/* ═══════════════════════════════════════════════════════════════
   SIGMALIGN RESEARCH SITE — Style Sheet
   Brand: teal #01696F / dark teal #0C4E54 / off-white #F5F3EF
   Fonts: DM Serif Display (display) + Plus Jakarta Sans (body)
═══════════════════════════════════════════════════════════════ */

/* ── DESIGN TOKENS ─────────────────────────────────────────── */
:root,
[data-theme='light'] {
  /* Type scale */
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1rem    + 0.75vw, 1.5rem);
  --text-xl:   clamp(1.5rem,   1.2rem  + 1.25vw, 2.25rem);
  --text-2xl:  clamp(2rem,     1.2rem  + 2.5vw,  3.5rem);
  --text-3xl:  clamp(2.5rem,   1rem    + 4vw,    5rem);

  /* Spacing */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Brand palette — Sigmalign */
  --color-bg:           #F5F3EF;
  --color-surface:      #FAFAF7;
  --color-surface-2:    #FFFFFF;
  --color-border:       #D4D0C8;
  --color-divider:      #E2DFD8;
  --color-text:         #1E1B16;
  --color-text-muted:   #756E61;
  --color-text-faint:   #B0A99C;
  --color-accent:       #01696F;
  --color-accent-hover: #0C4E54;
  --color-accent-dark:  #0C4E54;
  --color-accent-light: #A8D4D6;
  --color-accent-tint:  #EBF9FA;

  /* Band colours */
  --band-calibrated: #437A22;
  --band-active:     #D19900;
  --band-reactive:   #964219;
  --band-critical:   #A12C7B;

  /* Tokens */
  --radius-sm:  0.375rem;
  --radius-md:  0.5rem;
  --radius-lg:  0.75rem;
  --radius-xl:  1rem;
  --radius-full: 9999px;
  --shadow-sm:  0 1px 2px rgba(30,27,22,0.06);
  --shadow-md:  0 4px 12px rgba(30,27,22,0.08);
  --shadow-lg:  0 12px 32px rgba(30,27,22,0.12);
  --transition: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Content widths */
  --content-narrow:  680px;
  --content-default: 960px;
  --content-wide:    1160px;

  /* Fonts */
  --font-display: 'DM Serif Display', Georgia, serif;
  --font-body:    'Plus Jakarta Sans', 'Helvetica Neue', sans-serif;
}

[data-theme='dark'] {
  --color-bg:           #171614;
  --color-surface:      #1C1B19;
  --color-surface-2:    #222120;
  --color-border:       #393836;
  --color-divider:      #2C2B29;
  --color-text:         #CDCCCA;
  --color-text-muted:   #797876;
  --color-text-faint:   #5A5957;
  --color-accent:       #4F98A3;
  --color-accent-hover: #227F8B;
  --color-accent-dark:  #1A626B;
  --color-accent-light: #313B3B;
  --color-accent-tint:  #1A2D2E;
  --shadow-sm:  0 1px 2px rgba(0,0,0,0.25);
  --shadow-md:  0 4px 12px rgba(0,0,0,0.35);
  --shadow-lg:  0 12px 32px rgba(0,0,0,0.45);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg:           #171614;
    --color-surface:      #1C1B19;
    --color-surface-2:    #222120;
    --color-border:       #393836;
    --color-divider:      #2C2B29;
    --color-text:         #CDCCCA;
    --color-text-muted:   #797876;
    --color-text-faint:   #5A5957;
    --color-accent:       #4F98A3;
    --color-accent-hover: #227F8B;
    --color-accent-dark:  #1A626B;
    --color-accent-light: #313B3B;
    --color-accent-tint:  #1A2D2E;
  }
}

/* ── BASE RESET ────────────────────────────────────────────── */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-20);
  hanging-punctuation: first last;
}

body {
  min-height: 100dvh;
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--color-text);
  background-color: var(--color-bg);
}

img, picture, video, canvas, svg { display: block; max-width: 100%; }
ul[role='list'], ol[role='list'] { list-style: none; }
input, button, textarea, select { font: inherit; color: inherit; }

h1, h2, h3, h4, h5, h6 {
  text-wrap: balance;
  line-height: 1.15;
}

p, li, figcaption {
  text-wrap: pretty;
  max-width: 72ch;
}

::selection {
  background: color-mix(in oklab, var(--color-accent) 25%, transparent);
  color: var(--color-text);
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color var(--transition);
}
a:hover { color: var(--color-accent-hover); }

button {
  cursor: pointer;
  background: none;
  border: none;
}

table { border-collapse: collapse; width: 100%; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ── LAYOUT ────────────────────────────────────────────────── */
.container {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: clamp(var(--space-5), 5vw, var(--space-16));
}

