/* styles-frontend-v6.css — He thiet ke lay tu mockup-v6, ap cho trang hoc that.
   Mau: #143A6B / #1D6FD1 / #FFC107 / #FF7A29 / #1A9E57. Chu 19-20px. Nut >=56px. The bo 20-22px.
   Phan dau la CSS goc mockup-v6 (khong sua ten class), phan sau la lop ap dung cho trang hoc that. */
:root{--navy:#143A6B;--blue:#1D6FD1;--yellow:#FFC107;--orange:#FF7A29;--green:#1A9E57;--bg:#EEF3FB;--card:#fff;--muted:#5B6B82;--line:#DCE4F0;--radius:22px}
*{box-sizing:border-box}body{font-family:system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;background:var(--bg);color:var(--navy);margin:0;font-size:19px;line-height:1.55}
a{color:var(--blue);text-decoration:none}
.topbar{background:var(--navy);color:#fff;padding:10px 20px;font-size:16px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px}
header.site{position:sticky;top:0;background:#fff;box-shadow:0 2px 12px rgba(20,58,107,.12);z-index:20}
.head{max-width:1180px;margin:0 auto;padding:14px 20px;display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:12px}
.logo .mark{width:52px;height:52px;border-radius:14px;background:var(--navy);display:flex;align-items:center;justify-content:center;color:#fff;font-size:28px;font-weight:900}
.logo b{font-size:24px;line-height:1}.logo span{display:block;font-size:14px;color:var(--muted);font-weight:600}
nav.main{display:flex;gap:6px;flex-wrap:wrap;margin-left:auto}
nav.main button{background:transparent;border:0;padding:12px 14px;font-size:18px;font-weight:700;color:var(--navy);cursor:pointer;border-radius:999px}
nav.main button.active,nav.main button:hover{background:#E8EEF7}
.btn{background:var(--blue);color:#fff;border:0;border-radius:14px;padding:16px 22px;font-size:20px;min-height:56px;cursor:pointer;font-weight:700}
.btn.o{background:var(--orange)}.btn.g{background:var(--green)}.btn.y{background:var(--yellow);color:var(--navy)}.btn.light{background:#E8EEF7;color:var(--navy)}
.wrap{max-width:1180px;margin:0 auto;padding:24px 20px}
.card{background:var(--card);border-radius:var(--radius);padding:24px;box-shadow:0 4px 18px rgba(20,58,107,.08);margin-bottom:20px}
.hero{background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:28px;padding:36px}
.hero h1{font-size:42px;line-height:1.15;margin:0 0 12px}.hero p{font-size:21px;opacity:.95}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.course{border:2px solid var(--line);border-radius:20px;overflow:hidden;background:#fff}
.course .thumb{height:130px;background:linear-gradient(135deg,#1D6FD1,#FF7A29);color:#fff;display:flex;align-items:center;justify-content:center;font-size:44px;font-weight:900}
.course .thumb img{width:100%;height:100%;object-fit:cover;display:block}
.course .body{padding:18px}.course .body b{font-size:21px}
.badge{display:inline-block;background:#FFF3CD;color:#7A5A00;border-radius:999px;padding:6px 12px;font-size:15px;font-weight:700}
.badge.g{background:#E6F7EC;color:#0F6B33}.badge.r{background:#FDE8E0;color:#9A3412}
table{width:100%;border-collapse:collapse;font-size:18px}th,td{border-bottom:1px solid var(--line);padding:12px;text-align:left;vertical-align:top}
input,select{width:100%;font-size:19px;padding:14px;border:2px solid var(--line);border-radius:12px;margin:8px 0}
label.opt{display:block;border:2px solid var(--line);border-radius:16px;padding:16px;margin:12px 0;cursor:pointer}
.opts-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:10px 0}
@media(max-width:700px){.opts-grid{grid-template-columns:1fr}}
.opts-grid .opt,.opts-grid label.opt{margin:0}
.opt-letter{display:inline-flex;align-items:center;justify-content:center;flex:0 0 auto;width:32px;height:32px;border-radius:50%;background:#143A6B;color:#fff;font-weight:800;font-size:19px;line-height:1}
.bar{background:#DCE4F0;height:14px;border-radius:99px;overflow:hidden}.bar i{display:block;height:100%;background:var(--green)}
.screen{display:none;animation:fade .25s ease}.screen.show{display:block}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
footer.site{background:var(--navy);color:#fff;margin-top:30px}
footer.site .wrap{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:24px}
footer.site h3{color:var(--yellow)}footer.site a{color:#D6E4FF}
.swatch{display:flex;gap:12px;flex-wrap:wrap}.sw{border-radius:14px;padding:18px;color:#fff;min-width:150px}.sw small{display:block;opacity:.9}
.hint{background:#FFF8E1;border:1px solid var(--yellow);border-radius:14px;padding:14px;display:none}.hint.on{display:block}
.kpi{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px}.kpi .card{margin:0;text-align:center}.kpi b{font-size:36px;display:block}
.err{background:#FDE8E8}
@media(max-width:700px){
  .head{padding:10px 12px;gap:8px}
  .topbar{padding:8px 12px;font-size:15px}
  .topbar span:last-child{display:none}
  .logo .mark{width:40px;height:40px;font-size:22px;border-radius:10px}
  .logo b{font-size:20px}
  .head .btn{width:auto;min-height:44px;padding:10px 14px;font-size:17px}
  nav.main{flex-wrap:nowrap;overflow-x:auto;width:100%;margin-left:0;-webkit-overflow-scrolling:touch;gap:4px}
  nav.main button{white-space:nowrap;flex:0 0 auto}
  nav.main a{white-space:nowrap;flex:0 0 auto;padding:10px 12px;font-size:17px}
  .menu-btn{display:inline-flex;margin-left:auto}
  nav.main{display:none}
  nav.main.open{display:flex;position:absolute;top:100%;left:0;right:0;background:#fff;flex-direction:column;flex-wrap:wrap;overflow:visible;padding:12px;box-shadow:0 12px 24px rgba(20,58,107,.18);z-index:30}
  nav.main.open a{width:100%;padding:14px 16px;font-size:19px;border-radius:12px}
  .course-title{font-size:24px}
  .crumb{overflow-x:auto;white-space:nowrap;padding:6px 0;font-size:17px}
  .exam-topbar .btn{width:auto;flex:0 0 auto;white-space:nowrap;min-height:44px;padding:10px 14px;font-size:17px}
  .hero{padding:22px}.hero h1{font-size:28px}
  .wrap{padding:12px}.card{padding:16px}
  table{display:block;overflow-x:auto;white-space:nowrap}
  .btn{width:100%}
}

