/* ============================================================
   DUANDIGI GROWTH — Design System (độc lập, blue/black/white)
   Dự án riêng, KHÔNG dùng chung file với bất kỳ project nào khác.
   ============================================================ */
:root{
  --blue:#2563eb; --blue-d:#1d4ed8; --blue-l:#eff4ff; --blue-100:#dbe6ff; --blue-300:#93b4fd;
  --orange:#f97316; --orange-d:#ea580c; --orange-l:#fdba74;  /* nhấn: đỉnh tăng trưởng / thành tích */
  --navy:#0b1f4d; --navy-2:#081029;
  --ink:#0b1220; --ink-2:#26324a; --muted:#5b6675; --dim:#8a94a4;
  --bg:#ffffff; --soft:#f5f8ff; --line:#e6eaf2; --line-2:#d6deea;
  --radius:14px; --radius-lg:20px;
  --sans:system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --shadow:0 18px 44px -22px rgba(11,31,77,.32);
  --shadow-sm:0 4px 14px -6px rgba(11,31,77,.18);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:var(--blue-d);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{margin:0 0 .5em;color:var(--ink);font-weight:800;line-height:1.14;letter-spacing:-.03em}
img{max-width:100%}
:focus-visible{outline:3px solid rgba(37,99,235,.35);outline-offset:2px}

/* ---------- Buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:12px 22px;border:1.5px solid transparent;border-radius:12px;font:inherit;font-weight:700;cursor:pointer;transition:transform .16s,box-shadow .16s,background-color .16s,border-color .16s;text-decoration:none}
.btn:hover{text-decoration:none}
.btn-primary{position:relative;overflow:hidden;color:#fff;background:linear-gradient(135deg,var(--blue-d),var(--blue) 60%,#3b82f6);box-shadow:0 14px 26px -12px rgba(37,99,235,.6)}
.btn-primary::after{content:"";position:absolute;top:0;left:-60%;width:45%;height:100%;background:linear-gradient(100deg,transparent,rgba(255,255,255,.4),transparent);transform:skewX(-18deg);transition:left .55s ease}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 20px 34px -12px rgba(37,99,235,.66)}
.btn-primary:hover::after{left:130%}
.btn-ghost{color:var(--ink);background:#fff;border-color:var(--line-2)}
.btn-ghost:hover{color:var(--blue-d);border-color:var(--blue-300);background:var(--blue-l)}
.btn-lg{min-height:56px;padding:15px 28px;font-size:16px}
.btn:disabled{opacity:.5;cursor:not-allowed;transform:none;box-shadow:none}

/* ---------- Top nav ---------- */
.nav{position:sticky;top:0;z-index:40;display:flex;align-items:center;gap:20px;padding:12px clamp(18px,4vw,44px);background:rgba(255,255,255,.92);border-bottom:1px solid var(--line);backdrop-filter:blur(10px)}
.brand{display:flex;align-items:center;gap:11px;color:var(--ink);font-weight:800;letter-spacing:-.02em}
.brand:hover{text-decoration:none}
.brand .mark{display:grid;place-items:center;width:38px;height:38px;border-radius:11px;color:#fff;font-weight:800;letter-spacing:-1px;background:linear-gradient(135deg,var(--blue-d),#3b82f6);box-shadow:0 8px 18px -6px rgba(37,99,235,.5)}
.brand b{font-size:14.5px;line-height:1.05}
.brand small{display:block;font-size:10.5px;font-weight:600;letter-spacing:.4px;text-transform:uppercase;color:var(--dim)}
.nav-links{display:flex;gap:4px;margin-left:14px}
.nav-links a{padding:9px 13px;color:var(--muted);border-radius:9px;font-size:14.5px;font-weight:600}
.nav-links a:hover{color:var(--ink);background:var(--soft);text-decoration:none}
.nav-links a.active{color:var(--blue-d);background:var(--blue-l)}
.nav-spacer{flex:1}
.nav-state{font-size:13px;color:var(--dim)}
.nav-state b{color:var(--blue-d)}

/* ---------- Layout ---------- */
.wrap{max-width:1080px;margin:0 auto;padding:0 clamp(18px,4vw,44px)}
.section{padding:clamp(44px,6vw,80px) 0}
.eyebrow{display:inline-block;margin-bottom:12px;color:var(--blue-d);font-size:12px;font-weight:800;letter-spacing:.16em;text-transform:uppercase}
.lead{color:var(--muted);font-size:clamp(17px,1.6vw,20px);line-height:1.6;max-width:640px}
.footer{padding:34px 0;border-top:1px solid var(--line);color:var(--dim);font-size:13px;text-align:center}

/* ---------- Home hero ---------- */
.hero{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);gap:clamp(32px,5vw,70px);align-items:center;padding:clamp(40px,6vw,86px) 0}
.hero h1{font-size:clamp(34px,5vw,58px);letter-spacing:-.045em}
.hero .actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.hero-card{position:relative;overflow:hidden;padding:30px;color:#fff;background:linear-gradient(160deg,var(--navy-2),var(--navy) 55%,#15347e);border-radius:var(--radius-lg);box-shadow:var(--shadow)}
.hero-card::before{content:"";position:absolute;width:150%;aspect-ratio:1;top:-45%;right:-35%;background:conic-gradient(from 0deg,transparent,rgba(59,130,246,.32),transparent,rgba(147,180,253,.28),transparent);border-radius:50%;filter:blur(26px);animation:spin 26s linear infinite}
.hero-card *{position:relative}
.hero-card .k{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:#bcd3ff}
