/* ============================================
   ASCRI — Adversarial Systems & Complexity Research Initiative
   Light/dark academic theme · systems.ac
   ============================================ */

/* --- Custom Properties --- */
:root {
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8F7F5;
  --bg-tertiary: #F0EFEC;
  --text-primary: #1A1A1A;
  --text-secondary: #4A4A4A;
  --text-muted: #757575;
  --accent: #9B1B30;
  --accent-hover: #B22234;
  --accent-light: rgba(155, 27, 48, 0.08);
  --border: #E0DED9;
  --border-strong: #C5C3BD;
  --nav-bg: rgba(255, 255, 255, 0.92);
  --mobile-nav-bg: rgba(255, 255, 255, 0.97);
  --status-peer-bg: #e8f5e9;
  --status-peer-fg: #2e7d32;
  --status-published-bg: #e8f5e9;
  --status-published-fg: #1b5e20;
  --status-preprint-bg: #f1f8e9;
  --status-preprint-fg: #558b2f;

  --font-serif: 'Crimson Text', Georgia, 'Times New Roman', serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;

  --max-width-reading: 900px;
  --max-width-grid: 1100px;
  --radius: 2px;

  --transition: 200ms ease;
}

/* --- Dark Theme --- */
[data-theme="dark"] {
  --bg-primary: #121212;
  --bg-secondary: #1A1A1A;
  --bg-tertiary: #222222;
  --text-primary: #E8E6E1;
  --text-secondary: #B0ADA6;
  --text-muted: #807D76;
  --accent: #D44A5E;
  --accent-hover: #E8637A;
  --accent-light: rgba(212, 74, 94, 0.12);
  --border: #2A2926;
  --border-strong: #3A3835;
  --nav-bg: rgba(18, 18, 18, 0.92);
  --mobile-nav-bg: rgba(18, 18, 18, 0.97);
  --status-peer-bg: rgba(46, 125, 50, 0.15);
  --status-peer-fg: #66bb6a;
  --status-published-bg: rgba(27, 94, 32, 0.15);
  --status-published-fg: #4caf50;
  --status-preprint-bg: rgba(85, 139, 47, 0.15);
  --status-preprint-fg: #9ccc65;
}

/* --- Reset & Base --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
}

body.has-nav {
  padding-top: 56px;
}

/* --- Typography --- */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.25;
  color: var(--text-primary);
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
}

h2 {
  font-size: clamp(1.5rem, 3.5vw, 2rem);
  font-weight: 600;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

h4 {
  font-size: 1rem;
  font-weight: 600;
}

p {
  color: var(--text-secondary);
  max-width: 65ch;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--accent-hover);
}

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

/* --- Layout --- */
.container {
  width: 100%;
  max-width: var(--max-width-reading);
  margin: 0 auto;
  padding: 0 2rem;
}

.container--wide {
  max-width: var(--max-width-grid);
}

section {
  padding: 5rem 0;
}

section + section {
  border-top: 1px solid var(--border);
}

.section--alt {
  background: var(--bg-secondary);
}

/* --- Grid Utilities --- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

/* --- Site Navigation --- */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: 56px;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.site-nav__inner {
  max-width: var(--max-width-grid);
  margin: 0 auto;
  padding: 0 2rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-nav__brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.02em;
}

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

.site-nav__links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.site-nav__link {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-muted);
  text-decoration: none;
  letter-spacing: 0.01em;
  transition: color var(--transition);
}

.site-nav__link:hover,
.site-nav__link--active {
  color: var(--text-primary);
}

.site-nav__toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem;
  color: var(--text-secondary);
}

.site-nav__toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: currentColor;
  margin: 4px 0;
  transition: all var(--transition);
}

/* --- Hero --- */
.hero {
  padding: 6rem 0 5rem;
  border-bottom: 1px solid var(--border);
}

.hero__label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 1rem;
  display: block;
}

.hero__title {
  font-family: var(--font-serif);
  font-size: clamp(2.25rem, 6vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.hero__subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  font-weight: 300;
  max-width: 700px;
  line-height: 1.7;
  margin-bottom: 2.5rem;
}

.hero__meta {
  display: flex;
  gap: 3rem;
  font-size: 0.8125rem;
}

.hero__meta-item {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.hero__meta-label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.hero__meta-value {
  color: var(--text-primary);
  font-weight: 500;
}

