:root {
  --bg: #fbf8f4; --card: #ffffff; --ink: #1f2430; --muted: #6b7280; --line: #e7e1d8;
  --brand: #f07c1e; --brand-ink: #ffffff; --ok: #1f9d55; --ok-bg: #e5f6ec; --no: #d93b3b; --no-bg: #fdecec; --mid: #c98a00;
  --gw: #1d6f8f; --shadow: 0 1px 2px rgba(0,0,0,.06), 0 4px 14px rgba(0,0,0,.05);
  --listening: #e8443a; --speaking: #f07c1e; --grammar: #f07c1e; --vocabulary: #2aa39a; --reading: #8b55b8; --writing: #1d6f8f;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #15171c; --card: #1f2229; --ink: #eceef2; --muted: #9aa1ad; --line: #2e323b; --ok-bg: #173323; --no-bg: #3a1c1c;
    --shadow: none;
  }
}
:root[data-theme="dark"] { --bg: #15171c; --card: #1f2229; --ink: #eceef2; --muted: #9aa1ad; --line: #2e323b; --ok-bg: #173323; --no-bg: #3a1c1c; --shadow: none; }

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.5 Nunito, "Kantumruy Pro", system-ui, sans-serif; }
a { color: inherit; }
h1 { font-size: 1.6rem; margin: .3em 0; line-height: 1.2; }
h2 { font-size: 1.25rem; margin: .2em 0; }
h3 { margin: 0 0 .5em; font-size: 1.05rem; }
.muted { color: var(--muted); } .small { font-size: .85rem; }
main { max-width: 860px; margin: 0 auto; padding: 12px 16px 80px; }

/* top bar */
.top { position: sticky; top: 0; z-index: 5; display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: 8px 16px; background: var(--card); border-bottom: 1px solid var(--line); }
.brand { display: flex; align-items: center; gap: 8px; text-decoration: none; font-weight: 800; white-space: nowrap; }
.brand b { color: var(--brand); }
.topnav { display: flex; gap: 4px; }
.topnav a { text-decoration: none; padding: 6px 10px; border-radius: 999px; font-weight: 700; font-size: .95rem; }
.topnav a.on, .topnav a:hover { background: var(--bg); color: var(--brand); }
@media (max-width: 420px) { .brand span { display: none; } }

/* buttons and fields */
.btn { display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--line); background: var(--card); color: var(--ink);
  font: inherit; font-weight: 700; padding: 10px 16px; border-radius: 12px; cursor: pointer; text-decoration: none; min-height: 44px; }
.btn.primary { background: var(--brand); border-color: var(--brand); color: var(--brand-ink); }
.btn.ghost { background: transparent; }
.btn.small { padding: 6px 12px; min-height: 36px; font-size: .9rem; }
.btn:disabled { opacity: .5; cursor: default; }
.btn.rec { background: var(--no); color: #fff; border-color: var(--no); }
.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 10px 0; }
.field { width: 100%; font: inherit; padding: 10px 12px; border: 2px solid var(--line); border-radius: 10px; background: var(--card); color: var(--ink); margin: 6px 0; }
.field:focus { outline: none; border-color: var(--brand); }
.field.inline { width: auto; min-width: 7ch; max-width: 60%; display: inline-block; margin: 0 4px; padding: 4px 8px; }
.right { border-color: var(--ok) !important; background: var(--ok-bg) !important; }
.wrong { border-color: var(--no) !important; background: var(--no-bg) !important; }
.back { display: inline-block; text-decoration: none; color: var(--muted); font-weight: 700; margin: 4px 0 6px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 14px 16px; margin: 12px 0; box-shadow: var(--shadow); }
.card.note { border-left: 5px solid var(--brand); font-size: .95rem; }
.empty { text-align: center; color: var(--muted); }
.toast { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); background: var(--ink); color: var(--bg); padding: 10px 18px; border-radius: 12px; z-index: 20; max-width: 90vw; }

/* home */
.hero { padding: 8px 0; }
.books { display: grid; gap: 12px; }
@media (min-width: 700px) { .books { grid-template-columns: 1fr 1fr; } }
.bookcard { display: flex; gap: 14px; background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 14px; text-decoration: none; box-shadow: var(--shadow); }
.bookcard p { margin: 2px 0; }
.bookcard .stat { font-weight: 700; font-size: .9rem; }
.cover { flex: 0 0 92px; height: 124px; border-radius: 8px; display: flex; flex-direction: column; justify-content: center; align-items: center; color: #fff; text-align: center; padding: 6px; }
.efe .cover { background: linear-gradient(135deg, #f07c1e, #e8443a 55%, #2aa39a); }
.gw .cover { background: linear-gradient(160deg, #b5532b, #1d6f8f); }
.cover b { font-size: 1.05rem; letter-spacing: .5px; } .cover span { font-size: .62rem; letter-spacing: 1px; } .cover em { font-style: normal; font-size: .75rem; margin-top: 8px; background: rgba(0,0,0,.25); padding: 2px 6px; border-radius: 6px; }
.skills { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 8px; margin-top: 16px; }
.skill { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 10px 12px; display: grid; grid-template-columns: auto 1fr auto; gap: 8px; align-items: center; }
.skill .ic, .ic { display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 10px; color: #fff; font-weight: 800; font-size: .9rem; background: var(--grammar); flex: none; }
.listening > .ic, .skill.listening .ic { background: var(--listening); }
.speaking > .ic, .skill.speaking .ic { background: var(--speaking); }
.vocabulary > .ic, .skill.vocabulary .ic { background: var(--vocabulary); }
.reading > .ic { background: var(--reading); }
.writing > .ic, .skill.writing .ic { background: var(--writing); }