.hero-loop{margin:14px 0 22px;font-size:13px;color:rgba(219,234,254,.9);font-weight:600}
.hero-bars{display:flex;align-items:flex-end;gap:10px;height:78px}
.hero-bars i{flex:1;background:linear-gradient(180deg,#93c5fd,#3b82f6);border-radius:6px 6px 3px 3px;transform-origin:bottom;animation:grow .9s cubic-bezier(.2,.8,.2,1) both}
.hero-bars i:nth-child(1){height:40%;animation-delay:.12s}
.hero-bars i:nth-child(2){height:66%;animation-delay:.24s}
.hero-bars i:nth-child(3){height:52%;animation-delay:.36s}
.hero-bars i:nth-child(4){height:88%;background:linear-gradient(180deg,var(--orange-l),var(--orange));animation-delay:.48s}
.hero-bars i:nth-child(5){height:72%;animation-delay:.6s}
.hero-stats{display:flex;gap:26px;margin-top:26px}
.hero-stats b{display:block;font-size:26px;font-weight:800;letter-spacing:-.03em}
.hero-stats span{font-size:11.5px;color:rgba(191,219,254,.85);text-transform:uppercase;letter-spacing:.06em}

/* stage grid */
.stage-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:26px}
.stage{padding:18px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow-sm);transition:transform .16s,border-color .16s}
.stage:hover{transform:translateY(-2px);border-color:var(--blue-300)}
.stage .gd{font-size:12px;font-weight:800;color:var(--dim);font-variant-numeric:tabular-nums}
.stage h3{margin:4px 0 6px;font-size:16px}
.stage p{margin:0;color:var(--muted);font-size:13px}

/* ---------- Login (premium) ---------- */
.login{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(420px,.95fr);min-height:100dvh}
.login-form{align-self:center;justify-self:center;width:min(410px,calc(100% - 44px));padding:44px 0;animation:rise .55s cubic-bezier(.2,.8,.2,1) both}
.login-form .brand{margin-bottom:40px}
.login-form h1{font-size:clamp(28px,3.6vw,38px)}
.login-form label{display:block;margin:14px 0 5px;font-size:13px;font-weight:700;color:var(--ink)}
.field{position:relative}
.field input{width:100%;min-height:54px;padding:14px 16px;color:var(--ink);background:var(--soft);border:1.5px solid var(--line);border-radius:13px;font:inherit;font-size:16px;transition:border-color .16s,box-shadow .16s,background-color .16s}
.field input:hover{border-color:var(--line-2)}
.field input:focus{outline:0;background:#fff;border-color:var(--blue);box-shadow:0 0 0 4px rgba(37,99,235,.16)}
.field .toggle{position:absolute;top:7px;right:7px;min-width:58px;height:40px;color:var(--blue-d);background:transparent;border:0;border-radius:9px;font:inherit;font-weight:700;font-size:13px;cursor:pointer}
.field .toggle:hover{background:var(--blue-l)}
.login-form .btn-primary{width:100%;margin-top:20px}
.login-err{min-height:20px;margin-top:8px;color:var(--orange-d);font-size:13px;font-weight:600}
.login-err.ok{color:#16a34a}
.login-note{margin-top:18px;font-size:12.5px;color:var(--dim)}
/* Visual panel */
.login-visual{position:relative;overflow:hidden;display:flex;flex-direction:column;justify-content:flex-end;padding:clamp(44px,4.6vw,70px);color:#fff;background:linear-gradient(160deg,var(--navy-2) 0%,#0f2350 52%,#15347e 100%)}
.login-visual::before{content:"";position:absolute;width:150%;aspect-ratio:1;top:-40%;left:-25%;background:conic-gradient(from 0deg,transparent,rgba(59,130,246,.3),transparent,rgba(147,180,253,.3),transparent);border-radius:50%;filter:blur(30px);opacity:.75;animation:spin 26s linear infinite}
.login-visual::after{content:"";position:absolute;inset:0;opacity:.13;background-image:linear-gradient(rgba(255,255,255,.6) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.6) 1px,transparent 1px);background-size:54px 54px;-webkit-mask-image:radial-gradient(130% 90% at 50% 0,#000,transparent 72%);mask-image:radial-gradient(130% 90% at 50% 0,#000,transparent 72%)}
.login-visual .in{position:relative}
.badge{display:inline-block;margin-bottom:22px;padding:7px 14px;border:1px solid rgba(147,197,253,.35);border-radius:999px;background:rgba(37,99,235,.18);color:#dbeafe;font-size:11.5px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;backdrop-filter:blur(4px)}
.login-visual h2{font-size:clamp(34px,4.4vw,56px);letter-spacing:-.05em;color:#fff}
.login-visual .loop{margin:18px 0 0;font-size:13px;color:rgba(219,234,254,.85);font-weight:600}
.login-visual .bars{display:flex;align-items:flex-end;gap:10px;height:72px;margin-top:32px}
.login-visual .bars i{flex:1;background:linear-gradient(180deg,#93c5fd,#3b82f6);border-radius:6px 6px 3px 3px;transform-origin:bottom;animation:grow .9s cubic-bezier(.2,.8,.2,1) both}
.login-visual .bars i:nth-child(1){height:38%;animation-delay:.15s}.login-visual .bars i:nth-child(2){height:62%;animation-delay:.28s}.login-visual .bars i:nth-child(3){height:50%;animation-delay:.41s}.login-visual .bars i:nth-child(4){height:92%;background:linear-gradient(180deg,var(--orange-l),var(--orange));animation-delay:.54s}
.login-visual .stats{display:flex;gap:30px;margin-top:32px}