/* --- Section Headers --- */
.section-label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 0.75rem;
  display: block;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin-bottom: 3rem;
  line-height: 1.7;
}

/* --- Equation Blocks --- */
.equation {
  font-family: var(--font-mono);
  font-size: 1rem;
  background: var(--bg-tertiary);
  border-left: 3px solid var(--accent);
  padding: 1.5rem 2rem;
  margin: 2rem 0;
  line-height: 1.8;
  color: var(--text-primary);
  border-radius: var(--radius);
}

.equation__label {
  font-size: 0.6875rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.75rem;
  display: block;
}

.equation__detail {
  color: var(--text-muted);
  font-size: 0.875rem;
  padding-left: 1rem;
}

/* --- Notation Table --- */
.notation-table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  font-size: 0.9375rem;
}

.notation-table th {
  text-align: left;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.75rem 1rem;
  border-bottom: 2px solid var(--border-strong);
}

.notation-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.notation-table .symbol {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  color: var(--accent);
  font-weight: 500;
}

.notation-table .name {
  font-weight: 500;
  color: var(--text-primary);
}

.notation-table .desc {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* --- Programme Cards --- */
.programme-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.programme-card {
  background: var(--bg-primary);
  padding: 2rem;
  position: relative;
  transition: background var(--transition);
  text-decoration: none;
  color: inherit;
  display: block;
}

.programme-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 0;
  background: var(--accent);
  transition: height 0.3s ease;
}

.programme-card:hover {
  background: var(--bg-secondary);
}

.programme-card:hover::before {
  height: 100%;
}

.programme-card__index {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  display: block;
}

.programme-card__title {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  transition: color var(--transition);
}

.programme-card:hover .programme-card__title {
  color: var(--accent);
}

.programme-card__desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 0.75rem;
}

.programme-card__count {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* --- Paper Cards --- */
.paper-card {
  display: block;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
  color: inherit;
  transition: background var(--transition);
}

.paper-card:first-child {
  border-top: 1px solid var(--border);
}

.paper-card:hover {
  background: var(--bg-secondary);
  padding-left: 1rem;
  padding-right: 1rem;
  margin-left: -1rem;
  margin-right: -1rem;
}

.paper-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 0.5rem;
  font-size: 0.8125rem;
}

.paper-card__date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.paper-card__title {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 0.25rem;
  color: var(--text-primary);
  transition: color var(--transition);
}

.paper-card:hover .paper-card__title {
  color: var(--accent);
}

.paper-card__subtitle {
  font-style: italic;
  color: var(--text-muted);
  font-size: 0.9375rem;
  margin-bottom: 0.25rem;
}

.paper-card__authors {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.paper-card__abstract {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-top: 0.5rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* --- Status Badges --- */
.status {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius);
  display: inline-block;
}

.status--peer-review {
  background: var(--status-peer-bg);
  color: var(--status-peer-fg);
}

.status--published {
  background: var(--status-published-bg);
  color: var(--status-published-fg);
}

.status--preprint {
  background: var(--status-preprint-bg);
  color: var(--status-preprint-fg);
}

.status--working {
  background: var(--bg-tertiary);
  color: var(--text-muted);
}

.status--with-editor {
  background: rgba(230, 81, 0, 0.12);
  color: #e65100;
}

.status--submitted {
  background: rgba(21, 101, 192, 0.12);
  color: #1565c0;
}

[data-theme="dark"] .status--with-editor {
  background: rgba(230, 81, 0, 0.15);
  color: #ff9800;
}

[data-theme="dark"] .status--submitted {
  background: rgba(21, 101, 192, 0.15);
  color: #64b5f6;
}

/* --- Tag Pills --- */
.tag {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  padding: 0.2rem 0.5rem;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: var(--radius);
  display: inline-block;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* --- Citation Block --- */
.citation-block {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  background: var(--bg-secondary);
  border-left: 3px solid var(--accent);
  padding: 1rem 1.5rem;
  line-height: 1.7;
  color: var(--text-secondary);
  border-radius: var(--radius);
}

.citation-block em {
  color: var(--text-primary);
  font-style: italic;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius);
  text-decoration: none;
  transition: all var(--transition);
  cursor: pointer;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-secondary);
}

.btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.btn--primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn--primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #fff;
}

