:root{--bg: #f3efe6;--bg-elevated: #fffdf8;--ink: #1c2a22;--ink-muted: #5a6b60;--line: #d5cec0;--accent: #0f6b4c;--accent-soft: #d8efe4;--warn: #9a5b12;--warn-soft: #f5e6d0;--danger: #9b2c2c;--danger-soft: #f8e0e0;--ok: #0f6b4c;--ok-soft: #d8efe4;--shadow: 0 1px 0 rgba(28, 42, 34, .04);--radius: 14px;--font: "Be Vietnam Pro", system-ui, sans-serif;--display: "Source Serif 4", Georgia, serif;--max: 960px}*,*:before,*:after{box-sizing:border-box}html,body,#root{min-height:100%}body{margin:0;font-family:var(--font);color:var(--ink);background:radial-gradient(ellipse 80% 50% at 10% -10%,#e7f3ec 0%,transparent 55%),radial-gradient(ellipse 60% 40% at 100% 0%,#efe6d4 0%,transparent 50%),var(--bg);line-height:1.55}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}h1,h2,h3{font-family:var(--display);font-weight:700;line-height:1.25;margin:0 0 .5rem}p{margin:0 0 1rem;color:var(--ink-muted)}.app-shell{min-height:100vh;display:flex;flex-direction:column}.topbar{position:sticky;top:0;z-index:20;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);background:#f3efe6e6;border-bottom:1px solid var(--line)}.topbar-inner{max-width:var(--max);margin:0 auto;padding:.85rem 1.25rem;display:flex;align-items:center;justify-content:space-between;gap:1rem}.brand{font-family:var(--display);font-weight:700;color:var(--ink);text-decoration:none;font-size:1.05rem}.brand span{color:var(--accent)}.nav{display:flex;flex-wrap:wrap;gap:.35rem .85rem;font-size:.92rem}.nav-toggle{display:none;-webkit-appearance:none;-moz-appearance:none;appearance:none;border:1px solid var(--line);background:var(--bg-elevated);color:var(--ink);border-radius:999px;padding:.5rem .85rem;font:inherit;font-weight:600}.nav a{color:var(--ink-muted);text-decoration:none;padding:.2rem 0;border-bottom:2px solid transparent}.nav a.active,.nav a:hover{color:var(--accent);border-bottom-color:var(--accent);text-decoration:none}.breadcrumbs{display:flex;flex-wrap:wrap;gap:.35rem;margin-bottom:1rem;font-size:.88rem;color:var(--ink-muted)}.breadcrumbs strong{color:var(--ink)}.breadcrumbs-sep{margin:0 .15rem;color:var(--ink-muted)}.main{flex:1;max-width:var(--max);width:100%;margin:0 auto;padding:1.5rem 1.25rem 3rem}.hero{padding:1.5rem 0 2rem}.hero-kicker{text-transform:uppercase;letter-spacing:.08em;font-size:.75rem;font-weight:600;color:var(--accent);margin-bottom:.75rem}.hero h1{font-size:clamp(1.8rem,4vw,2.6rem);max-width:18ch}.hero-lead{font-size:1.05rem;max-width:42rem}.cta-row{display:flex;flex-wrap:wrap;gap:.75rem;margin-top:1.25rem}.btn{-webkit-appearance:none;-moz-appearance:none;appearance:none;border:1px solid transparent;border-radius:999px;padding:.7rem 1.2rem;font:inherit;font-weight:600;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:.4rem;text-decoration:none;transition:transform .15s ease,background .15s ease,border-color .15s ease}.btn:hover{transform:translateY(-1px);text-decoration:none}.btn:disabled{opacity:.55;cursor:not-allowed;transform:none}.btn-primary{background:var(--accent);color:#fff}.btn-secondary{background:var(--bg-elevated);color:var(--ink);border-color:var(--line)}.btn-ghost{background:transparent;color:var(--accent);border-color:transparent;padding-inline:.6rem}.btn-danger{background:var(--danger);color:#fff}.grid-modules{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:.9rem;margin-top:1.5rem}.module-card{background:var(--bg-elevated);border:1px solid var(--line);border-radius:var(--radius);padding:1rem 1.1rem;box-shadow:var(--shadow);text-decoration:none;color:inherit;display:block;transition:border-color .15s ease,transform .15s ease}.module-card:hover{border-color:var(--accent);transform:translateY(-2px);text-decoration:none}.module-id{font-size:.78rem;font-weight:700;color:var(--accent);letter-spacing:.04em}.module-card h3{font-size:1.05rem;margin-top:.35rem}.module-card p{font-size:.9rem;margin-bottom:.4rem}.meta{font-size:.82rem;color:var(--ink-muted)}.panel{background:var(--bg-elevated);border:1px solid var(--line);border-radius:var(--radius);padding:1.15rem 1.25rem;box-shadow:var(--shadow)}.panel+.panel{margin-top:1rem}.question-stem{font-size:1.08rem;color:var(--ink);font-weight:500;margin-bottom:1rem}.choices{display:grid;gap:.55rem}.choice{display:flex;gap:.75rem;align-items:flex-start;width:100%;text-align:left;border:1px solid var(--line);background:#fff;border-radius:12px;padding:.75rem .9rem;font:inherit;cursor:pointer;color:var(--ink);transition:border-color .15s ease,background .15s ease}.choice:hover:not(:disabled){border-color:var(--accent)}.choice:disabled{cursor:default}.choice-key{flex:0 0 auto;width:1.7rem;height:1.7rem;border-radius:50%;border:1px solid var(--line);display:grid;place-items:center;font-weight:700;font-size:.85rem;background:var(--bg)}.choice.selected{border-color:var(--accent);background:var(--accent-soft)}.choice.correct{border-color:var(--ok);background:var(--ok-soft)}.choice.wrong{border-color:var(--danger);background:var(--danger-soft)}.feedback{margin-top:1rem;padding:.85rem 1rem;border-radius:12px;font-size:.95rem}.feedback.ok{background:var(--ok-soft);color:var(--ok)}.feedback.bad{background:var(--danger-soft);color:var(--danger)}.feedback.warn{background:var(--warn-soft);color:var(--warn)}.toolbar{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.75rem;margin-bottom:1rem}.progress-bar{height:8px;background:#e4ddd0;border-radius:999px;overflow:hidden;margin:.75rem 0 1.25rem}.progress-bar>span{display:block;height:100%;background:var(--accent);border-radius:inherit}.timer{font-variant-numeric:tabular-nums;font-weight:700;color:var(--accent);background:var(--accent-soft);padding:.35rem .75rem;border-radius:999px}.timer.urgent{color:var(--danger);background:var(--danger-soft)}.exam-nav{display:flex;flex-wrap:wrap;gap:.35rem;margin:1rem 0}.exam-nav button{width:2.1rem;height:2.1rem;border-radius:8px;border:1px solid var(--line);background:#fff;font:inherit;font-size:.85rem;cursor:pointer}.exam-nav button.answered{background:var(--accent-soft);border-color:var(--accent)}.exam-nav button.current{outline:2px solid var(--accent)}.score-hero{text-align:center;padding:1.5rem 1rem}.score-hero .score{font-family:var(--display);font-size:3.2rem;color:var(--accent);line-height:1}.badge{display:inline-block;padding:.25rem .65rem;border-radius:999px;font-size:.82rem;font-weight:600}.badge.pass{background:var(--ok-soft);color:var(--ok)}.badge.fail{background:var(--danger-soft);color:var(--danger)}.table{width:100%;border-collapse:collapse;font-size:.92rem}.table th,.table td{text-align:left;padding:.55rem .4rem;border-bottom:1px solid var(--line)}.table th{color:var(--ink-muted);font-weight:600}.checklist{list-style:none;padding:0;margin:0}.checklist li{display:flex;gap:.65rem;align-items:flex-start;padding:.55rem 0;border-bottom:1px solid var(--line);color:var(--ink)}.checklist input{margin-top:.25rem}.footer-note{margin-top:2rem;font-size:.82rem;color:var(--ink-muted)}.landing-hero{position:relative;overflow:hidden;isolation:isolate;padding:2.5rem 2rem;margin-top:.5rem;border:1px