.login-visual .stats b{display:block;font-size:26px;font-weight:800;letter-spacing:-.03em}
.login-visual .stats span{font-size:11.5px;color:rgba(191,219,254,.82);text-transform:uppercase;letter-spacing:.06em}

/* ---------- Lesson ---------- */
.lesson-head{padding:36px 0 8px;border-bottom:1px solid var(--line)}
.lesson-layout{display:grid;grid-template-columns:238px minmax(0,1fr);gap:clamp(28px,4vw,56px);align-items:start;padding:26px 0 40px}
.lesson-side{position:sticky;top:76px;align-self:start;background:#fff;border:1px solid var(--line);border-radius:14px;padding:16px 16px 18px;box-shadow:var(--shadow-sm)}
.lesson-side .sk{font-size:12px;font-weight:800;letter-spacing:.12em;text-transform:uppercase;color:var(--blue-d);margin-bottom:12px}
.lesson-side ol{list-style:none;margin:0;padding:0}
.lesson-side a{display:block;padding:10px 12px;border-radius:10px;color:var(--ink-2);font-size:14px;font-weight:600;border-left:3px solid transparent}
.lesson-side a:hover{background:var(--soft);text-decoration:none;color:var(--blue-d)}
.lesson-side a.on{background:var(--blue-l);border-left-color:var(--blue);color:var(--blue-d)}
.lesson-side a small{display:block;font-weight:600;color:var(--dim);font-size:11.5px}
.lesson-side .note{margin-top:16px;padding:13px 15px;background:var(--soft);border:1px solid var(--line);border-radius:12px;font-size:12px;color:var(--muted);line-height:1.55}
.lesson-item{padding:16px 0 40px;border-bottom:1px solid var(--line);scroll-margin-top:80px}
.lesson-item:last-child{border-bottom:0}
.lw{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--orange-d)}
.lesson-item h2{font-size:clamp(23px,3.2vw,32px);margin:6px 0 4px}
@media(max-width:860px){.lesson-layout{grid-template-columns:1fr}.lesson-side{position:static}.lesson-side ol{display:flex;gap:6px;overflow-x:auto}.lesson-side a{white-space:nowrap;border-left:0;border-bottom:3px solid transparent}.lesson-side a.on{border-left:0;border-bottom-color:var(--blue)}.lesson-side .note,.lesson-side .sk{display:none}}
/* Hero trang bài học */
.lesson-hero{position:relative;overflow:hidden;margin:22px 0 14px;padding:clamp(28px,4vw,44px);border-radius:var(--radius-lg);color:#fff;background:linear-gradient(150deg,var(--navy-2) 0%,var(--navy) 55%,#15347e 100%);box-shadow:var(--shadow)}
.lesson-hero::before{content:"";position:absolute;width:150%;aspect-ratio:1;top:-55%;right:-30%;background:conic-gradient(from 0deg,transparent,rgba(59,130,246,.3),transparent,rgba(147,180,253,.28),transparent);border-radius:50%;filter:blur(28px);animation:spin 28s linear infinite;pointer-events:none}
.lesson-hero>*{position:relative}
.lesson-hero .badge{display:inline-block;margin:0 0 12px;padding:6px 13px;border:1px solid rgba(147,197,253,.4);border-radius:999px;background:rgba(37,99,235,.22);color:#dbeafe;font-size:11.5px;font-weight:800;letter-spacing:.08em;text-transform:uppercase}
.lesson-hero h1{font-size:clamp(28px,4vw,42px);letter-spacing:-.035em;margin:0 0 8px;color:#fff}
.lesson-hero p{max-width:640px;margin:0;color:rgba(219,234,254,.9);font-size:15.5px}
.lh-meta{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}
.lh-meta span{padding:7px 13px;border:1px solid rgba(147,197,253,.28);border-radius:999px;background:rgba(255,255,255,.06);font-size:12.5px;font-weight:600;color:#e0ecff}
.lh-meta span.dl{border-color:rgba(253,186,116,.55);background:rgba(249,115,22,.16);color:#fed7aa}
/* Tabs giai đoạn */
.stage-tabs{display:flex;gap:6px;overflow-x:auto;padding:2px 0 16px;margin-bottom:6px;-webkit-overflow-scrolling:touch}
.stage-tabs a{flex:none;padding:8px 13px;border-radius:10px;font-size:13.5px;font-weight:700;color:var(--muted);white-space:nowrap;text-align:center;border:1px solid var(--line)}
.stage-tabs a small{display:block;font-size:11px;color:var(--dim);font-weight:600}
.stage-tabs a:hover{background:var(--soft);color:var(--blue-d);text-decoration:none}
.stage-tabs a.on{background:var(--blue);border-color:var(--blue);color:#fff}
.stage-tabs a.on small{color:#cfe0ff}
.soon{margin:10px 0 0;padding:14px 16px;background:var(--soft);border:1px dashed var(--line-2);border-radius:12px;color:var(--muted);font-size:14px}
/* Trang lộ trình */
.rm-stage{padding:22px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow-sm);margin-bottom:16px}
.rm-head{display:flex;gap:14px;align-items:center}
.rm-gd{display:grid;place-items:center;flex:none;width:52px;height:52px;border-radius:13px;color:#fff;font-weight:800;font-size:13px;background:linear-gradient(135deg,var(--blue-d),#3b82f6)}
.rm-head h3{margin:0;font-size:19px}
.rm-wk{font-size:12.5px;color:var(--dim);font-weight:600}
.rm-sum{margin:12px 0;color:var(--muted);font-size:14.5px;line-height:1.55}
.rm-weeks{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:1fr 1fr;gap:6px}
.rm-weeks a{display:block;padding:9px 12px;background:var(--soft);border-radius:9px;color:var(--ink-2);font-size:13.5px}
