/* Music, Memory & Alzheimer's — editorial site styles */

:root {
  --bg-deep: #0c0f14;
  --bg-elevated: #141922;
  --bg-panel: #1a2130;
  --bg-light: #f7f4ed;
  --bg-light-warm: #efe9dc;
  --text-primary: #f2ebe3;
  --text-muted: rgba(242, 235, 227, 0.72);
  --text-on-light: #1a1a1f;
  --text-on-light-muted: #3d3a36;
  --accent: #d4a853;
  --accent-soft: rgba(212, 168, 83, 0.22);
  --accent-glow: rgba(212, 168, 83, 0.45);
  --border-subtle: rgba(242, 235, 227, 0.12);
  --font-display: "Playfair Display", Georgia, "Times New Roman", serif;
  --font-body: "Source Sans 3", system-ui, sans-serif;
  --content-max: 42rem;
  --header-h: 4rem;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

#intro,
#thesis,
#alzheimers,
#music-emotion,
#emotion-memory,
#therapy,
#closing,
#references {
  scroll-margin-top: calc(var(--header-h) + 0.75rem);
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--text-primary);
  background: var(--bg-deep);
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
  transition: color 0.2s ease, opacity 0.2s ease;
}

a:hover {
  color: #e8c06e;
}

a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 1000;
  padding: 0.75rem 1rem;
  background: var(--accent);
  color: var(--bg-deep);
  font-weight: 600;
  border-radius: 4px;
}

.skip-link:focus {
  top: 1rem;
}

/* ——— Site chrome ——— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.25rem;
  background: rgba(12, 15, 20, 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}

.site-header--light {
  background: rgba(247, 244, 237, 0.92);
  border-bottom-color: rgba(26, 26, 31, 0.08);
}

.site-header--light .site-logo,
.site-header--light .nav-toggle__bar {
  color: var(--text-on-light);
}

.site-header--light .nav-link {
  color: var(--text-on-light-muted);
}

.site-header--light .nav-link:hover,
.site-header--light .nav-link[aria-current="page"] {
  color: var(--text-on-light);
}

.site-logo {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--text-primary);
  text-decoration: none;
}

.site-logo:hover {
  color: var(--accent);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 0.5rem;
  background: transparent;
  border: none;
  cursor: pointer;
}

.nav-toggle__bar {
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
  transition: transform 0.25s var(--ease-out), opacity 0.2s;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 1rem;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-decoration: none;
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  color: var(--accent);
}

@media (max-width: 900px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 1rem 1.25rem 1.5rem;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border-subtle);
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    pointer-events: none;
    transition: max-height 0.45s var(--ease-out), opacity 0.3s ease;
  }

  .site-header--light .site-nav {
    background: var(--bg-light);
    border-bottom-color: rgba(26, 26, 31, 0.1);
  }

  .site-nav.is-open {
    max-height: 100vh;
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-subtle);
  }

  .site-header--light .nav-link {
    border-bottom-color: rgba(26, 26, 31, 0.08);
  }
}

/* ——— Layout ——— */
.content-wrap {
  width: min(100% - 2.5rem, var(--content-max));
  margin-inline: auto;
}

.section {
  padding: clamp(3rem, 8vw, 5.5rem) 0;
  position: relative;
}

.section--tight {
  padding: clamp(2rem, 5vw, 3rem) 0;
}

.section--light {
  background: var(--bg-light);
  color: var(--text-on-light);
}

.section--light .lede,
.section--light p {
  color: var(--text-on-light-muted);
}

.section--light h2,
.section--light h3 {
  color: var(--text-on-light);
}

/* Faint rule between major sections (on the visible content block, not the wrapper) */
#thesis.section--dark-panel {
  border-top: 1px solid rgba(242, 235, 227, 0.18);
}

main > section[id] > .section--light,
main > section#references.section--light {
  border-top: 1px solid rgba(26, 26, 31, 0.14);
}