solid rgba(15,107,76,.08);border-radius:24px;background:radial-gradient(circle at 18% 22%,rgba(255,255,255,.9) 0%,rgba(255,255,255,.4) 24%,transparent 44%),radial-gradient(circle at 84% 18%,rgba(216,239,228,.95) 0%,rgba(216,239,228,.3) 22%,transparent 48%),radial-gradient(circle at 78% 78%,rgba(239,230,212,.9) 0%,rgba(239,230,212,.24) 18%,transparent 44%),linear-gradient(135deg,#fffdf8f5,#f4f8f4fa 52%,#ecf4effa);box-shadow:0 18px 36px #1c2a220f}.landing-hero:before,.landing-hero:after{content:"";position:absolute;inset:auto;pointer-events:none;z-index:-1}.landing-hero:before{top:-8%;right:-10%;width:48%;height:120%;border-radius:40% 60% 52% 48%;background:linear-gradient(180deg,#0f6b4c1f,#0f6b4c08);transform:rotate(-10deg)}.landing-hero:after{right:5%;bottom:10%;width:34%;height:38%;border-radius:999px;background:repeating-linear-gradient(-18deg,#fff0 0,#fff0 14px,#ffffff73 14px,#ffffff73 15px);opacity:.65}.landing-hero>*{position:relative;z-index:1}.landing-section{margin-top:1.5rem}.landing-eyebrow{font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;font-weight:700;color:var(--accent);margin-bottom:.6rem}.landing-pill-list{display:flex;flex-wrap:wrap;gap:.55rem;margin-top:1rem}.landing-pill-list span{background:var(--accent-soft);color:var(--accent);border-radius:999px;padding:.45rem .8rem;font-size:.85rem;font-weight:600}.landing-grid-two,.landing-grid-three{display:grid;gap:1rem}.landing-grid-two{grid-template-columns:repeat(2,minmax(0,1fr))}.landing-grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}.landing-featured-list{display:grid;gap:1rem}.featured-course h2,.featured-course h3{margin-bottom:.4rem}.featured-primary{border-color:#b9dfcf}.landing-status{display:inline-block;margin-bottom:.6rem;padding:.25rem .6rem;border-radius:999px;background:var(--accent-soft);color:var(--accent);font-size:.78rem;font-weight:700}.landing-status.alt{background:var(--warn-soft);color:var(--warn)}.landing-path{color:var(--ink);font-weight:600;line-height:1.7}.roadmap-card{display:flex;flex-direction:column;gap:1rem}.roadmap-header{display:flex;align-items:center;gap:.9rem}.roadmap-header h3{margin-bottom:.2rem}.roadmap-subtitle{margin:0;font-size:.92rem}.roadmap-icon{width:3rem;height:3rem;flex:0 0 3rem;display:inline-grid;place-items:center;border-radius:16px;border:1px solid transparent}.roadmap-icon svg{width:1.5rem;height:1.5rem}.roadmap-steps{display:flex;flex-wrap:wrap;gap:.7rem}.roadmap-step{display:inline-flex;align-items:center;gap:.55rem;min-height:2.5rem;padding:.45rem .8rem .45rem .5rem;border-radius:999px;background:#fff;border:1px solid var(--line);color:var(--ink)}.roadmap-step-index{width:1.5rem;height:1.5rem;border-radius:999px;display:inline-grid;place-items:center;font-size:.78rem;font-weight:700;background:var(--accent-soft);color:var(--accent)}.roadmap-step-label{font-size:.92rem;font-weight:600}.roadmap-students{background:linear-gradient(180deg,#fffaf2,#fffdf9)}.roadmap-students .roadmap-icon{background:#fff2e8;border-color:#b95f1d2e;color:#b95f1d}.roadmap-college{background:linear-gradient(180deg,#f6f8ff,#fdfdff)}.roadmap-college .roadmap-icon{background:#edf2ff;border-color:#235b9c29;color:#235b9c}.roadmap-teachers{background:linear-gradient(180deg,#f7fbf8,#fdfefd)}.roadmap-teachers .roadmap-icon{background:#edf7f0;border-color:#0f6b4c24;color:#0f6b4c}.roadmap-professionals{background:linear-gradient(180deg,#f7f5ff,#fdfcff)}.roadmap-professionals .roadmap-icon{background:#f1eeff;border-color:#6546b82e;color:#6546b8}.landing-checks{margin:0;padding-left:1.2rem;color:var(--ink)}.landing-checks li+li{margin-top:.35rem}.landing-cta-panel{text-align:center}.landing-footer{padding-bottom:1rem}.site-footer{border-top:1px solid var(--line);background:#fffdf8b3}.site-footer-grid{max-width:var(--max);margin:0 auto;padding:1.25rem;display:grid;gap:1rem;grid-template-columns:1.5fr 1fr}.footer-brand{margin-bottom:.5rem}.footer-links{display:flex;flex-wrap:wrap;gap:.6rem 1rem;align-content:flex-start}.featured-link{display:block;color:inherit;text-decoration:none}.featured-link:hover{text-decoration:none;border-color:var(--accent)}.course-card-top{display:flex;align-items:center;gap:.7rem;margin-bottom:.65rem}.course-icon{width:2.6rem;height:2.6rem;flex:0 0 2.6rem;display:inline-grid;place-items:center;border-radius:14px;background:linear-gradient(180deg,#eef7f1,#f8fbf9);color:var(--accent);border:1px solid rgba(15,107,76,.14)}.course-icon svg{width:1.35rem;height:1.35rem}.course-icon-certificate{background:linear-gradient(180deg,#eef7f1,#f8fbf9);color:#0f6b4c;border-color:#0f6b4c24}.course-icon-globe{background:linear-gradient(180deg,#eef4fb,#f8fbff);color:#235b9c;border-color:#235b9c29}.course-icon-blocks{background:linear-gradient(180deg,#fff2e9,#fff9f5);color:#b95f1d;border-color:#b95f1d2e}.course-icon-code{background:linear-gradient(180deg,#f2f0fb,#fbfaff);color:#6546b8;border-color:#6546b82e}.course-icon-spark{background:linear-gradient(180deg,#fff6df,#fffdf4);color:#b88310;border-color:#b883102e}.course-icon-table{background:linear-gradient(180deg,#eaf7f3,#f8fcfb);color:#1f8a6a;border-color:#1f8a6a29}.course-icon-lg{width:3.4rem;height:3.4rem;margin-bottom:.8rem;border-radius:18px}.course-icon-lg svg{width:1.75rem;height:1.75rem}.course-filters{display:grid;grid-template-columns:2fr repeat(4,minmax(0,1fr));gap:.8rem;margin-top:1rem}.course-search,.course-filters select{width:100%;border:1px solid var(--line);background:#fff;border-radius:12px;padding:.75rem .9rem;font:inherit;color:var(--ink)}.course-card{display:flex;flex-direction:column}.course-focus-card{position:relative;border-color:#b9dfcf;background:radial-gradient(circle at top right,rgba(216,239,228,.95) 0%,rgba(216,239,228,.2) 22%,transparent 46%),linear-gradient(180deg,#fffdf8fa,#f7fcf9fa);box-shadow:0 16px 32px #0f6b4c14}.course-focus-card:before{content:"Ưu tiên";position:absolute;top:.9rem;right:.9rem;padding:.28rem .6rem;border-radius:999px;background:#0f6b4c1a;color:var(--accent);font-size:.72rem;font-weight:700;letter-spacing:.04em}.course-focus-hero{border:1px solid #b9dfcf;border-radius:22px;padding:2rem;background:radial-gradient(circle at 88% 12%,rgba(216,239,228,.95) 0%,rgba(216,239,228,.26) 20%,transparent 45%),linear-gradient(135deg,#fffdf8fa,#f4faf6fa);box-shadow:0 16px 32px #0f6b4c14}.course-meta-list{display:grid;gap:.5rem;color:var(--ink-muted);font-size:.92rem}.course-hero{padding-bottom:1rem}.faq-list{display:grid;gap:1rem}.faq-item p{margin-top:.4rem}.related-links{display:flex;flex-wrap:wrap;gap:.75rem;margin:.6rem 0 1rem}.related-links a{border:1px solid var(--line);background:#fff;color:var(--ink);border-radius:999px;padding:.55rem .85rem;text-decoration:none}.related-links a:hover{border-color:var(--accent);color:var(--accent)}.lesson-card .progress-bar{margin:.65rem 0 0}.lesson-layout{display:grid;grid-template-columns:minmax(200px,260px) 1fr;gap:1.25rem;align-items:start}.lesson-layout.is-fullscreen{box-sizing:border-box;width:100%;height:100%;overflow:auto;padding:1.25rem 