:root{
  --bg:#EDF2EF; --surface:#FFFFFF; --surface-2:#E1EAE5; --ink:#15211D; --muted:#5A6A64; --line:#D0DBD5;
  --jade:#11705B; --jade-soft:#D4E9E0; --on-jade:#FFFFFF;
  --seal:#B5332A; --on-seal:#FFF6F2;
  --good:#1D7A4B; --good-soft:#DAEFE2; --bad:#B5332A; --bad-soft:#F6DFDB; --warn:#9A6200; --warn-soft:#F6EBD3;
  --t1:#D03A2F; --t2:#CF7A00; --t3:#2C8A43; --t4:#2E60C4; --t5:#86918C;
  --grid:#E2BDB7; --ghost:rgba(21,33,29,.12); --ref:#9AA7A1;
  --shadow:0 1px 2px rgba(18,40,31,.05),0 10px 30px rgba(18,40,31,.08);
  --hz:"Noto Serif SC","Songti SC","STSong","SimSun",serif;
  --ui:"Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){
  :root{
    color-scheme:dark;
    --bg:#0D1412; --surface:#151F1C; --surface-2:#1D2925; --ink:#E3ECE8; --muted:#93A49E; --line:#283632;
    --jade:#4CBD9B; --jade-soft:#18362D; --on-jade:#05221A;
    --seal:#D9594E; --on-seal:#1C0806;
    --good:#5ACB8C; --good-soft:#163426; --bad:#EE7B70; --bad-soft:#3A1D1A; --warn:#E3A94A; --warn-soft:#3A2D14;
    --t1:#FF6E61; --t2:#F2A93B; --t3:#5DCB76; --t4:#7AA2FF; --t5:#8E9A95;
    --grid:#553431; --ghost:rgba(227,236,232,.13); --ref:#5E6D67;
    --shadow:0 1px 2px rgba(0,0,0,.3),0 10px 30px rgba(0,0,0,.35);
  }
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{background:var(--bg);-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--ui);font-size:15px;line-height:1.5;padding-inline:16px;-webkit-tap-highlight-color:transparent}
button{font:inherit;color:inherit;cursor:pointer}
input{font:inherit}
:focus-visible{outline:2px solid var(--jade);outline-offset:2px}
.app{max-width:600px;margin:0 auto;padding-top:calc(10px + env(safe-area-inset-top,0px));padding-bottom:calc(96px + env(safe-area-inset-bottom,0px))}
.hz{font-family:var(--hz);font-weight:500}
.t1{color:var(--t1)}.t2{color:var(--t2)}.t3{color:var(--t3)}.t4{color:var(--t4)}.t5{color:var(--t5)}
svg.i{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;flex:none}

/* top bar */
.top{display:flex;align-items:center;gap:10px;padding-block:6px 16px}
.seal{width:36px;height:36px;border-radius:7px;background:var(--seal);color:var(--on-seal);font-family:var(--hz);font-weight:700;font-size:21px;display:grid;place-items:center;transform:rotate(-4deg)}
.brand{font-weight:700;font-size:17px;line-height:1.15}
.brand small{display:block;font-weight:500;font-size:12px;color:var(--muted)}
.top .grow{flex:1}
.pill{display:inline-flex;align-items:center;gap:6px;padding:5px 11px;border-radius:999px;background:var(--surface);border:1px solid var(--line);font-weight:600;font-size:13px;font-variant-numeric:tabular-nums}
.pill svg{width:16px;height:16px;color:var(--seal)}

/* bottom nav */
nav.tabs{position:fixed;left:0;right:0;bottom:0;z-index:20;background:var(--surface);border-top:1px solid var(--line);padding:6px 8px calc(6px + env(safe-area-inset-bottom,0px));display:flex;justify-content:center}
nav.tabs .inner{display:grid;grid-template-columns:repeat(5,1fr);width:100%;max-width:600px}
nav.tabs button{background:none;border:0;color:var(--muted);font-size:11px;font-weight:600;display:flex;flex-direction:column;align-items:center;gap:3px;padding:6px 2px;border-radius:10px}
nav.tabs button svg{width:23px;height:23px}
nav.tabs button[aria-current="page"]{color:var(--jade)}

