*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

/* Font Viet am hon — tron trinh, bo cung. Nhung file da tai san, chay offline. */
@font-face{font-family:'Nunito-vi';src:url('../fonts/Nunito-vi.woff2') format('woff2');
  font-weight:400 700;font-display:swap;unicode-range:U+0000-00FF,U+0102-01B0,U+1EA0-1EF9,U+20AB;}
@font-face{font-family:'Quicksand-vi';src:url('../fonts/Quicksand-vi.woff2') format('woff2');
  font-weight:500 700;font-display:swap;unicode-range:U+0000-00FF,U+0102-01B0,U+1EA0-1EF9,U+20AB;}

:root{
  /* Tong am, mem — thay cho xanh navy/xam lanh truoc do. Tuong phan da kiem tra WCAG,
     tat ca >=4.5:1 (chuan AA), nhieu cho dat AAA (>=7). */
  --bg:#2e2419; --card:#3a2f22; --card2:#463829; --line:#5c4a35;
  --fg:#f5ece0; --dim:#c2ad96;
  --accent:#e07a5f;      /* coral — dung lam CHU/vien tren nen trang cua theme nay (>=4.5:1) */
  --accent-btn:#b8432a;  /* coral DAM hon — rieng cho nen nut, luon di voi CHU TRANG.
                             Mot mau, khong doi theo theme, vi tuong phan voi trang thi co dinh. */
  --ink-btn:#fff;        /* chu tren nut mau — TRANG, khong phai nau/den — dung yeu cau cua Tina */
  --gold:#e5b567;        /* giu nguyen — dung cho tag AM va co "mo mieng" */
  --ok:#5fbf8a; --no:#e2645c;
  --sem:#5b9cff; --pho:#c77dff;  /* GIU NGUYEN — day la ma mau NGHIA/AM co chuc nang su pham, khong doi */
  --pad:16px;
  /* MOT font duy nhat cho toan bo chu Viet — truoc co 2 font (Quicksand tieu de + Nunito
     than bai) bi phan anh la "khong thong nhat". Gop lai, dung Quicksand cho tat ca. */
  --vi: 'Quicksand-vi', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --vi-head: var(--vi);
}
@media (prefers-color-scheme:light){
  :root{--bg:#fbf3ec;--card:#fffaf6;--card2:#f6e9df;--line:#ecdccb;--fg:#3a281c;--dim:#8a7364;
    --accent:#b8432a}  /* accent nhat #e07a5f khong du tuong phan lam CHU tren nen sang — doi rieng */
}
html,body{height:100%}
body{
  background:var(--bg);color:var(--fg);
  font:16px/1.55 var(--vi);
  -webkit-font-smoothing:antialiased;
  padding-bottom:calc(64px + env(safe-area-inset-bottom));
  overscroll-behavior-y:contain;
}
main{max-width:640px;margin:0 auto;padding:var(--pad)}
h1{font-size:20px;margin-bottom:6px;font-family:var(--vi-head)}
.lead{color:var(--dim);font-size:14px;margin-bottom:14px}

/* thanh tren */
#bars{position:sticky;top:0;z-index:20;background:var(--bg)}
#timebar{height:3px;background:var(--accent);width:100%;transition:width .25s linear}
#timebar.low{background:var(--gold)}
#progress{height:2px;background:var(--dim);opacity:.5;width:0;transition:width .3s}

#counter{color:var(--dim);font-size:12px;text-align:right;letter-spacing:.05em;margin-bottom:8px}

/* the */
#card{display:flex;flex-direction:column;gap:12px}
.kicker{font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--dim);text-align:center}
.kicker.gold{color:var(--gold)}
.glyph-big{font-size:104px;line-height:1.1;text-align:center;font-family:var(--han)}
.glyph-mid{font-size:56px;line-height:1.2;text-align:center;font-family:var(--han)}
.hv{text-align:center;color:var(--dim);font-size:15px}
.variants{text-align:center;color:var(--dim);font-size:14px}
.guess-note{background:rgba(229,181,103,.12);border:1px solid rgba(229,181,103,.35);color:var(--gold);
  padding:10px 12px;border-radius:10px;font-size:14px;text-align:center}
.produced{background:rgba(91,156,255,.12);border:1px solid rgba(91,156,255,.3);
  padding:10px 12px;border-radius:10px;font-size:14px;text-align:center;color:var(--accent)}
.produced span{font-size:18px}

