/* =========================================================
   Chương trình Tu học GĐPT Việt Nam – style.css
   Màu lam chủ đạo; mỗi ngành một sắc riêng (rg1..rg5)
   ========================================================= */
:root{
  --bg:#eef3f6; --surface:#ffffff; --surface-2:#f6f9fb; --ink:#1b2a36; --muted:#56687a; --line:#d3dde4;
  --lam:#2c5f86; --lam-soft:#dce8f1; --gold:#9a7210; --gold-soft:#f6ecd2; --done:#2f8a57; --done-soft:#dff1e6;
  --r1:#e7f2e3; --r1-ink:#3f7a3a; --r2:#e2f0ee; --r2-ink:#1f6d64; --r3:#e1ebf6; --r3-ink:#2c5f86;
  --r4:#ebe6f4; --r4-ink:#5b3f8f; --r5:#f6f0de; --r5-ink:#82600f;
  --hill:rgba(44,95,134,.08); --trail:#b9a77a; --shadow:0 10px 30px rgba(20,40,60,.12); --scrim:rgba(10,20,30,.5);
  --display:"Alegreya",Georgia,"Times New Roman",serif;
  --body:"Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  --sen:#00a75a; --fs:16px; --radius:16px; --toph:62px; --k:1;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#0f1820; --surface:#16222d; --surface-2:#1a2834; --ink:#e4ecf2; --muted:#9db0bf; --line:#2a3946;
  --lam:#8fbde2; --lam-soft:#1d3346; --gold:#e0b54f; --gold-soft:#3a2f14; --done:#5cc58a; --done-soft:#173326;
  --r1:#16241a; --r1-ink:#8fcf86; --r2:#132522; --r2-ink:#6fcfbf; --r3:#14202d; --r3-ink:#8fbde2;
  --r4:#1d1a2a; --r4-ink:#c0aaf0; --r5:#221d10; --r5-ink:#e0b54f;
  --sen:#3fcf8a; --hill:rgba(127,178,218,.07); --trail:#7c6d47; --shadow:0 10px 30px rgba(0,0,0,.4); --scrim:rgba(0,0,0,.6);
  color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0f1820; --surface:#16222d; --surface-2:#1a2834; --ink:#e4ecf2; --muted:#9db0bf; --line:#2a3946;
  --lam:#8fbde2; --lam-soft:#1d3346; --gold:#e0b54f; --gold-soft:#3a2f14; --done:#5cc58a; --done-soft:#173326;
  --r1:#16241a; --r1-ink:#8fcf86; --r2:#132522; --r2-ink:#6fcfbf; --r3:#14202d; --r3-ink:#8fbde2;
  --r4:#1d1a2a; --r4-ink:#c0aaf0; --r5:#221d10; --r5-ink:#e0b54f;
  --sen:#3fcf8a; --hill:rgba(127,178,218,.07); --trail:#7c6d47; --shadow:0 10px 30px rgba(0,0,0,.4); --scrim:rgba(0,0,0,.6);
  color-scheme:dark}
:root[data-font="1"]{--fs:18px}
:root[data-font="2"]{--fs:20px}
.rg1{--rc:var(--r1-ink);--rb:var(--r1)} .rg2{--rc:var(--r2-ink);--rb:var(--r2)} .rg3{--rc:var(--r3-ink);--rb:var(--r3)}
.rg4{--rc:var(--r4-ink);--rb:var(--r4)} .rg5{--rc:var(--r5-ink);--rb:var(--r5)}

/* ---------- nền tảng ---------- */
*,*::before,*::after{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%;scroll-padding-top:calc(var(--toph) + 16px)}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--body);font-size:var(--fs);line-height:1.65;
  padding-bottom:env(safe-area-inset-bottom,0px)}
body::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);z-index:40;background:var(--surface)}
img{max-width:100%;height:auto}
a{color:var(--lam)}
h1,h2,h3{font-family:var(--display);text-wrap:balance;margin:0;line-height:1.15}
button{font:inherit;color:inherit}
:focus-visible{outline:3px solid var(--gold);outline-offset:2px}
.wrap{max-width:1180px;margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
.skip{position:absolute;left:-999px;top:8px;z-index:60;background:var(--surface);padding:8px 14px;border-radius:8px}
.skip:focus{left:12px}
.eyebrow{font-size:.75rem;letter-spacing:.14em;text-transform:uppercase;color:var(--rc,var(--gold));font-weight:700;margin:0}
.small{font-size:.8rem}

