/* Swiss International Style — DJY Personal Site
   Pure ink black + warm off-white, no accent color */

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

:root {
  --paper: #f5f5f0;
  --paper-rgb: 245, 245, 240;
  --ink: #0a0a0a;
  --ink-rgb: 10, 10, 10;
  --grey-1: #eaeae5;
  --grey-2: #d0d0cb;
  --grey-3: #737373;
  --max-width: 1200px;
  --sp-3: 8px;
  --sp-4: 12px;
  --sp-5: 16px;
  --sp-6: 24px;
  --sp-7: 32px;
  --sp-8: 40px;
  --sp-9: 48px;
  --sp-10: 64px;
  --sp-11: 80px;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: "Inter", "Helvetica Neue", Helvetica, "Microsoft YaHei UI", "Noto Sans SC", sans-serif;
  font-weight: 300;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  padding-top: calc(var(--sp-6) * 2 + 1.4rem);
}

/* Grid */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--sp-7);
}

main {
  flex: 1;
  width: 100%;
}

/* Typography */
h1, h2, h3, h4 {
  font-weight: 200;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h1 { font-size: min(5.6vw, 9.6vh); }
h2 { font-size: min(3.2vw, 5.2vh); }
h3 { font-size: min(2vw, 3.2vh); font-weight: 300; }

.t-cat {
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.t-meta {
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--grey-3);
}

.lead {
  font-size: min(1.6vw, 2.4vh);
  font-weight: 300;
  line-height: 1.6;
  color: var(--grey-3);
  max-width: 52ch;
}

.mono {
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
}

mark {
  background-color: #fcd34d;
  color: var(--ink);
  padding: 0 4px;
}

strong,
b {
  font-weight: 600;
}

/* Links */
a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--grey-2);
  transition: border-color 0.2s;
}

a:hover {
  border-bottom-color: var(--ink);
}

/* Hairline divider */
.hr-hairline {
  border: none;
  border-top: 1px solid var(--grey-2);
  margin: var(--sp-9) 0;
}

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: var(--sp-6) 0;
  background: var(--paper);
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.site-header.is-hidden {
  transform: translateY(-100%);
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-title {
  font-weight: 200;
  font-size: 1.4rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-bottom: none;
}

.site-title:hover {
  border-bottom: none;
}

.site-header nav {
  display: flex;
  gap: var(--sp-7);
}

.site-header nav a {
  font-size: 0.8rem;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--grey-3);
  border-bottom: none;
}

.site-header nav a:hover {
  color: var(--ink);
  border-bottom: none;
}

/* Hero section */
.hero {
  padding: var(--sp-11) 0 var(--sp-10);
}

/* Homepage hero — unified full-width container */
.home-hero-split {
  background: var(--paper);
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 80vh;
  margin-bottom: var(--sp-10);
  position: relative;
  overflow: hidden;
}

.home-hero-split canvas.ascii-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  opacity: .4;
}

.hero-content {
  grid-column: 1;
  color: var(--ink);
  padding: var(--sp-10) var(--sp-8);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  z-index: 1;
}

.split-left-content {
  position: relative;
  z-index: 1;
}

.split-left-footer {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: space-between;
  padding-top: var(--sp-6);
  border-top: 1px solid rgba(255,255,255,.22);
}

.rules-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.rule-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--sp-7);
  align-items: start;
  padding: var(--sp-6) 0;
  border-top: 1px solid var(--grey-2);
}

.rule-item.accent-bottom {
  border-bottom: 2px solid var(--ink);
}

.rule-num {
  font-family: var(--sans);
  font-weight: 200;
  font-size: min(4.4vw, 7.8vh);
  line-height: .9;
  color: var(--ink);
}

.rule-body h3 {
  font-family: var(--sans);
  font-weight: 400;
  font-size: max(18px, 1.8vw);
  line-height: 1.2;
  letter-spacing: -.015em;
  margin-bottom: var(--sp-3);
}

.rule-body p {
  font-family: var(--sans);
  font-size: max(12px, .92vw);
  line-height: 1.6;
  color: var(--grey-3);
  font-weight: 300;
}

@media (max-width: 768px) {
  .home-hero-split {
    grid-template-columns: 1fr;
  }

  .hero-content {
    padding: var(--sp-8) var(--sp-6);
    min-height: 50vh;
  }
}

.hero h1 {
  margin-bottom: var(--sp-7);
}

.hero .lead {
  margin-bottom: var(--sp-8);
}

/* Sections */
.section {
  padding: var(--sp-10) 0;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  border-bottom: 1px solid var(--ink);
  padding-bottom: var(--sp-5);
  margin-bottom: var(--sp-8);
}

