/* ============================================================
   RHCSA Lessons — shared stylesheet
   ออกแบบเพื่อการอ่านยาว: คอนทราสต์สูง บรรทัดไม่ยาวเกิน อ่านสบายตา
   ============================================================ */
:root {
  --bg: #faf7f2;
  --surface: #ffffff;
  --ink: #1d1a17;
  --ink-soft: #5c554d;
  --ink-faint: #8a8279;
  --line: #e7e0d6;
  --rh: #ee0000;          /* Red Hat red */
  --rh-deep: #a30000;
  --accent: #1769aa;
  --accent-soft: #eef4f9;
  --gold: #c08a2d;
  --gold-soft: #fdf6e7;
  --green: #2f8f5b;
  --green-soft: #f0f8f3;
  --term-bg: #1b1d22;
  --term-ink: #e6e6e6;
  --shadow: 0 1px 2px rgba(29,26,23,.06), 0 8px 24px -12px rgba(29,26,23,.18);
  --radius: 14px;
  --mono: ui-monospace, "Cascadia Code", "JetBrains Mono", Consolas, monospace;
  --sans: "Segoe UI", system-ui, -apple-system, "Noto Sans Thai", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--sans);
  background:
    radial-gradient(1100px 560px at 92% -12%, #fdeeee 0%, transparent 55%),
    radial-gradient(820px 460px at -8% 8%, #eef4f9 0%, transparent 52%),
    var(--bg);
  color: var(--ink);
  line-height: 1.78;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 820px; margin: 0 auto; padding: 0 22px 110px; }

/* ---------- TOP BAR ---------- */
.topbar {
  position: sticky; top: 0; z-index: 20;
  backdrop-filter: blur(8px);
  background: rgba(250,247,242,.86);
  border-bottom: 1px solid var(--line);
  margin-bottom: 0;
}
.topbar .row {
  max-width: 820px; margin: 0 auto; padding: 12px 22px;
  display: flex; align-items: center; justify-content: space-between; gap: 14px;
}
.topbar a.home { color: var(--rh-deep); font-weight: 700; text-decoration: none; font-size: .92rem; white-space: nowrap; }
.topbar a.home:hover { text-decoration: underline; }
.topbar .crumb { font-size: .85rem; color: var(--ink-faint); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ---------- HERO ---------- */
header.lesson-hero { padding: 54px 0 30px; border-bottom: 1px solid var(--line); }
.modtag {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--mono); font-weight: 700; font-size: .8rem;
  color: #fff; background: var(--ink); padding: 6px 13px; border-radius: 999px; letter-spacing: .04em;
}
.modtag.exam { background: var(--rh); }
.modtag.cap { background: var(--gold); }
h1 {
  font-size: clamp(1.9rem, 1.2rem + 3vw, 3rem);
  line-height: 1.1; letter-spacing: -.02em; margin: 18px 0 12px; font-weight: 800;
}
.hero-lead { font-size: 1.12rem; color: var(--ink-soft); max-width: 62ch; margin: 0; }
.beginner-badge {
  display: inline-flex; align-items: center; gap: 8px; margin-top: 20px;
  font-size: .85rem; color: var(--green); background: var(--green-soft);
  border: 1px solid #c7e6d3; padding: 7px 14px; border-radius: 999px; font-weight: 600;
}

/* ---------- IN-PAGE TOC ---------- */
.toc {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 22px; box-shadow: var(--shadow); margin: 30px 0;
}
.toc b { display: block; font-size: .8rem; text-transform: uppercase; letter-spacing: .1em; color: var(--ink-faint); margin-bottom: 10px; }
.toc ol { margin: 0; padding-left: 1.3em; }
.toc li { margin: 5px 0; }
.toc a { color: var(--accent); text-decoration: none; }
.toc a:hover { text-decoration: underline; }

/* ---------- BODY TYPOGRAPHY ---------- */
section.block { margin-top: 46px; scroll-margin-top: 70px; }
h2 {
  font-size: 1.5rem; letter-spacing: -.01em; margin: 0 0 14px;
  padding-bottom: 8px; border-bottom: 2px solid var(--line);
}
h2 .h2num { font-family: var(--mono); color: var(--rh); font-size: 1rem; margin-right: 8px; }
h3 { font-size: 1.16rem; margin: 30px 0 8px; }
p { margin: 14px 0; }
strong { color: var(--ink); }
ul, ol { padding-left: 1.45em; }
li { margin: 7px 0; }
a { color: var(--accent); }

code {
  font-family: var(--mono); font-size: .88em;
  background: #f1ece3; padding: 2px 7px; border-radius: 6px; color: var(--rh-deep);
  word-break: break-word;
}

