/* ==========================================================================
   Scimba showcase website — design system
   ========================================================================== */

:root {
  /* Palette */
  --color-bg: #ffffff;
  --color-bg-alt: #f6f7fb;
  --color-bg-dark: #0f1530;
  --color-bg-dark-alt: #161d42;
  --color-text: #1c2333;
  --color-text-muted: #5b6378;
  --color-text-on-dark: #eef0fb;
  --color-text-on-dark-muted: #aab0d6;
  --color-primary: #3454d1;
  --color-primary-dark: #233a9e;
  --color-primary-light: #5d79e6;
  --color-accent: #18b4a8;
  --color-accent-dark: #0e8c82;
  --color-warm: #f0a430;
  --color-warm-dark: #d3811b;
  --color-border: #e3e6f0;
  --color-card-bg: #ffffff;
  --color-jax: #8579ab;
  --color-torch: #c97a3f;

  /* Type */
  --font-sans:
    -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono:
    "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;

  /* Layout */
  --max-width: 1180px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --shadow-sm: 0 1px 3px rgba(20, 25, 60, 0.08);
  --shadow-md: 0 8px 24px rgba(20, 25, 60, 0.10);
  --shadow-lg: 0 18px 48px rgba(20, 25, 60, 0.16);
  --nav-height: 68px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

a:hover {
  color: var(--color-primary-dark);
}

code {
  font-family: var(--font-mono);
  background: var(--color-bg-alt);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.92em;
}

pre {
  font-family: var(--font-mono);
  background: var(--color-bg-alt);
  color: var(--color-text);
  padding: 1.1rem 1.3rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  overflow-x: auto;
  font-size: 0.85rem;
  line-height: 1.55;
}

pre code {
  background: none;
  padding: 0;
}

/* ── Displayed equations (KaTeX) ──────────────────────────────────────── */

.equation {
  color: var(--color-text-muted);
  text-align: center;
  margin: 0.9rem 0 1.3rem;
  padding: 0.7rem 0.5rem;
  overflow-x: auto;
}

.equation .katex {
  font-size: 1.05em;
}

/* ── Code blocks with copy button (Pygments-highlighted) ─────────────── */

.code-block {
  position: relative;
}

.code-block pre {
  margin: 0;
  padding-right: 3.6rem;
}

.copy-btn {
  position: absolute;
  top: 0.6rem;
  right: 0.6rem;
  font-family: var(--font-sans);
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.6rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.code-block:hover .copy-btn,
.copy-btn:focus-visible {
  opacity: 1;
}

.copy-btn:hover {
  color: var(--color-primary);
  border-color: var(--color-primary-light);
}

.copy-btn.is-copied {
  opacity: 1;
  color: var(--color-accent-dark);
  border-color: var(--color-accent);
}

/* Pygments token colors, scoped to highlighted code blocks. */
.code-block .hl .c, .code-block .hl .c1, .code-block .hl .cm { color: #6b7280; font-style: italic; }
.code-block .hl .k, .code-block .hl .kc, .code-block .hl .kd,
.code-block .hl .kn, .code-block .hl .kr, .code-block .hl .ow { color: #233a9e; font-weight: 600; }
.code-block .hl .kt { color: #902000; }
.code-block .hl .nb, .code-block .hl .bp { color: #0e8c82; }
.code-block .hl .nc, .code-block .hl .nn { color: #0e84b5; font-weight: 600; }
.code-block .hl .nf, .code-block .hl .fm { color: #06287e; }
.code-block .hl .nd { color: #5b6378; font-weight: 600; }
.code-block .hl .s, .code-block .hl .s1, .code-block .hl .s2,
.code-block .hl .sa, .code-block .hl .sb, .code-block .hl .sc,
.code-block .hl .sd, .code-block .hl .se, .code-block .hl .si { color: #4070a0; }
.code-block .hl .m, .code-block .hl .mf, .code-block .hl .mi,
.code-block .hl .mh, .code-block .hl .mo, .code-block .hl .mb { color: #18b4a8; }
.code-block .hl .o { color: #5b6378; }
.code-block .hl .nv, .code-block .hl .vm { color: #6c4cd6; }
.code-block .hl .err { color: #c0392b; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ── Navbar ───────────────────────────────────────────────────────────── */

.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  background-color: rgba(255, 255, 255, 0.75);
  background-image: linear-gradient(rgba(255, 255, 255, 0.82), rgba(255, 255, 255, 0.82)),
    url("/static/img/flow-field.webp");
  background-size: cover, cover;
  background-position: center, center 75%;
  background-repeat: no-repeat, no-repeat;
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: background-color 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.navbar.is-scrolled {
  background-color: rgba(255, 255, 255, 0.92);
  border-bottom-color: var(--color-border);
  box-shadow: 0 10px 28px rgba(20, 25, 60, 0.08);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: -0.01em;
  color: var(--color-text);
}