/* === Lop ap dung cho trang hoc that (khong co trong mockup demo) === */
/* Giu nguyen class mockup v6: .card .btn .badge .course .thumb .bar .grid .wrap */
/* Map tu class cu sang class v6, de module moi khong can doi logic API */
.topbar-inner{max-width:1180px;margin:0 auto;padding:14px 20px;display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:12px}
.brand .mark{width:52px;height:52px;border-radius:14px;background:var(--navy);display:flex;align-items:center;justify-content:center;color:#fff;font-size:28px;font-weight:900;flex:0 0 auto}
.brand b{font-size:24px;line-height:1;color:var(--navy)}
.brand small{display:block;font-size:14px;color:var(--muted);font-weight:600}
.topbar-nav{margin-left:auto;display:flex;gap:6px;flex-wrap:wrap}
.topbar-nav a{padding:12px 14px;font-size:18px;font-weight:700;color:var(--navy);border-radius:999px;white-space:nowrap}
.topbar-nav a:hover{background:#E8EEF7}
.grid2{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.student-head{display:flex;gap:16px;align-items:center;flex-wrap:wrap}
.avatar{width:72px;height:72px;border-radius:50%;background:linear-gradient(135deg,#1D6FD1,#FFC107);display:grid;place-items:center;font-size:32px;font-weight:800;color:#fff;flex:0 0 auto}
.tabs-v6{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0;background:#fff;padding:8px;border-radius:16px;box-shadow:0 4px 18px rgba(20,58,107,.08)}
.tabs-v6 button{background:transparent;border:0;padding:12px 16px;font-size:18px;font-weight:700;color:var(--navy);cursor:pointer;border-radius:999px;min-height:56px}
.tabs-v6 button.active{background:var(--navy);color:#fff}
.tabs-v6 button:not(.active){background:#EEF3FB}
.tabs-v6 button:not(.active):hover{background:#D6E0F0}
.course-title{font-size:28px;line-height:1.25;margin:12px 0 4px}
.video-box{aspect-ratio:16/9;background:#111;color:#fff;display:grid;place-items:center;border-radius:20px;text-align:center;padding:16px}
.video-box iframe{width:100%;height:100%;border:0;border-radius:12px}
.video-box{--media-accent-color:#1D6FD1}
.video-box video-player,.video-box video-skin{display:block;width:100%;height:100%}
.lesson-btn{display:block;width:100%;text-align:left;background:#EEF3FB;color:var(--navy);margin:6px 0;border:2px solid var(--line);border-radius:14px;padding:14px;font-size:19px;font-weight:700;cursor:pointer;min-height:56px}
.q{border-top:1px solid var(--line);padding:16px 0}
.q label{font-weight:400}
.muted{color:var(--muted);font-size:17px}.ok{color:var(--green)}.bad{color:#B42318}
.exam-bar{position:static;background:#EEF3FB;padding:14px 0}
input[type=radio],input[type=checkbox]{width:auto;min-width:24px;min-height:24px;margin:0 10px 0 0;vertical-align:middle}
label.opt{display:flex;align-items:flex-start;gap:10px;text-align:left}
label.opt input{flex:0 0 auto}
.exam-timer-pill{position:fixed;right:16px;bottom:16px;z-index:30;background:#143A6B;color:#fff;border-radius:999px;padding:10px 16px;font-weight:700;box-shadow:0 4px 18px rgba(0,0,0,.25)}
.exam-palette{display:flex;flex-wrap:wrap;gap:8px;margin-top:10px}
.exam-palette button{min-width:48px;min-height:48px;padding:10px}
.site-footer{background:var(--navy);color:#fff;margin-top:30px}
.site-footer .wrap{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:24px}
.site-footer a{color:#D6E4FF}
@media(max-width:700px){
  .topbar-nav{flex-wrap:nowrap;overflow-x:auto;width:100%;margin-left:0;-webkit-overflow-scrolling:touch}
  .topbar-nav a{white-space:nowrap;flex:0 0 auto}
  .tabs-v6{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch}
  .tabs-v6 button{white-space:nowrap;flex:0 0 auto}
  .student-head{flex-direction:column;align-items:flex-start}
  .avatar{width:60px;height:60px;font-size:26px}
  .exam-bar{top:64px}
}

.course-layout{display:grid;grid-template-columns:1fr 340px;gap:16px;align-items:start}
@media(max-width:800px){.course-layout{grid-template-columns:1fr}}

