:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-soft: #f1f4f9;
  --text: #18202a;
  --muted: #5d6776;
  --border: #d7dfeb;
  --accent: #2c5d95;
  --music-bg: #f4f6fb;
  --music-surface: #ffffff;
  --music-soft: #eef2f8;
  --music-text: #1b2430;
  --music-muted: #5f6b7a;
  --music-border: #d9e1ed;
  --music-accent: #41658c;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "IBM Plex Sans", "Noto Sans SC", sans-serif;
  color: var(--text);
  background: var(--bg);
}

body.music-page {
  color: var(--music-text);
  background: linear-gradient(180deg, var(--music-bg) 0%, color-mix(in srgb, var(--music-bg) 88%, #ffffff 12%) 100%);
  transition: background 320ms ease, color 320ms ease;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
}

.site-header {
  width: min(1120px, calc(100% - 32px));
  margin: 24px auto 0;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: flex-end;
}

.site-header.simple {
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border);
}

body.music-page .site-header.simple {
  border-bottom-color: var(--music-border);
}

.site-kicker,
.meta-line,
.group-title,
.badge,
.album-meta,
.detail-meta,
.rank-pill,
.topic-line {
  font-size: 0.86rem;
  color: var(--muted);
}

body.music-page .site-kicker,
body.music-page .meta-line,
body.music-page .group-title,
body.music-page .badge,
body.music-page .album-meta,
body.music-page .detail-meta,
body.music-page .topic-line {
  color: var(--music-muted);
}

.site-kicker,
.meta-line,
.group-title,
.rank-pill {
  margin: 0 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1 {
  font-size: clamp(2rem, 4vw, 2.9rem);
  font-weight: 700;
}

h2 {
  font-size: 1.4rem;
  font-weight: 700;
}

h3 {
  font-size: 1.05rem;
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.lang-button {
  min-width: 52px;
  height: 36px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}

body.music-page .lang-button {
  border-color: var(--music-border);
  background: var(--music-surface);
  color: var(--music-text);
}

.lang-button.is-active {
  border-color: var(--accent);
  color: var(--accent);
}

body.music-page .lang-button.is-active {
  border-color: var(--music-accent);
  color: var(--music-accent);
}

.site-nav a,
.plain-link,
.apple-link {
  color: var(--accent);
}

body.music-page .site-nav a,
body.music-page .plain-link,
body.music-page .apple-link {
  color: var(--music-accent);
}

.page-shell {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 40px;
}

.academic-shell {
  display: grid;
  gap: 28px;
}

.intro-panel {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.intro-panel > div,
.metric-card,
.paper-card,
.album-list-item,
.album-detail {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
}

body.music-page .album-list-item,
body.music-page .album-detail {
  background: var(--music-surface);
  border-color: var(--music-border);
}

.intro-panel > div {
  padding: 18px;
}

.contact-lines {
  display: grid;
  gap: 6px;
}

.section-head.compact {
  margin-bottom: 16px;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.metric-card {
  padding: 18px;
  display: grid;
  gap: 14px;
}

.metric-values {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.metric-cell {
  padding: 12px;
  border-radius: 12px;
  background: var(--surface-soft);
}

.metric-caption {
  display: block;
  margin-bottom: 6px;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.metric-value {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
}

.papers-grid {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}

.papers-table {
  display: grid;
}

.papers-header,
.paper-row-main {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 108px 72px;
  gap: 16px;
  align-items: start;
}

.papers-header {
  padding: 16px 18px;
  background: var(--surface-soft);
  border-bottom: 1px solid var(--border);
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.paper-row {
  padding: 18px;
  border-bottom: 1px solid var(--border);
}

.paper-row:last-child {
  border-bottom: 0;
}

.paper-main {
  min-width: 0;
}

.paper-title-link {
  display: inline-block;
  margin-bottom: 6px;
  font-size: 1.02rem;
  font-weight: 500;
  line-height: 1.35;
  color: #1a0dab;
}

.paper-title-link:hover {
  text-decoration: underline;
}

.paper-citation-line {
  color: var(--muted);
  line-height: 1.45;
}

.paper-side {
  justify-self: end;
  font-size: 1rem;
  line-height: 1.4;
  color: #1a0dab;
}

.rank-stack {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.paper-ranks {
  margin-top: 10px;
}

.rank-pill {
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 24%, white 76%);
  padding: 6px 10px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 8%, white 92%);
}

.abstract-toggle {
  margin-top: 10px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--accent);
  cursor: pointer;
}

.abstract-toggle:hover {
  text-decoration: underline;
}

.paper-expanded {
  display: grid;
  gap: 10px;
  padding-top: 14px;
}

.paper-summary {
  color: var(--text);
  line-height: 1.7;
}

.paper-expanded[hidden] {
  display: none;
}

.music-shell {
  padding-top: 24px;
}

.album-browser {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(320px, 0.85fr);
  gap: 24px;
  align-items: start;
}

.album-groups {
  display: grid;
  gap: 18px;
}

.artist-group {
  display: grid;
  gap: 12px;
}

.album-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.album-list-item {
  width: 100%;
  display: grid;
  grid-template-columns: 82px minmax(0, 1fr);
  gap: 12px;
  padding: 12px;
  cursor: pointer;
  text-align: left;
  transition: border-color 180ms ease, box-shadow 180ms ease, transform 180ms ease, background 180ms ease;
}

.album-list-item:hover {
  transform: translateY(-1px);
}

.album-list-item.is-active {
  border-color: var(--music-accent);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--music-accent) 22%, transparent 78%);
  background: color-mix(in srgb, var(--music-surface) 82%, var(--music-accent) 18%);
}

.album-thumb {
  width: 82px;
  height: 82px;
  border-radius: 10px;
  object-fit: cover;
}

.album-info {
  display: grid;
  gap: 6px;
  align-content: center;
}

.album-meta {
  line-height: 1.4;
}

.album-detail-shell {
  position: sticky;
  top: 18px;
}

.album-detail {
  padding: 18px;
  display: grid;
  gap: 16px;
  transition: border-color 240ms ease, background 240ms ease, box-shadow 240ms ease;
}

.detail-cover {
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: 16px;
  object-fit: cover;
  background: var(--music-soft);
}

.detail-meta {
  line-height: 1.5;
}

.detail-copy {
  line-height: 1.7;
}

.detail-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.apple-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 14px;
  border-radius: 999px;
  border: 1px solid color-mix(in srgb, var(--music-accent) 30%, white 70%);
  background: color-mix(in srgb, var(--music-accent) 10%, white 90%);
}

.color-note {
  padding-top: 10px;
  border-top: 1px solid var(--music-border);
  font-size: 0.92rem;
  color: var(--music-muted);
}

@media (max-width: 960px) {
  .intro-panel,
  .album-browser {
    grid-template-columns: 1fr;
  }

  .album-detail-shell {
    position: static;
  }
}

@media (max-width: 720px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .header-actions {
    justify-content: flex-start;
  }

  .album-grid {
    grid-template-columns: 1fr;
  }

  .papers-header,
  .paper-row-main {
    grid-template-columns: minmax(0, 1fr) 64px 56px;
    gap: 12px;
  }

  .paper-title-link {
    font-size: 0.95rem;
  }
}