:root{
  --bg:#f6f8fb;--card:#ffffff;--ink:#1c2530;--muted:#5b6776;--line:#e7ecf3;
  --brand:#1877f2;--brand-dark:#0f5bd0;--accent:#ff7a59;--accent-soft:#fff1ec;
  --green:#1f9d55;--green-soft:#e8f7ee;--amber:#f2a900;--amber-soft:#fff6e0;
  --shadow:0 10px 30px rgba(20,40,80,.08);--shadow-sm:0 4px 14px rgba(20,40,80,.06);--radius:18px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:90px}
body{margin:0;font-family:"Be Vietnam Pro",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;color:var(--ink);background:var(--bg);line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none}
img{max-width:100%}

#progressbar{position:fixed;top:0;left:0;height:4px;width:0;background:linear-gradient(90deg,var(--brand),var(--accent));z-index:200;transition:width .15s ease}

/* ===== Login ===== */
.login-wrap{min-height:100vh;display:grid;place-items:center;padding:20px;
  background:radial-gradient(900px 500px at 80% -10%,rgba(24,119,242,.18),transparent 60%),
  radial-gradient(700px 400px at 0% 110%,rgba(255,122,89,.16),transparent 60%),linear-gradient(180deg,#fff,#eef4ff)}
.login-card{width:100%;max-width:410px;background:#fff;border:1px solid var(--line);border-radius:22px;box-shadow:var(--shadow);padding:34px 30px}
.login-card .logo{width:54px;height:54px;border-radius:14px;background:linear-gradient(135deg,var(--brand),var(--accent));display:grid;place-items:center;color:#fff;font-weight:900;font-size:24px;margin:0 auto 16px;box-shadow:var(--shadow-sm)}
.login-card h1{text-align:center;font-size:22px;margin:0 0 4px}
.login-card .sub{text-align:center;color:var(--muted);font-size:14px;margin:0 0 24px}
.field{margin-bottom:14px}
.field label{display:block;font-size:13px;font-weight:600;color:var(--muted);margin-bottom:6px}
.field input{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:12px;font-size:15px;font-family:inherit;outline:none;transition:.15s}
.field input:focus{border-color:var(--brand);box-shadow:0 0 0 3px rgba(24,119,242,.12)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;cursor:pointer;border:0;font-weight:700;font-size:15px;padding:13px 22px;border-radius:13px;transition:.18s;font-family:inherit}
.btn-primary{background:var(--brand);color:#fff;box-shadow:var(--shadow-sm);width:100%}
.btn-primary:hover{background:var(--brand-dark)}
.btn-ghost{background:#fff;color:var(--ink);border:1px solid var(--line)}
.btn-ghost:hover{border-color:var(--brand);color:var(--brand)}
.login-err{background:var(--accent-soft);color:#c0392b;border:1px solid #ffd6c9;border-radius:11px;padding:10px 14px;font-size:14px;margin-bottom:14px;display:none}
.login-err.show{display:block}
.login-hint{margin-top:18px;font-size:12.5px;color:var(--muted);text-align:center;line-height:1.7}

/* ===== Nav ===== */
header.nav{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.88);backdrop-filter:saturate(180%) blur(10px);border-bottom:1px solid var(--line)}
.nav-inner{max-width:1180px;margin:0 auto;padding:12px 20px;display:flex;align-items:center;gap:14px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:18px}
.brand .logo{width:36px;height:36px;border-radius:10px;background:linear-gradient(135deg,var(--brand),var(--accent));display:grid;place-items:center;color:#fff;font-weight:900;box-shadow:var(--shadow-sm)}
.nav-spacer{flex:1}
.nav-links{display:flex;gap:6px;flex-wrap:wrap}
.nav-links a{padding:8px 12px;border-radius:10px;color:var(--muted);font-weight:600;font-size:14px}
.nav-links a:hover{background:var(--bg);color:var(--ink)}
.userchip{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--muted);background:var(--bg);border:1px solid var(--line);padding:6px 12px;border-radius:999px;font-weight:600}
.userchip .role{font-size:11px;background:var(--brand);color:#fff;padding:2px 8px;border-radius:999px;font-weight:700}
.userchip .role.admin{background:var(--accent)}
.icon-btn{border:1px solid var(--line);background:#fff;border-radius:10px;padding:7px 12px;cursor:pointer;font-weight:600;font-size:13px;color:var(--muted);font-family:inherit}
.icon-btn:hover{border-color:var(--brand);color:var(--brand)}
.menu-btn{display:none;border:0;background:transparent;font-size:24px;cursor:pointer;color:var(--ink)}