/* ---------- thanh trên cùng ---------- */
.top{position:sticky;top:env(safe-area-inset-top,0px);z-index:30;background:color-mix(in srgb,var(--surface) 92%,transparent);
  backdrop-filter:saturate(1.4) blur(10px);-webkit-backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--line)}
.topin{display:flex;align-items:center;gap:12px;min-height:60px}
.brand{display:flex;align-items:center;gap:8px;text-decoration:none;color:var(--ink);font-weight:600;white-space:nowrap;flex:none}
.brand b{color:var(--sen)}
.brand img{border-radius:50%}
.nganh{display:flex;gap:4px;overflow-x:auto;scrollbar-width:none;flex:1;min-width:0;mask-image:linear-gradient(90deg,#000 90%,transparent)}
.nganh::-webkit-scrollbar{display:none}
.nganh a{flex:none;font-size:.85rem;font-weight:600;text-decoration:none;padding:7px 12px;border-radius:999px;color:var(--ink);white-space:nowrap}
.nganh a:hover{background:var(--rb)}
.nganh a.on{background:var(--rb);color:var(--rc)}
.nganh .short{display:none}
@media (max-width:1024px){.nganh .full{display:none}.nganh .short{display:inline}.nganh{mask-image:none}}
.tools{display:flex;gap:4px;flex:none;margin-left:auto}
.tbtn{width:42px;height:42px;display:grid;place-items:center;border-radius:12px;border:1px solid transparent;background:none;cursor:pointer;font-weight:700;font-size:.95rem}
.tbtn:hover{background:var(--surface-2);border-color:var(--line)}
.tbtn svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
@media (max-width:720px){
  .topin{flex-wrap:wrap;gap:0 8px;min-height:0;padding-top:6px}
  .brand span{display:inline;font-size:.95rem}
  .nganh{order:3;flex-basis:100%;padding-bottom:6px;margin-inline:-4px}
  .nganh a{padding:6px 12px;font-size:.82rem;background:var(--surface-2)}
  .nganh .full{display:none}.nganh .short{display:inline}
  .nganh{mask-image:none}
  :root{--toph:100px}
}

/* ---------- tìm kiếm ---------- */
.searchbox{position:fixed;inset:0;z-index:50;background:var(--scrim);display:flex;justify-content:center;align-items:flex-start;
  padding:calc(env(safe-area-inset-top,0px) + 10vh) max(12px,env(safe-area-inset-right,0px)) 12px max(12px,env(safe-area-inset-left,0px))}
.sbin{width:min(680px,100%);background:var(--surface);border-radius:18px;box-shadow:var(--shadow);overflow:hidden;display:flex;flex-direction:column;max-height:78vh}
.sfield{display:flex;align-items:center;gap:8px;padding:8px 8px 8px 16px;border-bottom:1px solid var(--line)}
.sfield>svg{width:20px;height:20px;fill:none;stroke:var(--muted);stroke-width:2;flex:none}
.sfield input{flex:1;min-width:0;font:inherit;font-size:1.05rem;border:0;background:none;color:var(--ink);padding:10px 0;outline:none}
.shint{margin:0;padding:10px 16px;font-size:.85rem;color:var(--muted)}
.results{overflow:auto;padding:0 8px 8px}
.results a{display:block;text-decoration:none;color:var(--ink);padding:10px 12px;border-radius:12px}
.results a:hover,.results a.sel{background:var(--lam-soft)}
.results small{display:block;color:var(--muted);font-size:.8rem}
.results .rt{font-weight:600}
.results .m{display:inline-block;font-size:.7rem;font-weight:700;padding:0 6px;border-radius:6px;background:var(--gold-soft);color:var(--gold);margin-left:6px;vertical-align:1px}
@media (max-width:640px){.searchbox{padding-top:calc(env(safe-area-inset-top,0px) + 8px)}.sbin{max-height:calc(100dvh - 24px)}}

