: 1px solid var(--color-border);
    border-radius: 3px;
    color: var(--color-text-secondary);
    text-decoration: none;
}

.pdf-download:hover {
    background: var(--color-tag-bg);
    text-decoration: none;
}

/* Post Content */
.post-content {
    line-height: 1.65;
}

.post-content p {
    margin-bottom: 0.9em;
}

.post-content ul,
.post-content ol {
    margin-bottom: 0.9em;
    padding-left: 1.3em;
}

.post-content li {
    margin-bottom: 0.2em;
}

.post-content blockquote {
    border-left: 3px solid var(--color-border);
    padding-left: 1em;
    margin: 1.2em 0;
    color: var(--color-text-secondary);
    font-style: italic;
}

/* Table of Contents */
nav#TOC {
    background: #ffffff;
    border: 1px solid var(--color-border);
    border-left: 3px solid var(--color-link);
    border-radius: 0;
    padding: 0.9em 1em;
    margin: 1.2em 0 1.5em 0;
    font-size: 0.9em;
}

nav#TOC::before {
    content: "Contents";
    display: block;
    font-weight: 700;
    margin-bottom: 0.5em;
    font-size: 0.95em;
}

nav#TOC ul {
    list-style: none;
    padding-left: 0;
    margin: 0;
}

nav#TOC li {
    margin-bottom: 0.25em;
    padding-left: 0;
}

nav#TOC ul ul {
    margin-top: 0.2em;
    margin-left: 0;
    padding-left: 1.3em;
    border-left: 1px solid var(--color-border);
}

nav#TOC ul ul li {
    margin-bottom: 0.15em;
}

nav#TOC .toc-section-number {
    display: inline-block;
    min-width: 2.2em;
    color: var(--color-text-secondary);
    font-variant-numeric: tabular-nums;
}

nav#TOC a {
    color: var(--color-link);
}

nav#TOC a:hover {
    color: var(--color-link-hover);
}

/* Code */
code {
    font-family: var(--font-mono);
    font-size: 0.85em;
    background: var(--color-bg-inline-code);
    padding: 0.15em 0.35em;
    border-radius: 3px;
}

pre {
    background: var(--color-bg-code);
    border: 1px solid var(--color-border);
    border-radius: 2px;
    padding: 0;
    overflow-x: auto;
    margin: 0.8em 0;
    line-height: 1.5;
    font-size: 0.82em;
}

pre code {
    background: none;
    padding: 0.7em 0.9em;
    border-radius: 0;
    font-size: 1em;
    display: block;
}

pre code.hljs {
    padding: 0.7em 0.9em;
    background: var(--color-bg-code);
}

/* Tables */
table {
    border-collapse: collapse;
    width: 100%;
    margin: 0.9em 0;
    font-size: 0.85rem;
}

thead {
    border-bottom: 1.5px solid var(--color-text);
}

th {
    font-weight: 700;
    text-align: left;
    padding: 0.4em 0.6em;
}

td {
    padding: 0.4em 0.6em;
    border-bottom: 1px solid var(--color-border);
}

caption {
    caption-side: bottom;
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    padding-top: 0.5em;
    font-style: italic;
}

/* Figures */
figure {
    margin: 1.2em 0;
    text-align: center;
}

figure img {
    max-width: 100%;
    height: auto;
}

figcaption {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    margin-top: 0.4em;
    font-style: italic;
}

/* Math (KaTeX) */
.katex-display {
    margin: 0.9em 0;
    overflow-x: auto;
    overflow-y: hidden;
}

/* Post List (Index) */
.post-list h1 {
    margin-top: 0;
    margin-bottom: 1.5rem;
}

.post-summary {
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--color-border);
}

.post-summary:last-child {
    border-bottom: none;
}

.post-summary h2 {
    font-size: 1.15rem;
    margin-top: 0;
    margin-bottom: 0.2em;
}

.post-summary h2 a {
    color: var(--color-text);
    text-decoration: none;
}

.post-summary h2 a:hover {
    color: var(--color-link);
}

.summary {
    color: var(--color-text-secondary);
    font-size: 0.85rem;
    margin-top: 0.3em;
}

/* Sidenote (margin note) styling - inspired by Concrete Mathematics */
.sidenote {
    float: right;
    clear: right;
    margin-left: 1.5em;
    margin-right: -17em;
    width: 15em;
    font-size: 0.8em;
    line-height: 1.55;
    color: #4a4a4a;
    background: #ffffff;
    border-left: 2px solid #999;
    padding: 0.6em 1em;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.08);
    border-radius: 0;
    position: relative;
    z-index: 1;
    font-style: normal;
}

@media (max-width: 900px) {
    .sidenote {
        float: none;
        margin: 1em 0;
        width: auto;
        margin-right: 0;
        border-left: 4px solid #d4a574;
        background: #fafaf8;
        font-style: italic;
    }
}

/* Bibliography / References */
div#refs,
div.references {
    border-top: 1px solid var(--color-border);
    margin-top: 1.5em;
    padding-top: 1em;
}

div#refs h2,
div.references h2 {
    font-size: 1.1em;
    margin-top: 0;
}

div#refs div,
div.references div {
    margin-bottom: 0.7em;
    margin-left: 1.8em;
    text-indent: -1.8em;
    font-size: 0.9em;
}

/* Citation styling */
.citation {
    color: var(--color-link);
}

span.csl-block {
    display: block;
}

span.csl-right-inline {
    margin-left: 0;
}

/* Responsive */
@media (max-width: 600px) {
    html {
        font-size: 16px;
    }

    body {
        padding: 0 1rem;
    }

    h1 {
        font-size: 1.5rem;
    }
}