.hero .muted{color:#D6E4FF}
.hero h1{color:#fff}
.hero .student-head{color:#fff}

/* Loi giai noi bat rieng, khac khoi de bai va phuong an: nen xanh la, vien trai xanh dam, icon den */
.solution{background:linear-gradient(180deg,#EAF6EC,#E6F2FF);border-left:8px solid #1A9E57;border-radius:14px;padding:16px;margin:14px 0;box-shadow:0 2px 10px rgba(20,58,107,.10)}
.solution strong{color:#0F6B33;font-size:20px}
/* Nut Cau truoc sang goc trai, Cau sau sang goc phai, khong don ve mot ben */
.navrow{display:flex;justify-content:space-between;gap:12px;margin-top:14px}
.navrow button{flex:0 1 auto;min-height:56px}

nav.main a.active{background:var(--navy);color:#fff;border-radius:999px}

/* Nut danh dau: dung nhieu, phai noi bat nhat trong hang: cam, chu to, trai */
.btn-flag{background:#FF7A29;color:#fff;border:0;border-radius:14px;padding:14px 20px;font-size:20px;font-weight:800;min-height:56px;cursor:pointer;box-shadow:0 3px 10px rgba(255,122,41,.35)}
.btn-flag.on{background:#FFC107;color:#143A6B}
/* Nut bao loi: it dung, phai nho, mo, nam goc xa ben phai, khong tranh voi nut chinh */
.btn-report{background:#F1F3F6;color:#5B6B82;border:1px solid #DCE4F0;border-radius:999px;padding:8px 12px;font-size:15px;font-weight:600;min-height:40px;cursor:pointer}
.btn-report.on{background:#FDE8E0;color:#9A3412;border-color:#F5C6B3}
/* Nut xem dap an (luyen tap): xanh la, chu to, khac mau nut danh dau */
.btn-answer{background:#1A9E57;color:#fff;border:0;border-radius:14px;padding:14px 20px;font-size:20px;font-weight:800;min-height:56px;cursor:pointer;box-shadow:0 3px 10px rgba(26,158,87,.35)}
/* Hang nut: nut chinh ben trai, nut it dung day sang goc phai xa nhat */
.actionrow{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-top:14px;flex-wrap:wrap}
.actionrow .btn-report{margin-left:auto}

/* Hieu ung nut cho hoc sinh tieu hoc: di chuot vao doi mau ro rang, bam xuong doi mau khac + nut lun xuong 1 chut de biet la da bam va dang cho */
.btn,.btn-flag,.btn-answer,.btn-report{transition:background .15s ease,filter .15s ease,transform .1s ease,box-shadow .15s ease}
.btn:hover{filter:brightness(1.08);transform:translateY(-1px);box-shadow:0 6px 16px rgba(20,58,107,.25)}
.btn.light:hover{background:#D6E0F0}
.btn.o:hover{filter:brightness(1.05)}
.btn:active{filter:brightness(.82);transform:scale(.97) translateY(1px);box-shadow:0 1px 4px rgba(20,58,107,.2)}
.btn-flag:hover{filter:brightness(1.08);transform:translateY(-1px)}
.btn-flag:active{filter:brightness(.85);transform:scale(.97)}
.btn-answer:hover{filter:brightness(1.08);transform:translateY(-1px)}
.btn-answer:active{filter:brightness(.85);transform:scale(.97)}
.btn-report:hover{background:#E2E8F2;color:#143A6B}
.btn-report:active{background:#D6E0F0;transform:scale(.96)}
nav.main a{transition:background .15s ease;padding:12px 14px;font-size:18px;font-weight:700;border-radius:999px}
nav.main a:hover{background:#E8EEF7;border-radius:999px}
.tabs-v6 button:active{background:#D6E0F0;transform:scale(.97)}
button:focus-visible,.btn:focus-visible,a:focus-visible{outline:3px solid #FFC107;outline-offset:2px}
button:disabled,.btn:disabled{opacity:.55;cursor:not-allowed;transform:none;filter:none;box-shadow:none}
.btn.is-waiting{pointer-events:none;opacity:.7;cursor:wait}

/* Khoi hanh dong trong bao cao nhanh: phai nhin la biet bam duoc, khac han dong chu thuong */
.next-card{background:linear-gradient(135deg,#FFF3E0,#FFF8E1);border-left:8px solid #FF7A29;border-radius:16px;padding:18px;margin:14px 0;display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;box-shadow:0 3px 12px rgba(255,122,41,.18)}
.next-card .next-title{font-size:20px;font-weight:800;color:#143A6B}
.next-card .next-name{font-size:22px;font-weight:900;color:#143A6B;margin-top:4px}
.weak-card{background:#FDF0EC;border:2px solid #F5C6B3;border-radius:14px;padding:14px 16px;margin:10px 0;display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}
.weak-card .weak-title{font-size:20px;font-weight:800;color:#143A6B}
.score-badge{display:inline-block;background:#fff;border:2px solid #B42318;color:#B42318;border-radius:999px;padding:6px 14px;font-size:18px;font-weight:900}
.exam-row{background:#EEF3FB;border-radius:12px;padding:12px 16px;margin:8px 0;display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}
.exam-row .exam-title{font-size:19px;font-weight:700;color:#143A6B}
@media(max-width:700px){.next-card .btn,.weak-card .btn,.exam-row .btn{width:100%;text-align:center}}

