/* ==============================================================
   Design tokens — edit here to re-theme the whole site.
   ============================================================== */

:root {
  /* Colours — light */
  --bg:          #FBF9F4;
  --surface:     #FFFFFF;
  --surface-alt: #F4EFE4;
  --text:        #0F1E3D;
  --muted:       #4A5A78;
  --accent:      #1E3A5F;
  --accent-hover:#2B4E7E;
  --accent-warm: #B8845C;
  --border:      #E5E0D3;
  --shadow:      0 1px 2px rgba(15, 30, 61, 0.04), 0 8px 24px rgba(15, 30, 61, 0.06);
  --shadow-lg:   0 2px 6px rgba(15, 30, 61, 0.06), 0 20px 50px rgba(15, 30, 61, 0.10);
  --nav-bg:      rgba(251, 249, 244, 0.72);

  /* Type */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif: 'Lora', Georgia, 'Times New Roman', serif;

  /* Rhythm */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 999px;
  --container: 1120px;
  --gutter: clamp(1.25rem, 4vw, 2.5rem);

  /* Motion */
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  --dur: 600ms;
}

:root[data-theme="dark"] {
  --bg:          #0E1420;
  --surface:     #141C2B;
  --surface-alt: #182238;
  --text:        #E8ECF5;
  --muted:       #9AA7BE;
  --accent:      #8FB1DC;
  --accent-hover:#B0C9EA;
  --accent-warm: #D4A37E;
  --border:      #243249;
  --shadow:      0 1px 2px rgba(0,0,0,0.3), 0 8px 24px rgba(0,0,0,0.4);
  --shadow-lg:   0 2px 6px rgba(0,0,0,0.35), 0 20px 50px rgba(0,0,0,0.5);
  --nav-bg:      rgba(14, 20, 32, 0.72);
}

/* ==============================================================
   Reset + base
   ============================================================== */

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: clamp(16px, 1.02vw, 17px);
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 400ms var(--ease), color 400ms var(--ease);
}

img { max-width: 100%; display: block; }
h1, h2, h3, h4 { font-family: var(--font-serif); font-weight: 600; letter-spacing: -0.01em; color: var(--text); margin: 0; }
p { margin: 0 0 1em; color: var(--text); }
a { color: var(--accent); text-decoration: none; transition: color 200ms var(--ease); }
a:hover { color: var(--accent-warm); }

::selection { background: var(--accent); color: var(--bg); }

.skip-link {
  position: absolute; left: -9999px; top: 0;
  padding: 0.75rem 1rem; background: var(--accent); color: var(--bg);
  border-radius: var(--radius-sm); z-index: 100;
}
.skip-link:focus { left: 1rem; top: 1rem; }

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 var(--gutter); }

/* ==============================================================
   Navigation
   ============================================================== */

.nav {
  position: sticky; top: 0; z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 200ms var(--ease), background-color 400ms var(--ease);
}
.nav.is-scrolled { border-bottom-color: var(--border); }

.nav__inner {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 1rem; padding-bottom: 1rem;
}
.nav__brand { display: flex; align-items: center; gap: 0.65rem; color: var(--text); font-weight: 600; }
.nav__brand:hover { color: var(--text); }
.nav__monogram {
  width: 34px; height: 34px; display: grid; place-items: center;
  border-radius: var(--radius-sm);
  background: var(--accent); color: var(--bg);
  font-family: var(--font-serif); font-weight: 700; font-size: 0.95rem; letter-spacing: 0.02em;
}
.nav__name { font-family: var(--font-serif); font-size: 1.05rem; }

.nav__menu {
  display: flex; align-items: center; gap: 1.5rem;
}
.nav__menu a {
  color: var(--muted); font-size: 0.93rem; font-weight: 500; padding: 0.3rem 0; position: relative;
}
.nav__menu a::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px; height: 1px;
  background: var(--accent-warm); transform: scaleX(0); transform-origin: left;
  transition: transform 250ms var(--ease);
}
.nav__menu a:hover, .nav__menu a[aria-current="page"] { color: var(--text); }
.nav__menu a:hover::after, .nav__menu a[aria-current="page"]::after { transform: scaleX(1); }

