:root {
  --bg: #f7f7f5;
  --card: #ffffff;
  --ink: #1f2328;
  --muted: #5b6470;
  --line: #e3e5e8;
  --accent: #3157d5;
  --accent-soft: #e9eefc;
  --good: #1a7f4b;
  --good-soft: #e3f4ea;
  --bad: #c43d3d;
  --bad-soft: #fbe7e7;
  --warn: #9a6200;
  --warn-soft: #fff3d6;
  --hl: #ffe9a8;
  --radius: 10px;
  --mono: "Cascadia Mono", Consolas, Menlo, "Courier New", monospace;
  --sans: "Sarabun", "Leelawadee UI", Thonburi, "Noto Sans Thai", Tahoma, system-ui, -apple-system, sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body { margin: 0; font-family: var(--sans); font-size: 17px; line-height: 1.7; color: var(--ink); background: var(--bg); }
a { color: var(--accent); }
code, kbd, .mono { font-family: var(--mono); font-size: .92em; }
code { background: #f0f1f3; padding: 1px 5px; border-radius: 4px; }
h1, h2, h3, h4 { line-height: 1.35; }
h1 { font-size: 1.9rem; margin: .2em 0 .4em; }
h2 { font-size: 1.45rem; margin: 2.2em 0 .6em; padding-top: .4em; border-top: 1px solid var(--line); }
h3 { font-size: 1.15rem; margin: 1.6em 0 .5em; }
p { margin: .5em 0 .9em; }

/* ---------- top bar ---------- */
.topbar { position: sticky; top: 0; z-index: 50; background: #fff; border-bottom: 1px solid var(--line); }
.topbar .in { max-width: 1240px; margin: 0 auto; display: flex; align-items: center; gap: 6px; padding: 8px 16px; overflow-x: auto; }
.topbar .brand { font-weight: 700; margin-right: 10px; white-space: nowrap; text-decoration: none; color: var(--ink); }
.topbar nav a { white-space: nowrap; text-decoration: none; color: var(--muted); padding: 6px 10px; border-radius: 8px; font-size: .95rem; }
.topbar nav a:hover { background: #f1f2f4; color: var(--ink); }
.topbar nav a.on { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.topbar .star { color: #d08a00; }

/* ---------- layout ---------- */
.wrap { max-width: 1240px; margin: 0 auto; padding: 20px 16px 120px; display: grid; grid-template-columns: 230px minmax(0, 1fr); gap: 28px; }
.wrap.single { grid-template-columns: minmax(0, 1fr); max-width: 980px; }
.toc { position: sticky; top: 70px; align-self: start; max-height: calc(100vh - 90px); overflow: auto; font-size: .9rem; padding-right: 6px; }
.toc b { display: block; margin-bottom: 6px; color: var(--muted); font-size: .8rem; letter-spacing: .04em; }
.toc a { display: block; color: var(--muted); text-decoration: none; padding: 3px 8px; border-left: 2px solid transparent; }
.toc a:hover, .toc a.on { color: var(--accent); border-left-color: var(--accent); }
.toc a.sub { padding-left: 18px; font-size: .85rem; }
main { min-width: 0; }
@media (max-width: 900px) { .wrap { grid-template-columns: minmax(0, 1fr); } .toc { display: none; } body { font-size: 16px; } }

.lead { font-size: 1.08rem; color: var(--muted); }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; margin: 14px 0; }
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 14px; }
.grid3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; }

/* ---------- callouts ---------- */
.box { border-radius: var(--radius); padding: 12px 16px; margin: 14px 0; border: 1px solid var(--line); background: #fff; }
.box > :first-child { margin-top: 0; }
.box > :last-child { margin-bottom: 0; }
.box .t { font-weight: 700; display: block; margin-bottom: 4px; }
.goal { background: var(--accent-soft); border-color: #cdd8f7; }
.prof { background: #f3effc; border-color: #ddd2f5; }
.idea { background: var(--good-soft); border-color: #c4e6d2; }
.trap { background: var(--warn-soft); border-color: #f1dca4; }
.exam { background: #eef6f8; border-color: #c9e2e8; }
.prof q { quotes: "“" "”"; font-style: normal; }
.tag { display: inline-block; font-size: .78rem; padding: 1px 8px; border-radius: 99px; background: #eef0f3; color: var(--muted); margin-right: 4px; vertical-align: 2px; }
.tag.hot { background: #ffe8c2; color: #8a5300; }
.tag.no { background: #eee; color: #888; text-decoration: line-through; }

/* ---------- video timestamp button ---------- */
.ts { display: inline-flex; align-items: center; gap: 4px; border: 1px solid #cfc3ee; background: #fff; color: #5b3fb6; border-radius: 99px; padding: 0 10px; font-size: .85rem; cursor: pointer; font-family: var(--sans); line-height: 1.9; }
.ts:hover { background: #f3effc; }
.ts.off { cursor: default; border-color: #ddd; color: var(--muted); }
.ts.off:hover { background: #fff; }

