/* Hệ giao diện Học viện AI — theo bản thiết kế đã duyệt */
:root{
  --ink:#0B1220;--ink2:#262F3F;--muted:#5B6578;--line:#EEF0F3;--line2:#E7E9EE;--bg:#F6F7F9;--soft:#F1F3F6;
  --brand:#0D6E5C;--brand-d:#09564A;--brand-t:#E3F1ED;--mint:#8BE3C9;
  --ok-bg:#E6F4EF;--ok:#0B5E4E;--wait-bg:#FDF1DC;--wait:#8A4B06;--bad-bg:#FDE8E6;--bad:#A3231A;--info-bg:#E8EEFC;--info:#2B4BB8;
  --r:16px;--shadow:0 1px 2px rgba(16,24,40,.04),0 0 0 1px rgba(16,24,40,.07);
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:'Be Vietnam Pro',system-ui,-apple-system,'Segoe UI',sans-serif;font-size:15px;line-height:1.5}
a{color:var(--brand)}a:hover{color:var(--brand-d)}
h1,h2,h3{margin:0;letter-spacing:-0.01em}
p{margin:0}
.muted{color:var(--muted)}.small{font-size:13px}.num{font-variant-numeric:tabular-nums}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
:focus-visible{outline:2px solid var(--brand);outline-offset:2px}

/* Thanh trên cùng */
.top{display:flex;align-items:center;gap:8px 28px;flex-wrap:wrap;padding:0 32px;background:#fff;border-bottom:1px solid var(--line2)}
.top.dark{background:var(--ink);border-bottom:0}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:700;font-size:16px;min-height:64px}
.brand:hover{color:var(--ink)}
.top.dark .brand,.top.dark .brand:hover{color:#fff}
.mark{width:32px;height:32px;border-radius:9px;background:var(--brand);color:#fff;display:flex;align-items:center;justify-content:center}
.tabs{display:flex;gap:2px;flex-wrap:wrap;flex:1 1 auto}
.tabs a{display:flex;align-items:center;min-height:64px;padding:0 14px;color:#4A5468;text-decoration:none;font-size:14px;font-weight:600;border-bottom:2px solid transparent}
.tabs a:hover{color:var(--ink)}
.tabs a.on{color:var(--ink);border-bottom-color:var(--brand)}
.top.dark .tabs a{color:#AEB6C4}.top.dark .tabs a:hover,.top.dark .tabs a.on{color:#fff}.top.dark .tabs a.on{border-bottom-color:var(--mint)}
.tools{display:flex;align-items:center;gap:6px;margin-left:auto}
.ib{position:relative;width:44px;height:44px;border-radius:12px;border:0;background:transparent;display:flex;align-items:center;justify-content:center;color:#4A5468;cursor:pointer;text-decoration:none}
.ib:hover{background:var(--soft);color:var(--ink)}
.dot-new{position:absolute;top:10px;right:11px;width:8px;height:8px;border-radius:50%;background:#E5484D;border:2px solid #fff}
.av{width:36px;height:36px;border-radius:50%;background:var(--brand-t);color:var(--brand);font-weight:700;font-size:13px;display:inline-flex;align-items:center;justify-content:center;flex:0 0 36px;text-decoration:none}
.av.c1{background:var(--info-bg);color:var(--info)}.av.c2{background:var(--wait-bg);color:var(--wait)}.av.c3{background:var(--soft);color:#4A5468}
.menu{position:relative}
.menu summary{list-style:none;cursor:pointer}.menu summary::-webkit-details-marker{display:none}
.menu .pop{position:absolute;right:0;top:48px;z-index:20;min-width:220px;background:#fff;border-radius:12px;box-shadow:0 12px 32px rgba(16,24,40,.14),0 0 0 1px rgba(16,24,40,.07);padding:8px}
.menu .pop a,.menu .pop button{display:block;width:100%;text-align:left;padding:10px 12px;border-radius:8px;color:var(--ink);text-decoration:none;font:inherit;font-size:14px;background:none;border:0;cursor:pointer}
.menu .pop a:hover,.menu .pop button:hover{background:var(--soft)}

