/* ============================================================
   Minimal reading blog — design system  (v2)
   Sans-led · pure-neutral grayscale · reading-first
   New in v2: sticky identity rail (home), Tufte margin layout
   (post), tap-toggle sidenotes, reading progress, no-hover fixes.
   Edit the tokens below to retheme the whole site.
   ============================================================ */

:root {
  /* ---- Color (true neutral grayscale; never pure #000/#fff) ---- */
  --bg: #fcfcfc;
  --text: #1a1a1a;
  --text-2: #6e6e6e;
  --text-3: #9a9a9a;
  --rule: #e7e7e7;
  --rule-strong: #cfcfcf;
  --quote-rule: #d6d6d6;
  --link-underline: #bcbcbc;
  --code-bg: #f1f1f1;

  /* ---- Type ---- */
  --font-sans:
    "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif;
  --font-mono:
    "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;

  /* ---- Layout ---- */
  --measure: 37rem; /* ~592px reading column (mobile + home stream) */
  --rail: 192px; /* sticky identity rail (desktop home) */
  --rail-gap: 56px;
  --page-x: 24px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  -webkit-text-size-adjust: 100%;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 18px;
  line-height: 1.65;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
::selection {
  background: #e8e8e8;
}
a {
  color: inherit;
}

/* reading progress (post pages) */
.progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0;
  background: var(--text);
  z-index: 20;
}

/* ============================================================
   Identity rail / masthead (shared markup, responsive role)
   Mobile: horizontal masthead (name left, nav right)
   Desktop home: vertical sticky rail
   ============================================================ */
.rail {
  padding-top: 48px;
}
.rail-top {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
}
.site-name {
  font-size: 17px;
  font-weight: 500;
  letter-spacing: -0.01em;
  text-decoration: none;
}
.rail nav a {
  font-size: 14px;
  color: var(--text-3);
  text-decoration: none;
  margin-left: 18px;
}
.tagline {
  font-size: 15px;
  color: var(--text-2);
  margin: 8px 0 0;
}

/* ============================================================
   Homepage shell + stream
   ============================================================ */
.shell {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 var(--page-x);
}
.stream {
  margin-top: 48px;
}
.year {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-3);
  margin: 0 0 6px;
}
.entry {
  display: flex;
  gap: 22px;
  align-items: baseline;
  padding: 16px 0;
  border-top: 0.5px solid var(--rule);
  text-decoration: none;
  color: inherit;
}
.entry:last-child {
  border-bottom: 0.5px solid var(--rule);
}
.entry-date {
  flex: 0 0 58px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-3);
  white-space: nowrap;
}
.entry-main {
  flex: 1;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
}
.entry-title {
  font-size: 18px;
  line-height: 1.4;
  text-underline-offset: 3px;
}
.entry-kind {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.03em;
  color: var(--text-3);
}
.entry-go {
  flex: 0 0 auto;
  color: var(--text-3);
  font-size: 15px;
  transform: translateX(0);
}

/* desktop home: rail becomes a sticky left column */
@media (min-width: 1080px) {
  .shell {
    max-width: calc(var(--rail) + var(--rail-gap) + var(--measure));
    display: grid;
    grid-template-columns: var(--rail) minmax(0, 1fr);
    gap: var(--rail-gap);
  }
  .rail {
    position: sticky;
    top: 56px;
    align-self: start;
    padding-top: 56px;
  }
  .rail-top {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
  }
  .rail nav {
    margin-top: 22px;
  }
  .rail nav a {
    display: block;
    margin: 0 0 9px;
  }
  .stream {
    margin-top: 56px;
  }
}

/* ============================================================
   Post page  — Tufte margin layout
   ============================================================ */
.post-wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 var(--page-x);
}
.post-masthead {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding-top: 48px;
}
.post-masthead nav a {
  font-size: 14px;
  color: var(--text-3);
  text-decoration: none;
  margin-left: 18px;
}

.post-title {
  font-size: 33px;
  font-weight: 500;
  line-height: 1.18;
  letter-spacing: -0.02em;
  margin: 44px 0 14px;
}
.post-meta {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-3);
  margin: 0 0 42px;
}