/* muc */
.sec{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:13px 14px}
.sec-t{font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--dim);margin-bottom:6px}
.sec-b{font-size:15px}
.sec-b.why{color:var(--accent);margin-top:8px}
.sec.note{border-color:rgba(91,156,255,.4)}
.sec.warn{border-color:rgba(240,98,95,.45)}
.sec.warn .sec-t{color:var(--no)}
.sec.unlock{border-color:rgba(78,201,126,.4)}
.sec.unlock .sec-t{color:var(--ok)}
.share{font-size:13px;color:var(--gold);margin-bottom:8px}
.intro{color:var(--dim);font-size:15px;margin-bottom:14px}
.tip{margin-top:10px;padding-top:10px;border-top:1px solid var(--line);font-size:14px;color:var(--dim)}

/* luoi chu mo khoa */
.ugrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(74px,1fr));gap:8px;margin-top:8px}
.ucell{background:var(--card2);border-radius:9px;padding:8px 4px;text-align:center}
.ucell.phon{border:1px solid rgba(199,125,255,.5)}
.uc{font-size:30px;font-family:var(--han);line-height:1.2}
.uc.small{font-size:22px}
.up{font-size:12px;color:var(--accent)}
.um{font-size:12px;color:var(--dim);line-height:1.3}
.urole{font-size:10px;color:var(--pho);margin-top:2px}

/* lua chon */
.options{display:flex;flex-direction:column;gap:9px;margin-top:4px}
.opt{background:var(--card);border:1px solid var(--line);color:var(--fg);
  padding:15px 14px;border-radius:11px;font-size:16px;text-align:left;cursor:pointer;
  -webkit-tap-highlight-color:transparent;transition:transform .06s}
.opt:active{transform:scale(.985)}
.opt:disabled{opacity:.5}
.opt.right{background:rgba(78,201,126,.18);border-color:var(--ok);opacity:1}
.opt.wrong{background:rgba(240,98,95,.18);border-color:var(--no);opacity:1}

.feedback{padding:13px 14px;border-radius:11px;font-size:15px;line-height:1.6}
.feedback.ok{background:rgba(78,201,126,.12);border:1px solid rgba(78,201,126,.35)}
.feedback.no{background:rgba(240,98,95,.1);border:1px solid rgba(240,98,95,.3)}
.tag{font-size:10px;letter-spacing:.06em;text-transform:uppercase;padding:2px 6px;border-radius:5px;
  background:var(--card2);color:var(--dim)}
.tag.sem{background:rgba(91,156,255,.2);color:var(--sem)}
.tag.pho{background:rgba(199,125,255,.2);color:var(--pho)}

#sync-code{display:block;width:100%;box-sizing:border-box;background:var(--card2);color:var(--fg);
  border:1px solid var(--line);border-radius:9px;padding:11px 12px;font-size:15px;margin:10px 0}
#btn-sync{width:100%}
#sync-status{margin-top:8px;color:var(--dim)}
button.primary{background:var(--accent-btn);color:var(--ink-btn);border:0;padding:15px;border-radius:11px;
  font-size:16px;font-weight:700;font-family:var(--vi-head);cursor:pointer;margin-top:4px;width:100%}
label.ghost{display:block;text-align:center;color:var(--dim);font-size:14px;margin-top:10px;cursor:pointer;
  text-decoration:underline}

/* xong phien */
.done-num{font-size:64px;text-align:center;font-weight:700;color:var(--ok);line-height:1.1;font-family:var(--vi-head)}
.done-lbl{text-align:center;color:var(--dim);font-size:13px}
.donerow{display:grid;grid-template-columns:repeat(auto-fit,minmax(100px,1fr));gap:9px;margin-top:6px}
.st{background:var(--card);border:1px solid var(--line);border-radius:11px;padding:12px 8px;text-align:center}
.st-v{font-size:21px;font-weight:700;font-family:var(--vi-head)}
.st-l{font-size:11px;color:var(--dim);line-height:1.35;margin-top:3px}
.adapt{background:var(--card2);border-radius:9px;padding:10px 12px;font-size:13px;color:var(--dim)}