/* ---------- ANALOGY BOX ---------- */
.analogy {
  background: var(--accent-soft); border: 1px solid #cfe2f0; border-radius: var(--radius);
  padding: 18px 22px; margin: 22px 0;
}
.analogy .lbl { font-weight: 700; color: var(--accent); display: flex; align-items: center; gap: 8px; margin-bottom: 6px; }
.analogy p:last-child { margin-bottom: 0; }
.analogy p:first-of-type { margin-top: 4px; }

/* ---------- COMMAND DEMO ---------- */
.cmd { margin: 22px 0; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.cmd .cmd-head { background: #f3eee5; padding: 9px 16px; font-weight: 700; font-size: .9rem; border-bottom: 1px solid var(--line); display:flex; align-items:center; gap:8px; }
.cmd .cmd-body { padding: 0; }
.terminal {
  background: var(--term-bg); color: var(--term-ink); font-family: var(--mono);
  font-size: .86rem; line-height: 1.6; padding: 16px 18px; margin: 0; overflow-x: auto;
}
.terminal .pr { color: #57c7ff; }        /* prompt */
.terminal .cm { color: #ffffff; }         /* typed command */
.terminal .ot { color: #9aa0a6; }         /* output */
.terminal .hl { color: #ffd479; }         /* highlight */
.terminal .ok { color: #6fcf97; }
.cmd .explain { padding: 14px 18px; background: var(--surface); font-size: .95rem; }
.cmd .explain p { margin: 8px 0; }
.cmd .explain .row { display: grid; grid-template-columns: auto 1fr; gap: 12px; align-items: baseline; padding: 5px 0; border-top: 1px dashed var(--line); }
.cmd .explain .row:first-child { border-top: none; }
.cmd .explain .row code { white-space: nowrap; }

/* ---------- CALLOUTS ---------- */
.note, .warn, .tip, .persist {
  border-radius: 0 12px 12px 0; padding: 14px 18px; margin: 20px 0; border-left: 4px solid;
}
.note   { background: var(--accent-soft); border-color: var(--accent); }
.tip    { background: var(--green-soft);  border-color: var(--green); }
.warn   { background: var(--gold-soft);   border-color: var(--gold); }
.persist{ background: #fde7e7;             border-color: var(--rh); }
.note b, .tip b, .warn b, .persist b { display:block; margin-bottom: 3px; }
.note b { color: var(--accent); }
.tip b { color: var(--green); }
.warn b { color: var(--gold); }
.persist b { color: var(--rh-deep); }
.note p:last-child, .warn p:last-child, .tip p:last-child, .persist p:last-child { margin-bottom: 0; }

/* ---------- MISTAKES ---------- */
.mistakes { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 6px 22px; box-shadow: var(--shadow); margin: 22px 0; }
.mistakes li { margin: 12px 0; }
.mistakes li b { color: var(--rh-deep); }

/* ---------- CHEAT SHEET ---------- */
.cheat { width: 100%; border-collapse: collapse; margin: 18px 0; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.cheat th, .cheat td { text-align: left; padding: 11px 15px; border-bottom: 1px solid var(--line); vertical-align: top; }
.cheat th { background: #f3eee5; font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-soft); }
.cheat tr:last-child td { border-bottom: none; }
.cheat td code { background: #f1ece3; }
.cheat td:first-child { white-space: nowrap; }

/* ---------- KEY TERMS ---------- */
.term-row { display:grid; grid-template-columns: 160px 1fr; gap: 8px 18px; margin: 16px 0; }
.term-row dt { font-weight: 700; color: var(--rh-deep); font-family: var(--mono); font-size: .92rem; }
.term-row dd { margin: 0; color: var(--ink-soft); }

/* ---------- PREV / NEXT NAV ---------- */
.pager { display: flex; gap: 12px; margin-top: 60px; padding-top: 26px; border-top: 1px solid var(--line); }
.pager a {
  flex: 1; text-decoration: none; color: var(--ink); background: var(--surface);
  border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 18px; box-shadow: var(--shadow);
  transition: transform .16s ease, border-color .16s ease;
}
.pager a:hover { transform: translateY(-2px); border-color: #d9cfc0; }
.pager a span { display:block; font-size: .75rem; color: var(--ink-faint); text-transform: uppercase; letter-spacing: .08em; }
.pager a b { font-size: 1rem; }
.pager a.next { text-align: right; }
.pager a.disabled { opacity: .4; pointer-events: none; }

@media (max-width: 600px) {
  body { font-size: 16px; }
  .term-row { grid-template-columns: 1fr; gap: 2px; }
  .term-row dd { margin-bottom: 10px; }
  .cmd .explain .row { grid-template-columns: 1fr; gap: 2px; }
  .pager { flex-direction: column; }
}