.theme-toggle {
  background: transparent; border: 1px solid var(--border);
  width: 38px; height: 38px; border-radius: var(--radius-full);
  display: grid; place-items: center; cursor: pointer; color: var(--text);
  transition: background-color 200ms var(--ease), border-color 200ms var(--ease);
}
.theme-toggle:hover { background: var(--surface-alt); }
.theme-toggle .icon { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
:root[data-theme="light"] .icon--moon,
:root[data-theme="dark"] .icon--sun { display: none; }

.nav__toggle {
  display: none; background: transparent; border: 0; padding: 0.5rem; cursor: pointer;
  width: 40px; height: 40px; flex-direction: column; justify-content: center; gap: 5px;
}
.nav__toggle span {
  display: block; width: 22px; height: 2px; background: var(--text); border-radius: 2px;
  transition: transform 200ms var(--ease), opacity 200ms var(--ease);
}

@media (max-width: 760px) {
  .nav__toggle { display: inline-flex; }
  .nav__menu {
    position: fixed; inset: 64px 0 auto 0;
    flex-direction: column; align-items: stretch; gap: 0;
    padding: 1rem var(--gutter) 2rem;
    background: var(--bg); border-bottom: 1px solid var(--border);
    transform: translateY(-120%); transition: transform 300ms var(--ease);
    box-shadow: var(--shadow);
  }
  .nav__menu a { padding: 0.9rem 0; border-bottom: 1px solid var(--border); font-size: 1rem; }
  .nav__menu a:last-of-type { border-bottom: 0; }
  .nav__menu .theme-toggle { align-self: flex-start; margin-top: 0.75rem; }
  .nav.is-open .nav__menu { transform: translateY(0); }
  .nav.is-open .nav__toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav.is-open .nav__toggle span:nth-child(2) { opacity: 0; }
  .nav.is-open .nav__toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
}

/* ==============================================================
   Section base
   ============================================================== */

.section {
  padding: clamp(4rem, 8vw, 7rem) 0;
  border-top: 1px solid transparent;
}
.section--alt { background: var(--surface-alt); }
.section__header { margin-bottom: clamp(2rem, 4vw, 3rem); max-width: 60ch; }
.section__kicker {
  display: inline-block; font-family: var(--font-sans); font-size: 0.78rem;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--accent-warm);
  margin-bottom: 0.6rem; font-weight: 600;
}
.section__title {
  font-size: clamp(1.7rem, 3vw, 2.4rem); line-height: 1.2;
}
.subsection__title {
  font-family: var(--font-serif); font-size: 1.3rem; font-weight: 600;
  margin: 2.5rem 0 1.25rem; color: var(--text);
}
.subsection__title:first-of-type { margin-top: 0; }

/* ==============================================================
   Hero
   ============================================================== */

.hero {
  padding: clamp(3rem, 8vw, 7rem) 0 clamp(3rem, 6vw, 6rem);
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(184,132,92,0.08), transparent 60%),
    radial-gradient(900px 500px at 90% 0%, rgba(30,58,95,0.07), transparent 60%);
}
:root[data-theme="dark"] .hero {
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(212,163,126,0.10), transparent 60%),
    radial-gradient(900px 500px at 90% 0%, rgba(143,177,220,0.08), transparent 60%);
}

.hero__grid {
  display: grid; grid-template-columns: 1.5fr 1fr; gap: clamp(2rem, 4vw, 4rem);
  align-items: center;
}
@media (max-width: 820px) {
  .hero__grid { grid-template-columns: 1fr; text-align: left; }
  .hero__portrait { order: -1; }
}

.hero__eyebrow {
  font-size: 0.9rem; color: var(--muted); letter-spacing: 0.02em;
  margin: 0 0 1rem;
}
.hero__name {
  font-size: clamp(2.8rem, 6vw, 4.6rem); line-height: 1.02; letter-spacing: -0.02em;
  margin: 0 0 1.25rem;
}
.hero__tagline {
  font-family: var(--font-serif); font-style: italic; font-size: clamp(1.1rem, 1.6vw, 1.35rem);
  color: var(--muted); max-width: 38ch; margin: 0 0 2rem;
}

.hero__cta { display: flex; flex-wrap: wrap; gap: 0.75rem; }

.hero__portrait {
  justify-self: center;
  width: clamp(200px, 30vw, 300px); aspect-ratio: 1; border-radius: 50%;
  overflow: hidden; box-shadow: var(--shadow-lg);
  border: 4px solid var(--surface);
  position: relative;
}
.hero__portrait img { width: 100%; height: 100%; object-fit: cover; }
.hero__portrait::after {
  content: ""; position: absolute; inset: -4px; border-radius: 50%;
  box-shadow: inset 0 0 0 1px var(--border); pointer-events: none;
}