/* he thong */
.exlist{margin-top:9px;display:flex;flex-direction:column;gap:6px}
.ex{display:flex;gap:11px;align-items:baseline}
.ex-c{font-size:26px;font-family:var(--han);min-width:34px}
.ex-n{font-size:13px;color:var(--dim)}
.lay{padding:9px 0;border-top:1px solid var(--line)}
.lay-n{font-size:15px;font-weight:600}
.lay-f{font-size:12px;color:var(--dim)}
.lay-e{font-size:14px;color:var(--accent);margin-top:3px;font-family:var(--han)}
.lay.trap .lay-e{color:var(--no);font-family:inherit}

/* soi lai */
.search{width:100%;background:var(--card);border:1px solid var(--line);color:var(--fg);
  padding:13px;border-radius:11px;font-size:16px;margin-bottom:12px}
.sec.soi{margin-bottom:10px}
.soi-head{display:flex;gap:14px;align-items:center}
.soi-c{font-size:52px;font-family:var(--han);line-height:1}
.soi-p{color:var(--accent);font-size:15px}
.soi-m{font-size:15px}
.soi-hsk{font-size:11px;color:var(--dim)}
.soi-type{font-size:13px;color:var(--gold);margin:9px 0}
.part{background:var(--card2);border-radius:9px;padding:9px 11px;font-size:14px;margin-bottom:6px;line-height:1.55}
.part .ori{color:var(--dim);font-size:13px}
.fam{margin-top:8px;border-top:1px solid var(--line);padding-top:8px}
.fam-t{font-size:11px;text-transform:uppercase;letter-spacing:.08em;color:var(--dim);margin-bottom:6px}
.famrow{display:flex;flex-wrap:wrap;gap:7px}
.famc{background:var(--card2);border-radius:8px;padding:5px 8px;text-align:center;min-width:52px}

/* tab */
#tabs{position:fixed;left:0;right:0;bottom:0;display:flex;background:var(--card);
  border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom);z-index:30}
.tab{flex:1;background:none;border:0;color:var(--dim);padding:15px 4px;font-size:13px;cursor:pointer;
  font-family:var(--vi-head);font-weight:600}
.tab.on{color:var(--accent);font-weight:600}

/* ============ v0.1 — kham pha, ngon ngu mau, khong cuon ============ */

/* C: nut luon dinh day, khong bao gio phai cuon xuong moi bam duoc */
body{padding-bottom:calc(150px + env(safe-area-inset-bottom))}
.footbar{position:fixed;left:0;right:0;bottom:calc(56px + env(safe-area-inset-bottom));
  padding:10px 16px;background:linear-gradient(to top,var(--bg) 62%,transparent);z-index:25}
.footbar .primary{max-width:608px;margin:0 auto;display:block}
/* .footbar.held: khong con dung — bo auto-chuyen thi khong can trang thai "giu lai" nay nua */

/* A: the kham pha */
.ask{font-size:18px;font-weight:700;text-align:center;line-height:1.45;margin:2px 0 4px;font-family:var(--vi-head)}
.evrow{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin:8px 0}
.evc{background:var(--card);border:1px solid var(--line);border-radius:11px;padding:12px 4px;text-align:center}
.ev-ch{font-size:40px;line-height:1.1;font-family:var(--han)}
.ev-ch.small{font-size:30px}
.ev-p{font-size:11px;color:var(--accent);margin-top:2px}
.ev-m{font-size:12px;color:var(--dim);line-height:1.3;margin-top:3px}
.found{text-align:center;font-size:14px;color:var(--ok);
  background:rgba(78,201,126,.12);border-radius:9px;padding:7px 10px}
.han-opt{font-size:22px;font-family:var(--han);text-align:center;padding:13px}
.reveal-name{text-align:center;font-size:27px;font-weight:700;color:var(--sem);font-family:var(--vi-head)}
.sem-ink{color:var(--sem)}
.origin-box{background:var(--card);border:1px solid var(--line);border-left:3px solid var(--sem);
  border-radius:10px;padding:12px 14px;font-size:15px;line-height:1.6}
.ob-t{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--dim);display:block;margin-bottom:3px}
details.more{background:var(--card2);border-radius:10px;padding:10px 13px}
details.more summary{cursor:pointer;font-size:13px;color:var(--dim);list-style:none}
details.more summary::after{content:' ▾'}
details.more[open] summary::after{content:' ▴'}
.more-b{font-size:14px;line-height:1.6;margin-top:9px;color:var(--fg)}
.more-b.warn-b{color:var(--no)}