.rm-weeks a:hover{background:var(--blue-l);color:var(--blue-d);text-decoration:none}
.rm-weeks b{color:var(--orange-d);font-weight:800;margin-right:4px}
@media(max-width:600px){.rm-weeks{grid-template-columns:1fr}}
/* Bài học — khuôn chuẩn 13 phần */
.lesson-title{font-size:clamp(24px,3.4vw,34px);margin:4px 0 14px}
.blk-label{display:inline-flex;align-items:center;gap:9px;font-size:12px;font-weight:800;letter-spacing:.06em;text-transform:uppercase;color:var(--blue-d);margin-bottom:10px}
.blk-label .bn{display:grid;place-items:center;width:23px;height:23px;border-radius:7px;background:var(--blue);color:#fff;font-size:12px}
.block>p{margin:0;color:var(--ink-2);line-height:1.7;font-size:15.5px}
.kn-box{padding:18px 20px;background:var(--blue-l);border:1px solid var(--blue-100);border-radius:14px}
.kn-box p{margin:0;font-size:17px;line-height:1.62;color:var(--ink)}
.faq{display:grid;gap:8px}
.faq details{border:1px solid var(--line);border-radius:12px;background:#fff;overflow:hidden}
.faq summary{padding:14px 16px;cursor:pointer;font-weight:700;color:var(--ink);list-style:none;display:flex;gap:10px;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"H";display:grid;place-items:center;width:24px;height:24px;border-radius:7px;background:var(--blue);color:#fff;font-size:12px;font-weight:800;flex:none}
.faq summary::after{content:"+";margin-left:auto;color:var(--blue-d);font-size:20px;font-weight:700;flex:none}
.faq details[open] summary::after{content:"−"}
.faq details[open] summary{border-bottom:1px solid var(--line)}
.faq .fa{padding:14px 16px 16px 50px;color:var(--ink-2);line-height:1.6}
.check{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.check li{display:flex;gap:11px;align-items:flex-start;padding:11px 14px;background:var(--soft);border:1px solid var(--line);border-radius:11px;font-size:14.5px;color:var(--ink-2);line-height:1.45}
.check li::before{content:"✓";display:grid;place-items:center;width:22px;height:22px;border-radius:6px;background:var(--blue);color:#fff;font-size:12px;font-weight:800;flex:none}
.advice{display:flex;gap:14px;padding:18px 20px;background:#fff7ed;border:1px solid #fed7aa;border-left:4px solid var(--orange);border-radius:0 12px 12px 0}
.advice .ic{font-size:22px;flex:none;line-height:1.2}
.advice p{margin:0;color:#8a3d06;line-height:1.6}
.lquiz{padding:22px;background:linear-gradient(160deg,var(--navy-2),var(--navy));border-radius:16px;color:#fff;-webkit-print-color-adjust:exact;print-color-adjust:exact}
.lquiz .lq-h{display:flex;align-items:center;gap:10px;font-weight:800;margin-bottom:16px}
.lquiz .lq-h .n{display:grid;place-items:center;width:26px;height:26px;border-radius:8px;background:var(--orange);color:#fff;font-size:13px;flex:none}
.lqq{padding:14px 0;margin:0;border:0;border-top:1px solid rgba(255,255,255,.12)}
.lqq legend{font-weight:700;margin-bottom:10px;color:#fff}
.lqq label{position:relative;display:flex;gap:10px;align-items:center;padding:10px 13px;margin:6px 0;border:1.5px solid rgba(255,255,255,.16);border-radius:10px;cursor:pointer;color:#dbe6f7}
.lqq label:hover{border-color:var(--blue-300);background:rgba(255,255,255,.06)}
.lqq label:has(input:checked){border-color:var(--blue-300);background:rgba(37,99,235,.3)}
.lqq input{accent-color:var(--orange);flex:none}
.lqq label span{flex:1}
.lqq label.correct{border-color:#93c5fd;background:rgba(37,99,235,.4)}
.lqq label.correct::after{content:"✓";color:#bcd3ff;font-weight:800;flex:none}
.lqq label.wrong{border-color:var(--orange);background:rgba(249,115,22,.28)}
.lqq label.wrong::after{content:"✕";color:var(--orange-l);font-weight:800;flex:none}
.lq-btn{width:100%;margin-top:14px}
.lq-out{margin-top:14px;padding:14px 16px;border-radius:12px;font-weight:700;line-height:1.5}
.lq-out.pass{background:rgba(37,99,235,.3);color:#e0ecff;border:1px solid var(--blue-300)}
.lq-out.fail{background:rgba(255,255,255,.08);color:#fed7aa;border:1px solid rgba(253,186,116,.4)}
.lq-none{padding:8px 0}
.lesson-nav-btns{display:flex;justify-content:space-between;gap:12px;margin:30px 0 60px}
.lesson-side a.cur{background:var(--blue-l);border-left-color:var(--blue);color:var(--blue-d)}
.lesson-side a.done::after{content:" ✓";color:var(--blue-d);font-weight:800}
@media(max-width:600px){.lesson-nav-btns{flex-direction:column}}
/* Công cụ hỗ trợ */
.tools{display:grid;gap:12px}
.tool{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:#fff;box-shadow:var(--shadow-sm)}
.tool-h{padding:12px 16px;background:linear-gradient(160deg,var(--navy-2),var(--navy));color:#fff;font-weight:800;font-size:15px;display:flex;align-items:center;gap:9px;flex-wrap:wrap;-webkit-print-color-adjust:exact;print-color-adjust:exact}
.tool-h::before{content:"🛠";font-size:15px}
.tool-h>span{flex:1;min-width:150px}
