/* ============================================================
   Shared course stylesheet — WhatsApp Business API for Instructors
   Clean light theme, Tufte-inspired, print-friendly.
   Linked by every lesson and reference doc.
   ============================================================ */

:root {
  --bg:        #fbfaf7;
  --surface:   #ffffff;
  --ink:       #1c1b19;
  --ink-soft:  #55514b;
  --line:      #e7e3db;
  --line-strong:#cfc9bd;

  --accent:    #128c7e;   /* WhatsApp teal */
  --accent-2:  #25d366;   /* WhatsApp green */
  --accent-ink:#0b5c52;
  --warn:      #b4531a;
  --warn-bg:   #fdf1e7;
  --good-bg:   #ecf7ef;
  --info-bg:   #eef4fb;
  --info-ink:  #1e5aa8;
  --code-bg:   #f4f2ec;

  --maxw: 46rem;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(28,27,25,.05), 0 6px 20px rgba(28,27,25,.06);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  padding: 3.5rem 1.25rem 6rem;
}

.wrap { max-width: var(--maxw); margin: 0 auto; }

/* ---- Kicker / breadcrumb ---- */
.kicker {
  font-size: .74rem; letter-spacing: .11em; text-transform: uppercase;
  color: var(--accent-ink); font-weight: 700; margin: 0 0 .6rem;
}

/* ---- Headings ---- */
h1 {
  font-size: 2.05rem; line-height: 1.15; margin: 0 0 .5rem; letter-spacing: -.02em;
}
h2 {
  font-size: 1.32rem; margin: 2.6rem 0 .7rem; letter-spacing: -.01em;
  padding-bottom: .35rem; border-bottom: 2px solid var(--line);
}
h3 { font-size: 1.06rem; margin: 1.8rem 0 .4rem; }
.lede { font-size: 1.14rem; color: var(--ink-soft); margin: .3rem 0 1.6rem; }

p { margin: .7rem 0; }
a { color: var(--accent-ink); text-decoration-color: var(--line-strong); text-underline-offset: 2px; }
a:hover { text-decoration-color: var(--accent); }

strong { font-weight: 700; }
mark { background: #fef3c7; padding: 0 .15em; border-radius: 3px; }

/* ---- Meta row under title ---- */
.meta {
  display: flex; flex-wrap: wrap; gap: .5rem .9rem; align-items: center;
  font-size: .82rem; color: var(--ink-soft); margin-bottom: 1.4rem;
}
.chip {
  display: inline-block; padding: .12rem .55rem; border-radius: 999px;
  background: var(--good-bg); color: var(--accent-ink);
  border: 1px solid #cbe8d5; font-weight: 600; font-size: .74rem;
}

/* ---- Callouts ---- */
.callout {
  border: 1px solid var(--line); border-left: 4px solid var(--accent);
  background: var(--surface); border-radius: var(--radius);
  padding: .85rem 1.05rem; margin: 1.2rem 0; box-shadow: var(--shadow);
}
.callout.warn { border-left-color: var(--warn); background: var(--warn-bg); }
.callout.info { border-left-color: var(--info-ink); background: var(--info-bg); }
.callout.key  { border-left-color: var(--accent-2); background: var(--good-bg); }
.callout .label {
  font-size: .72rem; letter-spacing: .09em; text-transform: uppercase;
  font-weight: 700; display: block; margin-bottom: .25rem;
}
.callout.warn .label { color: var(--warn); }
.callout.info .label { color: var(--info-ink); }
.callout.key  .label { color: var(--accent-ink); }

/* ---- Code ---- */
code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .86em; background: var(--code-bg); padding: .1em .35em; border-radius: 4px;
}
pre {
  background: var(--code-bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1rem 1.1rem; overflow-x: auto; font-size: .82rem; line-height: 1.55;
}
pre code { background: none; padding: 0; }

/* ---- Diagram / cast cards ---- */
.stack { display: flex; flex-direction: column; gap: .6rem; margin: 1.2rem 0; }
.node {
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--surface); padding: .8rem 1rem; box-shadow: var(--shadow);
}
.node .role { font-weight: 700; }
.node .who  { color: var(--ink-soft); font-size: .9rem; }
.arrow { text-align: center; color: var(--accent); font-size: 1.1rem; line-height: 1; }

/* ---- Numbered flow ---- */
ol.flow { counter-reset: step; list-style: none; padding: 0; margin: 1.2rem 0; }
ol.flow > li {
  position: relative; padding: .55rem 0 .8rem 2.6rem; border-bottom: 1px dashed var(--line);
}
ol.flow > li:last-child { border-bottom: 0; }
ol.flow > li::before {
  counter-increment: step; content: counter(step);
  position: absolute; left: 0; top: .5rem;
  width: 1.7rem; height: 1.7rem; border-radius: 50%;
  background: var(--accent); color: #fff; font-size: .85rem; font-weight: 700;
  display: grid; place-items: center;
}

/* ---- Tables ---- */
table { border-collapse: collapse; width: 100%; margin: 1.2rem 0; font-size: .92rem; }
th, td { text-align: left; padding: .5rem .6rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--ink-soft); font-size: .78rem; text-transform: uppercase; letter-spacing: .05em; }

/* ---- Quiz widget ---- */
.quiz { margin: 1.2rem 0; }
.quiz .q { font-weight: 600; margin: 1.1rem 0 .5rem; }
.quiz button {
  display: block; width: 100%; text-align: left; margin: .35rem 0;
  padding: .6rem .8rem; border: 1px solid var(--line-strong); border-radius: 8px;
  background: var(--surface); color: var(--ink); font: inherit; font-size: .95rem;
  cursor: pointer; transition: border-color .15s, background .15s;
}
.quiz button:hover { border-color: var(--accent); }
.quiz button.correct { background: var(--good-bg); border-color: var(--accent-2); }
.quiz button.wrong   { background: var(--warn-bg); border-color: var(--warn); }
.quiz .fb { font-size: .88rem; color: var(--ink-soft); margin: .3rem 0 0; min-height: 1.2em; }

/* ---- Footer / nav ---- */
.foot {
  margin-top: 3.5rem; padding-top: 1.2rem; border-top: 2px solid var(--line);
  font-size: .9rem; color: var(--ink-soft);
}
.foot a { font-weight: 600; }
.ask {
  background: var(--good-bg); border: 1px dashed var(--accent-2); border-radius: var(--radius);
  padding: .8rem 1rem; margin: 1.6rem 0; font-size: .93rem;
}

/* ---- Print ---- */
@media print {
  body { background: #fff; padding: 0; font-size: 11pt; }
  .callout, .node, pre { box-shadow: none; }
  .quiz button { break-inside: avoid; }
  a { color: var(--ink); }
  .no-print { display: none; }
}