/* Hop xac nhan giua man hinh cho tre: chu to, nut to, bam de */
.modal-overlay{position:fixed;inset:0;background:rgba(20,58,107,.62);display:flex;align-items:center;justify-content:center;padding:16px;z-index:9999}
.modal-card{background:#fff;border-radius:22px;padding:26px;max-width:540px;width:100%;box-shadow:0 12px 40px rgba(0,0,0,.35);text-align:center}
.modal-card h2{font-size:28px;color:#143A6B;margin:0 0 14px}
.modal-card p{font-size:21px;line-height:1.55;color:#143A6B;margin:10px 0}
.modal-actions{margin-top:20px}
.modal-actions .btn{width:100%;min-height:64px;font-size:21px;margin:8px 0}

/* Danh sach kien thuc phan tang: Chuong > Chu de > Video, nut icon to ro cho tre */
.chapter-card{background:#fff;border-radius:20px;margin:16px 0;box-shadow:0 4px 18px rgba(20,58,107,.08);overflow:hidden}
.chapter-head{display:flex;align-items:center;gap:12px;background:#EEF3FB;padding:16px 18px}
.chapter-badge{width:40px;height:40px;border-radius:50%;background:#143A6B;color:#fff;display:inline-flex;align-items:center;justify-content:center;font-size:20px;font-weight:900;flex-shrink:0}
.chapter-head h2{font-size:24px;color:#143A6B;margin:0;flex:1}
.chapter-count{font-size:16px;color:#33475E;background:#fff;border-radius:999px;padding:6px 12px;flex-shrink:0}
.topic-row{display:flex;align-items:flex-start;justify-content:space-between;gap:14px;padding:16px 18px;border-top:2px solid #EEF3FB}
.topic-row .topic-name{font-size:20px;font-weight:800;color:#143A6B;line-height:1.4;padding-top:14px}
.icon-actions{display:flex;gap:12px;flex-shrink:0}
.icon-btn{width:56px;height:56px;border-radius:16px;display:inline-flex;align-items:center;justify-content:center;font-size:26px;text-decoration:none;border:0;cursor:pointer}
.icon-btn.video{background:#FF7A29;color:#fff}
.icon-btn.practice{background:#1A9E57;color:#fff}
.icon-btn.disabled{background:#E8EEF7;color:#8A9AB5;cursor:default}
.icon-legend{font-size:18px;color:#33475E;background:#EEF3FB;border-radius:12px;padding:12px 16px;margin:12px 0}

/* The de thi thu: the rieng, tieu de ro, nut vao thi to, khong con ghi chu kieu lap trinh vien */
.thi-hero{background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:28px;padding:28px;margin-bottom:24px;box-shadow:0 6px 20px rgba(20,58,107,.20)}
.thi-hero h2{color:#fff;margin:0 0 8px;font-size:28px}
.thi-hero p{color:#D6E4FF;margin:0;font-size:19px}
.exam-section{margin:28px 0 8px}
.exam-section h3{font-size:24px;color:#143A6B;margin:0 0 4px}
.exam-section .sec-sub{color:#5B6B82;font-size:17px;margin:0 0 14px}
.exam-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;align-items:stretch}
.exam-grid .exam-card{margin:0;height:100%;min-width:0}
.exam-grid .exam-card>div{min-width:0}
.exam-grid .exam-card-title{overflow-wrap:anywhere}
.exam-grid .exam-card .btn{flex-shrink:0}
.exam-empty{background:#fff;border:2px dashed #DCE4F0;border-radius:20px;padding:20px;color:#5B6B82;font-size:18px}
@media(max-width:900px){.exam-grid{grid-template-columns:1fr}}
.exam-card{background:#fff;border:2px solid #DCE4F0;border-radius:20px;padding:18px;margin:14px 0;box-shadow:0 4px 14px rgba(20,58,107,.06);display:flex;flex-direction:column;align-items:stretch;gap:10px;transition:transform .15s ease,box-shadow .15s ease}
.exam-card-title{font-size:21px;font-weight:900;color:#143A6B;line-height:1.4}
.exam-card-meta{font-size:18px;color:#33475E;margin-top:8px;display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.exam-card .btn{min-height:56px}
@media(max-width:700px){.exam-card .btn{width:100%;text-align:center}}

/* Khoi cuoi: menu mobile + tieu de + topbar, phai dung sau cac rule goc */
.menu-btn{display:none}
@media(max-width:700px){
  .topbar{display:none}
  .logo span{display:block;font-size:13px}
  .head .menu-btn{display:inline-flex;margin-left:auto}
  nav.main{display:none}
  nav.main.open{display:flex;position:absolute;top:100%;left:0;right:0;background:#fff;flex-direction:column;flex-wrap:wrap;overflow:visible;padding:12px;box-shadow:0 12px 24px rgba(20,58,107,.18);z-index:30}
  nav.main.open a{width:100%;padding:14px 16px;font-size:19px;border-radius:12px}
  nav.main.open .btn{width:100%;text-align:center}
  .course-title{font-size:24px}
  .tabs-v6 button.active{background:var(--navy);color:#fff;box-shadow:0 4px 14px rgba(20,58,107,.35)}
}
.tabs-v6 button.active{background:var(--navy);color:#fff;box-shadow:0 4px 14px rgba(20,58,107,.35)}