.tchip{display:inline-flex;align-items:center;gap:3px;padding:4px 11px;border-radius:999px;background:rgba(255,255,255,.14);border:1px solid rgba(147,197,253,.4);color:#dbeafe;font-size:11.5px;font-weight:700;text-decoration:none;white-space:nowrap;transition:background-color .15s,border-color .15s}
.tchip:hover{background:var(--blue);border-color:var(--blue);color:#fff;text-decoration:none}
/* Bản đồ lộ trình triển khai (capstone) */
.impl-bar{max-width:1000px;margin:20px auto 0;display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.impl-bar .sp{flex:1}
#impl-saved{font-size:12.5px;color:var(--blue-d);font-weight:700}
.impl{max-width:1000px;margin:16px auto 0}
.ed{outline:0;border:1.5px dashed var(--line-2);border-radius:10px;padding:10px 12px;min-height:22px;color:var(--ink);line-height:1.5;background:#fff;transition:border-color .15s,box-shadow .15s}
.ed:hover{border-color:var(--blue-300)}
.ed:focus{border-style:solid;border-color:var(--blue);box-shadow:0 0 0 4px rgba(37,99,235,.13)}
.ed:empty::before{content:attr(data-ph);color:var(--dim)}
.impl-top{display:grid;grid-template-columns:1.4fr 1fr;gap:14px;margin-bottom:8px}
.impl-constraint{padding:18px 20px;border-radius:16px;color:#fff;background:linear-gradient(150deg,var(--navy-2),var(--navy) 60%,#15347e);box-shadow:var(--shadow);-webkit-print-color-adjust:exact;print-color-adjust:exact}
.impl-constraint .lb{font-size:12px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:#bcd3ff;margin-bottom:9px}
.impl-constraint .ed{background:rgba(255,255,255,.08);border-color:rgba(147,197,253,.4);color:#fff;font-size:16px;font-weight:600}
.impl-constraint .ed:empty::before{color:rgba(219,234,254,.55)}
.impl-ns{display:grid;gap:12px}
.impl-ns .box{padding:14px 16px;border:1px solid var(--line);border-radius:14px;background:#fff;box-shadow:var(--shadow-sm)}
.impl-ns .box .lb{font-size:11.5px;font-weight:800;letter-spacing:.05em;text-transform:uppercase;margin-bottom:7px}
.impl-ns .box.ns .lb{color:var(--blue-d)}.impl-ns .box.gr .lb{color:var(--orange-d)}
.impl-path{position:relative;display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:28px 0 10px}
.impl-path::before{content:"";position:absolute;top:27px;left:9%;right:9%;height:4px;border-radius:3px;background:linear-gradient(90deg,var(--blue),#60a5fa 55%,var(--orange));z-index:0}
.node{position:relative;z-index:1;text-align:center}
.node .dot{width:56px;height:56px;margin:0 auto 8px;border-radius:50%;display:grid;place-items:center;color:#fff;font-weight:800;font-size:16px;background:linear-gradient(135deg,var(--blue-d),#3b82f6);box-shadow:0 8px 18px -6px rgba(37,99,235,.5);border:4px solid #fff;-webkit-print-color-adjust:exact;print-color-adjust:exact}
.node:last-child .dot{background:linear-gradient(135deg,var(--orange),var(--orange-d))}
.node .d{font-size:12.5px;color:var(--dim);font-weight:700}
.phases{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-bottom:22px}
.phase{border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:var(--shadow-sm);overflow:hidden}
.phase h3{margin:0;padding:13px 16px;font-size:15px;color:#fff;background:linear-gradient(160deg,var(--navy-2),var(--navy));-webkit-print-color-adjust:exact;print-color-adjust:exact}
.phase .pbody{padding:14px 16px;display:grid;gap:12px}
.phase .lb{font-size:11px;font-weight:800;letter-spacing:.04em;text-transform:uppercase;color:var(--blue-d);margin-bottom:6px}
.phase .lb.m{color:var(--orange-d)}
.impl-dec{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-top:8px}
.dec{border:1px solid var(--line);border-radius:14px;background:var(--soft);padding:14px}
.dec .lb{font-weight:800;font-size:13px;margin-bottom:9px;display:flex;align-items:center;gap:8px}
.dec .lb .k{display:grid;place-items:center;width:23px;height:23px;border-radius:7px;color:#fff;font-size:13px;background:var(--blue)}
.dec.iter .lb .k{background:var(--orange)}.dec.stop .lb .k{background:var(--ink-2)}
@media(max-width:820px){.impl-top,.impl-path,.phases{grid-template-columns:1fr}.impl-path::before{display:none}.impl-dec{grid-template-columns:1fr 1fr}}
@media print{@page{size:A4 portrait;margin:9mm}.impl-bar{display:none!important}.ed{border:1px solid #cbd5e1}.ed:empty::before{content:""}}
/* Infographic triển khai */
.impl .kn-box{margin-top:0}
.impl-constraint .ex,.impl-ns .ex{display:block;margin-top:8px;font-style:italic;font-size:13px;opacity:.85}
.impl-ns .box p{margin:0;font-size:14px;color:var(--ink-2);line-height:1.5}
.impl-constraint p{margin:0;font-size:15px;line-height:1.55}
.phase h3 .icon{font-size:19px;margin-right:7px}
.plist{list-style:none;margin:0;padding:0;display:grid;gap:7px}
.plist li{display:flex;gap:9px;font-size:14px;color:var(--ink-2);line-height:1.45}
.plist li::before{content:"▸";color:var(--blue-d);font-weight:800;flex:none}
.pmetric{margin-top:11px;padding:9px 12px;background:#fff7ed;border:1px solid #fed7aa;border-radius:10px;font-size:13px;color:#8a3d06;line-height:1.45}
.pmetric b{color:var(--orange-d)}
.gmos{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px}
