/* ============================================================
   MATE network — Mathematics Anxiety: Teaching and Evidence
   Design system. Calm, evidence-led, cool palette (no cream).
   Wayfinding by colour: each pillar owns a hue via --accent.
   ============================================================ */

:root {
  /* Ink + paper (cool, never warm) */
  --ink:        #14233b;   /* primary text, dark sections */
  --ink-2:      #3f4f66;   /* secondary text */
  --ink-3:      #6b788c;   /* muted captions */
  --paper:      #f4f7f9;   /* page background, cool off-white */
  --paper-2:    #eaf0f4;   /* alt band */
  --surface:    #ffffff;   /* cards */
  --line:       #d9e1ea;   /* hairlines */
  --line-soft:  #e7edf2;

  /* Neutral brand accent (home, about, neutral pages) */
  --accent:     #155e63;   /* deep teal-blue */
  --accent-ink: #0f4a4e;   /* darker, for text on white if needed */
  --accent-wash:#e7f0f1;

  /* Type */
  --serif: "Spectral", Georgia, "Times New Roman", serif;
  --sans:  "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono:  "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  /* Scale */
  --step--1: 0.86rem;
  --step-0:  1.0625rem;
  --step-1:  clamp(1.18rem, 1.6vw, 1.35rem);
  --step-2:  clamp(1.45rem, 2.4vw, 1.85rem);
  --step-3:  clamp(1.9rem, 3.6vw, 2.55rem);
  --step-4:  clamp(2.4rem, 6vw, 4rem);

  /* Layout */
  --maxw: 1120px;
  --prose: 760px;
  --radius: 14px;
  --radius-sm: 9px;

  --shadow-1: 0 1px 2px rgba(20,35,59,.04), 0 4px 14px rgba(20,35,59,.05);
  --shadow-2: 0 8px 30px rgba(20,35,59,.10);

  --ease: cubic-bezier(.22,.61,.36,1);
}

/* Per-pillar accent. Set on <body data-pillar="..."> */
body[data-pillar="understand"] { --accent:#1d4e89; --accent-ink:#173f70; --accent-wash:#e9eff8; }
body[data-pillar="observe"]    { --accent:#0e6e6c; --accent-ink:#0a5654; --accent-wash:#e3f0ef; }
body[data-pillar="implement"]  { --accent:#2a6e47; --accent-ink:#205539; --accent-wash:#e6f1ea; }
body[data-pillar="connect"]    { --accent:#564399; --accent-ink:#453579; --accent-wash:#eeebf6; }

/* ---------- reset / base ---------- */
*,*::before,*::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce){ html{ scroll-behavior:auto; } }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: var(--step-0);
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1,h2,h3,h4 { font-family: var(--serif); font-weight: 600; line-height: 1.12; color: var(--ink); margin: 0 0 .5em; letter-spacing: -.01em; }
h1 { font-size: var(--step-3); }
h2 { font-size: var(--step-2); }
h3 { font-size: var(--step-1); line-height: 1.25; }
p { margin: 0 0 1.1em; }
a { color: var(--accent); text-decoration-color: color-mix(in srgb, var(--accent) 35%, transparent); text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--accent); }
strong { font-weight: 600; }
img, svg { max-width: 100%; }
hr { border: 0; border-top: 1px solid var(--line); margin: 2.4rem 0; }

:focus-visible { outline: 3px solid color-mix(in srgb, var(--accent) 55%, white); outline-offset: 2px; border-radius: 4px; }

.skip-link {
  position: absolute; left: -999px; top: 0; background: var(--ink); color: #fff;
  padding: .7rem 1.1rem; z-index: 200; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------- layout helpers ---------- */
.wrap { width: min(var(--maxw), 100% - 2.5rem); margin-inline: auto; }
.prose { max-width: var(--prose); }
.section { padding: clamp(3rem, 7vw, 5.5rem) 0; }
.section--tight { padding: clamp(2rem, 5vw, 3.25rem) 0; }
.band { background: var(--surface); border-block: 1px solid var(--line); }
.center { text-align: center; }

.eyebrow {
  font-family: var(--mono); font-size: var(--step--1); font-weight: 500;
  letter-spacing: .16em; text-transform: uppercase; color: var(--accent);
  display: inline-flex; align-items: center; gap: .55rem; margin: 0 0 1rem;
}
.eyebrow::before { content:""; width: 1.6rem; height: 2px; background: var(--accent); display:inline-block; }

