:root {
  --margin-mobile: 16px;
  --margin-tablet: 60px;
  --margin-desktop: 110px;
  --color-link: #1EAEDB;
  --color-link-hover: #0FA0CE;
  --color-bg: #f5f7f9;
  --color-border: #eaecee;
  --color-meta: #939da3;
  --color-text: #222;
}

* { box-sizing: border-box; }

html { font-size: 62.5%; }

body {
  margin: 0;
  font-family: "Fira Sans", "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 1.6rem;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  font-synthesis: weight;
}

a { color: var(--color-link); text-decoration: none; }
a:hover { color: var(--color-link-hover); }

/* ---------- header ---------- */
.page-header {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 10px 18px;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
}
.site-title a {
  font-size: 2.5rem;
  font-weight: bold;
  color: var(--color-link);
}
.site-tagline {
  width: 100%;
  font-size: 1.3rem;
  color: #B5BFC5;
  margin-top: 2px;
}
.site-nav ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
}
.site-nav li {
  padding: 2px 0 2px 18px;
  text-transform: uppercase;
  font-size: 1.4rem;
}

/* ---------- content card ---------- */
.post-container {
  background-color: #fff;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  max-width: 960px;
  margin: 0 auto 28px;
  padding: 0 0 40px;
  text-align: justify;
  hyphens: auto;
}

.post-header {
  text-align: center;
  margin-bottom: 50px;
  padding: 30px 5px 0;
}
.post-header h2 {
  font-size: 3.3rem;
  line-height: 1.3;
  margin: 0 0 12px;
}
.post-header h2 a { color: var(--color-link); }
.post-header h2 a:hover { color: var(--color-link-hover); }

.post-meta {
  color: var(--color-meta);
  font-size: 90%;
  text-transform: uppercase;
}
.post-meta span { margin: 0 10px; }

/* ---------- typography ---------- */
.post-content p,
.post-content > h2,
.post-content > h3,
.post-content > h4,
.post-content blockquote,
.post-content table,
.post-content dl {
  margin-left: var(--margin-mobile);
  margin-right: var(--margin-mobile);
}
.post-content ul,
.post-content ol {
  margin-left: calc(var(--margin-mobile) + 20px);
  margin-right: var(--margin-mobile);
}
.post-content li p { margin-left: 0; margin-right: 0; }

.post-content h2,
.post-content h3,
.post-content h4 {
  font-size: 23px;
  line-height: 1.4;
  margin-top: 1.6em;
  margin-bottom: 0.6em;
}
.post-content h2::before { content: "# "; color: #d4d2d4; }
.post-content h3::before { content: "## "; color: #d4d2d4; }

.post-content img {
  display: block;
  max-width: calc(100% - 2 * var(--margin-mobile));
  margin: 20px auto;
}

.post-content blockquote {
  color: #555;
  border-left: 3px solid var(--color-border);
  padding-left: 16px;
  font-style: normal;
}

.post-content code {
  color: inherit;
  border: 1px solid #E3EDF3;
  background: #F7FAFB;
  border-radius: 2px;
  padding: 1px 4px;
  font-family: Menlo, Monaco, Consolas, monospace;
  font-size: 85%;
}

.post-content .highlight {
  background-color: var(--color-bg);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  margin: 0 0 25px;
  overflow-x: auto;
}
.post-content .highlight pre {
  font-size: 80%;
  font-family: Menlo, Monaco, Consolas, monospace;
  line-height: 1.5;
  margin: 0;
  padding: 12px var(--margin-mobile);
}
.post-content .highlight code {
  border: none;
  background: none;
  padding: 0;
  font-size: inherit;
}

.post-content table {
  border-collapse: collapse;
  max-width: calc(100% - 2 * var(--margin-mobile));
  overflow-x: auto;
  display: block;
}
.post-content table th,
.post-content table td {
  border: 1px solid var(--color-border);
  padding: 6px 14px;
}
.post-content table th { background: var(--color-bg); }

.post-content hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 30px var(--margin-mobile);
}

/* MathJax display math: allow horizontal scroll for long formulas */
.post-content mjx-container[jax="CHTML"][display="true"] {
  overflow-x: auto;
  overflow-y: hidden;
}