.section--divider::before {
  content: "";
  display: block;
  height: 1px;
  margin: 0 auto clamp(2.5rem, 6vw, 4rem);
  width: min(12rem, 40%);
  background: linear-gradient(
    90deg,
    transparent,
    var(--accent),
    transparent
  );
  opacity: 0.55;
}

.section--dark-panel {
  background: linear-gradient(180deg, var(--bg-elevated) 0%, var(--bg-deep) 100%);
}

.section--light.section--tight > .content-wrap > .page-hero__label:first-child {
  padding-top: clamp(2.5rem, 6vw, 4rem);
}

.page-hero__label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: #9a7328;
  margin: 0 0 0.75rem;
}

.page-hero__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2rem, 5vw, 2.85rem);
  line-height: 1.15;
  margin: 0;
  letter-spacing: -0.02em;
  color: var(--text-on-light);
}

.section--light .content-wrap > .page-hero__title + p {
  margin: 1rem 0 0;
  max-width: 36rem;
  color: var(--text-on-light-muted);
  font-size: 1.1rem;
}

.page-hero__title + h3 {
  margin-top: clamp(1.5rem, 4vw, 2.25rem);
}

/* ——— Home hero ——— */
.hero {
  position: relative;
  min-height: min(92vh, 52rem);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: calc(var(--header-h) + 2rem) 1.25rem 4rem;
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  background: radial-gradient(
      ellipse 120% 80% at 50% 0%,
      rgba(212, 168, 83, 0.12),
      transparent 55%
    ),
    radial-gradient(
      circle at 20% 60%,
      rgba(90, 120, 180, 0.08),
      transparent 45%
    ),
    var(--bg-deep);
  will-change: transform;
}

.hero__noise {
  position: absolute;
  inset: 0;
  opacity: 0.04;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  pointer-events: none;
}

.hero__waves {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 45%;
  opacity: 0.35;
  z-index: 1;
  pointer-events: none;
}

.hero__waves svg {
  width: 100%;
  height: 100%;
}

.hero__inner {
  position: relative;
  z-index: 2;
  width: min(100% - 2.5rem, 48rem);
  margin-inline: auto;
  text-align: center;
}

.hero h1 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.5rem, 7vw, 4.25rem);
  line-height: 1.08;
  margin: 0 0 1rem;
  letter-spacing: -0.03em;
  text-wrap: balance;
}

.hero__subtitle {
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(1.15rem, 2.8vw, 1.45rem);
  color: var(--text-muted);
  margin: 0 auto 2.5rem;
  max-width: 28rem;
  text-wrap: balance;
}

.hero__cta {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.hero__cta span:last-child {
  display: block;
  width: 1px;
  height: 2.5rem;
  background: linear-gradient(to bottom, var(--accent), transparent);
  animation: hero-line 2.2s ease-in-out infinite;
}

@keyframes hero-line {
  0%,
  100% {
    opacity: 0.4;
    transform: scaleY(0.85);
  }
  50% {
    opacity: 1;
    transform: scaleY(1);
  }
}

/* ——— Typography blocks ——— */
h2 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.65rem, 3.5vw, 2.15rem);
  margin: 0 0 1.25rem;
  letter-spacing: -0.02em;
}

h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem;
}

.lede {
  font-size: 1.2rem;
  line-height: 1.6;
  color: var(--text-muted);
}

p {
  margin: 0 0 1.15rem;
  color: var(--text-muted);
}

p:last-child {
  margin-bottom: 0;
}

.pull-quote {
  margin: 2.5rem 0;
  padding: 1.75rem 1.5rem 1.75rem 1.75rem;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 2.5vw, 1.45rem);
  font-style: italic;
  line-height: 1.45;
  color: var(--text-primary);
}

.section--light .pull-quote {
  background: rgba(212, 168, 83, 0.12);
  color: var(--text-on-light);
}

/* ——— Thesis chain ——— */
.chain {
  display: grid;
  gap: 1rem;
  margin-top: 2rem;
}

.chain__item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.1rem 1.25rem;
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
}

.chain__num {
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  display: grid;
  place-items: center;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--bg-deep);
  background: var(--accent);
  border-radius: 50%;
}