.lede { font-size: var(--step-1); line-height: 1.5; color: var(--ink-2); }

/* ---------- header / nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; gap: 1rem; min-height: 68px; }
.brand { display: inline-flex; align-items: center; gap: .65rem; text-decoration: none; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand .mark { width: 30px; height: 30px; flex: none; }
.brand .word { font-family: var(--serif); font-weight: 600; font-size: 1.18rem; letter-spacing: .02em; }
.brand .sub { font-family: var(--mono); font-size: .62rem; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); display:block; margin-top:-2px; }

.nav-links { display: flex; align-items: center; gap: .35rem; list-style: none; margin: 0; padding: 0; }
.nav-links a {
  display: inline-block; padding: .5rem .7rem; border-radius: 8px;
  color: var(--ink-2); text-decoration: none; font-size: .96rem; font-weight: 500;
}
.nav-links a:hover { color: var(--ink); background: var(--paper-2); }
.nav-links a[aria-current="page"] { color: var(--ink); }
.nav-links a[aria-current="page"]::after { content:""; display:block; height:2px; margin-top:3px; border-radius:2px; background: var(--accent); }

.nav-toggle { display: none; background: none; border: 1px solid var(--line); border-radius: 9px; padding: .5rem .6rem; cursor: pointer; color: var(--ink); }
.nav-toggle svg { display: block; }

@media (max-width: 860px) {
  .nav-toggle { display: inline-flex; }
  .nav-links {
    position: absolute; left: 0; right: 0; top: 100%;
    flex-direction: column; align-items: stretch; gap: .15rem;
    background: var(--surface); border-bottom: 1px solid var(--line);
    padding: .6rem clamp(1rem, 5vw, 2rem) 1rem; box-shadow: var(--shadow-2);
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: .8rem .6rem; font-size: 1.05rem; }
  .nav-links a[aria-current="page"]::after { display:none; }
  .nav-links a[aria-current="page"] { background: var(--accent-wash); }
}

/* ---------- hero ---------- */
.hero { padding: clamp(3.5rem, 9vw, 7rem) 0 clamp(2.5rem, 5vw, 4rem); position: relative; overflow: hidden; }
.hero::after {
  content:""; position:absolute; inset:0; z-index:-1; pointer-events:none;
  background:
    radial-gradient(60% 120% at 100% 0%, color-mix(in srgb, var(--accent) 9%, transparent), transparent 60%);
}
.hero h1 { font-size: var(--step-4); max-width: 16ch; }
.hero .lede { max-width: 56ch; margin-top: .4rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .8rem; margin-top: 1.8rem; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  font-family: var(--sans); font-weight: 600; font-size: .98rem;
  padding: .72rem 1.15rem; border-radius: 10px; cursor: pointer;
  text-decoration: none; border: 1px solid transparent; transition: transform .15s var(--ease), background .15s, box-shadow .15s;
}
.btn:hover { text-decoration: none; }
.btn--solid { background: var(--accent); color: #fff; }
.btn--solid:hover { transform: translateY(-1px); box-shadow: var(--shadow-2); }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn--ghost:hover { border-color: var(--accent); color: var(--accent); }
.btn .arr { transition: transform .2s var(--ease); }
.btn:hover .arr { transform: translateX(3px); }

/* ---------- pillar cards ---------- */
.pillars { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.1rem; }
@media (max-width: 680px){ .pillars { grid-template-columns: 1fr; } }

.pillar {
  --c: var(--accent);
  position: relative; display: block; text-decoration: none; color: inherit;
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.6rem 1.5rem 1.5rem; overflow: hidden;
  transition: transform .2s var(--ease), box-shadow .2s var(--ease), border-color .2s;
}
.pillar::before { content:""; position:absolute; left:0; top:0; height:100%; width:4px; background: var(--c); transition: width .2s var(--ease); }
.pillar:hover { transform: translateY(-3px); box-shadow: var(--shadow-2); border-color: color-mix(in srgb, var(--c) 40%, var(--line)); text-decoration: none; }
.pillar:hover::before { width: 7px; }
.pillar[data-c="understand"]{ --c:#1d4e89; } .pillar[data-c="understand"] .p-eye{ color:#1d4e89; }
.pillar[data-c="observe"]   { --c:#0e6e6c; } .pillar[data-c="observe"] .p-eye{ color:#0e6e6c; }
.pillar[data-c="implement"] { --c:#2a6e47; } .pillar[data-c="implement"] .p-eye{ color:#2a6e47; }
.pillar[data-c="connect"]   { --c:#564399; } .pillar[data-c="connect"] .p-eye{ color:#564399; }

