:root{--bg:#faf6ee;--card:#fff;--ink:#2b2a33;--mute:#6b6a75;--pri:#2f6f5e;--pri2:#e4f1ec;--acc:#d98c2b;--line:#e6dfd0;--ok:#2e8b57;--bad:#c0392b}
@media (prefers-color-scheme:dark){:root{--bg:#171a19;--card:#212625;--ink:#f1efe8;--mute:#a8a8a0;--pri:#6fc5aa;--pri2:#27403a;--acc:#f0b055;--line:#343b39}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif}
header{display:flex;align-items:center;gap:12px;padding:12px 16px;border-bottom:1px solid var(--line);background:var(--card);position:sticky;top:0;z-index:5}
header .logo{font-weight:700;color:var(--pri);text-decoration:none;font-size:18px}
header .info{color:var(--mute);font-size:14px;flex:1}
header a.cd{color:var(--mute);text-decoration:none;font-size:14px}
main{max-width:860px;margin:0 auto;padding:16px}
h1{font-size:26px;margin:8px 0 4px}h2{font-size:21px;margin:22px 0 8px}h3{font-size:18px;margin:0 0 6px}
.mute{color:var(--mute)}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px;margin:12px 0}
.grid{display:grid;gap:12px}
a.bai{display:block;text-decoration:none;color:inherit}
a.bai .so{display:inline-block;background:var(--pri);color:#fff;border-radius:999px;padding:2px 12px;font-size:14px;margin-bottom:6px}
a.bai.khoa{opacity:.55;pointer-events:none}
.btn{display:inline-block;border:0;background:var(--pri);color:#fff;padding:12px 20px;border-radius:12px;font-size:17px;cursor:pointer;text-decoration:none;min-height:44px}
.btn.phu{background:var(--pri2);color:var(--pri)}
.btn.nho{padding:8px 14px;font-size:15px;min-height:36px}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.tab{display:flex;gap:8px;margin:12px 0}
.tab a{flex:1;text-align:center;padding:12px;border-radius:12px;background:var(--pri2);color:var(--pri);text-decoration:none;font-weight:600}
.tab a.on{background:var(--pri);color:#fff}
textarea,input[type=text]{width:100%;font:inherit;padding:10px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--ink)}
textarea{min-height:90px}
label{display:block;margin:10px 0 4px;font-weight:600}
.opt{display:block;width:100%;text-align:left;margin:6px 0;padding:12px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--ink);font:inherit;cursor:pointer;min-height:44px}
.opt.dung{border-color:var(--ok);background:rgba(46,139,87,.15)}
.opt.sai{border-color:var(--bad);background:rgba(192,57,43,.13)}
.giaithich{margin-top:8px;color:var(--mute)}
.bar{height:10px;background:var(--pri2);border-radius:99px;overflow:hidden}.bar i{display:block;height:100%;background:var(--pri)}
.ring-wrap{display:flex;flex-direction:column;align-items:center;gap:12px}
svg.rings{width:min(86vw,420px);height:auto}
svg.rings circle{cursor:pointer;stroke:var(--card);stroke-width:2}
svg.rings text{pointer-events:none;font:600 13px system-ui;fill:#fff}
.ring-info{min-height:70px;text-align:center;max-width:560px}
.ring-info b{color:var(--pri)}
/* chế độ trên lớp */
body.lop main{max-width:1100px}
.slide{min-height:62vh;display:flex;flex-direction:column;justify-content:center;gap:16px;padding:10px 4px}
.slide h1{font-size:clamp(28px,5vw,48px)}
.slide .lon{font-size:clamp(22px,3.6vw,34px);line-height:1.4}
.slide li{font-size:clamp(18px,2.8vw,26px);margin:10px 0}
.dieuhuong{position:sticky;bottom:0;background:var(--card);border-top:1px solid var(--line);padding:10px 16px;display:flex;gap:10px;align-items:center;justify-content:space-between;margin:0 -16px}
.buoc{display:flex;gap:10px;flex-wrap:wrap}
.buoc span{background:var(--pri2);color:var(--pri);padding:14px 22px;border-radius:14px;font-weight:700;font-size:clamp(18px,3vw,28px)}
.hai{display:grid;gap:12px;grid-template-columns:1fr 1fr}
@media(max-width:620px){.hai{grid-template-columns:1fr}}
.th{cursor:pointer;border:2px solid var(--line)}
.th.mo{border-color:var(--pri)}
.hen{font-size:34px;font-weight:700;color:var(--acc)}
.sao{color:var(--ok);font-size:14px}