/* ---------- trang chủ ---------- */
.hero{padding-block:44px 8px}
.hero h1{font-size:clamp(2.1rem,6vw,3.6rem);color:var(--lam);margin-top:8px}
.lead{max-width:62ch;color:var(--muted);margin:12px 0 0;font-size:1.05em}
.stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:1px;margin:22px 0 0;max-width:640px;background:var(--line);border:1px solid var(--line);border-radius:14px;overflow:hidden}
.stats div{background:var(--surface);padding:10px 14px;display:flex;flex-direction:column-reverse}
.stats dt{font-size:.75rem;color:var(--muted)}
.stats dd{margin:0;font-family:var(--display);font-size:1.6rem;font-weight:700;color:var(--ink);font-variant-numeric:tabular-nums;line-height:1.1}
.resume{margin-top:18px}
.resume a{display:inline-flex;gap:10px;align-items:center;padding:10px 16px;border-radius:12px;background:var(--lam);color:var(--surface);text-decoration:none;font-weight:600}
.aud{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:10px;margin-top:22px}
.audc{display:flex;flex-direction:column;gap:2px;padding:14px 16px;border-radius:var(--radius);background:var(--surface);border:1px solid var(--line);text-decoration:none;color:var(--ink);transition:transform .15s,border-color .15s}
.audc:hover{transform:translateY(-2px);border-color:var(--lam)}
.audc b{font-family:var(--display);font-size:1.25rem;color:var(--lam)}
.audc span{font-size:.88rem;color:var(--muted)}
.legend{display:flex;gap:6px 18px;flex-wrap:wrap;font-size:.8rem;color:var(--muted);margin-top:18px}
.legend i{display:inline-block;width:12px;height:12px;border-radius:50%;vertical-align:-1px;margin-right:6px;background:var(--lam)}
.legend .lg-camp{border-radius:3px;transform:rotate(45deg);background:var(--gold)}
.legend .lg-done{background:none;border:3px solid var(--done)}