/* ===== Admin bar ===== */
.adminbar{display:none;background:linear-gradient(90deg,#10243f,#1b3a64);color:#fff;position:sticky;top:61px;z-index:99}
body.admin .adminbar{display:block}
.adminbar-inner{max-width:1180px;margin:0 auto;padding:9px 20px;display:flex;align-items:center;gap:12px;flex-wrap:wrap;font-size:13.5px}
.adminbar b{color:#ffd166}
.adminbar .spacer{flex:1}
.adminbar .ab-btn{background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.25);color:#fff;border-radius:9px;padding:7px 13px;cursor:pointer;font-weight:600;font-size:13px;font-family:inherit;transition:.15s}
.adminbar .ab-btn:hover{background:rgba(255,255,255,.26)}
.adminbar .ab-btn.save{background:var(--green);border-color:var(--green)}
.adminbar .ab-btn.save:hover{background:#18804a}
.adminbar .ab-btn.toggle.on{background:var(--accent);border-color:var(--accent)}
.savestate{font-size:12.5px;opacity:.85}

/* ===== Hero ===== */
.hero{position:relative;overflow:hidden;background:radial-gradient(900px 400px at 85% -10%,rgba(24,119,242,.18),transparent 60%),radial-gradient(700px 380px at 0% 110%,rgba(255,122,89,.16),transparent 60%),linear-gradient(180deg,#fff,#f3f7ff);border-bottom:1px solid var(--line)}
.hero-inner{max-width:1180px;margin:0 auto;padding:60px 20px 52px;display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.eyebrow{display:inline-flex;align-items:center;gap:8px;background:var(--accent-soft);color:#d24a2a;font-weight:700;font-size:13px;padding:7px 14px;border-radius:999px;margin-bottom:18px}
.hero h1{font-size:clamp(30px,4vw,46px);line-height:1.15;margin:0 0 16px;font-weight:800;letter-spacing:-.5px}
.hero h1 .hl{background:linear-gradient(120deg,var(--brand),var(--accent));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{font-size:18px;color:var(--muted);margin:0 0 26px;max-width:560px}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap}
.hero-stats{display:flex;gap:26px;margin-top:30px;flex-wrap:wrap}
.hero-stats .s b{display:block;font-size:24px;font-weight:800}
.hero-stats .s span{font-size:13px;color:var(--muted)}
.hero-art{display:grid;place-items:center;justify-items:stretch}
.hero-art svg{width:100%;max-width:440px;justify-self:center;filter:drop-shadow(0 20px 40px rgba(20,40,80,.12))}
.hero-art img.hero-img{width:100%;max-width:none;border-radius:18px;object-fit:cover;box-shadow:0 20px 44px rgba(20,40,80,.18)}

/* ===== Layout ===== */
.shell{max-width:1180px;margin:0 auto;padding:0 20px;display:grid;grid-template-columns:260px 1fr;gap:36px}
@media(max-width:980px){.shell{grid-template-columns:1fr}}
.sidebar{position:sticky;top:96px;align-self:start;height:max-content;padding:18px 0}
.sidebar h4{font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin:0 0 12px;padding:0 6px}
.toc{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:2px}
.toc a{display:flex;align-items:center;gap:10px;padding:9px 12px;border-radius:11px;color:var(--muted);font-weight:600;font-size:14px}
.toc a .dot{width:9px;height:9px;border-radius:50%;background:var(--line);flex:none;transition:.2s}
.toc a:hover{background:#fff;color:var(--ink)}
.toc a.active{background:#fff;color:var(--brand);box-shadow:var(--shadow-sm)}
.toc a.active .dot{background:var(--brand);box-shadow:0 0 0 4px rgba(24,119,242,.15)}
@media(max-width:980px){.sidebar{display:none}}
main{padding:30px 0 60px}