.brand:hover {
  color: var(--color-text);
}

.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: var(--color-bg-dark);
  background-image: url("/static/img/logo-mark.svg");
  background-repeat: no-repeat;
  background-position: 38% 60%;
  background-size: 78%;
  display: inline-flex;
  flex: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.9rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links > li {
  position: relative;
}

.nav-links a:not(.btn) {
  position: relative;
  color: var(--color-text-muted);
  font-weight: 600;
  font-size: 0.95rem;
  padding-bottom: 0.3rem;
}

.nav-links a:not(.btn)::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--color-warm);
  transition: right 0.18s ease;
}

.nav-links a:not(.btn):hover,
.nav-links a.active {
  color: var(--color-primary);
}

.nav-links a:not(.btn):hover::after,
.nav-links a.active::after {
  right: 0;
}

.nav-dropdown {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  cursor: default;
}

.nav-dropdown-menu {
  position: absolute;
  top: calc(100% + 0.9rem);
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-md);
  min-width: 190px;
  padding: 0.4rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.15s ease, transform 0.15s ease;
}

.nav-dropdown:hover .nav-dropdown-menu,
.nav-dropdown:focus-within .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.nav-dropdown-menu a {
  display: block;
  padding: 0.55rem 0.75rem;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text);
}

.nav-dropdown-menu a:hover {
  background: var(--color-bg-alt);
  color: var(--color-primary);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.4rem;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  margin: 4px 0;
  border-radius: 2px;
}

/* ── Buttons ──────────────────────────────────────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.3rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.92rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: #fff;
  box-shadow: var(--shadow-md);
}

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

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

.btn-on-dark {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.25);
  color: var(--color-text-on-dark);
}

.btn-on-dark:hover {
  background: rgba(255, 255, 255, 0.16);
  color: #fff;
}

/* ── Hero ─────────────────────────────────────────────────────────────── */

.hero {
  position: relative;
  background: var(--color-bg);
  color: var(--color-text);
  padding: 5rem 0 0;
  overflow: hidden;
}

/* ── PDE field motif — one base graphic, recolored per section ──────── */

.backend-card::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  -webkit-mask-image: url("/static/img/pde-field.svg");
  mask-image: url("/static/img/pde-field.svg");
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;
  -webkit-mask-mode: alpha;
  mask-mode: alpha;
}

.hero-visual {
  height: 230px;
  margin-top: 3rem;
  background-image: url("/static/img/flow-field.webp");
  background-size: cover;
  background-position: center 60%;
  background-repeat: no-repeat;
}

.hero > * {
  position: relative;
  z-index: 1;
}

.hero-eyebrow {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent-dark);
  background: rgba(24, 180, 168, 0.1);
  border: 1px solid rgba(24, 180, 168, 0.3);
  padding: 0.3rem 0.8rem;
  border-radius: 999px;
  margin-bottom: 1.4rem;
}

.hero h1 {
  font-size: clamp(2.2rem, 4.5vw, 3.4rem);
  line-height: 1.12;
  margin: 0 0 1.1rem;
  max-width: 18ch;
}

.hero p.lead {
  font-size: 1.18rem;
  color: var(--color-text-muted);
  max-width: 56ch;
  margin: 0 0 2.2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 2.6rem;
}

.pill {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 0.35rem 0.85rem;
}

/* ── Sections ─────────────────────────────────────────────────────────── */

.section {
  padding: 4.5rem 0;
}

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

.section-header {
  max-width: 62ch;
  margin: 0 0 2.6rem;
}

.section-eyebrow {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 0.6rem;
  display: block;
}

.section-header h2 {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  margin: 0 0 0.7rem;
}

.section-header p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  margin: 0;
}

/* ── Cards / grids ────────────────────────────────────────────────────── */

.grid {
  display: grid;
  gap: 1.5rem;
}

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

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

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.7rem;
  box-shadow: var(--shadow-sm);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.card-icon {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  background: rgba(52, 84, 209, 0.1);
  color: var(--color-primary);
  margin-bottom: 1rem;
}

.card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.08rem;
}

.card p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.card-link {
  display: block;
  color: inherit;
}

.card-link h3 {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.card-link-arrow {
  color: var(--color-primary);
  transition: transform 0.15s ease;
}

.card-link:hover .card-link-arrow {
  transform: translateX(3px);
}

/* ── Approximation method groups ──────────────────────────────────────── */

.approx-group {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-top: 3px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: 1.6rem 1.7rem 1.8rem;
  box-shadow: var(--shadow-sm);
}