.pillar .p-glyph { width: 34px; height: 34px; color: var(--c); margin-bottom: 1rem; }
.pillar .p-eye { font-family: var(--mono); font-size: .68rem; letter-spacing: .16em; text-transform: uppercase; }
.pillar h3 { margin: .35rem 0 .35rem; font-size: 1.4rem; }
.pillar p { color: var(--ink-2); margin: 0 0 1.1rem; font-size: .98rem; }
.pillar .enter { font-weight: 600; color: var(--c); font-size: .95rem; display: inline-flex; align-items: center; gap: .4rem; }
.pillar .enter .arr { transition: transform .2s var(--ease); }
.pillar:hover .enter .arr { transform: translateX(4px); }

/* ---------- generic cards / grid ---------- */
.grid { display: grid; gap: 1.1rem; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 820px){ .grid-3 { grid-template-columns: 1fr; } .grid-2 { grid-template-columns: 1fr; } }

.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.4rem 1.4rem 1.3rem; box-shadow: var(--shadow-1);
}
.card h3 { margin-top: 0; }
.card .tag { font-family: var(--mono); font-size: .66rem; letter-spacing: .14em; text-transform: uppercase; color: var(--accent); }

.subnav-card { display:block; text-decoration:none; color:inherit; transition: transform .2s var(--ease), box-shadow .2s var(--ease), border-color .2s; }
.subnav-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-2); border-color: color-mix(in srgb, var(--accent) 40%, var(--line)); text-decoration:none; }
.subnav-card .enter { color: var(--accent); font-weight:600; font-size:.95rem; display:inline-flex; gap:.4rem; align-items:center; }
.subnav-card:hover .enter .arr { transform: translateX(4px); }

/* ---------- page header ---------- */
.page-head { padding: clamp(2.6rem, 6vw, 4.5rem) 0 0; }
.page-head .eyebrow { color: var(--accent); }
.page-head h1 { max-width: 20ch; }
.page-head .lede { max-width: 62ch; }
.crumb { font-size: .9rem; color: var(--ink-3); margin-bottom: 1.1rem; }
.crumb a { color: var(--ink-3); }
.crumb a:hover { color: var(--accent); }

/* ---------- prose blocks ---------- */
.prose h2 { margin-top: 2.4rem; padding-top: 1.4rem; border-top: 1px solid var(--line-soft); }
.prose h2:first-child { border-top: 0; padding-top: 0; margin-top: 0; }
.prose h3 { margin-top: 1.8rem; }
.prose ul, .prose ol { margin: 0 0 1.1em; padding-left: 1.25rem; }
.prose li { margin-bottom: .4em; }
.prose ul.plain { list-style: none; padding-left: 0; }

/* ---------- accordion (details) ---------- */
.acc { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); margin-bottom: .85rem; overflow: hidden; box-shadow: var(--shadow-1); }
.acc[open] { border-color: color-mix(in srgb, var(--accent) 35%, var(--line)); }
.acc > summary {
  list-style: none; cursor: pointer; padding: 1.15rem 1.3rem; display: flex; gap: 1rem; align-items: flex-start;
  font-family: var(--serif); font-weight: 600; font-size: 1.18rem; color: var(--ink);
}
.acc > summary::-webkit-details-marker { display: none; }
.acc > summary:hover { background: var(--accent-wash); }
.acc .sum-meta { font-family: var(--mono); font-size: .66rem; letter-spacing:.12em; text-transform: uppercase; color: var(--accent); font-weight:500; display:block; margin-bottom:.25rem; }
.acc .chev { margin-left: auto; flex: none; color: var(--accent); transition: transform .25s var(--ease); margin-top: .15rem; }
.acc[open] .chev { transform: rotate(180deg); }
.acc .acc-body { padding: 0 1.3rem 1.3rem; }
.acc .acc-body > :first-child { margin-top: 0; }
.acc-num { font-family: var(--mono); color: var(--accent); font-weight: 600; flex: none; font-size: 1rem; margin-top: .2rem; }

.lbl { font-family: var(--sans); font-weight: 700; font-size: .78rem; letter-spacing: .06em; text-transform: uppercase; color: var(--accent-ink); margin: 1.3rem 0 .4rem; }

