/* ==========================================================================
   Involve - base: colours, type, buttons, links, motion.
   Palette: black, white, greys + the two logo colours (blue, orange) as accents.
   ========================================================================== */
/* RULE: colours are only ever written in this file's two variable blocks (:root and
   html[data-theme="dark"]). Everywhere else use var(--...). `python3 tools/check-colors.py` enforces it. */
:root {
  --ink: #111111;
  --text: #2a2a2a;
  --muted: #6b6b6b;
  --line: #e3e3e3;
  --paper: #f6f6f6;
  --white: #ffffff;
  --on-ink: #ffffff;   /* text on an --ink background (buttons) */
  --band: #111111;     /* dark bands: footer, forest section, video frame */
  --header-bg: rgba(255, 255, 255, .96);
  /* dark bands (footer, forest section): always dark, in both themes */
  --band-strong: #ffffff;  --band-text: #d4d4d4;  --band-link: #e6e6e6;
  --band-muted: #8a8a8a;   --band-border: #444444; --band-rule: #2c2c2c; --band-chip: #ffffff;
  --blue: #146cb4;     /* logo blue   - links, labels, some headings */
  --orange: #f47800;   /* logo orange - large accents and rules only (low contrast on white) */

  --serif: Georgia, "Times New Roman", "Noto Serif", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Noto Sans Malayalam", "Nirmala UI", sans-serif;

  --wrap: 1120px;
  --gutter: 24px;
  --section: clamp(72px, 12vw, 140px);
  --ease: cubic-bezier(.2, .7, .2, 1);
}

/* dark theme: switched by html[data-theme="dark"] (see js/theme-init.js and js/theme.js) */
html[data-theme="dark"] {
  --ink: #f2f2f2; --text: #cfcfcf; --muted: #9b9b9b; --line: #2e2e2e; --paper: #1a1a1a; --white: #121212;
  --on-ink: #121212; --band: #0a0a0a; --header-bg: rgba(18, 18, 18, .96);
  --blue: #5aa9e6;
  color-scheme: dark;
}
html { color-scheme: light; }
html[data-theme="dark"] { color-scheme: dark; }
body, .site-header, .section-paper { transition: background-color .35s var(--ease), color .35s var(--ease); }

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 88px; }
body { margin: 0; font-family: var(--sans); font-size: 1.0625rem; line-height: 1.7; color: var(--text); background: var(--white); overflow-x: hidden; animation: page-in .6s var(--ease) both; }
@keyframes page-in { from { opacity: 0; } to { opacity: 1; } }
html.menu-open { overflow: hidden; }

img, video, svg { max-width: 100%; height: auto; }
img { display: block; }
h1, h2, h3 { font-family: var(--serif); font-weight: 400; color: var(--ink); line-height: 1.12; margin: 0 0 .5em; letter-spacing: -.01em; }
h1 { font-size: clamp(2.6rem, 9vw, 5rem); }
h2 { font-size: clamp(2rem, 5.2vw, 3.25rem); }
h3 { font-size: clamp(1.35rem, 2.6vw, 1.75rem); }
p { margin: 0 0 1.2em; }
ul, ol { margin: 0; padding: 0; }
address { font-style: normal; }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

a { color: var(--blue); text-decoration: none; }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; }
.skip-link { position: absolute; left: -999px; top: 8px; background: var(--ink); color: var(--on-ink); padding: 10px 16px; z-index: 300; }
.skip-link:focus { left: 8px; }

/* small label above headings: blue text, short orange rule */
.eyebrow, .label { display: flex; align-items: center; gap: 12px; margin: 0 0 18px; font-family: var(--sans); font-size: .78rem; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; color: var(--blue); }
.eyebrow::before { content: ""; width: 28px; height: 2px; background: var(--orange); flex: none; }
.lead { font-size: clamp(1.15rem, 2.2vw, 1.35rem); color: var(--muted); max-width: 40em; }

/* text link with an underline that slides in */
.arrow-link, .prose a, .doc-body a, .footer-links a, .contact-big {
  background: linear-gradient(currentColor, currentColor) 0 100% / 0 1px no-repeat;
  transition: background-size .35s var(--ease), color .2s;
  padding-bottom: 2px;
}
.arrow-link:hover, .prose a:hover, .doc-body a:hover, .footer-links a:hover, .contact-big:hover { background-size: 100% 1px; }
.arrow-link { font-weight: 600; background-size: 100% 1px; display: inline-flex; align-items: center; min-height: 44px; padding: 0 0 2px; }
.arrow-link:hover { background-size: 0 1px; }
.doc-body a, .prose a, .split-text p a { background-size: 100% 1px; }

/* buttons: flat, square, fill slides in on hover */
.btn { --bg: var(--ink); --fg: var(--on-ink); --bd: var(--ink); --hbg: var(--white); --hfg: var(--ink);
  position: relative; isolation: isolate; overflow: hidden; display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  min-height: 52px; padding: 12px 30px; border: 1px solid var(--bd); background: var(--bg); color: var(--fg);
  font: inherit; font-size: .95rem; font-weight: 600; letter-spacing: .03em; cursor: pointer; transition: color .3s var(--ease); }
.btn::before { content: ""; position: absolute; inset: 0; z-index: -1; background: var(--hbg); transform: translateX(-101%); transition: transform .4s var(--ease); }
.btn:hover { color: var(--hfg); }
.btn:hover::before { transform: none; }
.btn-outline { --bg: transparent; --fg: var(--ink); --bd: var(--ink); --hbg: var(--ink); --hfg: var(--on-ink); }
.btn-row { display: flex; flex-wrap: wrap; gap: 14px; }
.btn .icon { width: 1.15em; height: 1.15em; fill: currentColor; }
.icon { width: 1.3em; height: 1.3em; fill: currentColor; flex: none; }

/* scroll reveal (switched on only when JS runs; see js/motion.js) */
.js .reveal { opacity: 0; transform: translateY(22px); transition: opacity .8s var(--ease), transform .8s var(--ease); transition-delay: calc(var(--d, 0) * 90ms); }
.js .reveal.is-visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  body { animation: none; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}