.section-header h2 {
  font-weight: 200;
}

.section-header .t-meta {
  flex-shrink: 0;
}

/* Post list */
.post-list {
  list-style: none;
}

.post-list li {
  display: grid;
  grid-template-columns: 120px 1fr auto;
  gap: var(--sp-6);
  align-items: baseline;
  padding: var(--sp-6) 0;
}

.post-list .post-date {
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: 0.75rem;
  color: var(--grey-3);
  letter-spacing: 0.04em;
  line-height: 31px;
}

.post-list .post-title {
  font-weight: 300;
  font-size: 1.15rem;
}

.post-list .post-category {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--grey-3);
}

/* Post page */
.post-layout {
  display: grid;
  grid-template-columns: 1fr 220px;
  gap: var(--sp-10);
  align-items: start;
}

.post-header {
  padding: var(--sp-10) 0 var(--sp-8);
  border-bottom: 1px solid var(--ink);
  margin-bottom: var(--sp-8);
}

.post-header h1 {
  font-size: min(4vw, 7vh);
  margin-bottom: var(--sp-5);
}

.post-header .post-meta {
  display: flex;
  gap: var(--sp-6);
  align-items: center;
}

.post-content h2 {
  font-size: min(2.2vw, 3.6vh);
  font-weight: 200;
  margin-top: var(--sp-9);
  margin-bottom: var(--sp-6);
}

.post-content h3 {
  font-size: 1.15rem;
  font-weight: 400;
  margin-top: var(--sp-8);
  margin-bottom: var(--sp-5);
}

.post-content p {
  margin-bottom: var(--sp-6);
  max-width: 65ch;
}

.post-content img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto var(--sp-6);
}

.post-content p:has(img) {
  max-width: none;
  text-align: center;
}

.post-content ul,
.post-content ol {
  margin-bottom: var(--sp-6);
  padding-left: var(--sp-7);
}

.post-content li {
  margin-bottom: var(--sp-3);
}

.post-content pre {
  margin-bottom: var(--sp-6);
  overflow-x: auto;
  background: var(--grey-1);
  padding: var(--sp-6);
  font-size: 0.85rem;
}

.post-content code {
  font-size: 0.85em;
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  background-color: var(--grey-1);
  padding: 2px 6px;
  border-radius: 4px;
}

.post-content blockquote {
  border-left: 2px solid var(--ink);
  padding-left: var(--sp-6);
  margin-bottom: var(--sp-6);
  color: var(--grey-3);
  font-style: italic;
}

/* GitHub Alerts */
.markdown-alert {
  border-left: 3px solid var(--grey-2);
  padding: var(--sp-5) var(--sp-6);
  margin-bottom: var(--sp-7);
  background: var(--grey-1);
}

.markdown-alert p {
  margin-bottom: 0;
  max-width: none;
}

.markdown-alert-title {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--sp-3);
  color: var(--ink);
}

.markdown-alert-title svg {
  flex-shrink: 0;
  fill: currentColor;
}

/* Tier 1: informational */
.markdown-alert-note,
.markdown-alert-tip {
  border-left-color: var(--grey-3);
}

/* Tier 2: action required */
.markdown-alert-important,
.markdown-alert-warning,
.markdown-alert-caution {
  border-left-color: var(--ink);
  border-left-width: 4px;
}

/* Tables */
.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--sp-7);
  font-size: 0.9rem;
}

.post-content thead {
  border-bottom: 2px solid var(--ink);
}

.post-content th {
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  text-align: left;
  padding: var(--sp-4) var(--sp-5);
  color: var(--ink);
}

.post-content td {
  padding: var(--sp-4) var(--sp-5);
  border-bottom: 1px solid var(--grey-1);
  vertical-align: top;
}

.post-content tbody tr:last-child td {
  border-bottom: 2px solid var(--ink);
}

/* Post sidebar */
.post-sidebar {
  padding-top: 170px;
}

/* Table of Contents */
.toc {
  padding: var(--sp-5) 0;
}

.toc-title {
  margin-bottom: var(--sp-5);
  border-bottom: 1px solid var(--grey-2);
  padding-bottom: var(--sp-4);
}

.toc-list {
  list-style: none;
  counter-reset: toc;
  padding: 0;
  margin: 0;
}

.toc-item {
  counter-increment: toc;
  padding: var(--sp-3) 0;
  border-bottom: 1px solid var(--grey-1);
  font-size: 0.8rem;
  line-height: 1.5;
}

