/* ==========================================================================
   style.css — the entire visual system.
   Design language: calm, editorial, spacious. One accent color.
   The recurring motif is a "pathway": thin trajectories moving through
   layers, echoing hidden-state trajectories and causal structure.
   ========================================================================== */

:root {
  --paper: #faf9f5;
  --paper-raised: #ffffff;
  --ink: #1c1b18;
  --ink-soft: #55524a;
  --ink-faint: #8a867c;
  --line: #e4e1d8;
  --accent: #2a5d68;        /* deep, calm teal-slate */
  --accent-soft: #dce8ea;
  --accent-faint: rgba(42, 93, 104, 0.09);
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --measure: 42rem;
  --wide: 68rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #16181a;
    --paper-raised: #1e2124;
    --ink: #e8e6e1;
    --ink-soft: #b0ada5;
    --ink-faint: #7c7970;
    --line: #2e3235;
    --accent: #7fb5bf;
    --accent-soft: #24393e;
    --accent-faint: rgba(127, 181, 191, 0.10);
  }
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---------- typography ---------- */

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.01em;
  margin: 0 0 0.5em;
}

h1 { font-size: clamp(2.2rem, 5.5vw, 3.4rem); }
h2 { font-size: clamp(1.5rem, 3.2vw, 2rem); }
h3 { font-size: 1.25rem; }

p { margin: 0 0 1em; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease;
}
a:hover, a:focus-visible { border-bottom-color: var(--accent); }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }

.kicker {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 1rem;
}

.lede {
  font-family: var(--serif);
  font-size: clamp(1.15rem, 2.4vw, 1.4rem);
  color: var(--ink-soft);
  line-height: 1.5;
}

.muted { color: var(--ink-soft); }
.faint { color: var(--ink-faint); }
.small { font-size: 0.9rem; }

/* ---------- layout ---------- */

.wrap {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.prose { max-width: var(--measure); }

section { padding: 4.5rem 0; }
section + section { border-top: 1px solid var(--line); }

.skip-link {
  position: absolute;
  left: -9999px;
  background: var(--accent);
  color: var(--paper);
  padding: 0.5rem 1rem;
  z-index: 100;
}
.skip-link:focus { left: 1rem; top: 1rem; }

/* ---------- navigation ---------- */

header.site {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--paper);
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

nav.site {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0.9rem 1.5rem;
}

nav.site .brand {
  font-family: var(--serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--ink);
  border: none;
  white-space: nowrap;
}

nav.site ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav.site ul a {
  font-size: 0.92rem;
  color: var(--ink-soft);
  border: none;
  padding-bottom: 2px;
}
nav.site ul a:hover { color: var(--accent); }
nav.site ul a[aria-current="page"] {
  color: var(--ink);
  border-bottom: 2px solid var(--accent);
}

/* ---------- hero ---------- */

.hero { padding: 5.5rem 0 4rem; position: relative; }

.hero .thesis {
  font-family: var(--serif);
  font-style: italic;
  color: var(--accent);
  font-size: clamp(1.1rem, 2.2vw, 1.3rem);
  margin: 1.4rem 0 0;
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1.6rem;
  margin-top: 2.2rem;
  font-size: 0.95rem;
}

.pathway-svg {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 3.5rem;
  color: var(--accent);
}
.pathway-svg .rail { stroke: var(--line); }
.pathway-svg text {
  font-family: var(--sans);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  fill: var(--ink-soft);
}
.pathway-svg .traj { stroke: var(--accent); fill: none; opacity: 0.55; }
.pathway-svg .traj-2 { opacity: 0.3; }
.pathway-svg .traj-3 { opacity: 0.16; }
.pathway-svg .node { fill: var(--accent); }

/* ---------- journey / featured projects ---------- */

.journey { position: relative; }

.journey-item {
  position: relative;
  display: grid;
  grid-template-columns: 9rem 1fr;
  gap: 2rem;
  padding: 2.6rem 0;
}
.journey-item + .journey-item { border-top: 1px solid var(--line); }

.stage-tag {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--accent);
  padding-top: 0.35rem;
}
.stage-tag .stage-num {
  display: block;
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 400;
  letter-spacing: 0;
  color: var(--ink-faint);
  margin-bottom: 0.2rem;
}

.journey-item h3 { margin-bottom: 0.15em; }
.journey-item .venue {
  font-size: 0.85rem;
  color: var(--ink-faint);
  margin-bottom: 0.9rem;
}
.status-badge {
  display: inline-block;
  border-radius: 99px;
  padding: 0.05rem 0.6rem;
  font-size: 0.78rem;
  font-weight: 600;
  margin-left: 0.4rem;
}
.status-badge.active {
  background: var(--accent-faint);
  color: var(--accent);
}
.status-badge.direction {
  background: transparent;
  border: 1px dashed var(--line);
  color: var(--ink-faint);
}

.project-q {
  font-family: var(--serif);
  font-size: 1.12rem;
  color: var(--ink);
  margin-bottom: 0.8rem;
}

.project-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.4rem;
  margin-top: 0.6rem;
  font-size: 0.9rem;
}

@media (max-width: 40rem) {
  .journey-item { grid-template-columns: 1fr; gap: 0.6rem; padding: 2rem 0; }
  .stage-tag .stage-num { display: inline; margin-right: 0.5rem; }
}