/* type + layout */
h1{font-size:25px;line-height:1.25;margin:0;text-wrap:balance;letter-spacing:-.01em;font-weight:700}
h2{font-size:12px;text-transform:uppercase;letter-spacing:.09em;color:var(--muted);margin:0 0 12px;font-weight:600}
p{margin:0}
.eyebrow{font-size:13px;color:var(--muted);font-weight:500;margin-bottom:4px}
.stack{display:flex;flex-direction:column;gap:22px}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.muted{color:var(--muted)}
.small{font-size:13px}
.panel{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:16px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:10px 18px;border-radius:13px;border:1px solid var(--line);background:var(--surface);font-weight:600}
.btn.primary{background:var(--jade);color:var(--on-jade);border-color:transparent}
.btn.block{width:100%}
.btn.small{min-height:36px;padding:6px 12px;font-size:14px;border-radius:10px}
.btn:disabled{opacity:.45;cursor:default}
.icon-btn{width:42px;height:42px;border-radius:50%;border:1px solid var(--line);background:var(--surface);display:inline-grid;place-items:center;color:var(--jade);flex:none}
.icon-btn.on{background:var(--jade-soft);border-color:transparent}
.seg{display:inline-flex;background:var(--surface-2);border-radius:999px;padding:3px;gap:2px;flex-wrap:wrap}
.seg button{border:0;background:none;padding:6px 13px;border-radius:999px;font-weight:600;font-size:14px;color:var(--muted)}
.seg button[aria-pressed="true"]{background:var(--surface);color:var(--ink);box-shadow:0 1px 3px rgba(0,0,0,.12)}
.back{background:none;border:0;display:inline-flex;align-items:center;gap:4px;color:var(--muted);font-weight:600;padding:4px 0}
.levels{display:grid;grid-template-columns:repeat(7,1fr);gap:5px}
.lvl{border:1px solid var(--line);background:var(--surface);border-radius:12px;padding:8px 2px;display:flex;flex-direction:column;align-items:center;font-weight:700;font-size:17px;line-height:1.1}
.lvl small{font-size:9px;letter-spacing:-.02em;font-weight:600;color:var(--muted);margin-top:2px}
.lvl[aria-pressed="true"]{background:var(--ink);color:var(--bg);border-color:transparent}
.lvl[aria-pressed="true"] small{color:inherit;opacity:.7}

/* home */
.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}
.stat{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:12px}
.stat b{display:block;font-size:26px;line-height:1.1;font-variant-numeric:tabular-nums}
.stat span{font-size:12px;color:var(--muted)}
.stat.due b{color:var(--seal)}
.stat.new b{color:var(--jade)}
.wod{display:grid;grid-template-columns:auto 1fr auto;gap:14px;align-items:center;cursor:pointer;text-align:left;width:100%}
.wod .big{font-size:48px;line-height:1}
.wod .py{font-size:17px;font-weight:600}
.tones{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}
.tone{border:1px solid var(--line);background:var(--surface);border-radius:12px;padding:10px 6px;display:flex;flex-direction:column;align-items:center;gap:1px}
.tone .hz{font-size:24px;line-height:1.2}
.tone b{font-size:16px}
.tone small{font-size:11px;color:var(--muted);text-align:center;line-height:1.3}
.bar{height:8px;border-radius:99px;background:var(--surface-2);overflow:hidden;display:flex}
.bar i{display:block;height:100%}
.bar .m{background:var(--jade)}
.bar .l{background:color-mix(in srgb,var(--jade) 40%,transparent)}
.prog{display:flex;flex-direction:column;gap:6px}
.prog + .prog{margin-top:12px}
.prog .row{justify-content:space-between;font-size:14px}
.prog .row span{font-variant-numeric:tabular-nums;color:var(--muted);font-size:13px}
.setting{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;padding-block:10px}
.setting + .setting{border-top:1px solid var(--line)}
.feature{display:grid;grid-template-columns:auto 1fr auto;gap:14px;align-items:center;text-align:left;width:100%;background:var(--jade-soft);border:0;border-radius:16px;padding:14px 16px}
.feature .mic-dot{width:44px;height:44px;border-radius:50%;background:var(--jade);color:var(--on-jade);display:grid;place-items:center}
.feature b{display:block}
.feature small{color:var(--muted);font-size:13px}