/* Thanh tập trung (bài học, thực hành, nộp bài) */
.fbar{display:flex;align-items:center;gap:16px;padding:0 24px;min-height:64px;background:#fff;border-bottom:1px solid var(--line2);flex-wrap:wrap}
.back{display:flex;align-items:center;gap:10px;color:var(--ink);text-decoration:none;font-size:14px;font-weight:600;min-height:44px}
.back:hover{color:var(--brand)}
.fcenter{flex:1 1 200px;display:flex;align-items:center;justify-content:center;gap:12px;font-size:13px;color:var(--muted)}

/* Bố cục */
.wrap{max-width:1180px;margin:0 auto;padding:40px 32px 72px;display:flex;flex-direction:column;gap:24px}
.wrap.wide{max-width:1240px}
.cols{display:flex;flex-wrap:wrap;gap:24px;align-items:flex-start}
.main{flex:3 1 560px;min-width:0;display:flex;flex-direction:column;gap:24px}
.side{flex:1 1 300px;min-width:0;display:flex;flex-direction:column;gap:20px}
.stack{display:flex;flex-direction:column;gap:20px}
.row{display:flex;flex-wrap:wrap;gap:12px;align-items:center}
.between{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:baseline;gap:8px 16px}
.h1{font-size:30px;font-weight:700;letter-spacing:-0.02em;line-height:1.25}
.h2{font-size:18px;font-weight:700}
.h3{font-size:16px;font-weight:700}
.sub{margin-top:6px;color:var(--muted);font-size:15px}
.card{background:#fff;border-radius:var(--r);padding:24px;box-shadow:var(--shadow)}
.card.flush{padding:0;overflow:hidden}
.card.tight{padding:20px}
.card.warn{background:#FFF8F0;box-shadow:0 0 0 1px #F6DDBE}
.card.mint{background:var(--brand-t);box-shadow:none}
a.card{display:block;text-decoration:none;color:var(--ink)}

/* Nút, nhãn */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:44px;padding:0 20px;border-radius:12px;font-family:inherit;font-weight:600;font-size:14px;text-decoration:none;border:0;cursor:pointer;white-space:nowrap}
.btn-p{background:var(--brand);color:#fff}.btn-p:hover{background:var(--brand-d);color:#fff}
.btn-g{background:var(--soft);color:var(--ink)}.btn-g:hover{background:var(--line2);color:var(--ink)}
.btn-w{background:#fff;color:var(--ink)}.btn-w:hover{background:var(--soft);color:var(--ink)}
.btn-r{background:#fff;color:var(--bad);box-shadow:inset 0 0 0 1px #F2C3BE}.btn-r:hover{background:#FDF3F2;color:var(--bad)}
.btn-sm{min-height:36px;padding:0 14px;font-size:13px}
.btn:disabled,.btn[aria-disabled=true]{background:var(--soft);color:#8A93A3;cursor:not-allowed}
.btn.block{width:100%}
.chip{display:inline-flex;align-items:center;gap:6px;height:26px;padding:0 10px;border-radius:999px;font-size:12px;font-weight:600;white-space:nowrap;text-decoration:none}
.c-ok{background:var(--ok-bg);color:var(--ok)}.c-wait{background:var(--wait-bg);color:var(--wait)}.c-bad{background:var(--bad-bg);color:var(--bad)}.c-info{background:var(--info-bg);color:var(--info)}.c-mute{background:var(--soft);color:#4A5468}
.tag{flex:0 0 auto;font-size:11px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;border-radius:6px;padding:3px 7px;margin-top:2px}
.bar{height:6px;border-radius:3px;background:#EDEFF3;overflow:hidden}
.bar>i{display:block;height:100%;background:var(--brand);border-radius:3px}