/* thanh menu */
header{display:block;padding:0}
header .hang{display:flex;align-items:center;gap:12px;padding:10px 16px}
header nav{border-top:1px solid var(--line);overflow-x:auto}
.menu{list-style:none;margin:0;padding:0 8px;display:flex;gap:4px;white-space:nowrap}
.menu a{display:block;padding:12px 12px;color:var(--ink);text-decoration:none;border-bottom:3px solid transparent;font-size:16px}
.menu a:hover{background:var(--pri2)}
.menu a.on{border-bottom-color:var(--pri);color:var(--pri);font-weight:700}
header .tg{display:none;margin-left:auto;border:1px solid var(--line);background:var(--bg);color:var(--ink);border-radius:10px;padding:8px 12px;font:inherit;min-height:44px}
header .vaibtn{margin-left:auto;color:var(--mute);text-decoration:none;font-size:14px;border:1px solid var(--line);border-radius:99px;padding:4px 12px}
@media(max-width:700px){
  header .info{display:none}
  header .tg{display:block}
  header .vaibtn{margin-left:0}
  header nav{display:none}
  header.mo nav{display:block}
  .menu{flex-direction:column;padding:4px 0}
  .menu a{border-bottom:0;border-left:4px solid transparent;padding:14px 16px}
  .menu a.on{border-left-color:var(--pri)}
}
header{position:sticky;top:0}
body.lop header{position:static}
.vai{text-decoration:none;color:inherit;display:block}
.noi-bat{border-color:var(--pri);background:var(--pri2)}
.huongdan{background:var(--pri2);border-color:var(--pri)}.huongdan ol{margin:6px 0 0;padding-left:22px}
.chk{display:flex;gap:10px;align-items:flex-start;font-weight:400;margin:8px 0}.chk input{width:22px;height:22px;margin-top:3px}
.hd{margin:8px 0}.pre{white-space:pre-wrap}
.buoc-dong{display:flex;gap:12px;align-items:center;padding:10px 0;text-decoration:none;color:inherit;border-bottom:1px solid var(--line)}
.tick{display:inline-flex;width:30px;height:30px;border-radius:50%;background:var(--line);align-items:center;justify-content:center;font-weight:700;flex:none}.tick.on{background:var(--pri);color:#fff}
.hd-buoc{display:flex;gap:12px;align-items:flex-start;margin:10px 0}
.opt{display:flex;justify-content:space-between;gap:8px;align-items:center}
.opt.chon{border-color:var(--pri);background:var(--pri2)}
.opt.so{justify-content:center;width:auto;flex:1;margin:0}
.thang{display:flex;gap:6px;margin:8px 0}.nho2{justify-content:space-between;font-size:13px}
.nhan{background:var(--acc);color:#222;border-radius:99px;padding:1px 10px;font-size:13px;flex:none}
.ai{background:rgba(217,140,43,.14);border:1px solid var(--acc);border-radius:12px;padding:10px 12px;margin:10px 0}
.em{border:1px solid var(--line);border-radius:12px;padding:10px 12px;margin:10px 0}.em.dung{border-color:var(--ok)}
.vs{color:var(--mute);margin-top:4px}
.hai.ba{grid-template-columns:repeat(3,1fr)}
.luoi21{display:grid;grid-template-columns:repeat(7,1fr);gap:6px;margin:10px 0}
.luoi21 .o{display:flex;align-items:center;justify-content:center;aspect-ratio:1;border:1px solid var(--line);border-radius:8px;font-size:14px;background:var(--bg)}
.luoi21 .o.on{background:var(--ok);color:#fff;border-color:var(--ok)}
table.bang{width:100%;border-collapse:collapse}table.bang th,table.bang td{border:1px solid var(--line);padding:8px;text-align:left}
table.bang input{width:70px}
.noi{border-style:dashed}
.het{color:var(--bad)}
.hen{font-size:48px;font-weight:700;font-variant-numeric:tabular-nums}
html.chu-to body{font-size:21px}
button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid var(--acc);outline-offset:2px}
@media print{header,.noprint,.dieuhuong{display:none!important}body{background:#fff;color:#000}.card{break-inside:avoid}}
header .vaibtn,header .tg{white-space:nowrap}
header .logo{white-space:nowrap}
@media(max-width:700px){header .logo{font-size:16px}header .hang{gap:8px;padding:8px 12px}header .tg{padding:6px 10px;min-height:40px}}