.btn--small {
  padding: 0.4rem 0.75rem;
  font-size: 0.8125rem;
}

/* --- Person Cards --- */
.person-card {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.5rem;
  align-items: start;
  padding: 2rem 0;
  border-bottom: 1px solid var(--border);
}

.person-card:first-child {
  border-top: 1px solid var(--border);
}

.person-card__avatar {
  width: 64px;
  height: 64px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 1.25rem;
  color: var(--accent);
  flex-shrink: 0;
}

.person-card__role {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.25rem;
}

.person-card__name {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.person-card__affiliation {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.person-card__bio {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: none;
}

.person-card__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 0.75rem;
}

.person-card__links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  transition: color var(--transition);
}

.person-card__links a:hover {
  color: var(--accent);
}

/* --- Paper Detail Page --- */
.paper-detail {
  padding: 3rem 0 5rem;
}

.paper-detail__back {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
  margin-bottom: 2rem;
  transition: color var(--transition);
}

.paper-detail__back:hover {
  color: var(--accent);
}

.paper-detail__header {
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2rem;
}

.paper-detail__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1.5rem;
}

.paper-detail__date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.paper-detail__programme {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background: var(--accent-light);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius);
}

.paper-detail__title {
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 0.5rem;
}

.paper-detail__subtitle {
  font-family: var(--font-serif);
  font-style: italic;
  color: var(--text-secondary);
  font-size: 1.0625rem;
  margin-bottom: 0.75rem;
  line-height: 1.5;
}

.paper-detail__authors {
  color: var(--text-secondary);
  font-size: 1rem;
}

.paper-detail__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border);
}

.paper-detail__section {
  padding: 2rem 0;
  border-bottom: 1px solid var(--border);
}

.paper-detail__section-title {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 1rem;
}

.paper-detail__abstract {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.8;
  max-width: none;
}

/* --- Programme Detail Page --- */
.programme-detail {
  padding: 3rem 0 5rem;
}

.programme-detail__header {
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2rem;
}

.programme-detail__index {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  display: block;
}

.programme-detail__title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  margin-bottom: 1rem;
}

.programme-detail__desc {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  max-width: none;
  line-height: 1.7;
}

/* --- Featured Papers (compact) --- */
.featured-papers {
  display: grid;
  gap: 0;
}

/* --- Footer --- */
.site-footer {
  padding: 3rem 0;
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.site-footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 2rem;
}

.site-footer__brand {
  font-family: var(--font-serif);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.site-footer__copy {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.site-footer__links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  font-size: 0.8125rem;
}

.site-footer__links a {
  color: var(--text-muted);
  transition: color var(--transition);
}

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

/* --- Theme Toggle --- */
.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  padding: 0.35rem 0.5rem;
  color: var(--text-muted);
  font-size: 0.875rem;
  line-height: 1;
  transition: color var(--transition), border-color var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-left: 1rem;
  flex-shrink: 0;
}

.theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent);
}

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

[data-theme="light"] .theme-toggle .icon-moon,
:root:not([data-theme]) .theme-toggle .icon-moon { display: block; }

[data-theme="dark"] .theme-toggle .icon-sun { display: block; }

/* Smooth theme transition on key elements */
html[data-theme] body,
html[data-theme] .site-nav,
html[data-theme] .site-footer,
html[data-theme] section,
html[data-theme] .section--alt,
html[data-theme] .programme-card,
html[data-theme] .equation,
html[data-theme] .citation-block,
html[data-theme] .person-card__avatar,
html[data-theme] .btn {
  transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .site-nav__toggle {
    display: block;
  }

  .site-nav__links {
    display: none;
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--mobile-nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 1rem 2rem;
    gap: 0.75rem;
    align-items: flex-start;
  }

  .site-nav__links.is-open {
    display: flex;
  }

  .hero {
    padding: 4rem 0 3rem;
  }

  .hero__meta {
    flex-direction: column;
    gap: 1rem;
  }

  section {
    padding: 3.5rem 0;
  }

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

  .grid-2 {
    grid-template-columns: 1fr;
  }

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .person-card {
    grid-template-columns: 1fr;
  }

  .site-footer__inner {
    flex-direction: column;
  }

  .paper-detail__meta {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .paper-detail__actions {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 1.25rem;
  }
}

/* --- Selection --- */
::selection {
  background: var(--accent);
  color: #fff;
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--border-strong);
}

/* --- Focus --- */
*:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}