.exam-section-head{display:flex;align-items:center;gap:12px;background:var(--sec-color,#143A6B);color:#fff;padding:14px 18px;border-radius:16px;margin-bottom:14px}
.exam-section-head h3{margin:0;color:#fff;font-size:22px;flex:1}
.sec-num{width:36px;height:36px;border-radius:50%;background:rgba(255,255,255,.25);display:inline-flex;align-items:center;justify-content:center;font-weight:900;flex-shrink:0}
.sec-count{background:rgba(255,255,255,.25);padding:6px 12px;border-radius:999px;font-size:16px;font-weight:700;white-space:nowrap}
.exam-section-head{cursor:pointer}
.exam-section-head .sec-chev{font-size:22px;font-weight:900;flex-shrink:0;transition:transform .15s ease}
.exam-section.open .sec-chev{transform:rotate(180deg)}
.exam-section-head:focus-visible{outline:3px solid #FFC107;outline-offset:2px}
.exam-grid[hidden],.exam-empty[hidden]{display:none}

.exam-card:hover{transform:translateY(-2px);box-shadow:0 8px 22px rgba(20,58,107,.14)}
.exam-card .btn{width:100%;text-align:center;margin-top:auto}

/* Sidebar trang bai hoc: giong danh sach Kien thuc, to ro chu de dang hoc */
.side-nav .chapter-head{padding:10px 12px}
.side-nav .chapter-badge{width:28px;height:28px;font-size:15px}
.side-nav .chapter-head h2{font-size:17px}
.side-nav .chapter-count{font-size:13px;padding:4px 10px}
.side-nav .icon-btn{width:36px;height:36px;font-size:18px;border-radius:12px}
.side-legend{font-size:14px;color:var(--muted);margin:0 0 8px}
.side-nav .icon-actions{gap:8px}
.side-topic-head{display:flex;align-items:center;gap:8px;padding:12px 14px;border-top:2px solid #EEF3FB}
.side-topic-head.current{background:#FFF8E1}
.side-topic-head.current .topic-name{color:#7A5A00}
.side-topic-head .topic-name{font-size:15px;font-weight:800;color:#143A6B;line-height:1.4;flex:1;padding-top:0}
.side-expand{width:28px;height:28px;border:0;background:#EEF3FB;border-radius:8px;font-size:18px;cursor:pointer;flex-shrink:0;color:var(--navy);font-weight:700;line-height:1}
.side-lessons{padding:0 12px 8px 44px}
.side-lesson-btn{display:block;width:100%;text-align:left;background:#fff;border:2px solid var(--line);border-radius:12px;padding:10px 12px;margin:6px 0;font-size:15px;font-weight:700;color:var(--navy);cursor:pointer;min-height:44px}
.side-lesson-btn.current{background:var(--navy);color:#fff;border-color:var(--navy)}
.lesson-actions{display:flex;gap:12px;flex-wrap:wrap;margin:16px 0}
.lesson-actions .btn{flex:1;min-height:56px;display:inline-flex;align-items:center;justify-content:center;text-align:center}
@media(max-width:700px){.lesson-actions{flex-direction:column}.lesson-actions .btn{width:100%}}

/* Dau luyen tap gop 1 thanh: tieu de + tien do + nut + hien tieng Viet trong 1 the */
.practice-head{background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:20px;padding:16px 18px;margin:8px 0 14px;box-shadow:0 6px 20px rgba(20,58,107,.20)}
.practice-head-top{display:flex;gap:12px;align-items:flex-start;justify-content:space-between;flex-wrap:wrap}
.practice-title{font-size:21px;font-weight:900;line-height:1.4}
.practice-meta{font-size:16px;color:#D6E4FF;margin-top:4px}
.practice-actions{display:flex;gap:8px;flex-wrap:wrap}
.practice-actions .btn{min-height:48px}
.practice-vi{display:inline-flex;align-items:center;gap:8px;background:rgba(255,255,255,.15);border-radius:999px;padding:8px 14px;margin-top:12px;font-size:17px;cursor:pointer}
.practice-vi input{width:20px;height:20px;accent-color:#FFC107}
@media(max-width:700px){
  .practice-head{padding:14px}
  .practice-title{font-size:20px}
  .practice-actions{width:100%}
  .practice-actions .btn{flex:1;width:auto;text-align:center}
}

/* Hinh cau hoi khong bao gio cao qua 1 phan man hinh, luon can giua */
.qcard img{max-width:100%;max-height:38vh;width:auto;height:auto;object-fit:contain;display:block;margin:8px auto;border-radius:12px}
@media(max-width:700px){
  .qcard img{max-height:26vh}
}

/* Trang lam-sai: dau trang gradient + thanh phan trang dang the + nut so trang dang vien */
.lamsai-head{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:20px;padding:18px 20px;margin:8px 0 14px;box-shadow:0 6px 20px rgba(20,58,107,.20)}
.lamsai-head h2{margin:0;color:#fff;font-size:26px}
.pager{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;background:#fff;border-radius:16px;padding:12px 16px;margin:12px 0;box-shadow:0 4px 18px rgba(20,58,107,.08)}
.pager-info{font-weight:800;color:#143A6B;font-size:18px}
.pager .btn{min-height:48px}
.pager .btn.disabled{opacity:.55;pointer-events:none}
.pager-pages{display:flex;gap:8px;flex-wrap:wrap;align-items:center;justify-content:center;margin:12px 0}
.page-num{display:inline-flex;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:10px 14px;border-radius:12px;background:#EEF3FB;border:2px solid #DCE4F0;color:#143A6B;font-weight:800;font-size:17px}
.page-cur{display:inline-flex;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:10px 14px;border-radius:12px;background:var(--navy);color:#fff;font-weight:900;font-size:17px}
.page-gap{color:#5B6B82;font-weight:800;padding:0 4px}
.lamsai-card img{max-width:100%;max-height:38vh;width:auto;height:auto;object-fit:contain;display:block;margin:8px auto;border-radius:12px}
@media(max-width:700px){
  .lamsai-head{padding:14px}
  .lamsai-head h2{font-size:22px}
  .pager-info{width:100%;text-align:center}
  .lamsai-card img{max-height:26vh}
}