.hinhbox{text-align:center}
img.hinh{max-width:100%;max-height:62vh;height:auto;border-radius:10px;border:1px solid var(--line);background:#fff;cursor:zoom-in}
img.hinh.phong{max-height:none;cursor:zoom-out}
.slide img.hinh{max-height:66vh}

/* ===== MÀU SẮC: mỗi bài một màu, mỗi loại bước một màu ===== */
:root{--c1:#6d4aff;--c2:#ea580c;--c3:#0d9488;--c4:#2563eb;--c5:#db2777;--vang:#facc15;--do:#e11d48}
body{--pri2:color-mix(in srgb,var(--pri) 14%,var(--card))}
body[data-bai="1"]{--pri:var(--c1)}body[data-bai="2"]{--pri:var(--c2)}body[data-bai="3"]{--pri:var(--c3)}body[data-bai="4"]{--pri:var(--c4)}body[data-bai="5"]{--pri:var(--c5)}
body{background-image:linear-gradient(180deg,color-mix(in srgb,var(--pri) 9%,var(--bg)) 0,var(--bg) 260px);background-repeat:no-repeat}
header{border-bottom:0;box-shadow:0 2px 10px rgba(0,0,0,.08)}
header::before{content:"";display:block;height:5px;background:linear-gradient(90deg,var(--c1),var(--c4),var(--c3),var(--c2),var(--c5))}
header .logo{background:linear-gradient(90deg,var(--c1),var(--c5));-webkit-background-clip:text;background-clip:text;color:transparent;font-weight:800}
.menu a::before{content:"";display:inline-block;width:9px;height:9px;border-radius:50%;margin-right:7px;background:var(--line)}
.menu a[data-b="1"]::before{background:var(--c1)}.menu a[data-b="2"]::before{background:var(--c2)}.menu a[data-b="3"]::before{background:var(--c3)}.menu a[data-b="4"]::before{background:var(--c4)}.menu a[data-b="5"]::before{background:var(--c5)}
.menu a[data-b="1"].on{border-bottom-color:var(--c1);color:var(--c1)}.menu a[data-b="2"].on{border-bottom-color:var(--c2);color:var(--c2)}.menu a[data-b="3"].on{border-bottom-color:var(--c3);color:var(--c3)}.menu a[data-b="4"].on{border-bottom-color:var(--c4);color:var(--c4)}.menu a[data-b="5"].on{border-bottom-color:var(--c5);color:var(--c5)}
h1{color:var(--pri);font-weight:800}
.btn{background:linear-gradient(135deg,var(--pri),color-mix(in srgb,var(--pri) 70%,#000));box-shadow:0 3px 8px color-mix(in srgb,var(--pri) 35%,transparent);font-weight:700;transition:transform .1s}
.btn:hover{transform:translateY(-1px)}
.btn.phu{background:var(--pri2);color:var(--pri);box-shadow:none}
/* thẻ bài ở trang chủ */
a.bai{border-left:8px solid var(--pri);transition:transform .15s,box-shadow .15s}
a.bai:hover{transform:translateY(-2px);box-shadow:0 6px 16px rgba(0,0,0,.12)}
a.bai.b1{--pri:var(--c1)}a.bai.b2{--pri:var(--c2)}a.bai.b3{--pri:var(--c3)}a.bai.b4{--pri:var(--c4)}a.bai.b5{--pri:var(--c5)}
a.bai .so{background:var(--pri);font-weight:700}
a.bai h3{color:var(--pri)}
.bar{background:color-mix(in srgb,var(--pri) 18%,var(--card))}.bar i{background:linear-gradient(90deg,var(--pri),color-mix(in srgb,var(--pri) 55%,#facc15))}
/* màu theo loại bước */
main[data-loai]{--tc:var(--pri)}
main[data-loai="doc"]{--tc:#2563eb}main[data-loai="tinhhuong"]{--tc:#ea580c}main[data-loai="quiz"]{--tc:#7c3aed}main[data-loai="viet"]{--tc:#db2777}
main[data-loai="danhgia"]{--tc:#0d9488}main[data-loai="camket"]{--tc:#e11d48}main[data-loai="phanloai"]{--tc:#0891b2}main[data-loai="nguluc"]{--tc:#65a30d}
main[data-loai] h1{color:var(--tc)}
main[data-loai] h1::before{margin-right:10px}
main[data-loai="doc"] h1::before{content:"📖"}main[data-loai="tinhhuong"] h1::before{content:"🤔"}main[data-loai="quiz"] h1::before{content:"🧠"}main[data-loai="viet"] h1::before{content:"✍️"}
main[data-loai="danhgia"] h1::before{content:"📊"}main[data-loai="camket"] h1::before{content:"🎯"}main[data-loai="phanloai"] h1::before{content:"🧩"}main[data-loai="nguluc"] h1::before{content:"🌱"}
main[data-loai] .card{border-left:6px solid var(--tc)}
main[data-loai] .card h3{color:var(--tc)}
main[data-loai] .btn:not(.goiy):not(.phu){background:linear-gradient(135deg,var(--tc),color-mix(in srgb,var(--tc) 70%,#000))}
main[data-loai] .bar i{background:var(--tc)}
main[data-loai] .opt.chon{border-color:var(--tc);background:color-mix(in srgb,var(--tc) 14%,var(--card))}
main[data-loai] .opt:hover:not(:disabled){border-color:var(--tc)}
.buoc-dong .tick{background:color-mix(in srgb,var(--pri) 20%,var(--card));color:var(--pri)}