.section {
  padding-block: clamp(var(--space-12), 8vw, var(--space-24));
}

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

/* ── SCROLL FADE ───────────────────────────────────────────── */
.fade-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.55s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.55s cubic-bezier(0.16, 1, 0.3, 1);
}
.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── HEADER ────────────────────────────────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--color-bg) 92%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition),
              transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.site-header.header--scrolled {
  border-bottom-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.site-header.header--hidden {
  transform: translateY(-100%);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  height: 64px;
}

/* Logo */
.logo {
  flex-shrink: 0;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
}

.logo-wordmark {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--color-text);
  text-decoration: none;
}

/* Nav */
.nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav a {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  letter-spacing: 0.01em;
  transition: color var(--transition);
}

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

/* Theme toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  transition: color var(--transition), background var(--transition);
}
.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-divider);
}

/* ── BUTTONS ───────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  letter-spacing: 0.01em;
  transition: background var(--transition), color var(--transition),
              box-shadow var(--transition), transform var(--transition);
  cursor: pointer;
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}
.btn-primary:hover {
  background: var(--color-accent-hover);
  color: #fff;
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}
.btn-ghost:hover {
  color: var(--color-text);
  border-color: var(--color-text-muted);
  background: var(--color-surface);
}

.btn-primary-invert {
  background: #fff;
  color: var(--color-accent-dark);
  font-weight: 600;
}
.btn-primary-invert:hover {
  background: var(--color-accent-tint);
  color: var(--color-accent-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}

/* ── HERO ──────────────────────────────────────────────────── */
.hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(var(--space-20), 12vw, var(--space-32));
  border-bottom: 1px solid var(--color-border);
}

.hero-grid-overlay {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--color-border) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-border) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: 0.35;
  pointer-events: none;
  mask-image: linear-gradient(to bottom, transparent 0%, rgba(0,0,0,0.3) 30%, rgba(0,0,0,0.3) 70%, transparent 100%);
}

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

.hero-label {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-6);
}

.hero-heading {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--space-6);
  max-width: 18ch;
}

.hero-heading em {
  font-style: italic;
  color: var(--color-accent);
}

.hero-body {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 58ch;
  margin-bottom: var(--space-8);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-12);
}

.dimension-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
}

.dim-badge {
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
}

.dim-sep {
  color: var(--color-text-faint);
}

/* ── SECTION LABELS & HEADINGS ─────────────────────────────── */
.section-label {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-4);
}

.section-heading {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--space-10);
  max-width: 28ch;
}

/* ── TWO-COL LAYOUT ────────────────────────────────────────── */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: start;
  margin-bottom: var(--space-12);
}

/* ── PROSE ─────────────────────────────────────────────────── */
.prose p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-5);
  line-height: 1.75;
}
.prose p:last-child { margin-bottom: 0; }

/* ── STUDY STAT CARDS ──────────────────────────────────────── */
.study-card-group {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}

.study-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-align: center;
}

.section-alt .study-card {
  background: var(--color-surface-2);
}

.study-card-value {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  color: var(--color-accent);
  line-height: 1;
  margin-bottom: var(--space-2);
}

.study-card-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: 500;
  letter-spacing: 0.04em;
}

/* ── ARMS GRID ─────────────────────────────────────────────── */
.arms-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
}

.arm-card {
  background: var(--color-accent-tint);
  border: 1px solid color-mix(in oklab, var(--color-accent) 20%, transparent);
  border-radius: var(--radius-lg);
  padding: var(--space-6) var(--space-8);
}

[data-theme='dark'] .arm-card {
  background: var(--color-accent-tint);
  border-color: var(--color-border);
}

.arm-label {
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: var(--space-3);
}

.arm-card p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: 1.7;
}

/* ── FULL BLEED DIVIDER ─────────────────────────────────────── */
.full-bleed-divider {
  width: 100%;
  height: 1px;
  background: var(--color-border);
}

/* ── METHODOLOGY ───────────────────────────────────────────── */
.method-intro {
  margin-bottom: var(--space-10);
  max-width: var(--content-narrow);
}

.method-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}

.method-block {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6) var(--space-8);
}

.method-block-title {
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-4);
  letter-spacing: 0.02em;
}

.method-block p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.75;
  margin-bottom: var(--space-3);
}
.method-block p:last-child { margin-bottom: 0; }

.method-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.method-list li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
  padding-left: var(--space-4);
  border-left: 2px solid var(--color-accent);
}

.method-list-label {
  display: block;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-1);
}

/* ── BAND TABLE ─────────────────────────────────────────────── */
.band-table-wrap {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  overflow-x: auto;
}

.band-table-label {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-5);
}

.band-table th {
  text-align: left;
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  white-space: nowrap;
}

.band-table td {
  padding: var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  border-bottom: 1px solid var(--color-divider);
  vertical-align: top;
  line-height: 1.6;
}