/* Trang Bao cao: banner Tong quan, tieu de muc, o chi so */
.report-head{background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:16px;padding:16px 20px;margin:0 0 16px;font-size:26px}
.report-sec{background:#EEF3FB;border-left:6px solid var(--navy);border-radius:12px;padding:12px 16px;font-size:21px;margin:28px 0 12px}
.report-kpi{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:14px 0}
.report-kpi>div{background:#EEF3FB;border-radius:16px;padding:14px;text-align:center}
.report-kpi b{font-size:28px;display:block}
.report-kpi span{font-size:16px;color:var(--muted)}
@media(max-width:700px){
  .report-head{font-size:22px;padding:14px 16px}
  .report-sec{font-size:20px}
  .report-kpi{grid-template-columns:repeat(2,1fr)}
}

/* Thi thu gop 1 the: tieu de + dong ho noi bat + hien tieng Viet dang vien + nut */
.exam-merged{background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:20px;padding:16px 18px;margin:8px 0 14px;box-shadow:0 6px 20px rgba(20,58,107,.20)}
.exam-merged-top{display:flex;gap:12px;align-items:flex-start;justify-content:space-between;flex-wrap:wrap}
.exam-merged-title{font-size:21px;font-weight:900;line-height:1.4}
.exam-merged-meta{font-size:16px;color:#D6E4FF;margin-top:4px}
.exam-timer{background:#FFC107;color:#143A6B;border-radius:999px;padding:10px 18px;font-size:22px;font-weight:900;white-space:nowrap;flex-shrink:0}
.exam-merged-actions{display:flex;gap:12px;align-items:center;justify-content:space-between;flex-wrap:wrap;margin-top:12px}
.exam-vi{display:inline-flex;align-items:center;gap:8px;background:rgba(255,255,255,.15);border-radius:999px;padding:8px 14px;font-size:17px;cursor:pointer}
.exam-vi input{width:20px;height:20px;accent-color:#FFC107}
.exam-merged-btns{display:flex;gap:8px;flex-wrap:wrap}
.exam-merged-btns .btn{min-height:48px}
@media(max-width:700px){
  .exam-merged{padding:14px}
  .exam-merged-title{font-size:20px}
  .exam-timer{width:100%;text-align:center;font-size:24px}
  .exam-merged-btns{width:100%}
  .exam-merged-btns .btn{flex:1;width:auto;text-align:center}
}

/* Trang /hoc: luoi khoa ghi danh chia deu hang (1 khoa thi rong het hang), nut trong the full-width */
.course-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:16px}
.course-grid .course .btn{width:100%}
@media(max-width:700px){
  .course-grid{grid-template-columns:1fr}
}

/* Tieu de muc trang /hoc: chu dam to + gach nhan cam ngan, khong dung banner nen xanh */
.hoc-sec{font-size:26px;font-weight:900;color:var(--navy);margin:28px 0 16px;padding-bottom:10px;border-bottom:3px solid #EEF3FB;position:relative}
.hoc-sec::after{content:'';position:absolute;left:0;bottom:-3px;width:64px;height:3px;background:var(--orange);border-radius:99px}
@media(max-width:700px){
  .hoc-sec{font-size:22px}
}

/* Desktop: bang so cau dinh khi cuon (mobile giu nguyen).
   Nut Truoc/Sau KHONG fixed 2 ben nua (10/11/2026, theo y user: mui ten
   2 ben cach nhau qua xa) — de trong luong duoi phan danh dau, hien ca chu. */
@media (min-width: 1024px) {
  .palette-grid { position: sticky; top: 92px; z-index: 55; background: #fff; padding: 6px 2px; border-radius: 12px; box-shadow: 0 4px 14px rgba(20,58,107,.08); }
  #prGrid { position: sticky; top: 92px; z-index: 55; background: #fff; padding: 6px 2px; border-radius: 12px; box-shadow: 0 4px 14px rgba(20,58,107,.08); }
}