.map{padding-bottom:20px}
.region{margin-top:28px;border-radius:24px;position:relative;overflow:hidden;overflow:clip;background:var(--rb);display:grid;grid-template-columns:minmax(0,1fr);scroll-margin-top:calc(var(--toph) + 12px)}
.rhead{padding:22px 22px 0;display:flex;gap:14px;align-items:flex-start;position:relative;z-index:1}
.seal{flex:none;width:52px;height:52px;border-radius:50%;display:grid;place-items:center;font-family:var(--display);font-weight:800;font-size:1.4rem;color:var(--surface);background:var(--rc)}
.region h2{font-size:clamp(1.5rem,4vw,2rem);color:var(--rc)}
.meta{font-size:.85rem;color:var(--muted);margin:4px 0 0}
.meta span+span::before{content:" · "}
.rinfo{position:relative;z-index:1;min-width:0}
.rlist{display:none;list-style:none;margin:16px 0 0;padding:0 16px 22px 22px}
.rlist a{display:flex;align-items:center;gap:12px;padding:9px 10px;border-radius:12px;text-decoration:none;color:var(--ink)}
.rlist a:hover{background:color-mix(in srgb,var(--surface) 70%,transparent)}
.rlist .ri{flex:none;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;background:var(--surface);color:var(--rc);font-family:var(--display);font-weight:800;font-size:.95rem}
.rlist .rn{flex:1;min-width:0;display:flex;flex-direction:column;line-height:1.3}
.rlist .rn small{color:var(--muted);font-size:.78rem}
.rlist .rc{flex:none;font-size:.78rem;color:var(--muted);font-variant-numeric:tabular-nums}
.rlist .rc.part{color:var(--done);font-weight:700}
@media (min-width:981px){.region{grid-template-columns:360px minmax(0,1fr);align-items:start}.rlist{display:block}.trail{margin-top:24px}.rinfo{position:sticky;top:calc(var(--toph) + 10px)}}
.scenery{position:absolute;inset:auto 0 0 0;height:160px;width:100%;pointer-events:none;fill:var(--hill)}
.trail{position:relative;margin-top:4px;width:100%;max-width:900px;margin-inline:auto}
.trail svg.path{position:absolute;inset:0;width:100%;height:100%;overflow:visible}
.trail svg.path path{fill:none;stroke:var(--trail);stroke-width:4;stroke-dasharray:2 9;stroke-linecap:round}
.node{position:absolute;transform:translateX(-50%);width:156px;display:flex;flex-direction:column;align-items:center;gap:6px;text-decoration:none;color:var(--ink)}
.medal{width:64px;height:64px;border-radius:50%;background:var(--surface);display:grid;place-items:center;position:relative;
  box-shadow:0 4px 0 var(--rc),0 8px 18px rgba(0,0,0,.12);transition:transform .15s}
.node:hover .medal,.node:focus-visible .medal{transform:translateY(-3px)}
.node:focus-visible{outline:none}.node:focus-visible .medal{outline:3px solid var(--gold);outline-offset:3px}
.medal svg{position:absolute;inset:0}
.medal .rbg,.medal .rfg{fill:none;stroke-width:3}
.medal .rbg{stroke:var(--line)} .medal .rfg{stroke:var(--done)} .medal .rfg.on{stroke-linecap:round}
.medal .num{font-family:var(--display);font-weight:800;font-size:1.3rem;color:var(--rc);font-variant-numeric:tabular-nums}
.node.camp .medal{border-radius:14px;transform:rotate(45deg);width:50px;height:50px;box-shadow:0 0 0 3px var(--gold),0 8px 18px rgba(0,0,0,.12)}
.node.camp .medal>*{transform:rotate(-45deg)}
.node.camp:hover .medal,.node.camp:focus-visible .medal{transform:rotate(45deg) translate(-2px,-2px)}
.node .lbl{font-weight:700;font-size:.9rem;line-height:1.25;text-align:center;background:var(--surface);padding:4px 10px;border-radius:8px;border:1px solid var(--line)}
.node.camp .lbl{border-color:var(--gold)}
.node .sub{font-size:.72rem;color:var(--muted);text-align:center;line-height:1.3;margin-top:-3px}
.book{position:absolute;left:-8px;bottom:-5px;font-size:.62rem;font-weight:700;background:var(--gold);color:var(--surface);border-radius:999px;padding:1px 6px;line-height:1.5}
.node.camp .book{left:auto;right:-14px;bottom:auto;top:18px}
.vbadge{position:absolute;right:-10px;bottom:-5px;font-size:.62rem;font-weight:700;background:#c4302b;color:#fff;border-radius:999px;padding:1px 6px;line-height:1.5}
.done-badge{position:absolute;right:-4px;top:-4px;width:22px;height:22px;border-radius:50%;background:var(--done);color:#fff;display:grid;place-items:center;font-size:.8rem;font-weight:700}
.x0{left:50%}.x1{left:72%}.x2{left:30%}.x3{left:68%}.x4{left:34%}.x5{left:70%}.x6{left:28%}.x7{left:62%}
.y0{top:calc(var(--k) * 36px)}.y1{top:calc(var(--k) * 186px)}.y2{top:calc(var(--k) * 336px)}.y3{top:calc(var(--k) * 486px)}.y4{top:calc(var(--k) * 636px)}.y5{top:calc(var(--k) * 786px)}.y6{top:calc(var(--k) * 936px)}.y7{top:calc(var(--k) * 1086px)}.y8{top:calc(var(--k) * 1236px)}.y9{top:calc(var(--k) * 1386px)}
.h1{height:calc(var(--k) * 216px)}.h2{height:calc(var(--k) * 366px)}.h3{height:calc(var(--k) * 516px)}.h4{height:calc(var(--k) * 666px)}.h5{height:calc(var(--k) * 816px)}.h6{height:calc(var(--k) * 966px)}.h7{height:calc(var(--k) * 1116px)}.h8{height:calc(var(--k) * 1266px)}.h9{height:calc(var(--k) * 1416px)}
@media (max-width:640px){:root{--k:.88}.stats{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:420px){.node{width:136px}.node .sub{font-size:.68rem}}

/* ---------- trang bậc học ---------- */
.btn{font-size:.88rem;font-weight:600;padding:9px 16px;border-radius:12px;border:1px solid var(--rc,var(--lam));background:var(--rc,var(--lam));color:var(--surface);cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;gap:6px;white-space:nowrap}
.btn.ghost{background:var(--surface);color:var(--rc,var(--lam))}
.lnk{border:0;background:none;padding:6px 8px;border-radius:8px;font-size:.85rem;font-weight:600;color:var(--rc,var(--lam));cursor:pointer}
.lnk:hover{background:var(--rb)}
.lnk[aria-pressed="true"]{background:var(--rc);color:var(--surface)}
.muted{color:var(--muted)}