/* B: ngon ngu mau NGHIA / AM */
.formula{display:flex;align-items:center;flex-wrap:wrap;gap:7px;
  background:var(--bg);border-radius:10px;padding:11px 10px;margin-top:9px}
.f-res{font-size:34px;font-family:var(--han);line-height:1}
.f-eq,.f-plus{font-size:16px;color:var(--dim);font-weight:700}
.chip{display:flex;flex-direction:column;align-items:center;gap:2px;min-width:58px;
  border-radius:9px;padding:6px 9px}
.chip-g{font-size:25px;line-height:1.15;font-family:var(--han)}
.chip-r{font-size:9.5px;font-weight:800;letter-spacing:.07em}
.chip-m{font-size:11px;text-align:center;line-height:1.25;opacity:.9}
.chip.sem{background:rgba(91,156,255,.16);color:var(--sem)}
.chip.pho{background:rgba(229,181,103,.18);color:var(--gold)}
.chip.oth{background:var(--card2);color:var(--dim)}
.fb-head{font-size:16px;font-weight:600;font-family:var(--han)}
.fb-story{font-size:13.5px;line-height:1.55;color:var(--dim);margin-top:8px;
  padding:9px 10px;border-radius:9px;background:var(--card2)}
.pho-ink{color:var(--gold)}
.power{background:rgba(78,201,126,.1);border:1px solid rgba(78,201,126,.35);
  border-radius:12px;padding:14px;font-size:15px;line-height:1.6;text-align:center}
.power b{color:var(--ok)}
.powerrow{display:flex;justify-content:center;flex-wrap:wrap;gap:8px;margin-top:9px}
.powerrow span{font-size:32px;font-family:var(--han);
  background:var(--card);border-radius:9px;padding:4px 11px}

/* D: tranh va chu la HAI O RIENG dat canh nhau — khong chong len nhau (chong lam mo ca hai). */
.morph-wrap{display:flex;flex-direction:column;align-items:center;gap:2px;width:100%;margin:0 auto}
.morph-row{display:flex;align-items:center;justify-content:center;gap:12px}
.morph-row .box{width:118px;height:118px;border-radius:16px;background:var(--card2);
  border:1px solid var(--line);display:flex;align-items:center;justify-content:center;flex-shrink:0}
.morph-row .box.pic svg{width:74%;height:74%;color:var(--ink)}
.morph-row .box.ch .glyph{font-family:var(--han);font-size:66px;line-height:1;color:var(--fg)}
.morph-ar{font-size:20px;color:var(--dim);flex-shrink:0}
.morph-v{font-size:13px;color:var(--dim);margin-top:10px}
.morph-cap{font-size:13.5px;color:var(--dim);text-align:center;font-style:italic;line-height:1.5;
  margin-top:2px}

.draw{width:118px;height:118px;color:var(--ink);background:var(--paper);
  border:1px solid var(--line);border-radius:14px;padding:9px}
.draw svg{width:100%;height:100%;display:block}
.draw.sm{width:64px;height:64px;padding:6px;border-radius:10px}

/* ============ FONT + MUC HINH VE ============ */
:root{
  /* 楷体 — chu viet but long, net co day mong, thay duoc huong but.
     Day la font day nhan mat chu o TQ. Windows: KaiTi. iOS: Kaiti SC.
     Android thuong khong co kai → tu roi ve Noto Serif SC. */
  --han: "KaiTi","Kaiti SC","STKaiti","楷体","TW-Kai","BiauKai",
         "Noto Serif SC","Songti SC","SimSun",serif;
  --ink:#6b4f3a;        /* muc nau am — khong phai xanh so do ky thuat */
  --paper:#faf6ef;
}
@media (prefers-color-scheme:dark){
  :root{ --ink:#e0c19c; --paper:#3a2f22 }
}