.approx-group--linear {
  border-top-color: var(--color-accent);
}

.approx-group--hybrid {
  border-top-color: var(--color-warm);
}

.approx-group-title {
  font-size: 1.05rem;
  margin: 0 0 1.1rem;
  color: var(--color-primary-dark);
}

.approx-group--linear .approx-group-title {
  color: var(--color-accent-dark);
}

.approx-group--hybrid .approx-group-title {
  color: var(--color-warm-dark);
}

.approx-items {
  display: flex;
  flex-direction: column;
}

.approx-item {
  padding: 0.85rem 0;
  border-top: 1px solid var(--color-border);
}

.approx-item:first-child {
  border-top: none;
  padding-top: 0;
}

.approx-item:last-child {
  padding-bottom: 0;
}

.approx-item h4 {
  margin: 0 0 0.25rem;
  font-size: 0.95rem;
}

.approx-item p {
  margin: 0;
  font-size: 0.86rem;
  color: var(--color-text-muted);
}

/* ── Backend cards (Code landing) ────────────────────────────────────── */

.backend-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.8rem;
}

.backend-card {
  border-radius: var(--radius-lg);
  padding: 2.4rem;
  color: #fff;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.backend-card.jax {
  background: var(--color-jax);
}

.backend-card.torch {
  background: var(--color-torch);
}

.backend-card::before {
  -webkit-mask-position: 88% 75%;
  mask-position: 88% 75%;
  -webkit-mask-size: 75%;
  mask-size: 75%;
  background: rgba(255, 255, 255, 0.85);
  opacity: 0.2;
}

.backend-card > * {
  position: relative;
  z-index: 1;
}

.backend-card .badge {
  display: inline-block;
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.3rem 0.7rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.18);
  margin-bottom: 1.1rem;
}

.backend-card h3 {
  font-size: 1.55rem;
  margin: 0 0 0.7rem;
}

.backend-card p {
  color: rgba(255, 255, 255, 0.88);
  font-size: 0.98rem;
  max-width: 42ch;
}

.backend-card .links {
  margin-top: 1.6rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.backend-card .links a {
  color: #fff;
  font-weight: 600;
  font-size: 0.92rem;
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}

.backend-card .links a:hover {
  color: #fff;
  opacity: 0.8;
}

/* ── Gallery ──────────────────────────────────────────────────────────── */

.gallery-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 2.2rem;
}

.filter-btn {
  font-size: 0.86rem;
  font-weight: 600;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background: var(--color-card-bg);
  color: var(--color-text-muted);
  cursor: pointer;
}

.filter-btn.active,
.filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 1.4rem;
}

.gallery-card {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
  background: var(--color-card-bg);
  box-shadow: var(--shadow-sm);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  display: block;
}

.gallery-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.gallery-thumb {
  aspect-ratio: 16 / 11;
  width: 100%;
  background: var(--color-bg-alt);
  overflow: hidden;
}

.gallery-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.gallery-body {
  padding: 1.1rem 1.2rem 1.3rem;
}

.gallery-tag {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-accent-dark);
}

.gallery-body h3 {
  font-size: 1rem;
  margin: 0.35rem 0 0.4rem;
  color: var(--color-text);
}

.gallery-body p {
  margin: 0;
  font-size: 0.88rem;
  color: var(--color-text-muted);
}

/* ── Team ─────────────────────────────────────────────────────────────── */

.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.6rem;
}

.team-card {
  text-align: center;
  padding: 2rem 1.3rem;
}

.team-avatar {
  width: 92px;
  height: 92px;
  border-radius: 50%;
  margin: 0 auto 1.1rem;
  background: var(--color-bg-alt);
  border: 2px dashed var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 1.6rem;
  overflow: hidden;
}

.team-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.team-card h3 {
  margin: 0 0 0.2rem;
  font-size: 1.02rem;
}

.team-role {
  font-size: 0.85rem;
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.team-card p.bio {
  font-size: 0.86rem;
  color: var(--color-text-muted);
  margin: 0;
}

.team-link {
  display: inline-block;
  margin-top: 0.5rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
}

.team-link:hover {
  text-decoration: underline;
}

.todo-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: #9a5b00;
  background: #fff2d9;
  border: 1px solid #f2cf8a;
  border-radius: 6px;
  padding: 0.15rem 0.45rem;
  margin-top: 0.5rem;
}

/* ── Projects ─────────────────────────────────────────────────────────── */

.project-list {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.project-card {
  display: flex;
  gap: 1.4rem;
  align-items: flex-start;
  padding: 1.6rem 1.8rem;
}