.prose {
  counter-reset: sidenote-counter;
}
.prose p {
  margin: 0 0 22px;
  line-height: 1.72;
}
.prose h2 {
  font-size: 21px;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin: 42px 0 14px;
}
.prose h3 {
  font-size: 17px;
  font-weight: 500;
  margin: 30px 0 10px;
}
.prose a {
  text-decoration: underline;
  text-decoration-color: var(--link-underline);
  text-decoration-skip-ink: auto;
  text-underline-offset: 2px;
}
.prose strong {
  font-weight: 500;
}
.prose blockquote {
  margin: 28px 0;
  padding-left: 20px;
  border-left: 2px solid var(--quote-rule);
  color: var(--text-2);
}
.prose blockquote p:last-child {
  margin-bottom: 0;
}
.prose ul,
.prose ol {
  margin: 0 0 22px;
  padding-left: 22px;
}
.prose li {
  margin: 0 0 8px;
  line-height: 1.6;
}
.prose code {
  font-family: var(--font-mono);
  font-size: 0.86em;
  background: var(--code-bg);
  padding: 1px 5px;
  border-radius: 3px;
}
.prose hr {
  border: none;
  border-top: 0.5px solid var(--rule);
  margin: 40px 0;
}

/* epigraph — a quiet opening pull quote */
.epigraph {
  margin: 0 0 34px;
  color: var(--text-2);
  font-style: italic;
  line-height: 1.55;
}

/* figures */
.prose figure {
  margin: 34px 0;
}
.prose figure svg,
.prose figure img {
  width: 100%;
  display: block;
  border-radius: 4px;
  border: 0.5px solid var(--rule);
}
.prose figcaption {
  font-size: 13px;
  color: var(--text-3);
  margin-top: 9px;
}

/* sidenotes + margin notes */
.sidenote-number {
  counter-increment: sidenote-counter;
}
.sidenote-number::after {
  content: counter(sidenote-counter);
  font-family: var(--font-mono);
  font-size: 0.62em;
  vertical-align: super;
  line-height: 0;
  margin-left: 1px;
}
.sidenote,
.marginnote {
  color: var(--text-2);
}
.sidenote::before {
  content: counter(sidenote-counter) " ";
  font-family: var(--font-mono);
  font-size: 0.7em;
  vertical-align: super;
  line-height: 0;
}
input.margin-toggle {
  display: none;
}
label.sidenote-number {
  display: inline;
  cursor: pointer;
}
label.margin-toggle:not(.sidenote-number) {
  display: none;
}

/* wide screens: notes float into the right margin (Tufte) */
@media (min-width: 860px) {
  .post-wrap {
    max-width: 1060px;
  }
  .post-title,
  .post-meta,
  .epigraph,
  .prose > p,
  .prose > h2,
  .prose > h3,
  .prose > ul,
  .prose > ol,
  .prose > blockquote,
  .post-footer {
    width: 55%;
  }
  .prose > figure.full {
    width: 90%;
  }
  .sidenote,
  .marginnote {
    float: right;
    clear: right;
    width: 46%;
    margin-right: -54%;
    margin-top: 3px;
    margin-bottom: 18px;
    font-size: 13px;
    line-height: 1.5;
    position: relative;
  }
  .prose figure.margin-fig {
    float: right;
    clear: right;
    width: 46%;
    margin-right: -54%;
  }
  .prose figure.margin-fig svg,
  .prose figure.margin-fig img {
    border: 0.5px solid var(--rule);
  }
}

/* narrow screens: notes hide, reveal on tap */
@media (max-width: 859px) {
  label.margin-toggle:not(.sidenote-number) {
    display: inline;
    cursor: pointer;
    color: var(--text-3);
    border-bottom: 0.5px dotted var(--text-3);
  }
  .sidenote,
  .marginnote {
    display: none;
  }
  .margin-toggle:checked + .sidenote,
  .margin-toggle:checked + .marginnote {
    display: block;
    float: none;
    width: 100%;
    margin: 14px 0;
    padding: 12px 16px;
    background: #f5f5f5;
    border-left: 2px solid var(--rule-strong);
    font-size: 15px;
    line-height: 1.55;
    position: relative;
  }
  .sidenote-number {
    border-bottom: 0.5px dotted var(--text-3);
  }
}

/* footers */
.post-footer {
  margin: 50px 0 0;
  padding-top: 20px;
  border-top: 0.5px solid var(--rule);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  font-size: 14px;
}
.post-footer a {
  color: var(--text-2);
  text-decoration: none;
}
.post-footer .filed {
  color: var(--text-3);
}
.site-footer {
  margin: 76px 0 48px;
  padding-top: 20px;
  border-top: 0.5px solid var(--rule);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  font-size: 13px;
  color: var(--text-3);
}
.site-footer a {
  color: var(--text-3);
  text-decoration: none;
}

