/* 3AI.nu — /style.css · Phase 1 brand tokens
 * Do NOT add new colors, fonts, or type sizes without an explicit design update.
 */

:root {
  /* ── Ink ─────────────────────────────────────────────── */
  --ink:      #0e0e0e;
  --ink-2:    #2a2a2a;
  --ink-3:    #4a4a4a;
  --muted:    #767472;

  /* ── Paper ──────────────────────────────────────────── */
  --paper:      #fafaf7;
  --paper-warm: #f4f1ea;
  --line:       #dcdad5;

  /* ── Signal — instructional callouts only ────────────
   * Never used for buttons, links, nav, or branding.
   * Reserved for Tips entries and case-study do/don't blocks. */
  --signal-green:    #1e7a3a;
  --signal-green-bg: #e8f3ec;
  --signal-red:      #c8361c;
  --signal-red-bg:   #fbece8;

  /* ── Typography ─────────────────────────────────────── */
  --font:  system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono:  ui-monospace, "Cascadia Code", "SF Mono", Menlo, monospace;

  --h1:    52px;
  --h2:    28px;
  --h3:    20px;
  --body:  16px;
  --small: 13px;

  /* ── Shape ──────────────────────────────────────────── */
  --radius:   3px;
  --pad-page: 48px;
}

/* ── Reset / base ─────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }
html { height: 100%; }
body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: var(--body);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── Type scale ───────────────────────────────────────── */
h1, h2, h3 { margin: 0; color: var(--ink); }
h1 { font-size: var(--h1); font-weight: 700; letter-spacing: -0.025em; line-height: 1.05; text-wrap: pretty; }
h2 { font-size: var(--h2); font-weight: 700; letter-spacing: -0.02em;  line-height: 1.2; }
h3 { font-size: var(--h3); font-weight: 700; letter-spacing: -0.015em; line-height: 1.25; }
p  { margin: 0; color: var(--ink-2); }

.small { font-size: var(--small); color: var(--ink-3); line-height: 1.4; }
.mono  { font-family: var(--mono); }

/* ── Eyebrow (mono, uppercase, muted) ────────────────── */
.eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--muted);
}

/* ── Links ────────────────────────────────────────────── */
a {
  color: var(--ink);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}
a:hover { text-decoration-thickness: 2px; }

/* ── Buttons ──────────────────────────────────────────── */
.btn-primary,
.btn-secondary {
  display: inline-block;
  padding: 14px 22px;
  border-radius: var(--radius);
  font-family: var(--font);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  line-height: 1;
  transition: background-color 120ms ease, color 120ms ease;
  cursor: pointer;
}
.btn-primary {
  background: var(--ink);
  color: var(--paper);
  border: 1px solid var(--ink);
}
.btn-primary:hover { background: var(--ink-2); border-color: var(--ink-2); color: var(--paper); }

.btn-secondary {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--ink);
  font-weight: 500;
  padding: 13px 21px;
}
.btn-secondary:hover { background: var(--paper-warm); }

/* ── Signal callouts (Tips entries only) ────────────── */
.signal-do,
.signal-dont {
  padding: 14px 16px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  border-left-width: 3px;
}
.signal-do {
  background: var(--signal-green-bg);
  border-color: rgba(30, 122, 58, 0.18);
  border-left-color: var(--signal-green);
}
.signal-dont {
  background: var(--signal-red-bg);
  border-color: rgba(200, 54, 28, 0.18);
  border-left-color: var(--signal-red);
}
.signal-do__label,
.signal-dont__label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 6px;
}
.signal-do__label   { color: var(--signal-green); }
.signal-dont__label { color: var(--signal-red); }
.signal-do__body,
.signal-dont__body  { font-size: 14px; line-height: 1.5; color: var(--ink-2); }

/* ── Layout helpers ───────────────────────────────────── */
.page { padding-inline: var(--pad-page); }
.divider { height: 1px; background: var(--line); border: 0; margin: 0; }

/* ── Site header ──────────────────────────────────────── */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px var(--pad-page);
  border-bottom: 1px solid var(--line);
  flex-shrink: 0;
}
.site-header__nav { display: flex; gap: 28px; font-size: 14px; }
.site-header__nav a { text-decoration: none; color: var(--ink-2); }
.site-header__nav a:hover,
.site-header__nav a.is-active { color: var(--ink); }

/* ── Site footer ──────────────────────────────────────── */
.site-footer {
  display: flex;
  justify-content: space-between;
  padding: 16px var(--pad-page);
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--muted);
  flex-shrink: 0;
  margin-top: auto;
}

/* ── Forms ────────────────────────────────────────────── */
input[type="text"],
input[type="email"],
input[type="search"],
textarea {
  font-family: var(--font);
  font-size: 13px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  color: var(--ink-2);
  outline: none;
  transition: border-color 120ms ease;
}
input:focus, textarea:focus { border-color: var(--ink); }

/* ── Responsive ───────────────────────────────────────── */
@media (max-width: 959px) {
  :root { --pad-page: 36px; --h1: 40px; }
  .services-grid { grid-template-columns: 1fr 1fr !important; }
}
@media (max-width: 639px) {
  :root { --pad-page: 24px; --h1: 32px; }
  .site-header__nav { display: none; }
  .services-grid { grid-template-columns: 1fr !important; }
  .signal-grid { grid-template-columns: 1fr !important; }
  .cta-row { flex-direction: column; }
}