/* ---------- slides ---------- */
.slides { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 12px; margin: 12px 0; }
.slides.one { grid-template-columns: minmax(0, 640px); }
.slides.wide { grid-template-columns: repeat(auto-fill, minmax(440px, 1fr)); }
figure.slide { margin: 0; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; display: flex; flex-direction: column; }
figure.slide img { width: 100%; display: block; cursor: zoom-in; background: #fbf6ec; }
figure.slide figcaption { font-size: .82rem; padding: 8px 10px; color: var(--muted); line-height: 1.5; border-top: 1px solid var(--line); }
figure.slide figcaption b { color: var(--ink); }
figure.slide figcaption a { white-space: nowrap; }
.lightbox { position: fixed; inset: 0; background: rgba(15, 18, 25, .88); z-index: 100; display: none; overflow: auto; padding: 24px; }
.lightbox.on { display: block; }
.lightbox img { display: block; margin: 0 auto; max-width: min(1200px, 100%); background: #fff; border-radius: 6px; }
.lightbox .cap { color: #fff; text-align: center; margin: 10px auto; max-width: 1000px; font-size: .95rem; }
.lightbox .x { position: fixed; top: 14px; right: 18px; font-size: 28px; color: #fff; background: none; border: 0; cursor: pointer; }

/* ---------- video dock ---------- */
.vdock { position: fixed; right: 16px; bottom: 16px; z-index: 60; width: 380px; max-width: calc(100vw - 32px); background: #111; border-radius: 12px; box-shadow: 0 8px 28px rgba(0,0,0,.3); overflow: hidden; display: none; }
.vdock.on { display: block; }
.vdock video { width: 100%; display: block; }
.vdock .bar { display: flex; justify-content: space-between; align-items: center; color: #ddd; font-size: .8rem; padding: 4px 10px; }
.vdock .bar button { background: none; border: 0; color: #ddd; cursor: pointer; font-size: 1rem; }
.vbtn { position: fixed; right: 16px; bottom: 16px; z-index: 59; border: 0; background: #5b3fb6; color: #fff; padding: 10px 14px; border-radius: 99px; cursor: pointer; font-family: var(--sans); box-shadow: 0 4px 14px rgba(0,0,0,.2); }

/* ---------- forms / widgets ---------- */
.widget { background: #fff; border: 1px solid #cfd8f3; border-radius: var(--radius); margin: 16px 0; overflow: hidden; }
.widget > .wh { background: var(--accent-soft); padding: 8px 14px; font-weight: 700; color: #233c99; display: flex; justify-content: space-between; align-items: center; gap: 8px; flex-wrap: wrap; }
.widget > .wb { padding: 14px; }
.row { display: flex; flex-wrap: wrap; gap: 8px 14px; align-items: center; margin: 6px 0; }
label.f { display: inline-flex; align-items: center; gap: 6px; font-size: .92rem; color: var(--muted); }
input[type=text], input[type=number], select, textarea { font: inherit; font-size: .95rem; padding: 5px 8px; border: 1px solid #c9ced6; border-radius: 7px; background: #fff; color: var(--ink); }
input[type=text].wide { flex: 1 1 auto; width: 100%; min-width: 0; font-family: var(--mono); }
label.f:has(input.wide) { flex: 1 1 460px; }
input[type=number] { width: 80px; }
textarea { width: 100%; font-family: var(--mono); }
button.b { font: inherit; font-size: .92rem; padding: 5px 12px; border-radius: 7px; border: 1px solid #c9ced6; background: #fff; cursor: pointer; color: var(--ink); }
button.b:hover { background: #f4f5f7; }
button.b.pri { background: var(--accent); border-color: var(--accent); color: #fff; }
button.b.pri:hover { background: #2747b8; }
button.b:disabled { opacity: .45; cursor: default; }
.seg { display: inline-flex; border: 1px solid #c9ced6; border-radius: 8px; overflow: hidden; }
.seg button { font: inherit; font-size: .9rem; border: 0; background: #fff; padding: 5px 12px; cursor: pointer; border-right: 1px solid #e1e4e8; }
.seg button:last-child { border-right: 0; }
.seg button.on { background: var(--accent); color: #fff; }
.explain { background: #fafbfc; border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; margin-top: 10px; font-size: .95rem; min-height: 2.6em; }
.explain .big { font-size: 1.05rem; font-weight: 700; }
.muted { color: var(--muted); }
.ok { color: var(--good); font-weight: 700; }
.no { color: var(--bad); font-weight: 700; }

/* ---------- tables ---------- */
.tblwrap { overflow-x: auto; }
table.t { border-collapse: collapse; margin: 8px 0; font-size: .95rem; }
table.t th, table.t td { border: 1px solid #d5d9df; padding: 4px 9px; text-align: center; }
table.t th { background: #f3f4f6; font-weight: 600; }
table.t.left td { text-align: left; }
table.pr td, table.pr th { min-width: 30px; padding: 3px 5px; font-family: var(--mono); }
table.pr td.cur, table.pr th.cur { outline: 2px solid var(--accent); outline-offset: -2px; }
table.pr td.new { background: var(--hl); font-weight: 700; }
table.pr td.hitc { background: var(--good-soft); }
table.pr td.fault { color: var(--bad); font-weight: 700; }
table.pr td.hit { color: var(--good); }
table.pr td.future { color: transparent; }
table.pr td.pick { cursor: pointer; background: #fff7e0; }
table.pr td.pick:hover { background: #ffe2a0; }
table.m td { font-family: var(--mono); min-width: 34px; }
table.m td input { width: 44px; text-align: center; padding: 2px; font-family: var(--mono); }
tr.hl td { background: var(--hl); }
tr.done td { background: var(--good-soft); }
tr.dead td { background: var(--bad-soft); }