/* --- Chrome chuẩn (port từ /assets/site.css, 09/11/2026) — header/footer dùng
   chung toàn site. Chỉ chứa selector .site-header/.site-footer/.logo__* :
   KHÔNG động vào .btn/.card/.wrap của app. Logo mark thống nhất theo trang
   chủ: ô vuông navy + "📖★". --- */
.site-header { position: sticky; top: 0; z-index: 50; background: #ffffff; border-bottom: 3px solid #dce4f0; box-shadow: 0 2px 12px rgba(20, 58, 107, 0.10); }
.site-header__inner { max-width: 1180px; margin: 0 auto; padding: 12px 20px; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.logo { display: flex; align-items: center; gap: 12px; color: #143a6b; }
.logo:hover { text-decoration: none; }
.logo__mark { width: 52px; height: 52px; flex: none; border-radius: 14px; background: #143a6b; color: #fff; display: flex; align-items: center; justify-content: center; font-size: 22px; font-weight: 900; line-height: 1; white-space: nowrap; overflow: hidden; }
.logo__name { font-size: 24px; font-weight: 900; line-height: 1.1; display: block; }
.logo__slogan { font-size: 14px; font-weight: 700; color: #4e5e75; display: block; }
.site-nav { display: flex; gap: 4px; flex-wrap: wrap; margin-left: auto; }
.site-nav a { display: inline-block; padding: 12px 14px; font-size: 18px; font-weight: 800; color: #143a6b; border-radius: 999px; min-height: 48px; }
.site-nav a:hover { background: #eaf2fd; text-decoration: none; }
.site-nav a[aria-current="page"] { background: #143a6b; color: #fff; }
.site-nav a[aria-current="page"]:hover { background: #0e2a4e; }
.site-header .btn { margin-left: 4px; }
/* Nút Đăng nhập trong header chuẩn: y hệt .btn của site.css (nút app
   .btn.light / .btn.secondary không đổi). */
.site-header .btn:not(.light):not(.secondary) { display: inline-flex; align-items: center; justify-content: center; gap: 10px; min-height: 56px; min-width: 56px; padding: 14px 24px; border: 3px solid transparent; border-radius: 999px; font-family: inherit; font-size: 20px; font-weight: 800; line-height: 1.2; background: #1d6fd1; color: #fff; box-shadow: 0 4px 0 rgba(20, 58, 107, 0.18), 0 6px 16px rgba(29, 111, 209, 0.28); text-decoration: none; text-align: center; }
.site-header .btn:not(.light):not(.secondary):hover { text-decoration: none; transform: translateY(-2px); box-shadow: 0 4px 0 rgba(20, 58, 107, 0.08), 0 10px 24px rgba(20, 58, 107, 0.10); background: #155cb4; filter: none; }
.site-header .btn:not(.light):not(.secondary):active { transform: translateY(2px); box-shadow: 0 1px 0 rgba(20, 58, 107, 0.18); filter: none; }
.site-footer { background: #143a6b; color: #fff; margin-top: 40px; }
.site-footer__grid { max-width: 1180px; margin: 0 auto; padding: 36px 20px 12px; display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 28px; }
.site-footer h3 { color: #ffc107; font-size: 19px; margin-bottom: 10px; }
.site-footer p, .site-footer li { color: #fff; font-size: 17px; }
.site-footer a { color: #d6e4ff; }
.site-footer a:hover { color: #fff; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: 8px; }
.site-footer__brand { font-size: 21px; font-weight: 900; color: #fff; }
.site-footer__bottom { text-align: center; padding: 0 20px 24px; color: #d6e4ff; font-size: 16px; }
.site-header, .site-footer { font-family: "Nunito", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif; }

/* Riêng v6: override `.logo span` sẵn có + giữ nút menu mobile. */
.logo .logo__mark { display: flex; align-items: center; justify-content: center; width: 52px; height: 52px; flex: none; border-radius: 14px; background: #143a6b; color: #fff; font-size: 22px; font-weight: 900; line-height: 1; white-space: nowrap; overflow: hidden; }
.logo .logo__name { display: block; font-size: 24px; font-weight: 900; line-height: 1.1; color: #143a6b; }
.logo .logo__slogan { display: block; font-size: 14px; font-weight: 700; color: #4e5e75; }
nav.site-nav a { font-weight: 800; }
/* Header app (hoc/thi/luyen): gọn nút cỡ chữ + khoảng cách để đủ 1 hàng ở desktop
   (nút A+/A- có style inline min-height:56px nên cần !important để ghi đè). */
#fontDown, #fontUp { min-height: 44px !important; padding: 8px 12px; font-size: 18px; }
.site-header__inner { gap: 10px; }
.site-nav a { padding: 10px 10px; }
@media (max-width: 700px) {
  .site-header__inner { padding: 10px 12px; gap: 8px; }
  .site-header__inner .menu-btn { display: inline-flex; margin-left: auto; }
  .site-header .btn:not(.light):not(.secondary) { width: 100%; margin-left: 0; }
  .site-footer__grid { padding-top: 28px; }
}