/* ---- Hover effects: only where a real pointer exists ---- */
@media (hover: hover) and (pointer: fine) {
  .masthead nav a,
  .rail nav a,
  .post-masthead nav a,
  .post-footer a,
  .site-footer a {
    transition: color 0.15s ease;
  }
  .rail nav a:hover,
  .post-masthead nav a:hover,
  .post-footer a:hover,
  .site-footer a:hover {
    color: var(--text);
  }
  .prose a {
    transition: text-decoration-color 0.15s ease;
  }
  .prose a:hover {
    text-decoration-color: var(--text);
  }
  .entry-go {
    transition:
      transform 0.15s ease,
      color 0.15s ease;
  }
  .entry:hover .entry-title {
    text-decoration: underline;
    text-decoration-color: var(--rule-strong);
  }
  .entry:hover .entry-date {
    color: var(--text-2);
  }
  .entry:hover .entry-go {
    transform: translateX(4px);
    color: var(--text);
  }
}

/* ---- Touch / no-hover: persistent affordances instead ---- */
@media (hover: none) {
  .entry-title {
    text-decoration: underline;
    text-decoration-color: var(--rule);
    text-underline-offset: 3px;
  }
}

/* ---- Accessibility floor ---- */
a:focus-visible,
.entry:focus-visible,
label.sidenote-number:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 3px;
  border-radius: 2px;
}
@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    animation: none !important;
  }
}

/* ---- Mobile type ---- */
@media (max-width: 480px) {
  body {
    font-size: 17px;
  }
  .rail {
    padding-top: 40px;
  }
  .post-masthead {
    padding-top: 40px;
  }
  .post-title {
    font-size: 28px;
  }
  .entry {
    gap: 16px;
  }
  .entry-date {
    flex-basis: 50px;
    font-size: 12px;
  }
  .entry-kind {
    display: none;
  }
}

/* ============================================================
   Portfolio (root index.html)
   ============================================================ */
.pf-wrap {
  max-width: 40rem;
  margin: 0 auto;
  padding: 0 var(--page-x);
}
.bar {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding-top: 48px;
}
.bar nav a {
  font-size: 14px;
  color: var(--text-3);
  text-decoration: none;
  margin-left: 18px;
}

.pf-hero {
  margin-top: 56px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}
.pf-photo {
  width: 150px;
  flex: 0 0 auto;
}
.pf-photo img {
  width: 100%;
  aspect-ratio: 1/1;
  object-fit: cover;
  display: block;
  border-radius: 6px;
  border: 0.5px solid var(--rule);
  background: #ededed;
}
.pf-name {
  font-size: 28px;
  font-weight: 500;
  letter-spacing: -0.02em;
  margin: 0 0 6px;
}
.pf-role {
  font-size: 15px;
  color: var(--text-2);
  margin: 0 0 22px;
}
.pf-about p {
  font-size: 18px;
  line-height: 1.7;
  margin: 0 0 16px;
}
.pf-links {
  margin-top: 24px;
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  font-size: 15px;
}
.pf-links a {
  color: var(--text);
  text-decoration: underline;
  text-decoration-color: var(--link-underline);
  text-underline-offset: 2px;
}

@media (min-width: 680px) {
  .pf-hero {
    flex-direction: row;
    align-items: flex-start;
    gap: 44px;
  }
  .pf-photo {
    width: 240px;
  }
  .pf-name {
    font-size: 32px;
  }
}

@media (hover: hover) and (pointer: fine) {
  .bar nav a {
    transition: color 0.15s ease;
  }
  .bar nav a:hover {
    color: var(--text);
  }
  .pf-links a {
    transition: text-decoration-color 0.15s ease;
  }
  .pf-links a:hover {
    text-decoration-color: var(--text);
  }
}

/* ---- Portfolio: education + internships ---- */
.pf-cv {
  margin-top: 60px;
}
.pf-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text-3);
  margin: 38px 0 14px;
}
.pf-cv .pf-label:first-child {
  margin-top: 0;
}
.cv-item {
  padding: 15px 0;
  border-top: 0.5px solid var(--rule);
}
.cv-line {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
}
.cv-place {
  font-size: 17px;
  font-weight: 500;
}
.cv-date {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-3);
  white-space: nowrap;
}
.cv-sub {
  font-size: 14px;
  color: var(--text-2);
  margin: 4px 0 0;
}
.tags {
  margin-top: 11px;
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}
.tag {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-2);
  border: 0.5px solid var(--rule);
  border-radius: 999px;
  padding: 3px 11px;
}