.buoc-dong .tick.on{background:var(--pri);color:#fff}
.buoc-dong[data-loai="doc"] .tick{box-shadow:0 0 0 3px #2563eb55}.buoc-dong[data-loai="tinhhuong"] .tick{box-shadow:0 0 0 3px #ea580c55}.buoc-dong[data-loai="quiz"] .tick{box-shadow:0 0 0 3px #7c3aed55}
.buoc-dong[data-loai="viet"] .tick{box-shadow:0 0 0 3px #db277755}.buoc-dong[data-loai="danhgia"] .tick{box-shadow:0 0 0 3px #0d948855}.buoc-dong[data-loai="camket"] .tick{box-shadow:0 0 0 3px #e11d4855}
.buoc-dong[data-loai="phanloai"] .tick{box-shadow:0 0 0 3px #0891b255}.buoc-dong[data-loai="nguluc"] .tick{box-shadow:0 0 0 3px #65a30d55}
.buoc-dong[data-loai="camket"] span:last-child{font-weight:700;color:var(--do)}
/* chỗ quan trọng */
.huongdan{background:color-mix(in srgb,#2563eb 11%,var(--card));border:2px dashed #2563eb;border-left-width:2px}
.huongdan b{color:#2563eb}
.ghinho{background:linear-gradient(135deg,color-mix(in srgb,var(--vang) 28%,var(--card)),color-mix(in srgb,var(--vang) 12%,var(--card)));border:2px solid var(--vang);border-radius:14px;padding:12px 16px;margin:12px 0;box-shadow:0 3px 10px rgba(250,204,21,.25)}
.ghinho b{font-size:18px}.ghinho .gn{font-size:18px;font-weight:700;margin-top:6px}
.ai{background:linear-gradient(135deg,color-mix(in srgb,#f59e0b 20%,var(--card)),color-mix(in srgb,#f59e0b 8%,var(--card)));border:2px solid #f59e0b}
.ai b{color:#b45309}
@media (prefers-color-scheme:dark){.ai b{color:#fbbf24}}
.em{border-width:2px}.em.dung{background:color-mix(in srgb,var(--ok) 14%,var(--card))}
.nhan{background:#f59e0b;color:#222;font-weight:700}
.opt{border-width:2px;border-radius:12px;font-weight:500}
.opt.dung{border-color:var(--ok);background:color-mix(in srgb,var(--ok) 20%,var(--card))}
.opt.sai{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 16%,var(--card))}
.opt.loai{opacity:.4;text-decoration:line-through}
.noi-bat{background:linear-gradient(135deg,color-mix(in srgb,var(--pri) 18%,var(--card)),color-mix(in srgb,var(--c5) 10%,var(--card)));border:2px solid var(--pri)}
.luoi21 .o.on{background:linear-gradient(135deg,var(--ok),#16a34a)}
/* gợi ý */
.goiywrap{margin:8px 0}
.btn.goiy{background:#0891b2;color:#fff;box-shadow:none;margin-right:6px}
.btn.goiy:disabled{opacity:.5}
.goiybox{background:color-mix(in srgb,#06b6d4 14%,var(--card));border:2px solid #06b6d4;border-left-width:8px;border-radius:10px;padding:10px 12px;margin:8px 0}
.goiybox.mo{display:block}
/* trình chiếu */
body.lop .slide h1{font-size:clamp(30px,5.2vw,54px)}
.slide .lon{background:color-mix(in srgb,var(--pri) 12%,var(--card));border-left:10px solid var(--pri);border-radius:14px;padding:16px 20px}
.slide ul{padding-left:0;list-style:none}
.slide li{background:var(--card);border:2px solid var(--line);border-left:10px solid var(--pri);border-radius:12px;padding:10px 16px}
.slide li:nth-child(5n+1){border-left-color:var(--c1)}.slide li:nth-child(5n+2){border-left-color:var(--c2)}.slide li:nth-child(5n+3){border-left-color:var(--c3)}.slide li:nth-child(5n+4){border-left-color:var(--c4)}.slide li:nth-child(5n+5){border-left-color:var(--c5)}
.slide ol li{border-left-color:var(--pri)}
.buoc span{color:#fff;background:var(--c1)}
.buoc span:nth-child(7n+2){background:var(--c4)}.buoc span:nth-child(7n+3){background:var(--c3)}.buoc span:nth-child(7n+4){background:var(--c2)}.buoc span:nth-child(7n+5){background:var(--c5)}.buoc span:nth-child(7n+6){background:#65a30d}.buoc span:nth-child(7n+7){background:var(--do)}
.slide .mute{font-size:clamp(16px,2.2vw,22px)}
.hai .card:first-child{border-top:6px solid var(--c2)}.hai .card:last-child{border-top:6px solid var(--c3)}
.th{border-width:3px}.th:nth-child(4n+1){border-color:var(--c1)}.th:nth-child(4n+2){border-color:var(--c2)}.th:nth-child(4n+3){border-color:var(--c3)}.th:nth-child(4n+4){border-color:var(--c5)}
.hen{color:var(--pri)}
table.bang th{background:var(--pri);color:#fff}
table.bang tr:nth-child(even) td{background:color-mix(in srgb,var(--pri) 7%,var(--card))}
.dieuhuong{border-top:4px solid var(--pri)}
.card.noi{border-color:var(--c5);background:color-mix(in srgb,var(--c5) 8%,var(--card))}
body:not([data-bai]){--pri:var(--c1)}