.band-table tr:last-child td { border-bottom: none; }

.band-chip {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.band-calibrated {
  background: color-mix(in oklab, #437A22 12%, transparent);
  color: #437A22;
}
.band-active {
  background: color-mix(in oklab, #D19900 12%, transparent);
  color: #a07800;
}
.band-reactive {
  background: color-mix(in oklab, #964219 12%, transparent);
  color: #964219;
}
.band-critical {
  background: color-mix(in oklab, #A12C7B 12%, transparent);
  color: #A12C7B;
}

[data-theme='dark'] .band-calibrated { background: rgba(67,122,34,0.18); color: #6daa45; }
[data-theme='dark'] .band-active     { background: rgba(209,153,0,0.18); color: #e8af34; }
[data-theme='dark'] .band-reactive   { background: rgba(150,66,25,0.18); color: #bb653b; }
[data-theme='dark'] .band-critical   { background: rgba(161,44,123,0.18); color: #d163a7; }

.band-note {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-5);
  max-width: none;
  line-height: 1.65;
  font-style: italic;
}

/* ── FOUNDER ───────────────────────────────────────────────── */
.founder-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--space-12);
  align-items: start;
}

.founder-identity {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.founder-photo {
  width: 120px;
  height: 120px;
  border-radius: var(--radius-full);
  object-fit: cover;
  object-position: center top;
  border: 3px solid var(--color-border);
  flex-shrink: 0;
  box-shadow: var(--shadow-md);
}

.founder-name {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.founder-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-1);
}

.founder-org {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-1);
}

.founder-location {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

.founder-contact-line {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-top: var(--space-6);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
}

.contact-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-accent);
  text-decoration: none;
}
.contact-link:hover { color: var(--color-accent-hover); }

.contact-sep {
  color: var(--color-text-faint);
}

/* ── COLLABORATE ───────────────────────────────────────────── */
.section-collaborate {
  background: var(--color-accent-dark);
  padding-block: clamp(var(--space-16), 10vw, var(--space-32));
}

.section-collaborate .section-heading {
  color: #fff;
}

.collab-layout {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: var(--space-12);
  align-items: start;
}

.collab-body p {
  color: rgba(255,255,255,0.75);
  margin-bottom: var(--space-5);
  line-height: 1.75;
}

.collab-list {
  margin: var(--space-4) 0 var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.collab-list li {
  color: rgba(255,255,255,0.75);
  font-size: var(--text-sm);
  padding-left: var(--space-5);
  position: relative;
  line-height: 1.6;
}

.collab-list li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--color-accent-light);
}

.collab-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  backdrop-filter: blur(8px);
}

.collab-card-title {
  font-size: var(--text-sm);
  font-weight: 700;
  color: #fff;
  margin-bottom: var(--space-3);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.collab-card-body {
  color: rgba(255,255,255,0.65);
  font-size: var(--text-sm);
  line-height: 1.7;
  margin-bottom: var(--space-6);
  max-width: none;
}

.collab-card-detail {
  margin-top: var(--space-5);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-xs);
  color: rgba(255,255,255,0.45);
}

.collab-email {
  color: var(--color-accent-light);
  text-decoration: none;
}
.collab-email:hover { color: #fff; }

/* ── FOOTER ────────────────────────────────────────────────── */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-block: var(--space-12);
}

.footer-inner {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-10);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.footer-wordmark {
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-text-muted);
  font-weight: 700;
}

.footer-tagline {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 32ch;
  font-style: italic;
}

.footer-meta {
  text-align: right;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-meta p {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  max-width: none;
}

.footer-meta a {
  color: var(--color-text-muted);
  text-decoration: none;
}
.footer-meta a:hover { color: var(--color-accent); }

.footer-legal {
  color: var(--color-text-faint) !important;
  font-size: 0.7rem !important;
  font-style: italic;
  margin-top: var(--space-2);
}

/* ── RESPONSIVE ─────────────────────────────────────────────── */
@media (max-width: 900px) {
  .two-col,
  .arms-grid,
  .method-grid,
  .collab-layout {
    grid-template-columns: 1fr;
  }

  .founder-layout {
    grid-template-columns: 1fr;
  }

  .founder-identity {
    flex-direction: row;
    align-items: center;
  }

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

  .footer-inner {
    flex-direction: column;
  }

  .footer-meta {
    text-align: left;
  }
}

@media (max-width: 640px) {
  .nav {
    display: none;
  }

  .hero-heading {
    font-size: clamp(1.75rem, 1rem + 4vw, 2.5rem);
  }

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

  .collab-layout {
    grid-template-columns: 1fr;
  }

  .hero-actions {
    flex-direction: column;
    align-items: flex-start;
  }

  .founder-identity {
    flex-direction: column;
    align-items: flex-start;
  }
}