/* === Bo cuc hoc tap moi: Nhiem vu tiep theo, Ban do thu thach, Bai hoc, Luyen tap, Bao cao ===
   Chi them class moi, khong xoa class cu. Font Nunito, mau thuong hieu Hoc Cung Son.
   Nut toi thieu 56px, chu 19-20px, mobile 1 cot o <=700px. */
.hoc-sec-title{font-family:"Nunito",system-ui,sans-serif;font-size:24px;font-weight:900;color:#143A6B;margin:28px 0 12px}
.hoc-empty{background:#FFF8E1;border:2px solid #FFC107;border-radius:18px;padding:18px;font-size:19px;color:#143A6B}
.hoc-chip{display:inline-block;background:#EEF3FB;color:#143A6B;border-radius:999px;padding:6px 14px;font-size:16px;font-weight:800}
.hoc-chip.green{background:#E6F7EC;color:#0F6B33}
.hoc-chip.amber{background:#FFF3CD;color:#7A5A00}
/* The Nhiem vu tiep theo: nen navy, chu trang, nut 3D co moi duoi */
.hoc-next{background:linear-gradient(135deg,#143A6B,#1D6FD1);color:#fff;border-radius:24px;padding:28px;margin-bottom:20px;border-bottom:6px solid #0E2A4E;font-family:"Nunito",system-ui,sans-serif}
.hoc-next h2{font-size:26px;font-weight:900;margin:0 0 8px;line-height:1.3}
.hoc-next p{font-size:19px;font-weight:700;color:#DBEAFE;margin:6px 0}
.hoc-next .hoc-points{font-size:19px;font-weight:800;color:#FFC107}
.hoc-btn3d{display:inline-block;background:#1A9E57;color:#fff;border:0;border-bottom:5px solid #0F6B33;border-radius:16px;padding:16px 26px;font-size:20px;font-weight:800;min-height:56px;cursor:pointer;text-decoration:none;font-family:"Nunito",system-ui,sans-serif}
.hoc-btn3d:active{transform:translateY(3px);border-bottom-width:2px}
.hoc-btn3d.blue{background:#1D6FD1;border-bottom-color:#143A6B}
.hoc-btn3d.orange{background:#FF7A29;border-bottom-color:#C2410C}
.hoc-btn3d.light{background:#fff;color:#143A6B;border-bottom-color:#DCE4F0}
/* Ban do thu thach: 10 nut theo thu tu bai hoc */
.hoc-map{background:#FBF9F5;border:2px solid #E5DEC9;border-radius:24px;padding:24px;margin-bottom:20px}
.hoc-nodes{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:14px}
.hoc-node{display:flex;align-items:center;gap:12px;background:#fff;border:2px solid #DCE4F0;border-bottom:5px solid #DCE4F0;border-radius:18px;padding:16px;min-height:64px;cursor:pointer;text-align:left;font-family:"Nunito",system-ui,sans-serif;font-size:19px;font-weight:800;color:#143A6B;width:100%}
.hoc-node:active{transform:translateY(3px);border-bottom-width:2px}
.hoc-node .hoc-node-num{flex:0 0 auto;width:44px;height:44px;border-radius:50%;background:#EEF3FB;color:#143A6B;display:flex;align-items:center;justify-content:center;font-size:20px;font-weight:900}
.hoc-node.done{border-color:#1A9E57;border-bottom-color:#0F6B33;background:#E6F7EC}
.hoc-node.done .hoc-node-num{background:#1A9E57;color:#fff}
.hoc-node.doing{border-color:#FFC107;border-bottom-color:#B45309;background:#FFF8E1}
.hoc-node.doing .hoc-node-num{background:#FFC107;color:#143A6B}
.hoc-node .hoc-node-sub{display:block;font-size:16px;font-weight:700;color:#5B6B82}
.hoc-bar-track{background:#DCE4F0;height:14px;border-radius:99px;overflow:hidden}
.hoc-bar-fill{display:block;height:100%;background:#1A9E57;border-radius:99px}
/* Tab trong khoa: nhan trung tinh, khong danh so kieu cu */
.hoc-tabs{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0;background:#fff;padding:8px;border-radius:16px;box-shadow:0 4px 18px rgba(20,58,107,.08)}
.hoc-tabs button{background:#EEF3FB;border:0;padding:12px 16px;font-size:19px;font-weight:800;color:#143A6B;cursor:pointer;border-radius:999px;min-height:56px;font-family:"Nunito",system-ui,sans-serif}
.hoc-tabs button.active{background:#143A6B;color:#fff}
/* Bai hoc: the mo dau chi hien khi co du lieu that */
.hoc-lesson-card{font-family:"Nunito",system-ui,sans-serif}
.hoc-story{background:#FFF8E1;border:2px solid #FFC107;border-bottom:5px solid #FFC107;border-radius:18px;padding:18px;margin:14px 0}
/* Luyen tap (Arena): HUD, bang nhap, ban phim so */
.arena-hud{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:10px;background:#fff;border:2px solid #DCE4F0;border-radius:16px;padding:12px 16px;margin:12px 0}
.arena-hud .arena-progress{flex:1 1 200px}
.arena-tools{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}
.arena-tool-btn{background:#fff;border:2px solid #DCE4F0;border-bottom:4px solid #DCE4F0;border-radius:14px;padding:10px 16px;font-size:18px;font-weight:800;min-height:56px;cursor:pointer;color:#143A6B;font-family:"Nunito",system-ui,sans-serif}
.arena-tool-btn:active{transform:translateY(2px);border-bottom-width:2px}
.arena-tool-btn.on{background:#EEF3FB;border-color:#1D6FD1}
.arena-scratch{border:2px solid #DCE4F0;border-radius:16px;background:#fff;width:100%;height:220px;touch-action:none;display:block}
.arena-numpad{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;max-width:360px;margin:12px 0}
.arena-numpad button{background:#fff;border:2px solid #DCE4F0;border-bottom:4px solid #DCE4F0;border-radius:14px;padding:12px;font-size:22px;font-weight:900;min-height:56px;cursor:pointer;color:#143A6B;font-family:"Nunito",system-ui,sans-serif}
.arena-numpad button:active{transform:translateY(2px);border-bottom-width:2px}
/* Bao cao: thanh nang luc theo chuyen de */
.radar-strand{background:#fff;border:2px solid #DCE4F0;border-radius:18px;padding:18px;margin:12px 0}
.radar-strand h4{margin:0 0 6px;font-size:20px;font-weight:900;color:#143A6B;font-family:"Nunito",system-ui,sans-serif}
.radar-strand .hoc-bar-track{margin:10px 0}
.radar-strand .radar-note{font-size:17px;color:#5B6B82;font-weight:700}
@media(max-width:700px){
  .hoc-next{padding:20px}
  .hoc-next h2{font-size:23px}
  .hoc-nodes{grid-template-columns:1fr}
  .hoc-tabs{flex-wrap:nowrap;overflow-x:auto}
  .hoc-tabs button{white-space:nowrap;flex:0 0 auto}
  .hoc-btn3d{width:100%;text-align:center}
}