/* ============================================
   SECTION PAGE SHELL
   Shared by Home, Publication, Project, Blog, Service and Resume: base type,
   the page title, the nav with its underline and theme switch, page
   transitions, and the small-caps link rows. Color tokens live in theme.css;
   each page file keeps only its own layout. css/blog.css repeats the body,
   --content-width and @view-transition for posts and surveys, which do not
   load this file, so change both together.
   ============================================ */

:root {
  --content-width: 1000px;
}

body {
  font-family: et-book, Palatino, "Palatino Linotype", "Palatino LT STD", "Book Antiqua", Georgia, serif;
  font-size: 1.1rem;
  line-height: 1.7;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 2rem;
  color: var(--text-color);
  background: var(--bg);
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 400;
}

.header {
  margin-bottom: 2rem;
}

.header h1 {
  font-size: 2.5rem;
  margin: 0 0 0.5rem;
  color: var(--ink);
  view-transition-name: page-title;
}

/* ---------- Navigation ---------- */

nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  margin: 2rem 0;
  padding: 1rem 0;
  border-top: 1px solid var(--nav-border);
  border-bottom: 1px solid var(--nav-border);
  view-transition-name: site-nav;
}

nav a {
  position: relative;
  color: var(--nav-text);
  text-decoration: none;
  margin-right: 1.5rem;
  font-weight: 400;
  transition: color 0.2s ease, font-weight 0.2s ease;
}

nav a:hover {
  color: var(--nav-active);
}

nav a.active {
  color: var(--nav-active);
  font-weight: 600;
}

nav a:visited {
  color: var(--nav-text);
}

nav a:active {
  color: var(--nav-active);
}

/* A thin ink line under the current section. It follows the pointer across
   the nav (js/site.js), returns to the current section on leave, and morphs
   to the new section during a page transition. */
.nav-indicator {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -0.4em;
  height: 1.5px;
  border-radius: 1px;
  background: var(--indicator);
  box-shadow: var(--indicator-glow);
  transform-origin: 0 50%;
  pointer-events: none;
  view-transition-name: nav-indicator;
  transition: transform 420ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

/* Light and dark switch at the end of the nav (js/theme.js) */
.theme-toggle {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  border: 1px solid var(--rule);
  border-radius: 50%;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease, transform 0.45s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.theme-toggle[hidden] {
  display: none;
}

.theme-toggle:hover {
  color: var(--ink);
  border-color: var(--rule-strong);
  transform: rotate(-25deg);
}

.theme-toggle:focus-visible {
  outline: 1px solid var(--ink);
  outline-offset: 3px;
}

.theme-toggle svg {
  width: 1rem;
  height: 1rem;
}

.theme-toggle .icon-sun,
.theme-toggle.is-dark .icon-moon {
  display: none;
}

.theme-toggle.is-dark .icon-sun {
  display: block;
}

/* ---------- Small-caps link rows and TL;DR labels (publication, project, service) ---------- */

.publication-links a,
.project-links a,
.service-links a {
  color: var(--ink);
  font-variant-caps: all-small-caps;
  letter-spacing: 0.06em;
  font-size: 1.05rem;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--link-underline);
  text-underline-offset: 3px;
  transition: text-decoration-color 0.2s ease;
}

.publication-links a:hover,
.project-links a:hover,
.service-links a:hover {
  text-decoration-color: var(--ink);
}

.publication-links a:focus-visible,
.project-links a:focus-visible,
.service-links a:focus-visible {
  outline: 1px solid var(--ink);
  outline-offset: 3px;
}

/* Small gray icons, ink on hover */
.publication-links .icon,
.project-links .icon,
.service-links .icon {
  margin-right: calc(0.35em + 0.064rem); /* + the link letter-spacing the font glyph carried */
  font-size: 0.8em;
  color: var(--muted);
  transition: color 0.2s ease;
}

.publication-links a:hover .icon,
.project-links a:hover .icon,
.service-links a:hover .icon {
  color: var(--ink);
}

/* The TL;DR lead-in of publication and project summaries */
.tldr-label {
  font-variant-caps: all-small-caps;
  letter-spacing: 0.08em;
  color: var(--ink);
  margin-right: 0.3em;
}

/* ---------- Responsive ---------- */

/* On phones the nav wraps and centers, so the switch joins the row */
@media (max-width: 700px) {
  body {
    padding: 1rem;
  }

  nav {
    justify-content: center;
    gap: 1rem;
  }

  nav a {
    margin: 0 0.75rem;
  }

  .theme-toggle {
    margin-left: 0;
  }
}

/* ============================================
   PAGE TRANSITIONS
   Browsers with cross-document View Transitions (Chrome, Edge, Safari 18.2+)
   keep the nav still, glide the active underline to the new section, slide
   the page title, and let the content fade up. Other browsers get the
   html.pt-fallback fade below, driven by js/site.js.
   ============================================ */

@view-transition {
  navigation: auto;
}

::view-transition-group(*) {
  animation-duration: 460ms;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
}

/* Content: the old page drifts up and fades quickly, the new one rises in
   from slightly below and comes into focus. */
::view-transition-old(root) {
  animation: pt-content-out 180ms cubic-bezier(0.4, 0, 1, 1) both;
}

::view-transition-new(root) {
  animation: pt-content-in 460ms cubic-bezier(0.2, 0.8, 0.2, 1) 70ms both;
}

/* Title: one word slides out upward while the next slides in from below.
   Natural size keeps the text from stretching between titles of different width. */
::view-transition-old(page-title),
::view-transition-new(page-title) {
  width: auto;
  height: auto;
  inset: 0 auto auto 0;
}

::view-transition-old(page-title) {
  animation: pt-title-out 220ms cubic-bezier(0.4, 0, 1, 1) both;
}

::view-transition-new(page-title) {
  animation: pt-title-in 520ms cubic-bezier(0.2, 0.8, 0.2, 1) 90ms both;
}

/* Nav: only the bold weight of the active link changes, so a short crossfade. */
::view-transition-old(site-nav),
::view-transition-new(site-nav) {
  width: auto;
  height: auto;
  inset: 0 auto auto 0;
  animation-duration: 260ms;
}

@keyframes pt-content-out {
  to {
    opacity: 0;
    transform: translateY(-8px);
  }
}

@keyframes pt-content-in {
  from {
    opacity: 0;
    transform: translateY(14px);
    filter: blur(4px);
  }
}

@keyframes pt-title-out {
  to {
    opacity: 0;
    transform: translateY(-45%);
  }
}

@keyframes pt-title-in {
  from {
    opacity: 0;
    transform: translateY(45%);
  }
}

/* Fallback fade (no cross-document View Transitions) */
html.pt-fallback body {
  transition: opacity 340ms cubic-bezier(0.2, 0.8, 0.2, 1),
    transform 340ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

html.pt-fallback.pt-enter body {
  opacity: 0;
  transform: translateY(12px);
}

html.pt-fallback.pt-exit body {
  opacity: 0;
  transform: translateY(-8px);
  transition-duration: 180ms;
}

/* Gentle color easing everywhere unless a rule sets its own transition */
a {
  transition: color 200ms ease;
}

*, *::before, *::after {
  transition-property: background-color, border-color, color, opacity, transform;
  transition-duration: 100ms;
  transition-timing-function: ease-in-out;
}

@media (prefers-reduced-motion: reduce) {
  @view-transition {
    navigation: none;
  }

  .nav-indicator,
  .theme-toggle,
  html.pt-fallback body {
    transition: none;
  }

  .theme-toggle:hover {
    transform: none;
  }
}