/* ==============================================================
   Buttons
   ============================================================== */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
  padding: 0.75rem 1.4rem; border-radius: var(--radius-full);
  font-family: var(--font-sans); font-weight: 500; font-size: 0.95rem;
  border: 1px solid transparent; cursor: pointer; text-decoration: none;
  transition: transform 150ms var(--ease), background-color 200ms var(--ease),
              color 200ms var(--ease), border-color 200ms var(--ease),
              box-shadow 200ms var(--ease);
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn--primary { background: var(--accent); color: var(--bg); }
:root[data-theme="dark"] .btn--primary { color: #0E1420; }
.btn--primary:hover { background: var(--accent-hover); color: var(--bg); box-shadow: var(--shadow); }
:root[data-theme="dark"] .btn--primary:hover { color: #0E1420; }

.btn--secondary {
  background: var(--surface); color: var(--text); border-color: var(--border);
}
.btn--secondary:hover { border-color: var(--accent); color: var(--accent); }

.btn--ghost { background: transparent; color: var(--text); border-color: transparent; }
.btn--ghost:hover { color: var(--accent-warm); }

/* ==============================================================
   About
   ============================================================== */

.about__grid {
  display: grid; grid-template-columns: 2fr 1fr; gap: clamp(2rem, 4vw, 4rem);
  align-items: start;
}
@media (max-width: 820px) { .about__grid { grid-template-columns: 1fr; } }

.about__body p { font-size: 1.05rem; color: var(--text); }
.about__body p + p { margin-top: 1rem; }

.tag-list {
  list-style: none; padding: 0; margin: 1.5rem 0 0;
  display: flex; flex-wrap: wrap; gap: 0.5rem;
}
.tag {
  display: inline-block;
  padding: 0.35rem 0.85rem; font-size: 0.82rem; font-weight: 500;
  background: var(--surface); color: var(--accent);
  border: 1px solid var(--border); border-radius: var(--radius-full);
}

.about__facts {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: 1.5rem; box-shadow: var(--shadow);
}
.about__facts dl { margin: 0; display: grid; gap: 0.9rem; }
.about__facts dl > div { display: grid; gap: 0.15rem; }
.about__facts dt {
  font-size: 0.75rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--muted); font-weight: 600;
}
.about__facts dd { margin: 0; font-size: 0.95rem; color: var(--text); }

/* ==============================================================
   Research / Papers
   ============================================================== */

.research__preamble {
  max-width: 64ch; font-size: 1.05rem; color: var(--text);
  margin: 0 0 clamp(2rem, 4vw, 3rem);
}

.paper-list { display: grid; gap: 1rem; }

.paper-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: 1.5rem 1.75rem;
  box-shadow: var(--shadow);
  transition: transform 200ms var(--ease), box-shadow 200ms var(--ease), border-color 200ms var(--ease);
}
.paper-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); border-color: color-mix(in srgb, var(--accent) 30%, var(--border)); }
.paper-card--placeholder { opacity: 0.85; }

.paper-card__head {
  display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem;
  flex-wrap: wrap;
}
.paper-card__title { font-size: 1.2rem; font-family: var(--font-serif); font-weight: 600; margin: 0; }
.paper-card__coauthors { margin: 0.35rem 0 0.9rem; color: var(--muted); font-size: 0.92rem; font-style: italic; }
.paper-card__desc { margin: 0.6rem 0 0; color: var(--text); font-size: 0.97rem; max-width: 64ch; }
.paper-card__abstract { margin-top: 0.75rem; color: var(--text); }
.paper-card__abstract summary {
  cursor: pointer; font-size: 0.88rem; font-weight: 500; color: var(--accent);
  padding: 0.3rem 0; list-style: none;
}
.paper-card__abstract summary::-webkit-details-marker { display: none; }
.paper-card__abstract summary::before {
  content: "▸"; display: inline-block; margin-right: 0.4rem; transition: transform 200ms var(--ease); color: var(--accent-warm);
}
.paper-card__abstract[open] summary::before { transform: rotate(90deg); }
.paper-card__abstract p { margin: 0.6rem 0 0; color: var(--muted); font-size: 0.95rem; }
.paper-card__links { margin-top: 0.9rem; display: flex; gap: 1rem; flex-wrap: wrap; }