.toc-item:last-child {
  border-bottom: none;
}

.toc-item::before {
  content: counter(toc, decimal-leading-zero);
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: 0.65rem;
  color: var(--grey-3);
  margin-right: var(--sp-4);
  letter-spacing: 0.04em;
}

.toc-sub {
  padding-left: var(--sp-6);
  font-size: 0.75rem;
}

.toc-sub::before {
  content: "—";
  font-size: 0.65rem;
}

.toc-item a {
  color: var(--grey-3);
  border-bottom: none;
  border-left: 2px solid transparent;
  padding-left: var(--sp-4);
  display: block;
}

.toc-item a:hover {
  color: var(--ink);
  border-bottom: none;
}

.toc-item a.active {
  color: var(--ink);
  font-weight: 400;
  border-left: 2px solid var(--ink);
  padding-left: var(--sp-4);
}

/* Footnote tooltip */
.footnote-tooltip {
  position: absolute;
  z-index: 100;
  max-width: 360px;
  padding: var(--sp-4) var(--sp-5);
  background: var(--paper);
  border: 1px solid var(--grey-2);
  font-size: 0.8rem;
  line-height: 1.6;
  color: var(--ink);
  box-shadow: none;
}

.footnote-tooltip p {
  margin: 0;
  max-width: none;
}

.footnote-ref {
  cursor: help;
  font-weight: 600;
  border-bottom: 1px dashed var(--grey-3);
}

/* Keyboard keys */
.post-content kbd {
  display: inline-block;
  padding: 0.1em 0.5em;
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: 0.8em;
  line-height: 1.4;
  color: var(--ink);
  background: var(--grey-1);
  border: 1px solid var(--grey-2);
  vertical-align: baseline;
}

/* Definition lists */
.post-content dl {
  margin-bottom: var(--sp-7);
}

.post-content dt {
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: var(--sp-3);
}

.post-content dd {
  margin-left: var(--sp-7);
  margin-bottom: var(--sp-5);
  color: var(--grey-3);
}

.post-content dd::before {
  content: "";
  display: block;
  width: 24px;
  border-top: 1px solid var(--grey-2);
  margin-bottom: var(--sp-4);
}

/* Abbreviations */
.post-content abbr {
  text-decoration: underline dotted var(--grey-3);
  cursor: help;
}

/* Details/Summary */
.post-content details {
  border: 1px solid var(--grey-2);
  padding: var(--sp-5) var(--sp-6);
  margin-bottom: var(--sp-7);
  background: var(--grey-1);
}

.post-content summary {
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  user-select: none;
}

.post-content details[open] summary {
  margin-bottom: var(--sp-5);
  padding-bottom: var(--sp-4);
  border-bottom: 1px solid var(--grey-2);
}

/* Tabs */
.tab-group {
  margin-bottom: var(--sp-7);
  border: 1px solid var(--grey-2);
}

.tab-list {
  display: flex;
  border-bottom: 1px solid var(--grey-2);
  background: var(--grey-1);
}

.tab-btn {
  padding: var(--sp-4) var(--sp-6);
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: 0.75rem;
  font-weight: 400;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--grey-3);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
}

.tab-btn:hover {
  color: var(--ink);
}

.tab-btn.active {
  color: var(--ink);
  font-weight: 600;
  border-bottom-color: var(--ink);
  background: var(--paper);
}

.tab-panel {
  display: none;
  padding: var(--sp-5) var(--sp-6);
}

.tab-panel.active {
  display: block;
}

.tab-panel > :last-child {
  margin-bottom: 0;
}

/* Lighter code block styles inside tab panels */
.tab-panel pre,
.tab-panel pre[class*="language-"] {
  background: var(--grey-1);
  padding: var(--sp-5);
  border: none;
  border-left: 2px solid var(--grey-2);
  margin-bottom: 0;
}

/* Mermaid diagrams */
.mermaid {
  margin-bottom: var(--sp-7);
  overflow-x: auto;
  text-align: center;
}

.mermaid svg {
  max-width: 100%;
  height: auto;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--grey-2);
  padding: var(--sp-8) 0;
}

.site-footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-footer p {
  font-size: 0.75rem;
  color: var(--grey-3);
}

/* Responsive */
@media (max-width: 768px) {
  :root {
    --sp-7: 24px;
    --sp-8: 32px;
    --sp-9: 40px;
    --sp-10: 48px;
    --sp-11: 64px;
  }

  .post-list li {
    grid-template-columns: 1fr;
    gap: var(--sp-3);
  }

  .post-list .post-category {
    display: none;
  }

  .site-header nav {
    gap: var(--sp-5);
  }

  .post-layout {
    grid-template-columns: 1fr;
  }

  .post-sidebar {
    display: none;
  }
}