/* unit list */
.units { display: grid; gap: 8px; margin-top: 12px; }
.unit { display: flex; align-items: center; gap: 12px; background: var(--card); border: 1px solid var(--line); border-left: 6px solid var(--c); border-radius: 14px; padding: 10px 12px; text-decoration: none; }
.unit .num { font-size: 1.3rem; font-weight: 800; color: var(--c); min-width: 2ch; }
.unit .ut { flex: 1; display: flex; flex-direction: column; min-width: 0; }
.unit small { color: var(--muted); }
.ring { --p: 0; width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center; flex: none;
  background: conic-gradient(var(--ok) calc(var(--p) * 1%), var(--line) 0); }
.ring span { width: 34px; height: 34px; border-radius: 50%; background: var(--card); display: grid; place-items: center; font-size: .66rem; font-weight: 800; }

/* unit header and tabs */
.unithead { border-top: 6px solid var(--c); background: var(--card); border-radius: 0 0 16px 16px; padding: 4px 16px 12px; margin: 0 -16px; }
.unithead .uh { display: flex; align-items: center; gap: 10px; }
.unithead .num { background: var(--c); color: #fff; font-weight: 800; padding: 2px 10px; border-radius: 8px; font-size: 1.2rem; }
.unithead .meta { display: flex; flex-wrap: wrap; gap: 4px 16px; font-size: .9rem; }
.unithead .meta b { color: var(--c); }
.unithead .pages { color: var(--muted); font-size: .85rem; margin-top: 4px; }
.summary { margin: 8px 0 0; }
.obj { margin: 6px 0 0; padding-left: 20px; font-size: .92rem; }
.tabs { display: flex; gap: 4px; overflow-x: auto; margin: 12px 0 4px; padding-bottom: 2px; }
.tabs a { white-space: nowrap; text-decoration: none; padding: 8px 14px; border-radius: 999px; font-weight: 700; background: var(--card); border: 1px solid var(--line); }
.tabs a.on { background: var(--brand); color: #fff; border-color: var(--brand); }

/* book modules */
.module { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 10px 12px; margin: 8px 0; }
.module.key, .module.examples, .module.form, .module.tip { background: color-mix(in srgb, var(--card) 88%, var(--brand)); }
.mh { display: flex; align-items: center; gap: 10px; }
.mid { font-weight: 800; min-width: 3.2ch; }
.mt { flex: 1; display: flex; flex-direction: column; } .mt small { color: var(--muted); }
.done { font-size: .85rem; white-space: nowrap; }
.maudio { margin-top: 8px; }
.items { display: flex; flex-wrap: wrap; gap: 6px; margin: 6px 0; }
.it { min-width: 40px; height: 40px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg); color: var(--ink); font: inherit; font-weight: 700; cursor: pointer; }
.playing { background: var(--brand) !important; color: #fff !important; border-color: var(--brand) !important; }

/* practice list */
.acts { display: grid; gap: 8px; }
.actcard { display: flex; align-items: center; gap: 12px; text-decoration: none; background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 10px 12px; }
.actcard .at { flex: 1; display: flex; flex-direction: column; } .actcard small { color: var(--muted); }
.score { font-weight: 800; font-size: .9rem; padding: 4px 10px; border-radius: 999px; background: var(--bg); }
.score.ok { color: var(--ok); background: var(--ok-bg); } .score.mid { color: var(--mid); }