.gmos .step{flex:1;min-width:132px;padding:13px 15px;border-radius:11px;color:#fff;background:linear-gradient(135deg,var(--blue-d),#3b82f6);-webkit-print-color-adjust:exact;print-color-adjust:exact}
.gmos .step:nth-child(even){background:linear-gradient(135deg,#0f2a6b,var(--blue-d))}
.gmos .step:last-child{background:linear-gradient(135deg,var(--orange),var(--orange-d))}
.gmos .step b{display:block;font-size:11px;opacity:.85;font-weight:700;margin-bottom:3px}
.gmos .step span{font-size:14.5px;font-weight:700}
.gmos-note{margin-top:10px;font-size:12.5px;color:var(--muted);text-align:center}
.spine{display:grid;grid-template-columns:repeat(5,1fr);gap:10px;margin-top:8px}
.spine .s{padding:16px 12px;border:1px solid var(--line);border-radius:14px;background:#fff;box-shadow:var(--shadow-sm);text-align:center}
.spine .s .ic{font-size:22px}
.spine .s b{display:block;font-size:13.5px;margin-top:5px;color:var(--ink)}
.spine .s span{font-size:11.5px;color:var(--muted)}
@media(max-width:820px){.spine{grid-template-columns:1fr 1fr}.gmos .step{min-width:0}}
.tool-row{display:grid;grid-template-columns:132px 1fr;gap:14px;padding:12px 16px;border-top:1px solid var(--line)}
.tool-row b{font-size:12px;font-weight:800;color:var(--blue-d);text-transform:uppercase;letter-spacing:.03em}
.tool-row:last-child{background:#fff7ed}
.tool-row:last-child b{color:var(--orange-d)}
.tool-row p{margin:0;color:var(--ink-2);line-height:1.55;font-size:14.5px}
@media(max-width:600px){.tool-row{grid-template-columns:1fr;gap:4px}}
.lesson-core{margin:22px 0;padding:22px 26px 22px 60px;position:relative;background:var(--soft);border-left:4px solid var(--blue);border-radius:0 12px 12px 0}
.lesson-core::before{content:"\201C";position:absolute;left:16px;top:2px;font:700 58px/1 Georgia,"Times New Roman",serif;color:var(--blue-300)}
.lesson-core p{margin:0;font-size:18px;line-height:1.7;color:var(--ink)}
.block{margin:30px 0}
.block h2{font-size:clamp(21px,2.6vw,27px);padding-bottom:10px;border-bottom:2px solid var(--blue);display:inline-block}
.mind{width:100%;border-collapse:collapse;margin-top:8px}
.mind th,.mind td{padding:12px 14px;border:1px solid var(--line);text-align:left;font-size:15px}
.mind th{background:var(--soft);color:var(--ink);font-size:13px}
.steps{margin:0;padding-left:20px}.steps li{margin:8px 0}
.case{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:8px}
.case>div{padding:16px 18px;border-radius:12px;font-size:14.5px}
.case .ok{background:var(--blue-l);border:1px solid var(--blue-100)}
.case .no{background:#f4f6fa;border:1px solid var(--line)}
.case b{display:block;margin-bottom:6px;color:var(--blue-d)}
.case .no b{color:var(--ink)}
.term{color:var(--blue-d);font-weight:800;border-bottom:2px dotted var(--blue-300);cursor:help}
/* Ví dụ diễn giải (tình huống → suy luận → bài học) */
.wex{margin:8px 0 0;border:1px solid var(--line);border-radius:14px;overflow:hidden;background:#fff;box-shadow:var(--shadow-sm)}
.wex-label{padding:11px 18px;background:var(--soft);border-bottom:1px solid var(--line);font-size:12px;font-weight:800;letter-spacing:.06em;text-transform:uppercase;color:var(--blue-d)}
.wex-row{display:grid;grid-template-columns:150px 1fr;gap:14px;padding:15px 18px;border-bottom:1px solid var(--line);align-items:start}
.wex-row:last-child{border-bottom:0}
.wex-row b{display:flex;align-items:center;gap:9px;font-size:13.5px;font-weight:800;color:var(--ink)}
.wex-row .n{display:grid;place-items:center;width:23px;height:23px;border-radius:7px;background:var(--blue);color:#fff;font-size:12px;flex:none}
.wex-row p{margin:0;color:var(--ink-2);line-height:1.62}
.wex-row.take{background:#fff7ed}
.wex-row.take .n{background:var(--orange)}
.wex-row.take b{color:var(--orange-d)}
@media(max-width:600px){.wex-row{grid-template-columns:1fr;gap:6px}}

/* ---------- Bài kiểm tra ---------- */
.quiz-card{max-width:780px;margin:0 auto;padding:clamp(22px,4vw,38px);background:#fff;border:1px solid var(--line);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm)}
.quiz-top{position:sticky;top:62px;z-index:5;margin:-10px 0 18px;padding:12px 0 10px;background:linear-gradient(#fff 72%,rgba(255,255,255,0))}
.quiz-prog{height:9px;border-radius:999px;background:var(--soft);border:1px solid var(--line);overflow:hidden}
.quiz-prog-bar{height:100%;width:0;border-radius:999px;background:linear-gradient(90deg,var(--blue),var(--blue-d));transition:width .35s cubic-bezier(.2,.8,.2,1)}
.quiz-prog-label{margin-top:8px;font-size:13px;font-weight:700;color:var(--muted)}
.quiz-prog-label b{color:var(--blue-d);font-variant-numeric:tabular-nums}
.q{padding:22px 0;margin:0;border:0;border-bottom:1px solid var(--line)}
.q:last-of-type{border-bottom:0}
.q legend{display:flex;gap:11px;align-items:flex-start;width:100%;font-weight:700;font-size:17px;line-height:1.42;margin-bottom:14px}