.link {
  font-size: 0.88rem; font-weight: 500; color: var(--accent);
  border-bottom: 1px solid transparent; padding-bottom: 1px;
  transition: border-color 180ms var(--ease), color 180ms var(--ease);
}
.link:hover { border-color: var(--accent-warm); color: var(--accent-warm); }

.status {
  display: inline-block; font-size: 0.72rem; font-weight: 600; letter-spacing: 0.06em;
  text-transform: uppercase; padding: 0.3rem 0.7rem; border-radius: var(--radius-full);
  white-space: nowrap;
}
.status--wip       { background: color-mix(in srgb, var(--accent-warm) 15%, transparent); color: var(--accent-warm); }
.status--review    { background: color-mix(in srgb, var(--accent) 12%, transparent);      color: var(--accent); }
.status--published { background: color-mix(in srgb, #2e8b57 20%, transparent);              color: #2e8b57; }
:root[data-theme="dark"] .status--published { color: #7dd3a3; background: rgba(125, 211, 163, 0.12); }

/* ==============================================================
   Teaching / Courses
   ============================================================== */

.course-list { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }

.course-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: 1.5rem 1.75rem;
  box-shadow: var(--shadow);
  transition: transform 200ms var(--ease), box-shadow 200ms var(--ease);
}
.course-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }

.course-card__meta {
  display: flex; align-items: center; gap: 0.9rem; margin-bottom: 0.8rem;
  font-size: 0.78rem; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--muted); font-weight: 600;
}
.course-card__code {
  color: var(--bg); background: var(--accent);
  padding: 0.2rem 0.55rem; border-radius: var(--radius-sm);
  letter-spacing: 0.04em;
}
:root[data-theme="dark"] .course-card__code { color: #0E1420; }
.course-card__title { font-size: 1.15rem; margin-bottom: 0.35rem; }
.course-card__role { color: var(--muted); font-size: 0.92rem; margin: 0 0 0.7rem; }
.course-card__desc { font-size: 0.95rem; color: var(--text); margin: 0 0 0.9rem; }
.course-card__eval {
  display: inline-flex; align-items: baseline; gap: 0.55rem;
  margin: 0 0 1rem; padding: 0.5rem 0.9rem;
  background: color-mix(in srgb, var(--accent-warm) 12%, transparent);
  border-radius: var(--radius-sm);
}
.course-card__eval-score {
  font-family: var(--font-serif); font-weight: 700; font-size: 1.05rem;
  color: var(--accent-warm); letter-spacing: 0.01em;
}
.course-card__eval-label {
  font-size: 0.78rem; letter-spacing: 0.04em; color: var(--muted);
}
.course-card__links { display: flex; gap: 1rem; }

/* ==============================================================
   CV
   ============================================================== */

.cv__download p { font-size: 1.05rem; max-width: 60ch; }

/* ==============================================================
   Contact
   ============================================================== */

.contact__grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 0.85rem;
}
.contact-card {
  display: grid; gap: 0.35rem;
  padding: 1.15rem 1.35rem;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-md); color: var(--text);
  transition: transform 200ms var(--ease), border-color 200ms var(--ease), box-shadow 200ms var(--ease);
}
.contact-card:hover {
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--accent) 30%, var(--border));
  box-shadow: var(--shadow);
  color: var(--text);
}
.contact-card__label {
  font-size: 0.75rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--muted); font-weight: 600;
}
.contact-card__value {
  font-family: var(--font-sans); font-size: 0.95rem; color: var(--accent);
  word-break: break-word;
}

/* ==============================================================
   Footer
   ============================================================== */

.footer {
  border-top: 1px solid var(--border); padding: 2rem 0 3rem;
  background: var(--bg);
}
.footer__inner {
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.5rem;
  color: var(--muted); font-size: 0.88rem;
}
.footer p { margin: 0; }
.footer__meta { color: var(--muted); }

/* ==============================================================
   Reveal animation (IntersectionObserver adds .in-view)
   ============================================================== */

[data-animate] {
  opacity: 0; transform: translateY(12px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
  will-change: opacity, transform;
}
[data-animate].in-view { opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  [data-animate] { opacity: 1; transform: none; }
}

/* ==============================================================
   Focus states
   ============================================================== */

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}
.btn:focus-visible { outline-offset: 4px; }