.lhero{background:var(--rb);padding-block:14px 26px;border-bottom:1px solid color-mix(in srgb,var(--rc) 18%,transparent)}
.crumb{display:flex;flex-wrap:wrap;gap:8px;font-size:.8rem;color:var(--muted)}
.crumb a{color:var(--muted);text-decoration:none}
.crumb a:hover{color:var(--rc);text-decoration:underline}
.lhgrid{display:flex;gap:24px;align-items:flex-end;justify-content:space-between;flex-wrap:wrap;margin-top:12px}
.lhtext{min-width:0;flex:1 1 380px}
.lhero h1{font-size:clamp(2.1rem,6vw,3.2rem);color:var(--rc);margin-top:4px}
.spirit{margin:10px 0 0;display:flex;align-items:baseline;gap:8px;flex-wrap:wrap}
.spirit span{font-size:.75rem;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);font-weight:600}
.spirit b{font-family:var(--display);font-size:1.35rem;color:var(--gold)}
.lmeta{list-style:none;margin:10px 0 0;padding:0;display:flex;flex-wrap:wrap;gap:4px 0;font-size:.88rem;color:var(--muted)}
.lmeta li+li::before{content:"·";margin:0 9px;opacity:.6}
.pcard{flex:0 1 380px;min-width:0;max-width:100%;display:flex;align-items:center;gap:12px;background:var(--surface);border-radius:18px;padding:12px 12px 12px 14px;box-shadow:0 1px 0 var(--line),0 6px 20px rgba(20,40,60,.08)}
.pring{width:44px;height:44px;flex:none}
.pring .rbg,.pring .rfg{fill:none;stroke-width:5}
.pring .rbg{stroke:var(--line)}.pring .rfg{stroke:var(--done);stroke-linecap:round;transition:stroke-dasharray .3s}
.pinfo{flex:1;min-width:0;display:flex;flex-direction:column;line-height:1.3}
.pinfo b{font-size:.95rem}
.pinfo small{color:var(--muted);font-size:.78rem;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

.secbar{position:sticky;top:calc(env(safe-area-inset-top,0px) + var(--toph));z-index:25;background:color-mix(in srgb,var(--bg) 92%,transparent);
  backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.secin{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;padding-block:8px;mask-image:linear-gradient(90deg,#000 92%,transparent)}
.secin::-webkit-scrollbar{display:none}
.secin a{flex:none;display:flex;gap:6px;align-items:center;font-size:.82rem;font-weight:600;text-decoration:none;color:var(--ink);padding:6px 12px;border-radius:999px;background:var(--surface);border:1px solid var(--line);white-space:nowrap}
.secin a small,.toc a small{color:var(--muted);font-weight:500;font-variant-numeric:tabular-nums}
.secin a.on{background:var(--rc);border-color:var(--rc);color:var(--surface)}
.secin a.on small{color:inherit;opacity:.8}