.q .qn{flex:none;margin-top:1px;padding:3px 11px;border-radius:999px;background:var(--blue-l);color:var(--blue-d);font-size:12.5px;font-weight:800;white-space:nowrap}
.opts{display:grid;gap:9px}
.opt{position:relative;display:flex;align-items:center;gap:12px;padding:13px 15px;border:1.5px solid var(--line);border-radius:12px;cursor:pointer;transition:border-color .15s,background-color .15s,box-shadow .15s,transform .08s}
.opt:hover{border-color:var(--blue-300);background:var(--blue-l)}
.opt:active{transform:scale(.996)}
.opt input{position:absolute;opacity:0;width:0;height:0}
.opt .ol{flex:none;display:grid;place-items:center;width:30px;height:30px;border-radius:9px;background:var(--soft);border:1.5px solid var(--line-2);color:var(--muted);font-weight:800;font-size:14px;transition:.15s}
.opt .ot{flex:1;color:var(--ink-2);line-height:1.45}
.opt:has(input:checked){border-color:var(--blue);background:var(--blue-l);box-shadow:0 0 0 3px rgba(37,99,235,.13)}
.opt:has(input:checked) .ol{background:var(--blue);border-color:var(--blue);color:#fff}
.opt:has(input:checked) .ot{color:var(--ink)}
.q.done .opt{cursor:default}
.q.done .opt:hover{background:transparent}
.q.done .opt:has(input:checked):not(.correct):not(.wrong){background:transparent;border-color:var(--line);box-shadow:none}
.opt.correct{border-color:var(--blue)!important;background:var(--blue-l)!important}
.opt.correct .ol{background:var(--blue)!important;border-color:var(--blue)!important;color:#fff!important}
.opt.correct::after{content:"✓ Đúng";flex:none;color:var(--blue-d);font-weight:800;font-size:12.5px}
.opt.wrong{border-color:var(--orange)!important;background:#fff7ed!important}
.opt.wrong .ol{background:var(--orange)!important;border-color:var(--orange)!important;color:#fff!important}
.opt.wrong::after{content:"✕ Bạn chọn";flex:none;color:var(--orange-d);font-weight:800;font-size:12.5px}
#quiz-submit{width:100%;margin-top:26px}
.quiz-result{margin-top:26px;padding:24px;border-radius:16px;display:grid;grid-template-columns:auto 1fr;gap:22px;align-items:center;animation:rise .4s ease both}
.qr-ring{--p:0;position:relative;flex:none;width:104px;height:104px;border-radius:50%;display:grid;place-items:center;background:conic-gradient(var(--rc,var(--blue)) calc(var(--p)*3.6deg),var(--line) 0)}
.qr-ring::before{content:"";position:absolute;inset:10px;border-radius:50%;background:#fff}
.qr-ring b{position:relative;font-size:30px;font-weight:800;font-variant-numeric:tabular-nums;color:var(--ink)}
.quiz-result h3{margin:0 0 5px;font-size:20px}
.quiz-result p{margin:0;color:var(--muted);line-height:1.5}
.quiz-result.pass{background:var(--blue-l);border:1px solid var(--blue-100)}
.quiz-result.pass .qr-ring{--rc:var(--orange)}
.quiz-result.fail{background:var(--soft);border:1px solid var(--line)}
.quiz-result.fail .qr-ring{--rc:var(--ink-2)}
@media(max-width:600px){.quiz-result{grid-template-columns:1fr;justify-items:center;text-align:center}.opt.correct::after,.opt.wrong::after{display:none}}

/* ---------- Certificate ---------- */
.cert-controls{max-width:1000px;margin:26px auto 16px;display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.cert-controls .lockbar{flex:1;min-width:240px;padding:11px 16px;border-radius:12px;font-size:13px;font-weight:600}
.lockbar.ok{background:var(--blue-l);color:var(--blue-d);border:1px solid var(--blue-100)}
.lockbar.locked{background:#f4f6fa;color:var(--ink-2);border:1px solid var(--line)}
.cert-wrap{max-width:1000px;margin:0 auto}
.cert{position:relative;aspect-ratio:1000/752;background:#fff;box-shadow:var(--shadow);overflow:hidden;-webkit-print-color-adjust:exact;print-color-adjust:exact}
/* Viền đôi mảnh thanh lịch */
.cert .fr{position:absolute;inset:18px;z-index:1;border:1.5px solid #c3d1e8;pointer-events:none}
.cert .fr::after{content:"";position:absolute;inset:5px;border:1px solid #dde5f2}
.cert .corner{position:absolute;z-index:2;width:26px;height:26px;border:1.5px solid #9fb4d6;pointer-events:none}
.cert .corner.tl{top:26px;left:26px;border-right:0;border-bottom:0}
.cert .corner.tr{top:26px;right:26px;border-left:0;border-bottom:0}
.cert .corner.bl{bottom:26px;left:26px;border-right:0;border-top:0}
.cert .corner.br{bottom:26px;right:26px;border-left:0;border-top:0}
/* Ruy băng treo góc phải (bookmark, đuôi nhọn) chứa con dấu */
.cert-hang{position:absolute;top:18px;right:11%;z-index:2;width:142px;height:56%;padding:24px 12px 0;display:flex;flex-direction:column;align-items:center;color:#fff;background:linear-gradient(180deg,#1d4ed8 0%,#12327a 68%,#0b214f 100%);clip-path:polygon(0 0,100% 0,100% 100%,50% 82%,0 100%);box-shadow:0 16px 28px -18px rgba(11,31,77,.55);-webkit-print-color-adjust:exact;print-color-adjust:exact}
.cert-hang::before{content:"";position:absolute;inset:0;opacity:.14;background-image:linear-gradient(rgba(255,255,255,.7) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.7) 1px,transparent 1px);background-size:24px 24px}