/* Danh sách */
.li{display:flex;align-items:center;gap:14px;padding:14px 4px;border-top:1px solid var(--line);text-decoration:none;color:var(--ink)}
.li:first-child{border-top:0}
a.li:hover{background:#FAFBFC;color:var(--ink)}
.li .grow{flex:1 1 auto;min-width:0}
.tick{flex:0 0 24px;height:24px;border-radius:50%;display:flex;align-items:center;justify-content:center;border:2px solid #C5CBD5}
.tick.done{background:var(--brand);border-color:var(--brand);color:#fff}
.tick.cur{border-color:var(--info)}
.tick.cur::after{content:"";width:10px;height:10px;border-radius:50%;background:var(--info)}
.kv{display:flex;justify-content:space-between;gap:16px;padding:11px 0;border-top:1px solid var(--line);font-size:14px}
.kv:first-of-type{border-top:0}
.kv>span{color:var(--muted)}.kv>b{text-align:right;font-weight:600}

/* Bảng */
.tbl-wrap{overflow-x:auto}
table.tbl{border-collapse:collapse;width:100%;min-width:640px}
.tbl th,.tbl td{text-align:left;padding:14px 12px;font-size:14px;border-top:1px solid var(--line);vertical-align:middle}
.tbl th{font-size:12px;font-weight:600;color:var(--muted);letter-spacing:.04em;text-transform:uppercase;border-top:0;padding-top:4px}
.tbl .r{text-align:right;font-variant-numeric:tabular-nums}
.tbl tr.me td{background:#F1F8F6}

/* Biểu mẫu */
label.l{display:block;font-size:13px;font-weight:600;color:#3E4859;margin-bottom:6px}
.inp,textarea.inp,select.inp{width:100%;border:1px solid #D5DAE2;border-radius:10px;padding:11px 14px;font-family:inherit;font-size:15px;color:var(--ink);background:#fff}
textarea.inp{resize:vertical;line-height:1.6}
select.inp{max-width:100%;text-overflow:ellipsis}
.inp:focus{outline:2px solid var(--brand);outline-offset:1px;border-color:var(--brand)}
.field{display:flex;flex-direction:column;gap:2px}
.hint{font-size:13px;color:var(--muted);line-height:1.5}
.ck{display:flex;align-items:center;gap:12px;font-size:15px;min-height:40px}
.ck input{width:20px;height:20px;accent-color:var(--brand);flex:0 0 20px}
.tg{position:relative;display:inline-flex;align-items:center;gap:8px;min-height:40px;padding:0 14px;border-radius:999px;border:1px solid #D5DAE2;font-size:14px;font-weight:500;cursor:pointer;background:#fff}
.tg input{position:absolute;opacity:0;width:1px;height:1px}
.tg:has(input:checked){background:var(--brand-t);border-color:var(--brand);color:var(--ok);font-weight:600}
.tg:has(input:focus-visible){outline:2px solid var(--brand);outline-offset:2px}
.sec{display:flex;gap:18px;padding:26px 0;border-top:1px solid var(--line)}
.sec:first-child{border-top:0;padding-top:4px}
.n{flex:0 0 28px;height:28px;border-radius:50%;background:var(--ink);color:#fff;font-size:13px;font-weight:700;display:flex;align-items:center;justify-content:center}
.sb{flex:1 1 auto;min-width:0;display:flex;flex-direction:column;gap:10px}
.drop{border:1.5px dashed #C5CBD5;border-radius:12px;padding:16px;background:#FAFBFC;display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.flash{padding:14px 18px;border-radius:12px;font-size:14px}
.flash.ok{background:var(--ok-bg);color:var(--ok)}.flash.err{background:var(--bad-bg);color:var(--bad)}

/* Phân đoạn */
.seg{display:inline-flex;background:#E9ECF0;border-radius:12px;padding:4px;gap:4px;max-width:100%;overflow-x:auto}
.seg a{display:flex;align-items:center;min-height:38px;padding:0 16px;border-radius:9px;font-size:14px;font-weight:600;color:#4A5468;text-decoration:none;white-space:nowrap}
.seg a.on{background:#fff;color:var(--ink);box-shadow:0 1px 2px rgba(16,24,40,.12)}