/* ===== SLIDE SINH ĐỘNG ===== */
@keyframes lenXuong{from{opacity:0;transform:translateY(22px) scale(.97)}to{opacity:1;transform:none}}
@keyframes noi{0%,100%{transform:translateY(0)}50%{transform:translateY(-8px)}}
@keyframes nhip{0%,100%{transform:scale(1)}50%{transform:scale(1.06)}}
.anim{animation:lenXuong .55s cubic-bezier(.2,.8,.2,1) both;animation-delay:calc(var(--i,0)*110ms)}
@media (prefers-reduced-motion:reduce){.anim,.bigico,.so-lon,.dongho.sap .hen{animation:none!important}}
body.lop main{max-width:1180px}
.slide{--pc:var(--pri);position:relative;overflow:hidden;min-height:64vh;justify-content:flex-start;gap:18px;padding:26px clamp(16px,3vw,40px) 30px;border-radius:26px;
  background:radial-gradient(circle at 100% 0,color-mix(in srgb,var(--pc) 26%,transparent) 0,transparent 42%),radial-gradient(circle at 0 100%,color-mix(in srgb,var(--pc) 16%,transparent) 0,transparent 38%),linear-gradient(160deg,color-mix(in srgb,var(--pc) 9%,var(--card)),var(--card) 55%);
  border:3px solid color-mix(in srgb,var(--pc) 40%,var(--line));box-shadow:0 10px 30px color-mix(in srgb,var(--pc) 18%,transparent)}
.slide::before{content:"";position:absolute;right:-60px;top:-60px;width:220px;height:220px;border-radius:50%;background:color-mix(in srgb,var(--pc) 14%,transparent);pointer-events:none}
.slide::after{content:"";position:absolute;left:-40px;bottom:-50px;width:150px;height:150px;border-radius:50%;background:color-mix(in srgb,var(--pc) 10%,transparent);pointer-events:none}
.slide>*{position:relative;z-index:1}
.slide h1{color:var(--pc);margin:0;line-height:1.15}
.chip{align-self:flex-start;display:inline-flex;align-items:center;gap:8px;background:var(--pc);color:#fff;border-radius:99px;padding:5px 16px 5px 8px;font-weight:700;font-size:15px;letter-spacing:.3px;text-transform:uppercase;box-shadow:0 3px 8px color-mix(in srgb,var(--pc) 40%,transparent)}
.chip .ico{display:inline-flex;width:28px;height:28px;border-radius:50%;background:#fff3;align-items:center;justify-content:center;font-size:17px}
.slide .lon{background:none;border:0;padding:0;font-size:clamp(22px,3.4vw,36px);line-height:1.4}
/* mở đầu */
.slide.p-md{align-items:center;text-align:center;justify-content:center;min-height:66vh}
.slide.p-md .chip{align-self:center}
.so-lon{font-size:clamp(64px,13vw,150px);font-weight:900;line-height:1;background:linear-gradient(90deg,var(--c1),var(--c5),var(--c2));-webkit-background-clip:text;background-clip:text;color:transparent;letter-spacing:4px;animation:nhip 3s ease-in-out infinite}
.slide.p-md h1{font-size:clamp(28px,5vw,56px)}
.bieutuong{font-size:clamp(28px,4vw,46px);letter-spacing:10px;animation:noi 3s ease-in-out infinite}
/* thẻ đánh số */
.luoi-the{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr));gap:14px}
.luoi-the.mot-cot{grid-template-columns:1fr}
.slide .the{display:flex;gap:14px;align-items:center;background:var(--card);border:2px solid color-mix(in srgb,var(--pc) 30%,var(--line));border-radius:18px;padding:14px 16px;box-shadow:0 4px 12px rgba(0,0,0,.06);font-size:clamp(18px,2.6vw,26px);line-height:1.4}
.slide .the .stt{flex:none;display:inline-flex;width:clamp(40px,5vw,56px);height:clamp(40px,5vw,56px);border-radius:50%;background:var(--pc);color:#fff;align-items:center;justify-content:center;font-weight:800;font-size:clamp(20px,3vw,30px)}
.luoi-the .the:nth-child(5n+2) .stt{background:var(--c2)}.luoi-the .the:nth-child(5n+3) .stt{background:var(--c3)}.luoi-the .the:nth-child(5n+4) .stt{background:var(--c4)}.luoi-the .the:nth-child(5n+5) .stt{background:var(--c5)}
.slide li{all:unset}
/* câu trích lớn */
.trich{position:relative;background:var(--card);border-radius:20px;padding:22px 26px 22px 70px;border:2px solid color-mix(in srgb,var(--pc) 35%,var(--line));box-shadow:0 6px 16px rgba(0,0,0,.07)}