/* ---------- quiz ---------- */
.quiz { margin: 14px 0; }
.q { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 16px; margin: 12px 0; }
.q .qt { font-weight: 600; margin-bottom: 6px; }
.q .qn { color: var(--accent); margin-right: 6px; }
.q .opts { display: grid; gap: 6px; margin: 6px 0; }
.q .opt { text-align: left; font: inherit; font-size: .95rem; padding: 6px 10px; border: 1px solid #d5d9df; border-radius: 8px; background: #fff; cursor: pointer; }
.q .opt:hover { background: #f6f7f9; }
.q .opt.right { background: var(--good-soft); border-color: #8fd0aa; }
.q .opt.wrong { background: var(--bad-soft); border-color: #eaa7a7; }
.q .fb { margin-top: 8px; font-size: .93rem; display: none; }
.q .fb.on { display: block; }
.q .ans { display: none; background: #fafbfc; border-left: 3px solid var(--accent); padding: 8px 12px; margin-top: 8px; font-size: .95rem; }
.q .ans.on { display: block; }
.q.solved { border-color: #9ad4b3; }
.q pre { margin: 6px 0; }
pre { background: #f6f7f9; border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; overflow-x: auto; font-family: var(--mono); font-size: .88rem; line-height: 1.5; }

/* ---------- home ---------- */
.hero { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 22px 24px; }
.roadmap { counter-reset: s; display: grid; gap: 10px; }
.roadmap a.step { display: grid; grid-template-columns: 44px 1fr auto; gap: 12px; align-items: center; text-decoration: none; color: var(--ink); background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; }
.roadmap a.step:hover { border-color: var(--accent); }
.roadmap .n { width: 40px; height: 40px; border-radius: 50%; display: grid; place-items: center; background: var(--accent-soft); color: var(--accent); font-weight: 700; }
.roadmap .w { font-size: .82rem; color: var(--muted); }
.stars { color: #d08a00; letter-spacing: 1px; white-space: nowrap; }
.progress { height: 8px; background: #eceef1; border-radius: 99px; overflow: hidden; }
.progress > i { display: block; height: 100%; background: var(--good); width: 0; transition: width .3s; }
.check { display: flex; gap: 8px; align-items: flex-start; padding: 4px 0; }
.check input { margin-top: 6px; }

svg text { font-family: var(--sans); }
.legend { font-size: .85rem; color: var(--muted); }
.legend span { display: inline-flex; align-items: center; gap: 4px; margin-right: 12px; }
.legend i { width: 14px; height: 14px; border-radius: 3px; display: inline-block; }
.nextprev { display: flex; justify-content: space-between; gap: 12px; margin-top: 40px; }
.nextprev a { flex: 1; text-decoration: none; background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; }
.nextprev a:hover { border-color: var(--accent); }
.nextprev .r { text-align: right; }

/* iPad / touch */
@media (hover: none) { button.b, .seg button, .q .opt { min-height: 38px; } table.m td input { width: 48px; min-height: 32px; } }

/* กล่องสอนแบบไม่รู้มาก่อน */
.learn { background: #fff; border: 1px solid var(--line); border-left: 4px solid var(--accent); border-radius: var(--radius); padding: 12px 18px; margin: 14px 0; }
.learn h4 { margin: 1em 0 .25em; font-size: 1rem; color: #233c99; }
.learn h4:first-child { margin-top: .2em; }
.learn ol, .learn ul { margin: .3em 0 .6em; padding-left: 1.4em; }
.learn p { margin: .3em 0 .6em; }
.gotit { background: #fffdf3; border: 1px dashed #e2c46b; border-radius: var(--radius); padding: 8px 14px; margin: 10px 0 18px; }
.gotit > .t { font-weight: 700; color: #8a6300; }
table.gloss td:first-child { white-space: nowrap; font-weight: 600; }
.flow { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin: 8px 0; }
.flow span { background: var(--accent-soft); border: 1px solid #cdd8f7; border-radius: 8px; padding: 3px 10px; font-size: .92rem; }
.flow i { color: var(--muted); font-style: normal; }

.topbar .ver { margin-left: auto; padding-left: 12px; font-size: .78rem; color: var(--muted); white-space: nowrap; }

details.skip { border: 1px dashed #c9ced6; border-radius: var(--radius); background: #f4f5f7; margin: 12px 0; padding: 0 14px; }
details.skip > summary { cursor: pointer; padding: 10px 0; color: var(--muted); font-weight: 600; }
details.skip[open] { background: #fff; padding-bottom: 10px; }
.tag.skip { background: #e4e7ec; color: #555; }