.cert-hang .t{position:relative;font-size:13px;font-weight:800;letter-spacing:3px;text-transform:uppercase;text-align:center;line-height:1.5;color:#dbe8ff;padding-bottom:11px;border-bottom:2px solid #f97316}
/* Nội dung: logo lớn trên, thân giữa, chân dưới */
.cert .pad{position:absolute;inset:0;z-index:1;padding:clamp(36px,4.6vw,58px) clamp(42px,5vw,64px);display:flex;flex-direction:column}
.cert-logo{display:flex;align-items:center;gap:15px}
.cert-logo .m{width:56px;height:56px;border-radius:15px;display:grid;place-items:center;color:#fff;font-weight:800;font-size:22px;background:linear-gradient(135deg,var(--blue-d),#3b82f6);box-shadow:0 10px 20px -8px rgba(37,99,235,.55)}
.cert-logo b{display:block;font-family:Georgia,"Times New Roman",serif;font-size:clamp(26px,3.4vw,40px);letter-spacing:-.01em;color:var(--ink);line-height:1}
.cert-logo b i{color:var(--blue);font-style:normal}
.cert-logo span{display:block;margin-top:4px;font-size:11px;letter-spacing:2.5px;text-transform:uppercase;color:var(--muted)}
.cert-body{flex:1;display:flex;flex-direction:column;justify-content:center;max-width:66%}
.cert-date{font-size:12px;letter-spacing:1.4px;text-transform:uppercase;color:var(--muted);margin-bottom:14px}
.cert-name{font-family:Georgia,"Times New Roman",serif;font-size:clamp(30px,5vw,50px);font-weight:700;letter-spacing:-.01em;color:var(--ink);margin:0 0 8px;border:0;background:transparent;width:100%;padding:2px 0}
.cert-name:focus{outline:0;border-bottom:1px dashed var(--blue)}
.cert-rule{width:min(520px,70%);height:3px;border-radius:2px;background:linear-gradient(90deg,#f97316,#fdba74 62%,transparent);margin:2px 0 14px}
.cert-has{font-size:13.5px;color:var(--muted);margin-bottom:10px}
.cert-course{position:relative;padding-left:15px;font-family:Georgia,"Times New Roman",serif;font-size:clamp(20px,2.6vw,28px);font-weight:700;color:var(--blue-d);line-height:1.22}
.cert-course::before{content:"";position:absolute;left:0;top:4px;bottom:4px;width:4px;border-radius:3px;background:#f97316}
.cert-course small{display:block;font-family:var(--sans);font-size:12.5px;font-weight:500;color:var(--muted);margin-top:7px;letter-spacing:.2px;max-width:520px;line-height:1.55}
.cert-foot{display:flex;justify-content:space-between;align-items:flex-end;gap:20px}
.cert-sign svg{height:40px;display:block}
.cert-sign .l{border-top:1px solid #b9c4d8;padding-top:6px;margin-top:2px;font-size:11px;color:var(--muted)}
.cert-sign .l b{color:var(--ink);font-family:Georgia,"Times New Roman",serif}
.cert-verify{text-align:right;font-size:10px;color:var(--muted);line-height:1.7}
.cert-verify a{color:var(--blue-d)}
.cert-verify .code{font-family:ui-monospace,Menlo,monospace;font-size:11.5px;letter-spacing:1px;color:var(--ink);font-weight:700}
/* Con dấu trong ruy băng (nét sáng trên nền xanh) */
.cert-seal{position:relative;z-index:1;width:112px;height:112px;margin-top:18px}
.cert-seal .rt{font-size:8px;letter-spacing:2px;fill:#cfe0ff;font-weight:700;text-transform:uppercase}
.cert-seal circle{fill:none;stroke:#9fc0ff}
.cert-seal .mid{font-weight:800;fill:#fff;font-size:14px}
.cert-seal .sub{font-size:6.5px;letter-spacing:2px;fill:#cfe0ff;font-weight:700}
.cert-seal .star{fill:#f97316}

/* ---------- Animations ---------- */
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes grow{from{transform:scaleY(0);opacity:0}to{transform:scaleY(1);opacity:1}}
@keyframes rise{from{opacity:0;transform:translateY(16px)}to{opacity:1;transform:none}}

/* ---------- Glossary tooltip ---------- */
.tip{position:fixed;z-index:1000;max-width:300px;padding:10px 12px;color:#fff;background:var(--navy);border-radius:10px;box-shadow:var(--shadow);font-size:13px;line-height:1.5;opacity:0;visibility:hidden;transform:translateY(5px);transition:opacity .14s,transform .14s,visibility .14s;pointer-events:none}
.tip.show{opacity:1;visibility:visible;transform:translateY(0)}

/* ---------- Responsive ---------- */
@media(max-width:860px){
  .hero,.login{grid-template-columns:1fr}
  .login-visual{display:none}
  .stage-grid,.case{grid-template-columns:1fr}
  .nav-links{margin-left:6px;overflow-x:auto;max-width:100%;-webkit-overflow-scrolling:touch}
  .nav-links a{white-space:nowrap}
  .brand small{display:none}
}
@media print{
  @page{size:A4 landscape;margin:6mm}
  html,body{background:#fff}
  .nav,.footer,.cert-controls,.hint{display:none!important}
  .cert-wrap{max-width:none;margin:0}
  #cert{filter:none!important}                                   /* bỏ mờ/xám khi in */
  .cert{box-shadow:none;aspect-ratio:auto;height:190mm}
  .cert,.cert *,.cert::before,.cert-hang,.cert-hang::before,.cert-seal,.cert-rule,.cert-logo .m{
    -webkit-print-color-adjust:exact!important;print-color-adjust:exact!important}  /* buộc in đủ màu */
  .cert-name:focus{border:0;border-bottom:0}
}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}