.project-year {
  flex: 0 0 auto;
  width: 64px;
  font-weight: 800;
  font-size: 1.05rem;
  color: var(--color-primary);
}

.project-body h3 {
  margin: 0 0 0.4rem;
  font-size: 1.08rem;
}

.project-authors {
  font-size: 0.86rem;
  color: var(--color-text-muted);
  margin: 0 0 0.6rem;
}

.project-body p.abstract {
  margin: 0 0 0.7rem;
  font-size: 0.93rem;
  color: var(--color-text-muted);
}

.project-links {
  display: flex;
  gap: 1rem;
  font-size: 0.86rem;
  font-weight: 600;
}

/* ── CTA banner ───────────────────────────────────────────────────────── */

.cta-banner {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  color: var(--color-text);
  padding: 3rem 3rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  flex-wrap: wrap;
}

.cta-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: url("/static/img/flow-field.webp");
  background-size: cover;
  background-position: center 65%;
  background-repeat: no-repeat;
  opacity: 0.22;
}

.cta-banner > * {
  position: relative;
  z-index: 1;
}

.cta-banner h2 {
  margin: 0 0 0.4rem;
  font-size: 1.5rem;
}

.cta-banner p {
  margin: 0;
  color: var(--color-text-muted);
}

/* ── Footer ───────────────────────────────────────────────────────────── */

.site-footer {
  background: var(--color-bg-dark);
  color: var(--color-text-on-dark-muted);
  padding: 3.2rem 0 2rem;
  margin-top: 3rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2.2rem;
}

.footer-grid h4 {
  color: var(--color-text-on-dark);
  font-size: 0.85rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin: 0 0 0.9rem;
}

.footer-grid ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.footer-grid a {
  color: var(--color-text-on-dark-muted);
  font-size: 0.9rem;
}

.footer-grid a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 1.4rem;
  font-size: 0.84rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.6rem;
}

/* ── Page header (non-home pages) ────────────────────────────────────── */

.page-header {
  position: relative;
  overflow: hidden;
  background: var(--color-bg-alt);
  color: var(--color-text);
  padding: 3.4rem 0 3rem;
  border-bottom: 1px solid var(--color-border);
}

.page-header::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: url("/static/img/flow-field.webp");
  background-size: cover;
  background-position: center 70%;
  background-repeat: no-repeat;
  opacity: 0.16;
}

.page-header > * {
  position: relative;
  z-index: 1;
}

.page-header .section-eyebrow {
  color: var(--color-accent-dark);
}

.page-header h1 {
  margin: 0 0 0.7rem;
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
}

.page-header p {
  color: var(--color-text-muted);
  max-width: 60ch;
  margin: 0;
  font-size: 1.05rem;
}

/* ── Module detail pages (e.g. domains & meshes) ─────────────────────── */

.detail-back {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.92rem;
  font-weight: 600;
}

.detail-diagram {
  display: block;
  width: auto;
  max-width: 620px;
  height: auto;
  max-height: 420px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: #ffffff;
  box-shadow: var(--shadow-sm);
  padding: 0.5rem;
  margin: 0 auto 0.8rem;
}

.detail-diagram-caption {
  color: var(--color-text-muted);
  font-size: 0.92rem;
  margin: 0 0 2.6rem;
}

.detail-row {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 2.4rem;
  align-items: start;
  margin-bottom: 3rem;
}

.detail-row h3 {
  font-size: 1.25rem;
  margin: 0 0 0.7rem;
}

.detail-row p {
  color: var(--color-text-muted);
  margin: 0 0 0.8rem;
  overflow-wrap: break-word;
}

.detail-row p:last-child {
  margin-bottom: 0;
}

.detail-row pre {
  margin: 0;
}

.detail-row.text-only {
  grid-template-columns: 1fr;
  max-width: 68ch;
}

/* ── Responsive ───────────────────────────────────────────────────────── */

@media (max-width: 900px) {
  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .detail-row {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
}

@media (max-width: 720px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    align-items: flex-start;
    padding: 1.2rem 1.5rem 1.6rem;
    gap: 1rem;
    transform: translateY(-130%);
    transition: transform 0.2s ease;
  }

  .nav-links.open {
    transform: translateY(0);
  }

  .nav-dropdown-menu {
    position: static;
    transform: none;
    opacity: 1;
    visibility: visible;
    box-shadow: none;
    border: none;
    padding-left: 0.6rem;
    display: none;
  }

  .nav-dropdown.open .nav-dropdown-menu {
    display: block;
  }

  .nav-toggle {
    display: block;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .cta-banner {
    flex-direction: column;
    align-items: flex-start;
  }

  .project-card {
    flex-direction: column;
  }
}