.trich .mo{position:absolute;left:14px;top:-6px;font-size:90px;line-height:1;color:var(--pc);font-family:Georgia,serif}
.ruy{background:color-mix(in srgb,var(--vang) 30%,var(--card));border:2px solid var(--vang);border-radius:14px;padding:12px 18px;font-size:clamp(17px,2.4vw,24px);font-weight:600;color:var(--ink)}
.ruy.ket{background:color-mix(in srgb,var(--pc) 16%,var(--card));border-color:var(--pc);font-size:clamp(20px,3vw,32px);font-weight:800;text-align:center}
.slide p.mute{margin:0}
/* chuỗi bước có mũi tên */
.dong-buoc{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.dong-buoc .o{background:var(--pc);color:#fff;border-radius:16px;padding:14px 22px;font-weight:800;font-size:clamp(18px,3vw,30px);box-shadow:0 4px 10px color-mix(in srgb,var(--pc) 35%,transparent)}
.dong-buoc .o:nth-of-type(7n+2){background:var(--c4)}.dong-buoc .o:nth-of-type(7n+3){background:var(--c3)}.dong-buoc .o:nth-of-type(7n+4){background:var(--c2)}.dong-buoc .o:nth-of-type(7n+5){background:var(--c5)}.dong-buoc .o:nth-of-type(7n+6){background:#65a30d}.dong-buoc .o:nth-of-type(7n+7){background:var(--do)}
.dong-buoc .mui{font-size:clamp(22px,3vw,34px);color:var(--pc);font-weight:900}
/* hai con đường */
.lane{text-align:center;border-top-width:10px;padding:20px}
.lane.a{border-top-color:var(--c2)}.lane.b{border-top-color:var(--c3)}
.lane h3{font-size:clamp(20px,2.8vw,30px);margin:6px 0}
.bigico{font-size:clamp(44px,7vw,76px);line-height:1.1;animation:noi 3.5s ease-in-out infinite}
/* tình huống */
.th{text-align:left}.th .bigico{font-size:48px;animation:none}
.th.mo{background:color-mix(in srgb,var(--pc) 10%,var(--card))}
/* hoạt động */
.hd2{display:grid;grid-template-columns:1fr 1fr;gap:20px;align-items:start}
.hd2.mot{grid-template-columns:1fr}
@media(max-width:820px){.hd2{grid-template-columns:1fr}}
.hd-trai,.hd-phai{display:flex;flex-direction:column;gap:12px}
.cauhoi{display:flex;gap:12px;align-items:center;background:var(--card);border:2px solid color-mix(in srgb,var(--pc) 30%,var(--line));border-radius:16px;padding:12px 14px;font-size:clamp(17px,2.4vw,24px)}
.cauhoi .hoi-ico{flex:none;display:inline-flex;width:38px;height:38px;border-radius:50%;background:var(--c2);color:#fff;font-weight:900;align-items:center;justify-content:center}
.cauhoi:nth-child(3n+2) .hoi-ico{background:var(--c3)}.cauhoi:nth-child(3n+3) .hoi-ico{background:var(--c5)}
/* đồng hồ vòng */
.dongho{display:flex;flex-direction:column;align-items:flex-start;gap:10px}
.vg{position:relative;width:170px;height:170px}
.vong-gio{width:100%;height:100%}
.vong-gio .nen{stroke:color-mix(in srgb,var(--pc) 18%,var(--line))}
.vong-gio .tien{stroke:var(--pc);transition:stroke-dashoffset 1s linear,stroke .3s}
.vg .hen{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;font-size:38px;color:var(--ink)}
.dongho.sap .tien{stroke:var(--do)}.dongho.sap .hen{color:var(--do);animation:nhip .8s infinite}
.dongho.het .tien{stroke:var(--do)}.dongho.het .hen{color:var(--do)}
/* thanh điều hướng dưới */
.dieuhuong{gap:12px}
.giua{display:flex;flex-direction:column;align-items:center;gap:4px;flex:1;min-width:0}
.cham-dots{display:flex;flex-wrap:wrap;gap:6px;justify-content:center}
.cham-dots .cd{width:13px;height:13px;border-radius:50%;background:color-mix(in srgb,var(--pc) 35%,var(--card));border:2px solid var(--pc);transition:transform .15s}
.cham-dots .cd:hover{transform:scale(1.35)}
.cham-dots .cd.on{background:var(--pc);transform:scale(1.5)}
/* khung ảnh & bảng trong slide */
.slide .hinhbox{background:#fff;border-radius:16px;padding:10px;border:2px solid color-mix(in srgb,var(--pc) 35%,var(--line))}
.slide table.bang{font-size:clamp(16px,2.2vw,24px);border-radius:14px;overflow:hidden}
.slide table.bang th{background:var(--pc)}
.slide .ring-wrap svg.rings{width:min(86vw,460px)}
@media(max-width:700px){.cham-dots{display:none}.dieuhuong .giua{flex:none}}