/* Trang chủ */
.hero{display:flex;flex-wrap:wrap;gap:32px;align-items:center;justify-content:space-between;background:var(--brand);color:#fff;border-radius:20px;padding:36px 40px}
.hero h2{font-size:26px;line-height:1.3;margin:14px 0 8px}
.hero .lead{color:#D3EDE6;font-size:15px}
.hero .chip{background:rgba(255,255,255,.16);color:#fff}
.btn-ghost-w{color:#fff;background:rgba(255,255,255,.12)}.btn-ghost-w:hover{color:#fff;background:rgba(255,255,255,.2)}
.ms{display:flex;gap:12px;align-items:center;font-size:14px;padding:6px 0}
.mdot{flex:0 0 10px;height:10px;border-radius:50%;background:#D5DAE2}
.mdot.cur{background:var(--info);box-shadow:0 0 0 4px var(--info-bg)}.mdot.done{background:var(--brand)}

/* Lộ trình */
.phase{font-size:13px;font-weight:600;color:var(--muted);margin:0 0 10px 4px}
.mod{display:flex;align-items:center;gap:16px;padding:18px 22px;border-top:1px solid var(--line);text-decoration:none;color:var(--ink)}
.mod:first-child{border-top:0}
a.mod:hover{background:#FAFBFC;color:var(--ink)}
.mod.locked{opacity:.75}
.st{flex:0 0 36px;height:36px;border-radius:50%;display:flex;align-items:center;justify-content:center;background:var(--soft);color:#8A93A3}
.st.ok{background:var(--ok-bg);color:var(--ok)}.st.cur{background:var(--brand);color:#fff}
.mt{flex:1 1 auto;min-width:0}.mt b{display:block;font-size:15px;font-weight:600}.mt span{font-size:13px;color:var(--muted)}
.card.current{box-shadow:0 0 0 2px var(--brand),0 8px 24px rgba(13,110,92,.10)}
.lessons{background:#FAFBFC;border-top:1px solid var(--line);padding:8px 22px 16px 74px}
.ls{display:flex;align-items:center;gap:12px;padding:9px 0;font-size:14px;text-decoration:none;color:var(--ink)}
.ls:hover{color:var(--brand)}
.tl .item{display:flex;gap:12px;position:relative;padding-bottom:18px;font-size:14px}
.tl .item:last-child{padding-bottom:0}
.tl .d{flex:0 0 12px;height:12px;border-radius:50%;margin-top:4px;background:#D5DAE2;position:relative;z-index:1}
.tl .d.done{background:var(--brand)}.tl .d.cur{background:#fff;box-shadow:inset 0 0 0 3px var(--info)}
.tl .item:not(:last-child)::before{content:"";position:absolute;left:5px;top:16px;bottom:-4px;width:2px;background:#D5DAE2}