.lgrid{display:grid;grid-template-columns:250px minmax(0,1fr);gap:32px;margin-top:22px;align-items:start;padding-bottom:30px}
.side{position:sticky;top:calc(var(--toph) + 20px);display:flex;flex-direction:column;gap:14px;max-height:calc(100vh - var(--toph) - 40px);overflow:auto}
.sidebox h2{font-family:var(--body);font-size:.7rem;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin:0 0 6px 10px}
.toc,.sibs{list-style:none;margin:0;padding:0;font-size:.88rem;display:flex;flex-direction:column;gap:1px}
.toc a,.sibs a{display:flex;justify-content:space-between;gap:8px;padding:7px 10px;border-radius:10px;text-decoration:none;color:var(--ink);border-left:3px solid transparent}
.toc a:hover,.sibs a:hover{background:var(--surface)}
.toc a.on{background:var(--surface);color:var(--rc);font-weight:600;border-left-color:var(--rc)}
.sibs a[aria-current]{background:var(--rb);color:var(--rc);font-weight:700}
.content{min-width:0;max-width:820px}
@media (min-width:981px){.secbar{display:none}}
@media (max-width:980px){
  :root{--secbar:47px}
  .lgrid{grid-template-columns:minmax(0,1fr);margin-top:16px}
  .side{display:none}
}
.ltools{display:flex;justify-content:space-between;align-items:center;gap:8px;flex-wrap:wrap;font-size:.85rem;margin-bottom:4px}
.ltr{display:flex;gap:2px;margin-left:auto}
.note{background:var(--surface);border-left:4px solid var(--gold);border-radius:12px;padding:12px 16px;margin-bottom:18px;font-size:.92rem}
.note p{margin:4px 0 0;color:var(--muted)}
.sec{margin-top:22px;scroll-margin-top:calc(var(--toph) + var(--secbar,0px) + 12px)}
.sec>h2{display:flex;justify-content:space-between;align-items:baseline;gap:10px;font-family:var(--body);font-size:.78rem;letter-spacing:.12em;text-transform:uppercase;color:var(--rc,var(--muted));margin-bottom:10px}
.sec>h2 small{letter-spacing:0;text-transform:none;font-weight:500;color:var(--muted);font-size:.8rem;white-space:nowrap}
.sec>h2 small.full{color:var(--done);font-weight:700}
.lessons{list-style:none;margin:0;padding:0;background:var(--surface);border:1px solid var(--line);border-radius:16px;overflow:clip}
.lesson{scroll-margin-top:calc(var(--toph) + var(--secbar,0px) + 12px)}
.lesson+.lesson{border-top:1px solid var(--line)}
.ls,.ld>summary{display:flex;gap:12px;align-items:center;padding:12px 14px;min-height:54px}
.ld>summary{cursor:pointer;list-style:none}
.ld>summary::-webkit-details-marker{display:none}
.ld>summary:hover{background:var(--surface-2)}
.ld[open]>summary{position:sticky;top:calc(env(safe-area-inset-top,0px) + var(--toph) + var(--secbar,0px));background:var(--surface);z-index:3;border-bottom:1px solid var(--line);box-shadow:0 4px 10px -8px rgba(0,0,0,.3)}
.ld[open]{background:var(--surface)}
.lesson.nodoc .lt{color:var(--muted)}
.n,.ckb{flex:none;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;font-size:.8rem;font-weight:700;font-variant-numeric:tabular-nums;color:var(--muted);background:var(--surface-2);border:1.5px solid var(--line)}
.ckb{cursor:pointer;padding:0;transition:background .15s,border-color .15s}
.ckb:hover{border-color:var(--done);color:var(--done)}
.ckb[aria-pressed="true"]{background:var(--done);border-color:var(--done);color:#fff;font-size:0}
.ckb[aria-pressed="true"]::after{content:"✓";font-size:.95rem}
.lt{flex:1;min-width:0;font-weight:500;line-height:1.4}
.lesson.done .lt{color:var(--muted)}
.badges{display:flex;gap:4px;flex:none;align-items:center}
.badges:empty{display:none}
.bd{font-size:.72rem;font-weight:700;padding:2px 8px;border-radius:999px;border:1px solid currentColor;white-space:nowrap}
.bd.v{color:#c4302b}
.bd.g{color:var(--gold)}
.chev{flex:none;width:10px;height:10px;border-right:2px solid var(--muted);border-bottom:2px solid var(--muted);transform:rotate(45deg) translate(-2px,-2px);transition:transform .2s;margin-right:4px}
.ld[open] .chev{transform:rotate(-135deg) translate(-2px,-2px);border-color:var(--rc)}
.ld[open] .lt{color:var(--rc);font-weight:600}
.lesson.hit{box-shadow:inset 4px 0 0 var(--gold)}
body.only-doc .lesson.nodoc{display:none}