/* ---------- post footer (single) ---------- */
.post-footer {
  margin: 40px var(--margin-mobile) 0;
  font-size: 90%;
}
.post-tags { margin-bottom: 24px; }
.tag-list a {
  color: rgba(0,0,0,0.44);
  background-color: #fcfcfc;
  border: 1px solid #f0f0f0;
  border-radius: 2px;
  padding: 3px 10px;
  margin: 4px 8px 4px 0;
  display: inline-block;
}
.tag-list a:hover { color: var(--color-link); }

.post-nav {
  display: flex;
  justify-content: space-between;
  gap: 20px;
}
.post-nav a { max-width: 48%; }

/* ---------- intro / list / archive ---------- */
.intro-card p { margin-left: var(--margin-mobile); margin-right: var(--margin-mobile); }

.archive-list { padding: 10px 0; }
.archive-year {
  font-size: 2.2rem;
  margin: 24px var(--margin-mobile) 8px;
  color: var(--color-meta);
}
.archive-item {
  margin: 6px var(--margin-mobile);
  display: flex;
  gap: 14px;
  align-items: baseline;
}
.archive-item time {
  color: var(--color-meta);
  font-size: 85%;
  white-space: nowrap;
}

.terms-cloud { padding: 20px var(--margin-mobile) 10px; }

/* ---------- pagination ---------- */
.read-more {
  text-align: center;
  text-transform: uppercase;
  font-size: 1.4rem;
  margin: 20px;
}
.pagination {
  max-width: 960px;
  margin: 0 auto 40px;
  display: flex;
  justify-content: center;
  gap: 10px;
  font-size: 1.4rem;
}
.pagination a, .pagination span {
  padding: 4px 12px;
  border: 1px solid var(--color-border);
  background: #fff;
  border-radius: 2px;
}
.pagination .active {
  background: var(--color-link);
  border-color: var(--color-link);
  color: #fff;
}

/* ---------- footer ---------- */
.page-footer {
  max-width: 960px;
  margin: 40px auto 30px;
  padding: 0 10px;
  text-align: center;
  color: var(--color-meta);
  font-size: 1.3rem;
}

/* ---------- responsive margins ---------- */
@media (min-width: 550px) {
  .post-content p,
  .post-content > h2,
  .post-content > h3,
  .post-content > h4,
  .post-content blockquote,
  .post-content table,
  .post-content dl { margin-left: var(--margin-tablet); margin-right: var(--margin-tablet); }
  .post-content ul, .post-content ol { margin-left: calc(var(--margin-tablet) + 20px); margin-right: var(--margin-tablet); }
  .post-content .highlight pre { padding: 12px var(--margin-tablet); }
  .post-content hr { margin: 30px var(--margin-tablet); }
  .post-content img { max-width: calc(100% - 2 * var(--margin-tablet)); }
  .post-content table { max-width: calc(100% - 2 * var(--margin-tablet)); }
  .post-footer { margin: 40px var(--margin-tablet) 0; }
  .archive-year, .archive-item { margin-left: var(--margin-tablet); margin-right: var(--margin-tablet); }
  .intro-card p { margin-left: var(--margin-tablet); margin-right: var(--margin-tablet); }
  .terms-cloud { padding: 20px var(--margin-tablet) 10px; }
}
@media (min-width: 1000px) {
  .post-content p,
  .post-content > h2,
  .post-content > h3,
  .post-content > h4,
  .post-content blockquote,
  .post-content table,
  .post-content dl { margin-left: var(--margin-desktop); margin-right: var(--margin-desktop); }
  .post-content ul, .post-content ol { margin-left: calc(var(--margin-desktop) + 20px); margin-right: var(--margin-desktop); }
  .post-content .highlight pre { padding: 12px var(--margin-desktop); }
  .post-content hr { margin: 30px var(--margin-desktop); }
  .post-content img { max-width: calc(100% - 2 * var(--margin-desktop)); }
  .post-content table { max-width: calc(100% - 2 * var(--margin-desktop)); }
  .post-footer { margin: 40px var(--margin-desktop) 0; }
  .archive-year, .archive-item { margin-left: var(--margin-desktop); margin-right: var(--margin-desktop); }
  .intro-card p { margin-left: var(--margin-desktop); margin-right: var(--margin-desktop); }
  .terms-cloud { padding: 20px var(--margin-desktop) 10px; }
}