.chain__text {
  font-size: 0.98rem;
  color: var(--text-muted);
  margin: 0;
}

.section--light .chain__item {
  background: #fff;
  border-color: rgba(26, 26, 31, 0.08);
}

.section--light .chain__text {
  color: var(--text-on-light-muted);
}

/* ——— Brain figure ——— */
.brain-figure-wrap {
  --brain-wide: min(100vw - 2.5rem, 52rem);
  width: var(--brain-wide);
  margin-inline: calc((100% - var(--brain-wide)) / 2);
}

.brain-figure {
  margin: 2.5rem 0 0;
  padding: 1.5rem;
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
}

.section--light .brain-figure {
  background: #fff;
  border-color: rgba(26, 26, 31, 0.1);
}

.brain-figure__layout {
  display: grid;
  gap: 1.25rem;
  align-items: start;
}

.brain-figure figcaption {
  margin-top: 1rem;
  font-size: 0.95rem;
  font-style: italic;
  color: var(--text-muted);
  text-align: center;
}

.section--light .brain-figure figcaption {
  color: var(--text-on-light-muted);
}

.brain-figure__media {
  display: block;
  width: 100%;
}

.brain-figure__img {
  display: block;
  width: 100%;
  max-width: none;
  height: auto;
  border-radius: 6px;
  border: 1px solid rgba(26, 26, 31, 0.08);
}

.marker-key {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.65rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .marker-key {
    grid-template-columns: repeat(2, 1fr);
    column-gap: 1.5rem;
  }
}

.marker-key li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.65rem;
  align-items: start;
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.section--light .marker-key li {
  color: var(--text-on-light-muted);
}

.marker-key strong {
  color: var(--text-primary);
  font-weight: 600;
}

.section--light .marker-key strong {
  color: var(--text-on-light);
}

.marker-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-top: 0.35rem;
  flex-shrink: 0;
}

/* ——— Research briefs (details) ——— */
.research-stack {
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

details.research-brief {
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.02);
  overflow: hidden;
}

.section--light details.research-brief {
  background: #fff;
  border-color: rgba(26, 26, 31, 0.12);
}

details.research-brief summary {
  list-style: none;
  cursor: pointer;
  padding: 1.15rem 1.35rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: background 0.2s ease;
}

.section--light details.research-brief summary {
  color: var(--text-on-light);
}

details.research-brief summary::-webkit-details-marker {
  display: none;
}

details.research-brief summary::after {
  content: "";
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  transform: rotate(45deg);
  transition: transform 0.35s var(--ease-out);
  flex-shrink: 0;
}

details.research-brief[open] summary::after {
  transform: rotate(-135deg);
}

details.research-brief summary:hover {
  background: var(--accent-soft);
}

.section--light details.research-brief summary:hover {
  background: rgba(212, 168, 83, 0.1);
}

.research-brief__body {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.45s var(--ease-out);
}

details.research-brief[open] .research-brief__body {
  grid-template-rows: 1fr;
}

.research-brief__inner {
  overflow: hidden;
}

.research-brief__inner p {
  padding: 0 1.35rem 1.35rem;
  margin: 0;
  font-size: 0.98rem;
}

/* ——— References ——— */
.ref-list {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.ref-list li {
  padding-bottom: 1rem;
  border-bottom: 1px solid rgba(26, 26, 31, 0.1);
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--text-on-light-muted);
}

.ref-list li:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.ref-list em {
  font-style: italic;
  color: var(--text-on-light);
}

/* ——— Footer ——— */
.site-footer {
  padding: 2.5rem 1.25rem;
  border-top: 1px solid var(--border-subtle);
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.site-footer--light {
  background: var(--bg-light-warm);
  border-top-color: rgba(26, 26, 31, 0.08);
  color: var(--text-on-light-muted);
}

/* ——— Scroll reveal ——— */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 {
  transition-delay: 0.08s;
}

.reveal-delay-2 {
  transition-delay: 0.16s;
}

.reveal-delay-3 {
  transition-delay: 0.24s;
}