/* Bài học */
.lesson-shell{display:flex;align-items:stretch;min-height:calc(100vh - 64px);background:#fff}
.toc{flex:0 1 300px;min-width:240px;border-right:1px solid var(--line);padding:24px 16px;background:#FAFBFC}
.toc a{display:flex;gap:12px;align-items:flex-start;padding:10px 12px;border-radius:10px;text-decoration:none;color:var(--ink);font-size:14px;line-height:1.45}
.toc a:hover{background:var(--soft);color:var(--ink)}
.toc a.cur{background:var(--brand-t);font-weight:600}
.toc svg{flex:0 0 18px;margin-top:1px}
.art{flex:1 1 560px;min-width:0;padding:48px 40px 80px}
.prose{max-width:720px;margin:0 auto}
.prose h1{font-size:36px;line-height:1.2;font-weight:700;letter-spacing:-0.02em;margin:10px 0 16px}
.prose h2{font-size:22px;font-weight:700;margin:44px 0 12px}
.prose h3{font-size:18px;font-weight:700;margin:28px 0 8px}
.prose p,.prose li{font-size:17px;line-height:1.75;color:var(--ink2)}
.prose p{margin:0 0 14px}
.prose ul,.prose ol{padding-left:22px;margin:10px 0 14px}
.prose li{margin:4px 0}
.prose code{font-family:'JetBrains Mono',ui-monospace,Menlo,Consolas,monospace;font-size:.88em;background:var(--soft);padding:2px 5px;border-radius:5px}
.prose pre{margin:18px 0;background:#0F1729;color:#E5EAF3;border-radius:14px;padding:22px 24px;font-size:14px;line-height:1.7;overflow-x:auto}
.prose pre code{background:none;padding:0;font-size:14px;color:inherit}
.prose .lead{font-size:19px;color:#3E4859}
.callout{padding:18px 20px;border-radius:14px;margin:24px 0;background:var(--brand-t)}
.callout b{display:block;font-size:15px;margin-bottom:6px}
.callout p,.callout li{font-size:15px;line-height:1.65}
.callout p:last-child{margin-bottom:0}
.callout-warn{background:#FFF8F0}.callout-ai{background:var(--brand-t)}.callout-note{background:#F4F6FB}
.res{display:flex;align-items:center;gap:12px;padding:14px 16px;border-radius:12px;background:var(--bg);text-decoration:none;color:var(--ink);font-size:14px;flex:1 1 220px;min-width:0}
.res:hover{background:#EEF0F3;color:var(--ink)}

/* Thực hành */
.tile{flex:1 1 200px;min-width:0;background:#fff;border-radius:14px;padding:18px;box-shadow:0 0 0 1px rgba(16,24,40,.07)}
.tile b{display:block;font-size:12px;font-weight:600;letter-spacing:.05em;text-transform:uppercase;color:var(--muted);margin-bottom:6px}
.tile span{font-size:14px;line-height:1.55}
.crit{display:flex;gap:14px;align-items:flex-start;padding:14px 0;border-top:1px solid var(--line);font-size:15px;line-height:1.55}
.crit:first-of-type{border-top:0}
.hintx{border-top:1px solid var(--line);padding:16px 0}
.hintx:first-of-type{border-top:0;padding-top:4px}
.lvl{width:28px;height:28px;border-radius:8px;display:inline-flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;margin-right:10px}
.hint-body{margin:10px 0 0 38px}
.hint-body p,.hint-body li{font-size:15px;line-height:1.65}

/* Kết quả */
.comp{flex:1 1 180px;min-width:0}
.track{position:relative;height:8px;border-radius:4px;background:#EDEFF3;margin:10px 0 6px}
.track .fill{position:absolute;left:0;top:0;bottom:0;border-radius:4px;background:var(--brand)}
.track .min{position:absolute;top:-4px;width:2px;height:16px;background:var(--ink);opacity:.35;left:70%}
.rr{display:flex;align-items:flex-start;gap:16px;padding:18px 0;border-top:1px solid var(--line);flex-wrap:wrap}
.rr:first-of-type{border-top:0}
.sc{flex:0 0 auto;margin-left:auto;text-align:right;font-weight:700;font-size:18px}

/* Dự án */
.flow{display:flex;flex-wrap:wrap;align-items:center;gap:6px}
.flow .s{display:inline-flex;align-items:center;height:32px;padding:0 12px;border-radius:8px;background:var(--soft);font-size:13px;font-weight:500}
.steps{display:flex;flex-wrap:wrap}
.step{flex:1 1 120px;min-width:0;position:relative;padding-right:8px}
.step .ln{position:absolute;top:13px;left:30px;right:6px;height:2px;background:#E2E5EA}
.step .d{position:relative;z-index:1;width:28px;height:28px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;background:var(--soft);color:#8A93A3}
.step .d.done{background:var(--brand);color:#fff}.step .d.cur{background:#fff;color:var(--info);box-shadow:inset 0 0 0 2px var(--info)}
.step b{display:block;font-size:13px;margin-top:10px;line-height:1.4}
.step .w{display:block;font-size:12px;color:var(--muted);margin-top:2px}