.btn.video{background:linear-gradient(135deg,#ef4444,#b91c1c);text-decoration:none;align-self:flex-start}

.hang-chieu{justify-content:space-between;align-items:center;margin-bottom:6px}
.chip{font-size:clamp(16px,1.7vw,22px)}
@media print{.hang-chieu{display:none}}
.card.noi{font-size:clamp(17px,1.9vw,21px);line-height:1.55}

/* bài tập trên lớp: trạm và thẻ lật */
.tram-luoi{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
@media(max-width:900px){.tram-luoi{grid-template-columns:1fr}}
.slide .tram{background:var(--card);border-radius:20px;padding:14px 16px;border:3px solid var(--c3);text-align:center;box-shadow:0 6px 16px rgba(0,0,0,.08)}
.slide .tram.t0{border-color:var(--c3)}.slide .tram.t1{border-color:var(--c5)}.slide .tram.t2{border-color:var(--c4)}
.tram h3{font-size:clamp(20px,2.4vw,28px);margin:4px 0 8px}.tram.t0 h3{color:var(--c3)}.tram.t1 h3{color:var(--c5)}.tram.t2 h3{color:var(--c4)}
.slide .tram ol{text-align:left;padding-left:24px;margin:0}
.slide .tram li{display:list-item;list-style:decimal;margin:8px 0;font-size:clamp(15px,1.7vw,20px);line-height:1.4;background:none;border:0;padding:0}
.lat-luoi{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr));gap:14px}
.card.lat{position:relative;padding:16px 16px 16px 66px;cursor:pointer;border:3px solid var(--line);font-size:clamp(17px,2vw,24px);transition:transform .15s}
.card.lat:hover{transform:translateY(-2px)}
.card.lat .stt{position:absolute;left:14px;top:14px;display:inline-flex;width:40px;height:40px;border-radius:50%;background:var(--pc);color:#fff;font-weight:800;align-items:center;justify-content:center}
.card.lat.xanh{border-color:var(--ok);background:color-mix(in srgb,var(--ok) 14%,var(--card))}
.card.lat.do{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 12%,var(--card))}
.lat-kq{margin-top:10px;padding-top:8px;border-top:2px dashed var(--line);font-size:.9em}
.card.lat.tim{border-color:var(--c5);background:color-mix(in srgb,var(--c5) 12%,var(--card))}

/* vào học, lớp học */
.o-ma{display:block;margin:8px 0;font-size:20px;letter-spacing:2px;text-transform:uppercase}
.o-ma[type=password]{text-transform:none;letter-spacing:0}
.loi-vao{color:var(--bad);font-weight:700;min-height:1.4em}
.ma-lon{font-family:ui-monospace,Menlo,monospace;font-size:clamp(34px,8vw,64px);font-weight:800;letter-spacing:8px;color:var(--pri)}
.ruy-nho{background:color-mix(in srgb,var(--vang) 28%,var(--card));border:2px solid var(--vang);border-radius:10px;padding:8px 12px;margin:8px 0;font-weight:600}
select{font:inherit;padding:10px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--ink);max-width:100%}
header a.vaibtn{cursor:pointer}

/* chiếu mã to */
.phu-ma{position:fixed;inset:0;z-index:60;background:color-mix(in srgb,var(--bg) 94%,#000);display:flex;align-items:center;justify-content:center;padding:16px;overflow:auto}
.phu-ma-nd{text-align:center;max-width:900px;width:100%}
.phu-ma-nd.hop{background:var(--card);border:2px solid var(--pri);border-radius:20px;padding:18px;max-width:560px;text-align:left}
.phu-ma-so{font-family:ui-monospace,Menlo,monospace;font-weight:800;letter-spacing:.12em;color:var(--pri);font-size:clamp(40px,12vw,150px);line-height:1.1;margin:4px 0 16px}
.chon-lop label{display:block;margin:6px 0 4px}