.intro-card{background:linear-gradient(135deg,#fff,#f7faff);border:1px solid var(--line);border-radius:var(--radius);padding:26px 28px;box-shadow:var(--shadow-sm);margin-bottom:34px}
.intro-card h2{margin:0 0 8px;font-size:22px}
.intro-card p{margin:0;color:var(--muted)}

.module{margin:0 0 46px;scroll-margin-top:120px}
.module-head{display:flex;align-items:center;gap:16px;margin-bottom:8px}
.module-badge{width:54px;height:54px;border-radius:16px;flex:none;display:grid;place-items:center;color:#fff;font-weight:800;font-size:20px;box-shadow:var(--shadow-sm)}
.module-head h2{margin:0;font-size:25px;letter-spacing:-.3px}
.module-head .sub{color:var(--muted);font-size:14px;margin-top:2px}
.module-banner{border-radius:var(--radius);overflow:hidden;margin:14px 0 22px;border:1px solid var(--line);background:#fff;box-shadow:var(--shadow-sm)}
.module-banner svg{display:block;width:100%;height:auto}

.lesson{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow-sm);margin-bottom:18px;overflow:hidden;transition:.2s}
.lesson:hover{box-shadow:var(--shadow)}
.lesson-head{display:flex;align-items:center;gap:14px;padding:18px 22px;cursor:pointer;user-select:none}
.lesson-ico{width:44px;height:44px;border-radius:12px;flex:none;display:grid;place-items:center;background:var(--bg)}
.lesson-ico svg{width:24px;height:24px}
.lesson-titles{flex:1;min-width:0}
.lesson-code{font-size:12px;font-weight:800;letter-spacing:.04em;color:var(--accent)}
.lesson-title{font-size:17px;font-weight:700;margin:1px 0 0;line-height:1.35}
.chev{transition:.25s;color:var(--muted);flex:none}
.lesson.open .chev{transform:rotate(180deg)}
.lesson-check{flex:none;width:26px;height:26px;border-radius:8px;border:2px solid var(--line);display:grid;place-items:center;background:#fff;cursor:pointer;color:#fff;transition:.18s}
.lesson-check.done{background:var(--green);border-color:var(--green)}
.lesson-body{max-height:0;overflow:hidden;transition:max-height .35s ease;border-top:1px solid transparent}
.lesson.open .lesson-body{border-top-color:var(--line)}
.lesson-body-inner{padding:6px 22px 24px}
.lesson-body p{margin:14px 0}
.lesson-body .quote{border-left:4px solid var(--accent);background:var(--accent-soft);padding:12px 16px;border-radius:0 12px 12px 0;color:#7a3a26;font-style:italic;margin:16px 0}
.lesson-body ol,.lesson-body ul{margin:12px 0;padding-left:22px}
.lesson-body li{margin:7px 0}
.lesson-body h5{margin:20px 0 6px;font-size:15px;text-transform:uppercase;letter-spacing:.05em;color:var(--brand)}
.tip,.warn,.note{display:flex;gap:12px;padding:14px 16px;border-radius:14px;margin:16px 0;font-size:14.5px}
.tip{background:var(--green-soft);border:1px solid #c8ecd6}
.warn{background:var(--accent-soft);border:1px solid #ffd6c9}
.note{background:var(--amber-soft);border:1px solid #ffe7a3}
.tip .ti,.warn .ti,.note .ti{font-size:20px;flex:none;line-height:1.4}
.tip .cardttl,.warn .cardttl,.note .cardttl{display:block;margin-bottom:2px;font-weight:700}
.script-box{background:#0f1b2d;color:#e9eef7;border-radius:14px;padding:16px 18px;margin:14px 0;font-size:14px;line-height:1.7;white-space:pre-wrap}
.script-box .lbl{display:block;font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:#7fb3ff;margin-bottom:8px;font-weight:700}
.lesson-img{display:block;border-radius:14px;margin:16px 0 6px;border:1px solid var(--line)}
.lesson-img-cap{font-size:13px;color:var(--muted);text-align:center;margin:0 0 8px}
.pc{display:grid;grid-template-columns:1fr;gap:10px;margin:14px 0}
.pc .row{border:1px solid var(--line);border-radius:14px;padding:12px 16px;background:#fff}
.pc .row b{display:block;margin-bottom:6px}
.pc .pro{color:var(--green)}
.pc .con{color:#d24a2a}