/* look-fors checklist */
ul.lookfor { list-style: none; padding-left: 0; margin: .3rem 0 1.1em; }
ul.lookfor li { position: relative; padding-left: 1.8rem; margin-bottom: .5em; }
ul.lookfor li::before {
  content: "✓"; position: absolute; left: 0; top: .05em;
  color: var(--accent); font-weight: 700;
  width: 1.25rem; height: 1.25rem; line-height: 1.25rem; text-align: center;
  background: var(--accent-wash); border-radius: 50%; font-size: .8rem;
}

/* myth card */
.myth { border-left: 4px solid var(--accent); }
.myth .myth-no { font-family: var(--mono); color: var(--accent); font-size: .72rem; letter-spacing:.1em; }
.myth h3 { margin: .2rem 0 .9rem; }
.myth .blk { margin-bottom: .9rem; }
.myth .blk:last-child { margin-bottom: 0; }

/* reflective question callout */
.reflectq {
  background: var(--accent-wash); border-radius: var(--radius-sm);
  padding: 1rem 1.15rem; margin: 1.3rem 0 0; font-style: italic;
  color: var(--accent-ink); border: 1px solid color-mix(in srgb, var(--accent) 20%, var(--line));
}
.reflectq::before { content: "Reflective question"; display:block; font-style: normal; font-family: var(--mono); font-size:.64rem; letter-spacing:.14em; text-transform:uppercase; color: var(--accent); margin-bottom:.35rem; }

.note {
  border: 1px dashed color-mix(in srgb, var(--accent) 45%, var(--line));
  background: var(--accent-wash); border-radius: var(--radius-sm);
  padding: .95rem 1.1rem; font-size: .95rem; color: var(--ink-2);
}
.note strong { color: var(--accent-ink); }

/* ---------- chooser chips (observe) ---------- */
.chooser { display: flex; flex-wrap: wrap; gap: .6rem; margin: 1.4rem 0 0; }
.chip {
  font-family: var(--mono); font-size: .8rem; letter-spacing: .04em;
  padding: .5rem .9rem; border-radius: 999px; border: 1px solid var(--line);
  background: var(--surface); color: var(--ink-2); text-decoration: none; transition: all .15s;
}
.chip:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-wash); text-decoration: none; }

/* ---------- forms ---------- */
.form { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.6rem; box-shadow: var(--shadow-1); }
.field { margin-bottom: 1.1rem; }
.field label { display: block; font-weight: 600; font-size: .95rem; margin-bottom: .4rem; }
.field .hint { font-size: .86rem; color: var(--ink-3); margin: 0 0 .5rem; }
.field input, .field textarea, .field select {
  width: 100%; font: inherit; color: var(--ink); background: var(--paper);
  border: 1px solid var(--line); border-radius: 9px; padding: .7rem .85rem;
}
.field input:focus, .field textarea:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-wash); background: #fff; }
.field textarea { min-height: 130px; resize: vertical; }

/* ---------- footer ---------- */
.site-footer { background: var(--ink); color: #c9d4e2; margin-top: 2rem; }
.site-footer a { color: #e4ebf3; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 2rem; padding: clamp(2.6rem,5vw,3.6rem) 0 2rem; }
@media (max-width: 760px){ .footer-grid { grid-template-columns: 1fr; gap: 1.6rem; } }
.site-footer .brand .word { color: #fff; }
.site-footer .brand .sub { color: #8a99ad; }
.site-footer h4 { color: #fff; font-family: var(--sans); font-size: .78rem; letter-spacing: .1em; text-transform: uppercase; margin: 0 0 .9rem; }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: .5rem; }
.site-footer .muted { color: #8a99ad; font-size: .9rem; max-width: 36ch; }
.footer-base { border-top: 1px solid rgba(255,255,255,.12); padding: 1.2rem 0 2rem; display:flex; flex-wrap:wrap; gap:.6rem 1.5rem; justify-content: space-between; font-size: .85rem; color: #8a99ad; }

/* ---------- scroll reveal ---------- */
.reveal { opacity: 1; }
html.js .reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s var(--ease), transform .6s var(--ease); }
html.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce){
  html.js .reveal { opacity: 1; transform: none; transition: none; }
  .btn, .pillar, .acc .chev { transition: none !important; }
}

/* utility */
.stack > * + * { margin-top: 1.1rem; }
.mt-0{margin-top:0}.mb-0{margin-bottom:0}
.measure { max-width: 62ch; }
.divider-top { border-top: 1px solid var(--line); }