/* activity player */
.player { background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 14px 16px; box-shadow: var(--shadow); }
.chip { display: inline-block; font-size: .8rem; font-weight: 800; padding: 2px 10px; border-radius: 999px; background: var(--bg); color: var(--grammar); }
.chip.listening { color: var(--listening); } .chip.vocabulary { color: var(--vocabulary); } .chip.writing { color: var(--writing); } .chip.reading { color: var(--reading); }
.instr { margin: 4px 0 8px; color: var(--muted); }
.passage { background: var(--bg); border-radius: 10px; padding: 10px 12px; margin: 8px 0; white-space: pre-line; }
.bank { display: flex; flex-wrap: wrap; gap: 6px; margin: 8px 0; padding: 8px; border: 1px dashed var(--line); border-radius: 10px; }
.bank span { padding: 2px 8px; background: var(--bg); border-radius: 6px; }
.bar { height: 6px; background: var(--line); border-radius: 6px; overflow: hidden; margin: 8px 0 12px; }
.bar i { display: block; height: 100%; width: 0; background: var(--brand); transition: width .3s; }
.count { color: var(--muted); font-weight: 700; font-size: .85rem; }
.sentence { font-size: 1.2rem; margin: 10px 0; line-height: 2; }
.q { font-size: 1.12rem; font-weight: 600; margin: 10px 0; }
.hint { color: var(--muted); font-size: .9rem; }
.picks { display: inline-flex; gap: 4px; align-items: center; margin: 0 4px; }
.pick { font: inherit; font-weight: 700; padding: 2px 12px; border-radius: 8px; border: 2px solid var(--line); background: var(--bg); color: var(--ink); cursor: pointer; }
.pick.struck { text-decoration: line-through; opacity: .6; }
.slash { color: var(--muted); }
.opts { display: grid; gap: 8px; margin: 8px 0; }
.opts.two { grid-template-columns: 1fr 1fr; }
.opt { font: inherit; text-align: left; padding: 12px 14px; border: 2px solid var(--line); border-radius: 12px; background: var(--card); color: var(--ink); cursor: pointer; }
.opt:hover:not(:disabled) { border-color: var(--brand); }
.fb { margin: 12px 0 6px; padding: 0; border-radius: 10px; }
.fb.ok, .fb.no { padding: 10px 12px; } .fb.ok { background: var(--ok-bg); color: var(--ok); } .fb.no { background: var(--no-bg); color: var(--no); }
.fb div { color: var(--ink); }
.next { margin-top: 6px; }
.listenrow { display: flex; align-items: center; gap: 8px; margin: 8px 0; flex-wrap: wrap; }
.sound { width: 52px; height: 52px; border-radius: 50%; border: none; background: var(--listening); color: #fff; font-size: 1.4rem; cursor: pointer; }
.examples .sound { width: 34px; height: 34px; font-size: .95rem; }
.ex { display: flex; align-items: center; gap: 8px; margin: 6px 0; }
.line, .pool { display: flex; flex-wrap: wrap; gap: 6px; min-height: 52px; padding: 8px; border-radius: 12px; margin: 8px 0; }
.line { border: 2px dashed var(--line); }
.tile { font: inherit; font-weight: 700; padding: 8px 12px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg); color: var(--ink); cursor: pointer; }
.match { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.mcol { display: grid; gap: 6px; align-content: start; }
.mcard { font: inherit; padding: 10px; border-radius: 10px; border: 2px solid var(--line); background: var(--card); color: var(--ink); cursor: pointer; text-align: left; }
.mcard.sel { border-color: var(--brand); }
.tapline .word { font: inherit; border: none; background: none; color: var(--ink); padding: 0 2px; border-radius: 6px; cursor: pointer; border-bottom: 2px dotted var(--line); }
.tapline .word.sel { background: color-mix(in srgb, var(--brand) 25%, transparent); }
.speak { text-align: center; }
.mic { width: 84px; height: 84px; border-radius: 50%; border: none; font-size: 2rem; background: var(--speaking); color: #fff; cursor: pointer; margin: 8px auto; display: block; box-shadow: 0 4px 14px rgba(240,124,30,.35); }
.mic.on { animation: pulse 1s infinite; background: var(--no); }
@keyframes pulse { 50% { transform: scale(1.08); } }
.speak .listenrow, .speak .row { justify-content: center; }
.heard { min-height: 1.5em; }
.result { text-align: center; padding: 10px 0; }
.result .big { font-size: 3rem; font-weight: 800; } .big.ok { color: var(--ok); } .big.mid { color: var(--mid); } .big.no { color: var(--no); }
.result .row { justify-content: center; }

/* words */
.flash { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 8px; margin-top: 8px; }
.fcard { font: inherit; display: flex; gap: 8px; align-items: center; padding: 12px; border-radius: 12px; border: 1px solid var(--line); background: var(--card); color: var(--ink); cursor: pointer; text-align: left; }

/* checklists and writing */
.checkline { display: flex; gap: 8px; align-items: baseline; padding: 6px 0; border-bottom: 1px solid var(--line); }
.checkline:last-child { border-bottom: none; }
.checkline input, .done input { width: 20px; height: 20px; accent-color: var(--ok); }
.writer { width: 100%; font: inherit; font-size: 1.05rem; line-height: 1.7; padding: 12px; border: 2px solid var(--line); border-radius: 12px; background: var(--card); color: var(--ink); resize: vertical; }
.writer:focus { outline: none; border-color: var(--gw); }
.wstats { color: var(--muted); font-size: .9rem; } .wstats .ok { color: var(--ok); font-weight: 800; }
.wtips { color: var(--no); font-size: .92rem; } .wtips .ok { color: var(--ok); }
.timer { font-size: 1.4rem; font-weight: 800; color: var(--gw); }
.lesson ul { padding-left: 20px; }
.tbl { width: 100%; border-collapse: collapse; } .tbl th, .tbl td { text-align: left; padding: 6px 4px; border-bottom: 1px solid var(--line); }