.outro{margin:60px 0 0;border-radius:24px;overflow:hidden;color:#fff;background:linear-gradient(135deg,var(--brand),#5a8dff 60%,var(--accent));box-shadow:var(--shadow)}
.outro-inner{padding:48px 36px}
.outro h2{margin:0 0 10px;font-size:28px}
.outro p{margin:0 0 22px;font-size:17px;opacity:.95;max-width:640px}
.outro .btn-ghost{background:#fff;color:var(--brand)}
.checklist{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px;margin-top:8px}
.checklist .ci{background:rgba(255,255,255,.15);border:1px solid rgba(255,255,255,.25);border-radius:14px;padding:14px 16px;font-weight:600;font-size:14.5px;display:flex;gap:10px;align-items:flex-start}

footer{max-width:1180px;margin:0 auto;padding:34px 20px 60px;color:var(--muted);font-size:14px;text-align:center}

/* ===== Admin editing ===== */
body.editing [data-edit]{outline:1.5px dashed transparent;border-radius:6px;transition:outline-color .15s;cursor:text}
body.editing [data-edit]:hover{outline-color:var(--brand)}
body.editing [data-edit]:focus{outline:2px solid var(--brand);background:#fff;cursor:text}
body.editing .lesson-head{cursor:default}
.edit-toolbar{display:none}
body.editing .edit-toolbar{display:flex;gap:6px;flex-wrap:wrap;align-items:center;padding:8px 12px;margin:10px 0;background:#eef4ff;border:1px dashed var(--brand);border-radius:12px}
.edit-toolbar .et{font-size:12px;font-weight:700;color:var(--brand);margin-right:4px}
.mini{border:1px solid var(--line);background:#fff;border-radius:8px;padding:5px 10px;font-size:12.5px;cursor:pointer;font-weight:600;color:var(--ink);font-family:inherit}
.mini:hover{border-color:var(--brand);color:var(--brand)}
.mini.danger:hover{border-color:#e0392b;color:#e0392b}
.drag-handle{display:none}
body.editing .drag-handle{display:inline-grid;place-items:center;width:26px;height:26px;border-radius:7px;background:var(--bg);border:1px solid var(--line);color:var(--muted);cursor:grab;flex:none}
body.editing .drag-handle:active{cursor:grabbing}
.dragging{opacity:.45}
.drop-target{outline:2px dashed var(--accent);outline-offset:3px}
body.editing .lesson,body.editing .module{position:relative}
.block-wrap{position:relative}
body.editing .block-wrap{padding-left:4px;border-left:2px solid transparent}
body.editing .block-wrap:hover{border-left-color:var(--accent)}
.block-tools{display:none}
body.editing .block-tools{position:absolute;top:-2px;right:0;display:none;gap:4px;z-index:5}
body.editing .block-wrap:hover>.block-tools{display:flex}
.block-tools .mini{padding:3px 8px;font-size:11px}

/* Modal */
.modal-back{position:fixed;inset:0;background:rgba(12,22,40,.5);z-index:300;display:none;place-items:center;padding:20px}
.modal-back.show{display:grid}
.modal{background:#fff;border-radius:18px;max-width:460px;width:100%;padding:26px;box-shadow:var(--shadow)}
.modal h3{margin:0 0 14px}
.modal .field{margin-bottom:12px}
.modal-actions{display:flex;gap:10px;justify-content:flex-end;margin-top:18px}
.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%) translateY(20px);background:#10243f;color:#fff;padding:12px 22px;border-radius:12px;font-size:14px;font-weight:600;box-shadow:var(--shadow);opacity:0;pointer-events:none;transition:.25s;z-index:400}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

@media(max-width:760px){
  .hero-inner{grid-template-columns:1fr;padding:42px 20px}
  .hero-art{order:-1}.hero-art svg{max-width:320px}.hero-art img.hero-img{max-width:100%}
  .nav-links{display:none}
  .userchip .uname{display:none}
}