/* flashcards */
.sess{display:flex;align-items:center;gap:12px;font-size:13px;color:var(--muted);font-variant-numeric:tabular-nums}
.sess .bar{flex:1}
.sess .bar i{background:var(--jade)}
.flash{background:var(--surface);border:1px solid var(--line);border-radius:22px;box-shadow:var(--shadow);padding:18px 16px 22px;min-height:380px;display:flex;flex-direction:column;align-items:center;gap:14px;cursor:pointer;text-align:center;position:relative}
.flash .tag{align-self:flex-start;font-size:12px;font-weight:600;padding:3px 9px;border-radius:99px;background:var(--surface-2);color:var(--muted)}
.flash .tag.new{background:var(--jade-soft);color:var(--jade)}
.flash .corner{position:absolute;top:12px;right:12px;display:flex;gap:8px}
.boxes{display:flex;gap:6px;justify-content:center;flex-wrap:wrap;align-items:center;max-width:100%}
.mizi{width:var(--s);height:var(--s);max-width:calc((100vw - 80px) / var(--n,1));max-height:calc((100vw - 80px) / var(--n,1));display:grid;place-items:center;font-size:calc(min(var(--s), (100vw - 80px) / var(--n,1)) * .74);line-height:1;border:1.5px solid var(--grid);
  background:
    linear-gradient(90deg,transparent calc(50% - .5px),var(--grid) calc(50% - .5px),var(--grid) calc(50% + .5px),transparent calc(50% + .5px)),
    linear-gradient(0deg,transparent calc(50% - .5px),var(--grid) calc(50% - .5px),var(--grid) calc(50% + .5px),transparent calc(50% + .5px)),
    linear-gradient(45deg,transparent calc(50% - .5px),color-mix(in srgb,var(--grid) 55%,transparent) 50%,transparent calc(50% + .5px)),
    linear-gradient(-45deg,transparent calc(50% - .5px),color-mix(in srgb,var(--grid) 55%,transparent) 50%,transparent calc(50% + .5px))}
.boxes .sep{font-size:28px;color:var(--muted)}
.flash .py{font-size:24px;font-weight:600;letter-spacing:.01em}
.hv{font-size:13px;color:var(--muted)}
.hv b{color:var(--seal);font-weight:600}
.flash .vi{font-size:20px;font-weight:600;text-wrap:balance}
.hint{margin-top:auto;font-size:14px;color:var(--jade);font-weight:600;display:flex;align-items:center;gap:6px}
.ex{width:100%;text-align:left;background:var(--surface-2);border-radius:14px;padding:12px 14px;display:grid;grid-template-columns:1fr auto;gap:2px 10px;align-items:center}
.ex .hz{font-size:19px}
.ex .expy{font-size:13px;color:var(--muted)}
.ex .exvi{font-size:14px}
.ex .ex-btns{grid-row:1/4;grid-column:2;display:flex;flex-direction:column;gap:6px}
.ex .icon-btn{width:38px;height:38px}
.grades{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}
.grade{border-radius:14px;padding:10px 4px;border:1px solid var(--line);background:var(--surface);font-weight:700;display:flex;flex-direction:column;align-items:center;gap:1px}
.grade small{font-weight:500;color:var(--muted);font-size:11px}
.grade.g0{color:var(--bad)}.grade.g1{color:var(--warn)}.grade.g2{color:var(--jade)}.grade.g3{color:var(--t4)}
.kbd{font-size:12px;color:var(--muted);text-align:center}
@media (hover:none){.kbd{display:none}}