/* theo dõi tiến độ */
.o-ten{display:block;margin:8px 0;font-size:18px}
.tomtat{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:12px 0}
.o-tt{background:var(--card);border:2px solid var(--line);border-radius:14px;padding:12px;text-align:center}
.o-tt b{display:block;font-size:34px;color:var(--pri)}.o-tt.do{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 10%,var(--card))}.o-tt.do b{color:var(--bad)}
.card.kiet{border:2px solid var(--bad);background:color-mix(in srgb,var(--bad) 8%,var(--card))}
tr.kiet-dong td{background:color-mix(in srgb,var(--bad) 10%,var(--card))}
.cuon{overflow-x:auto}
table.bang .bar{margin-top:4px;min-width:90px}
input[type=number],input[type=password]{width:100%;font:inherit;padding:10px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--ink)}

/* câu cả lớp hay sai */
.cs-dong{padding:10px 0;border-bottom:1px solid var(--line)}
.cs-c{font-weight:700}
.cs-bar{height:12px;background:color-mix(in srgb,var(--ok) 20%,var(--card));border-radius:99px;overflow:hidden;margin:6px 0}
.cs-bar i{display:block;height:100%;background:var(--bad)}
.cs-so{font-weight:700}.cs-dong.nhieu .cs-so{color:var(--bad)}
.cs-dong.nhieu{background:color-mix(in srgb,var(--bad) 7%,var(--card))}

/* mở tất cả các lớp, màn hình của cô, chiếu nhiều mã */
.tat-ca{margin-top:14px;padding-top:10px;border-top:2px dashed var(--line)}
.hang-ma{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin:8px 0}
.ma-vua{font-family:ui-monospace,Menlo,monospace;font-weight:800;font-size:clamp(18px,3vw,26px);color:var(--pri);background:var(--pri2);border-radius:10px;padding:4px 10px}
.phu-ma-lop{margin:10px 0}.phu-ma-ten{font-size:clamp(20px,3vw,34px);font-weight:800}
.phu-ma-hai{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.phu-ma-so.nho{font-size:clamp(28px,7vw,72px)}
body.nguoi-day{background-image:none}
.noi-to{font-size:clamp(20px,3.2vw,30px);line-height:1.6;border-width:3px}
.noi-to .nd-noi{margin-top:8px;white-space:pre-wrap}
/* Điện thoại nhỏ: thanh đầu trang không tràn ra ngoài màn hình */
@media(max-width:430px){header .logo{font-size:14px;min-width:0;overflow:hidden;text-overflow:ellipsis}header .vaibtn{font-size:12px;padding:4px 8px}header .tg{padding:6px 8px;font-size:14px}header .hang{gap:6px;padding:8px 10px}}
html{overflow-x:hidden}
/* Trang chúc mừng cuối bài */
.xong-the{position:relative;overflow:hidden;text-align:center}
.xong-the .cup{font-size:56px;line-height:1;animation:nay 1.2s ease-out}
.hang-chip{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin:14px 0}
.chip-xong{background:#fff;border:2px solid var(--c1);border-radius:14px;padding:8px 14px;display:flex;flex-direction:column;min-width:80px;flex:1 1 80px;max-width:120px}
.chip-xong b{font-size:22px;color:var(--c1)}.chip-xong span{font-size:13px;color:var(--mute)}
.viec-nho{background:#fff7d6;border:2px dashed #e0a800;border-radius:12px;padding:10px 12px;margin:10px 0;text-align:left}
.xong-the .row{justify-content:center}
.phao span{position:absolute;top:-30px;font-size:24px;animation:roi 2.4s ease-in 1}
@keyframes roi{to{transform:translateY(340px) rotate(40deg);opacity:0}}
@keyframes nay{0%{transform:scale(.3)}60%{transform:scale(1.25)}100%{transform:scale(1)}}
@media(prefers-reduced-motion:reduce){.phao span,.xong-the .cup{animation:none}.phao{display:none}}
.dieuhuong a{white-space:nowrap}

/* Giấy đồng ý và thẻ mã: chỉ hiện khi in */
.giay-in,.the-in{display:none}
.the-ma{border:1px dashed #555;padding:10px 12px;margin:0 0 10px;break-inside:avoid}
@media print{
  body.in-giay #top,body.in-giay .noprint,body.in-giay .the-in,body.in-the #top,body.in-the .noprint,body.in-the .giay-in{display:none!important}
  body.in-giay .giay-in,body.in-the .the-in{display:block}
  body.in-giay h1,body.in-the h1{display:none}
  .giay-in p{font-size:14px;line-height:1.5;margin:8px 0}
}

.o-ma.mk{text-transform:none;letter-spacing:0}

.nguy{margin-top:20px;padding-top:12px;border-top:1px solid #e2d8c6}
.nguy .btn{color:#b3261e}

html:fullscreen header#top,html:fullscreen #top{display:none}
.slide{transform-origin:top left}

details.huongdan summary{font-weight:700;cursor:pointer;padding:2px 0}
details.huongdan[open] summary{margin-bottom:6px}

.rieng-nho{padding:10px 14px;font-size:15px;background:transparent;box-shadow:none}