/* Cộng đồng */
.kanban{display:flex;flex-wrap:wrap;gap:16px}
.kcol{flex:1 1 200px;min-width:0;display:flex;flex-direction:column;gap:10px}
.kcol h3{font-size:13px;font-weight:600;color:var(--muted);display:flex;justify-content:space-between}
.kt{background:var(--bg);border-radius:12px;padding:14px;font-size:14px;display:flex;flex-direction:column;gap:8px}
.msg{display:flex;gap:14px;padding:18px 0;border-top:1px solid var(--line)}
.msg:first-of-type{border-top:0;padding-top:6px}
.msg .body{font-size:15px;line-height:1.6;color:var(--ink2);margin-top:4px;white-space:pre-wrap;overflow-wrap:anywhere}
.rk{display:inline-flex;width:28px;height:28px;border-radius:50%;align-items:center;justify-content:center;font-size:13px;font-weight:700;background:var(--soft);color:#4A5468}
.rk.gold{background:#FFF4D6;color:#9A6200}
.who{display:flex;align-items:center;gap:12px}
.stat{flex:1 1 180px;min-width:0}.stat .v{font-size:32px;font-weight:700;letter-spacing:-0.02em;margin-top:4px}

/* Chấm bài */
.q{display:flex;flex-direction:column;gap:4px;padding:14px 16px;border-radius:12px;text-decoration:none;color:var(--ink)}
.q:hover{background:var(--bg);color:var(--ink)}.q.cur{background:var(--brand-t)}
.metric{flex:1 1 140px;min-width:0;background:var(--bg);border-radius:12px;padding:14px 16px}
.metric .v{font-size:22px;font-weight:700;margin-top:2px}
.rc{display:grid;grid-template-columns:minmax(0,1fr) 100px;gap:16px;align-items:center;padding:16px 0;border-top:1px solid var(--line)}
.rc input{text-align:right;font-weight:600;font-variant-numeric:tabular-nums}

/* Xác thực */
.auth{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px 16px;background:var(--bg)}
.auth .card{width:100%;max-width:420px;padding:32px}

footer.foot{max-width:1180px;margin:0 auto;padding:0 32px 40px;font-size:12px;color:#8A93A3}

@media (max-width:720px){
  .top{padding:0 16px;gap:0 8px}
  .tabs{order:3;flex:1 1 100%;flex-wrap:nowrap;overflow-x:auto;margin:0 -16px;padding:0 6px;border-top:1px solid var(--line)}
  .top.dark .tabs{border-top-color:#1F2940}
  .tabs a{min-height:48px;white-space:nowrap}
  .hide-sm{display:none !important}
  .wrap{padding:24px 16px 48px;gap:20px}
  .h1{font-size:26px}
  .card{padding:20px}
  .hero{padding:24px;border-radius:16px}
  .hero-ring{display:none}
  .fbar{padding:0 12px}
  .toc{display:none}
  .art{padding:28px 18px 56px}
  .prose h1{font-size:28px}
  .prose p,.prose li{font-size:16px}
  .mod{padding:16px}
  .lessons{padding:8px 16px 14px}
  .sec{gap:12px}
  .step{flex:1 1 100%;display:flex;gap:12px;align-items:flex-start;padding-bottom:14px}
  .step .ln{display:none}
  .step b{margin-top:4px}
  .seg{width:100%}
  .seg a{flex:1 0 auto;justify-content:center}
  .rc{grid-template-columns:minmax(0,1fr) 76px;gap:10px}
}
.mdt-wrap{overflow-x:auto;margin:16px 0}
table.mdt{border-collapse:collapse;width:100%;font-size:15px;line-height:1.55}
table.mdt th,table.mdt td{border:1px solid #E4E7EC;padding:8px 12px;text-align:left;vertical-align:top}
table.mdt th{background:#F6F7F9;font-weight:600;color:var(--ink)}
table.mdt td{color:var(--ink2)}