/* practice */
.modes{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.mode{text-align:left;border:1px solid var(--line);background:var(--surface);border-radius:14px;padding:14px;display:flex;flex-direction:column;gap:4px}
.mode .hz{font-size:24px;color:var(--jade);line-height:1.2}
.mode b{font-size:15px}
.mode small{font-size:12px;color:var(--muted);line-height:1.4}
.mode.wide{grid-column:1/-1;flex-direction:row;align-items:center;gap:14px}
.mode.wide .hz{font-size:34px}
.mode.accent{background:var(--jade-soft);border-color:transparent}
.q{display:flex;flex-direction:column;gap:18px}
.q .prompt{background:var(--surface);border:1px solid var(--line);border-radius:20px;padding:22px 16px;display:flex;flex-direction:column;align-items:center;gap:12px;text-align:center;min-height:200px;justify-content:center}
.q .prompt .vi{font-size:24px;font-weight:700;text-wrap:balance}
.q .ask{font-size:14px;color:var(--muted);font-weight:500}
.listen-btn{width:96px;height:96px;border-radius:50%;border:0;background:var(--jade);color:var(--on-jade);display:grid;place-items:center}
.listen-btn svg{width:40px;height:40px}
.opts{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.opt{min-height:62px;padding:10px 12px;border-radius:14px;border:1.5px solid var(--line);background:var(--surface);font-weight:600;font-size:15px;line-height:1.3;display:flex;align-items:center;justify-content:center;text-align:center;gap:8px}
.opt.hzopt{font-family:var(--hz);font-size:26px;font-weight:500}
.opt.pyopt{font-size:22px}
.opt.correct{background:var(--good-soft);border-color:var(--good);color:var(--good)}
.opt.wrong{background:var(--bad-soft);border-color:var(--bad);color:var(--bad)}
.opt:disabled{cursor:default}
.reveal{display:flex;align-items:center;gap:12px;background:var(--surface-2);border-radius:14px;padding:12px 14px}
.reveal .hz{font-size:30px}
.reveal .txt{flex:1;min-width:0}
.score{font-size:64px;font-weight:700;line-height:1;font-variant-numeric:tabular-nums}
.score small{font-size:24px;color:var(--muted)}
.pads{display:flex;flex-wrap:wrap;gap:12px;justify-content:center}
.pad{position:relative;width:min(100%,240px);aspect-ratio:1;background:var(--surface);border-radius:6px}
.pads.multi .pad{width:min(calc(50% - 6px),200px)}
.pad canvas{position:absolute;inset:0;width:100%;height:100%;touch-action:none}