/* ---------- project detail blocks (research page) ---------- */

details.project-more {
  margin-top: 0.4rem;
}
details.project-more summary {
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--accent);
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  user-select: none;
}
details.project-more summary::-webkit-details-marker { display: none; }
details.project-more summary::before {
  content: "+";
  font-size: 1rem;
  line-height: 1;
  transition: transform 0.15s ease;
}
details.project-more[open] summary::before { content: "–"; }
details.project-more .more-body {
  margin-top: 0.9rem;
  padding-left: 1rem;
  border-left: 2px solid var(--accent-soft);
}
.more-body dt {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-top: 0.9rem;
}
.more-body dd { margin: 0.25rem 0 0; }
.more-body dl { margin: 0; }

/* ---------- theme cards ---------- */

.theme-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(17rem, 1fr));
  gap: 1.2rem;
  margin-top: 2rem;
}

.theme-card {
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 1.5rem 1.5rem 1.2rem;
}
.theme-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5em;
}
.theme-card p { margin: 0; font-size: 0.95rem; color: var(--ink-soft); }
.theme-card .theme-projects {
  margin-top: 0.8rem;
  font-size: 0.85rem;
  color: var(--ink-faint);
}

/* ---------- publications ---------- */

.pub-year {
  font-family: var(--serif);
  font-size: 1.4rem;
  color: var(--ink-faint);
  margin: 2.6rem 0 0.4rem;
}

.pub-item {
  padding: 1.15rem 0;
  border-top: 1px solid var(--line);
  max-width: var(--measure);
}
.pub-item .pub-title { font-weight: 600; }
.pub-item .pub-authors { display: block; color: var(--ink-soft); font-size: 0.95rem; }
.pub-item .pub-authors strong { color: var(--ink); font-weight: 600; }
.pub-item .pub-venue { color: var(--ink-faint); font-size: 0.9rem; font-style: italic; }
.pub-item .pub-note {
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 600;
}
.pub-links { margin-top: 0.3rem; display: flex; gap: 1.2rem; font-size: 0.88rem; }

.patent-list { list-style: none; padding: 0; margin: 1rem 0 0; max-width: var(--measure); }
.patent-list li {
  padding: 0.55rem 0;
  border-top: 1px solid var(--line);
  font-size: 0.95rem;
  color: var(--ink-soft);
}
.patent-list .pid {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.82rem;
  color: var(--accent);
  margin-right: 0.6rem;
}

/* ---------- writing ---------- */

.writing-item {
  padding: 1.4rem 0;
  border-top: 1px solid var(--line);
  max-width: var(--measure);
}
.writing-item h3 { margin-bottom: 0.2em; }
.writing-item .meta { font-size: 0.85rem; color: var(--ink-faint); margin-bottom: 0.5rem; }
.writing-item .meta .kind {
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
  color: var(--accent);
  margin-right: 0.7rem;
}

.empty-note {
  background: var(--paper-raised);
  border: 1px dashed var(--line);
  border-radius: 10px;
  padding: 1.6rem;
  color: var(--ink-soft);
  max-width: var(--measure);
}

/* ---------- now ---------- */

.now-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  gap: 1.2rem;
  margin-top: 1.6rem;
}
.now-card {
  border-left: 3px solid var(--accent);
  background: var(--accent-faint);
  border-radius: 0 10px 10px 0;
  padding: 1.2rem 1.4rem;
}
.now-card h3 { font-size: 1.05rem; margin-bottom: 0.4em; }
.now-card p { margin: 0; font-size: 0.93rem; color: var(--ink-soft); }

/* ---------- about ---------- */

.fact-row {
  display: grid;
  grid-template-columns: 11rem 1fr;
  gap: 1.5rem;
  padding: 1.1rem 0;
  border-top: 1px solid var(--line);
  max-width: var(--measure);
}
.fact-row .when { color: var(--ink-faint); font-size: 0.9rem; padding-top: 0.15rem; }
.fact-row h3 { font-size: 1.05rem; margin-bottom: 0.15em; }
.fact-row p { margin: 0.3rem 0 0; font-size: 0.95rem; color: var(--ink-soft); }

ul.plain {
  list-style: none;
  padding: 0;
  margin: 1rem 0 0;
  max-width: var(--measure);
}
ul.plain li {
  padding: 0.5rem 0;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* ---------- footer ---------- */

footer.site {
  border-top: 1px solid var(--line);
  padding: 3rem 0 3.5rem;
  color: var(--ink-faint);
  font-size: 0.9rem;
}
footer.site .foot-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.6rem;
  margin-bottom: 1rem;
}

/* ---------- buttons ---------- */

.btn {
  display: inline-block;
  border: 1px solid var(--accent);
  border-radius: 99px;
  padding: 0.45rem 1.2rem;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--accent);
  transition: background 0.15s ease, color 0.15s ease;
}
.btn:hover {
  background: var(--accent);
  color: var(--paper);
  border-bottom-color: var(--accent);
}

/* ---------- article pages (writing/) ---------- */

article.note {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 4rem 1.5rem 5rem;
}
article.note h1 { font-size: clamp(1.8rem, 4vw, 2.5rem); }
article.note .meta { color: var(--ink-faint); font-size: 0.9rem; margin-bottom: 2.5rem; }
article.note p { font-size: 1.05rem; }
article.note blockquote {
  margin: 1.5rem 0;
  padding-left: 1.2rem;
  border-left: 3px solid var(--accent-soft);
  color: var(--ink-soft);
  font-style: italic;
}