/* nội dung bài */
.doc{padding:16px 18px 22px 56px;font-size:.95em;line-height:1.75}
@media (max-width:640px){.doc{padding-left:14px}}
.doc>*:first-child{margin-top:0}
.doc p{margin:0 0 .6em}
.doc h3.ptitle{font-size:1.35rem;margin:6px 0 10px;color:var(--ink)}
.doc h4{font-family:var(--body);margin:18px 0 6px;font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;color:var(--rc,var(--lam))}
.doc h5{margin:12px 0 4px;font-size:1em;font-weight:700}
.doc ul{margin:0 0 .6em;padding-left:1.3em}.doc li{margin:3px 0}
.doc figure{margin:14px 0;text-align:center}
.doc figure img{border-radius:10px;background:#fff;max-height:80vh;width:auto}
.doc hr.psep{border:0;border-top:2px dashed var(--line);margin:22px 0}
.doc .src{margin-top:14px;padding-top:10px;border-top:1px solid var(--line);font-size:.82rem;color:var(--muted)}
.tag{display:inline-block;padding:2px 10px;border-radius:999px;font-size:.75rem;font-weight:700;background:var(--gold-soft);color:var(--gold)}
.act{margin-top:16px;padding:12px 14px;border-radius:12px;background:var(--surface-2);border:1px dashed var(--rc,var(--lam))}
.act h4{margin-top:0}
.course{border:1px solid var(--rc,var(--lam));border-radius:14px;padding:14px 16px;background:var(--rb,var(--surface-2));margin-bottom:14px}
.course .ck{font-size:.7rem;letter-spacing:.1em;text-transform:uppercase;font-weight:700;color:var(--rc,var(--lam))}
.course .ct{font-family:var(--display);font-size:1.35rem;font-weight:700;margin:2px 0 6px}
.course .cm{display:flex;gap:8px;flex-wrap:wrap;font-size:.8rem;color:var(--muted);margin-bottom:6px}
.course .cs{padding:1px 9px;border-radius:999px;background:var(--surface);color:var(--ink);font-weight:600;border:1px solid var(--line)}
.course .cs.ok{background:var(--done);color:#fff;border-color:transparent}
.course .cs.rd{background:var(--gold-soft);color:var(--gold);border-color:transparent}
.course p{margin:0 0 .4em}

/* video YouTube */
.vids{margin:0 0 16px}
.vids>h4{margin-top:0}
.vgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}
.yt{position:relative;display:block;width:100%;aspect-ratio:16/9;max-width:100%;border:0;padding:0;border-radius:12px;overflow:hidden;background:#000;cursor:pointer}
.yt img{width:100%;height:100%;object-fit:cover;opacity:.85;transition:opacity .2s}
.yt:hover img{opacity:1}
.yt .play{position:absolute;left:50%;top:50%;width:64px;height:44px;transform:translate(-50%,-50%);border-radius:12px;background:#c4302b;display:grid;place-items:center}
.yt .play::after{content:"";border-style:solid;border-width:9px 0 9px 15px;border-color:transparent transparent transparent #fff;margin-left:3px}
.yt .vt{position:absolute;left:0;right:0;bottom:0;padding:22px 10px 8px;font-size:.8rem;font-weight:600;color:#fff;text-align:left;background:linear-gradient(transparent,rgba(0,0,0,.8))}
.yt.list .play{background:#1b2a36}
.ytf{position:relative;width:100%;aspect-ratio:16/9;border-radius:12px;overflow:hidden;background:#000}
.ytf iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.vcap{font-size:.8rem;color:var(--muted);margin:4px 2px 0;display:flex;justify-content:space-between;gap:8px}
.lvlvids{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:14px 16px;margin-bottom:18px}
.lvlvids h2{font-family:var(--body);font-size:.8rem;letter-spacing:.12em;text-transform:uppercase;color:#c4302b;margin-bottom:10px}

/* chuyển bậc */
.pnav{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:36px}
.pn{display:flex;flex-direction:column;padding:14px 16px;border-radius:14px;background:var(--surface);border:1px solid var(--line);text-decoration:none;color:var(--ink);min-width:0}
.pn:hover{border-color:var(--rc,var(--lam))}
.pn small{color:var(--muted);font-size:.75rem}
.pn b{font-family:var(--display);font-size:1.15rem;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.pn.next{text-align:right}