/* speaking */
.speak{display:flex;flex-direction:column;gap:14px;background:var(--surface);border:1px solid var(--line);border-radius:20px;padding:18px 16px}
.speak .target{display:flex;flex-wrap:wrap;justify-content:center;gap:6px 4px;align-items:flex-end}
.syl{display:flex;flex-direction:column;align-items:center;gap:2px;padding:4px 6px;border-radius:10px;min-width:36px}
.syl .hz{font-size:30px;line-height:1.1}
.syl .p{font-size:14px;font-weight:600}
.speak.long .syl .hz{font-size:22px}
.speak.long .syl{min-width:26px;padding:3px 3px}
.syl.good{background:var(--good-soft)}
.syl.tone{background:var(--warn-soft)}
.syl.bad{background:var(--bad-soft)}
.speak .vi{text-align:center;font-size:15px;color:var(--muted)}
.speak .controls{display:flex;justify-content:center;align-items:center;gap:22px}
.mic{width:84px;height:84px;border-radius:50%;border:0;background:var(--seal);color:var(--on-seal);display:grid;place-items:center;position:relative;box-shadow:0 6px 20px color-mix(in srgb,var(--seal) 35%,transparent)}
.mic svg{width:36px;height:36px}
.mic .ring{position:absolute;inset:-6px;border-radius:50%;border:3px solid var(--seal);opacity:0;transform:scale(calc(1 + var(--lv,0) * .35))}
.mic.rec .ring{opacity:.5}
.mic.rec{background:var(--ink);color:var(--bg)}
.mic.busy{opacity:.6}
.ctl{display:flex;flex-direction:column;align-items:center;gap:4px;font-size:12px;color:var(--muted);font-weight:600;background:none;border:0}
.ctl .icon-btn{width:48px;height:48px}
.ctl:disabled{opacity:.4}
.speak .status{text-align:center;font-size:14px;color:var(--muted);min-height:21px}
.pitchbox{position:relative}
.pitchbox canvas{width:100%;height:120px;display:block;border-radius:12px;background:var(--surface-2)}
.legend{display:flex;gap:14px;justify-content:center;font-size:12px;color:var(--muted);margin-top:6px}
.legend i{display:inline-block;width:14px;height:3px;border-radius:2px;vertical-align:middle;margin-right:5px}
.result{display:grid;grid-template-columns:auto 1fr;gap:14px;align-items:center}
.ring-score{--v:0;--c:var(--jade);width:84px;height:84px;border-radius:50%;background:conic-gradient(var(--c) calc(var(--v)*1%),var(--surface-2) 0);display:grid;place-items:center}
.ring-score span{width:66px;height:66px;border-radius:50%;background:var(--surface);display:grid;place-items:center;font-size:26px;font-weight:700;font-variant-numeric:tabular-nums}
.result b{font-size:17px}
.result .sub{font-size:13px;color:var(--muted);display:flex;flex-direction:column;gap:2px;margin-top:2px}
.heard{font-size:13px;color:var(--muted)}
.heard .hz{color:var(--ink);font-size:16px}

/* dictionary */
.search{display:flex;align-items:center;gap:8px;background:var(--surface);border:1.5px solid var(--line);border-radius:14px;padding:0 14px}
.search:focus-within{border-color:var(--jade)}
.search input{flex:1;min-width:0;border:0;background:none;font-size:16px;color:var(--ink);padding:13px 0;outline:none}
.chips{display:flex;gap:6px;flex-wrap:wrap}
.chip{border:1px solid var(--line);background:var(--surface);border-radius:99px;padding:5px 12px;font-size:13px;font-weight:600;color:var(--muted)}
.chip[aria-pressed="true"]{background:var(--ink);color:var(--bg);border-color:transparent}
.list{display:flex;flex-direction:column;background:var(--surface);border:1px solid var(--line);border-radius:16px;overflow:hidden}
.item{display:grid;grid-template-columns:minmax(64px,auto) 1fr auto;gap:12px;align-items:center;padding:11px 14px;border:0;background:none;text-align:left;width:100%}
.item + .item{border-top:1px solid var(--line)}
.item .hz{font-size:26px;line-height:1.2}
.item .l1{font-weight:600}
.item .l2{font-size:13px;color:var(--muted);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.item .lv{font-size:11px;font-weight:700;color:var(--muted);border:1px solid var(--line);border-radius:6px;padding:1px 6px}
.dot{width:8px;height:8px;border-radius:50%;display:inline-block;margin-left:6px;vertical-align:middle}
.dot.l{background:color-mix(in srgb,var(--jade) 45%,transparent)}.dot.m{background:var(--jade)}
.empty{padding:28px 16px;text-align:center;color:var(--muted)}