/* Hai do day net: net chinh day, net phu mong → co lop lang, bot cam giac so do */
.draw svg{stroke-width:4.2}
.draw svg [opacity]{stroke-width:2.1}
.draw.sm svg{stroke-width:5}
.draw.sm svg [opacity]{stroke-width:2.6}

/* Net tu ve ra — dong luc chinh cua "sinh dong" */
@keyframes ink-draw{to{stroke-dashoffset:0}}
.draw svg>*{transition:opacity .32s ease}

/* O hinh ve: giay am, vien mem */
.draw{border:1px solid rgba(140,110,80,.22);box-shadow:0 1px 3px rgba(90,60,30,.07)}
.morph-g{color:var(--fg)}

/* Kenh Nghe — icon SVG rieng (khong dung emoji, render lech giua cac may) */
.play-box{display:flex;flex-direction:column;align-items:center;gap:12px;padding:24px 0}
.play-btn{width:104px;height:104px;border-radius:50%;border:0;background:var(--accent-btn);
  color:var(--ink-btn);cursor:pointer;box-shadow:0 8px 20px rgba(184,67,42,.4);
  -webkit-tap-highlight-color:transparent;display:flex;align-items:center;justify-content:center;
  padding:0;animation:pulse-invite 1.8s ease-out 2}
.play-btn svg{width:42px;height:42px}
.play-btn:active{transform:scale(.92)}
@keyframes pulse-invite{
  0%{box-shadow:0 8px 20px rgba(184,67,42,.4),0 0 0 0 rgba(184,67,42,.5)}
  70%{box-shadow:0 8px 20px rgba(184,67,42,.4),0 0 0 16px rgba(184,67,42,0)}
  100%{box-shadow:0 8px 20px rgba(184,67,42,.4),0 0 0 0 rgba(184,67,42,0)}
}
.play-hint{font-size:13.5px;color:var(--dim)}

/* Tu vung HSK3 */
.vocab-m{text-align:center;font-size:17px;margin-top:2px}
.vocab-hv{text-align:center;font-size:13px;margin-top:8px;padding:8px 12px;border-radius:9px}
.vocab-hv.ok{background:rgba(95,191,138,.14);color:var(--ok)}
.vocab-hv.warn{background:rgba(226,100,92,.14);color:var(--no)}

/* Het the cho luc nay */
.empty-icon{font-size:56px;text-align:center;color:var(--ok);margin:20px 0 8px}
.empty-msg{text-align:center;color:var(--dim);font-size:15px;line-height:1.6;
  max-width:320px;margin:0 auto;padding:0 12px}

.override-note{font-size:12.5px;color:var(--dim);text-align:center;line-height:1.6;
  max-width:320px;margin:16px auto 0;padding:10px 14px;background:var(--card2);border-radius:10px}

.unclear-link{display:block;width:100%;background:none;border:0;color:var(--dim);
  font-size:13.5px;text-decoration:underline;padding:10px;margin-top:2px;cursor:pointer;
  font-family:var(--vi)}

#piper-banner{position:sticky;top:5px;z-index:19;margin:0 auto;max-width:600px;
  background:var(--card2);border:1px solid var(--line);border-radius:10px;
  padding:8px 14px;text-align:center;font-size:12.5px;color:var(--dim)}

/* Nghe + khung tinh tung net, o man lo dap an (bo thu + tu vung moi) */
.listen-inline{display:inline-flex;align-items:center;gap:6px;margin:10px auto 2px;
  padding:8px 16px;background:var(--card2);border-radius:20px;color:var(--accent);
  font-size:13.5px;cursor:pointer;width:fit-content}
.strip-holder{margin-top:10px}
.stroke-strip{display:flex;gap:6px;overflow-x:auto;padding:2px 2px 8px}
.stroke-frame{flex:0 0 auto;width:52px;height:52px;background:var(--card2);
  border:1px solid var(--line);border-radius:9px}
.stroke-frame svg{width:100%;height:100%;display:block}
.stroke-word-wrap{display:flex;flex-direction:column;gap:8px;margin-top:8px}
.stroke-word-row{display:flex;align-items:center;gap:8px}
.stroke-word-label{flex:0 0 auto;width:36px;height:36px;display:flex;align-items:center;
  justify-content:center;font-family:var(--han);font-size:20px;color:var(--dim);
  background:var(--card2);border-radius:8px}