/* chân trang */
.foot{margin-top:48px;background:var(--surface);border-top:1px solid var(--line);color:var(--muted);font-size:.88rem;padding-bottom:env(safe-area-inset-bottom,0px)}
.ftop{display:grid;grid-template-columns:minmax(0,300px) minmax(0,1fr);gap:40px;padding-block:40px 28px}
.flogo{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ink)}
.flogo img{border-radius:50%;flex:none}
.flogo span{display:flex;flex-direction:column;line-height:1.25}
.flogo b{font-family:var(--display);font-size:1.3rem;color:var(--ink)}
.flogo small{font-size:.75rem;letter-spacing:.08em;text-transform:uppercase;color:var(--sen)}
.fbrand p{margin:14px 0 0;max-width:36ch}
.fmotto{font-family:var(--display);font-style:italic;font-size:1.1rem;color:var(--gold)}
.fcols{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:24px}
.fcol h2{font-family:var(--body);font-size:.72rem;letter-spacing:.12em;text-transform:uppercase;margin:0 0 10px}
.fcol h2 a{color:var(--ink);text-decoration:none}
.fcol ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:6px}
.fcol a{color:var(--muted);text-decoration:none}
.fcol a:hover,.fcol h2 a:hover{color:var(--lam);text-decoration:underline}
.fnote{border-top:1px solid var(--line);padding-block:18px;font-size:.82rem;line-height:1.6}
.fnote p{margin:0;max-width:110ch}
.fnote a{color:var(--lam)}
.fbot{border-top:1px solid var(--line);padding-block:16px 26px;padding-right:64px;display:flex;flex-wrap:wrap;justify-content:space-between;gap:6px 24px;font-size:.78rem}
@media (max-width:1100px){.ftop{grid-template-columns:minmax(0,1fr)}.fcols{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media (max-width:640px){.ftop{padding-top:30px;gap:26px}.fcols{grid-template-columns:repeat(2,minmax(0,1fr));gap:22px 16px}.fbot{flex-direction:column}}
.totop{position:fixed;right:max(16px,env(safe-area-inset-right,0px));bottom:calc(16px + env(safe-area-inset-bottom,0px));z-index:20;width:46px;height:46px;border-radius:50%;
  border:1px solid var(--line);background:var(--surface);box-shadow:var(--shadow);cursor:pointer;font-size:1.2rem}

@media (max-width:640px){
  .hero{padding-top:28px}
  .aud{display:flex;overflow-x:auto;scroll-snap-type:x mandatory;scroll-padding-inline:16px;margin-inline:-16px;padding:2px 16px 6px;gap:8px;scrollbar-width:none}
  .aud::-webkit-scrollbar{display:none}
  .audc{flex:0 0 78%;scroll-snap-align:start;padding:12px 14px}
  .audc b{font-size:1.1rem}

  .doc{padding:14px}
  .ls,.ld>summary{padding:10px 12px;gap:10px}
  .lessons{border-radius:14px;margin-inline:-4px}
  .pcard{flex-basis:100%}
  .lhero{padding-bottom:20px}
  .pn b{font-size:1rem}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media print{.top,.side,.secbar,.ltools,.pcard,.totop,.pnav{display:none!important}.ld>.doc{display:block}.lgrid{display:block}}

/* hình ảnh minh họa (thêm qua công cụ quản trị) */
.gal{margin-top:18px}
.ggrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:12px}
.gal figure{margin:0;display:flex;flex-direction:column;gap:6px}
.zoom{display:block;padding:0;border:1px solid var(--line);border-radius:12px;overflow:hidden;background:var(--surface-2);cursor:zoom-in;aspect-ratio:4/3;width:100%}
.zoom img{width:100%;height:100%;object-fit:cover;transition:transform .25s}
.zoom:hover img{transform:scale(1.04)}
.gal figcaption{font-size:.82rem;color:var(--muted);line-height:1.4}
.bd.g{border-color:var(--gold);color:var(--gold)}
.lvlvids h2.gh{color:var(--gold)}
.lb{border:0;padding:0;background:rgba(0,0,0,.88);max-width:100vw;max-height:100vh;width:100vw;height:100dvh;margin:0}
.lb[open]{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:10px}
.lb::backdrop{background:rgba(0,0,0,.85)}
.lb img{max-width:min(96vw,1400px);max-height:82dvh;border-radius:10px;background:#fff}
.lb p{color:#fff;margin:0;padding:0 16px;text-align:center;max-width:70ch}
.lb .lbx{position:absolute;top:calc(12px + env(safe-area-inset-top,0px));right:max(12px,env(safe-area-inset-right,0px));color:#fff;background:rgba(255,255,255,.15)}
@media (max-width:640px){.ggrid{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}}