/* dialogues */
.topics{display:flex;flex-direction:column;gap:10px}
.topic{display:grid;grid-template-columns:52px 1fr auto;gap:14px;align-items:center;text-align:left;border:1px solid var(--line);background:var(--surface);border-radius:16px;padding:12px 14px}
.topic .hz{font-size:30px;color:var(--jade);text-align:center}
.topic b{display:block}
.topic small{color:var(--muted);font-size:13px}
.lines{display:flex;flex-direction:column;gap:10px}
.lineWrap{display:flex;align-items:flex-end;gap:6px}
.lineWrap.b{flex-direction:row-reverse}
.line{max-width:84%;padding:10px 14px;border-radius:16px;border:1px solid var(--line);background:var(--surface);text-align:left;display:flex;flex-direction:column;gap:2px}
.lineWrap.b .line{background:var(--jade-soft);border-color:transparent;border-bottom-right-radius:4px}
.lineWrap.a .line{border-bottom-left-radius:4px}
.line .who{font-size:11px;font-weight:700;color:var(--muted);text-transform:uppercase;letter-spacing:.06em}
.line .hz{font-size:21px;line-height:1.45}
.line .lpy{font-size:13px;color:var(--muted)}
.line .lvi{font-size:14px}
.line.speaking{box-shadow:0 0 0 2px var(--jade)}
.lineWrap .icon-btn{width:36px;height:36px;color:var(--seal)}
.sticky-actions{position:sticky;bottom:calc(76px + env(safe-area-inset-bottom,0px));display:flex;gap:8px;justify-content:center;padding-top:8px}

/* sheet */
.backdrop{position:fixed;inset:0;z-index:40;background:rgba(6,14,11,.45);display:flex;align-items:flex-end;justify-content:center}
.sheet{background:var(--bg);width:100%;max-width:600px;max-height:92%;overflow:auto;border-radius:22px 22px 0 0;padding:14px 16px calc(24px + env(safe-area-inset-bottom,0px));display:flex;flex-direction:column;gap:16px}
.sheet .grab{width:40px;height:5px;border-radius:9px;background:var(--line);align-self:center}
.sheet .head{display:flex;flex-direction:column;align-items:center;gap:8px;text-align:center}
.sheet .py{font-size:24px;font-weight:600}
.sheet .vi{font-size:19px;font-weight:600}
.status-pill{font-size:13px;font-weight:600;padding:4px 10px;border-radius:99px;background:var(--surface-2);color:var(--muted)}
.status-pill.learn{background:var(--jade-soft);color:var(--jade)}

.toast{position:fixed;left:50%;transform:translateX(-50%);bottom:calc(84px + env(safe-area-inset-bottom,0px));z-index:60;background:var(--ink);color:var(--bg);padding:10px 16px;border-radius:12px;font-size:14px;max-width:min(92vw,460px);text-align:center;box-shadow:var(--shadow)}
.loading{padding:40px 0;text-align:center;color:var(--muted)}
@media (max-width:380px){.opts{grid-template-columns:1fr}.modes{grid-template-columns:1fr}}
@media (prefers-reduced-motion:no-preference){
  .opt,.grade,.btn,.mode,.topic,.lvl{transition:transform .12s ease,background-color .15s}
  .opt:active,.grade:active,.btn:active,.mode:active,.topic:active,.lvl:active{transform:scale(.97)}
  .mic .ring{transition:transform .08s linear,opacity .2s}
}

/* viết chữ: thứ tự nét */
.writers{display:flex;flex-wrap:wrap;gap:16px;justify-content:center}
.wchar{display:flex;flex-direction:column;align-items:center;gap:8px;width:min(100%,260px)}
.writers.multi .wchar{width:min(calc(50% - 8px),220px)}
.wbox{width:100%!important;max-width:100%!important;max-height:none!important;background-color:var(--surface);border-radius:6px;touch-action:none}
.wbox svg{display:block}
.wmeta{font-size:13px;color:var(--muted);text-align:center;min-height:38px}
.wbtns{display:flex;gap:6px;flex-wrap:wrap;justify-content:center}
.wbtns .btn.small{padding:6px 10px;min-height:34px;font-size:13px}
.rules{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:12px 14px;margin-top:12px}
.rules summary{font-weight:600;cursor:pointer}
.rule-list{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:12px 0 8px}
.rule{display:flex;align-items:center;gap:10px;text-align:left;border:1px solid var(--line);background:var(--bg);border-radius:10px;padding:6px 10px;font-size:13px}
.rule .hz{font-size:26px;color:var(--jade);line-height:1.2}
@media (max-width:380px){.rule-list{grid-template-columns:1fr}}