1.5rem 2rem;background:radial-gradient(ellipse 80% 50% at 10% -10%,#e7f3ec 0%,transparent 55%),radial-gradient(ellipse 60% 40% at 100% 0%,#efe6d4 0%,transparent 50%),var(--bg)}.lesson-layout.is-fullscreen .lesson-toc{top:1rem;max-height:calc(100vh - 2rem);overflow:auto}.lesson-layout.is-fullscreen .lesson-main{max-width:920px}.lesson-toc{position:sticky;top:4.5rem}.lesson-toc-list{display:flex;flex-direction:column;gap:.35rem;margin:1rem 0}.lesson-toc-item{display:flex;gap:.55rem;align-items:flex-start;text-align:left;border:1px solid transparent;background:transparent;border-radius:10px;padding:.55rem .6rem;font:inherit;font-size:.9rem;color:var(--ink-muted);cursor:pointer}.lesson-toc-item span{flex:0 0 1.4rem;height:1.4rem;border-radius:50%;background:var(--bg);border:1px solid var(--line);display:grid;place-items:center;font-size:.75rem;font-weight:700}.lesson-toc-item.active{background:var(--accent-soft);color:var(--accent);border-color:transparent}.lesson-toc-item.done span{background:var(--accent);color:#fff;border-color:var(--accent)}.lesson-focus ul{margin:0;padding-left:1.1rem;color:var(--ink);font-size:.88rem}.lesson-content>*+*{margin-top:1rem}.lesson-text{color:var(--ink);font-size:1.02rem}.lesson-bullets{margin:0;padding-left:1.2rem;color:var(--ink)}.lesson-callout{border-radius:12px;padding:.9rem 1rem;border:1px solid var(--line)}.lesson-callout p{margin:.35rem 0 0;color:inherit}.lesson-callout.tone-exam{background:var(--accent-soft);color:var(--accent);border-color:transparent}.lesson-callout.tone-tip{background:#e8eef8;color:#1e3a5f;border-color:transparent}.lesson-callout.tone-warn{background:var(--warn-soft);color:var(--warn);border-color:transparent}.lesson-diagram{background:linear-gradient(180deg,#f7faf7,#fff);border:1px solid var(--line);border-radius:14px;padding:1rem}.lesson-diagram-title{font-weight:600;margin-bottom:.85rem;color:var(--ink)}.lesson-diagram-nodes{display:flex;flex-wrap:wrap;gap:.65rem}.layout-stack .lesson-diagram-nodes{flex-direction:column}.layout-flow .lesson-node{display:flex;align-items:center;gap:.45rem}.lesson-node-card{background:#fff;border:1px solid var(--line);border-radius:12px;padding:.7rem .85rem;min-width:120px;animation:lesson-pop .45s ease both}.lesson-node-label{font-weight:600;color:var(--ink)}.lesson-arrow:before{content:"→";color:var(--accent);font-weight:700}.layout-stack .lesson-arrow:before{content:"↓"}.lesson-steps{list-style:none;margin:0;padding:0;display:grid;gap:.75rem}.lesson-steps li{display:flex;gap:.75rem;align-items:flex-start}.lesson-steps p{margin:.2rem 0 0}.lesson-step-num{flex:0 0 1.8rem;height:1.8rem;border-radius:50%;background:var(--accent);color:#fff;display:grid;place-items:center;font-weight:700;font-size:.85rem}.lesson-keys{display:grid;gap:.45rem}.lesson-key-row{display:grid;grid-template-columns:minmax(140px,200px) 1fr;gap:.75rem;align-items:center;padding:.45rem 0;border-bottom:1px dashed var(--line);color:var(--ink)}.lesson-key-row kbd{display:inline-block;font-family:var(--font);font-weight:600;font-size:.85rem;background:var(--ink);color:#fff;padding:.35rem .55rem;border-radius:8px}.lesson-formula{display:grid;gap:.35rem;background:#1c2a22;color:#e7f3ec;border-radius:12px;padding:.85rem 1rem}.lesson-formula code{font-family:ui-monospace,Consolas,monospace;font-size:.95rem;color:#b8f0d4}.lesson-formula span{font-size:.88rem;opacity:.9}.lesson-practice h4{margin:0 0 .5rem;font-family:var(--font)}.lesson-exercise,.lesson-case{border:1px solid var(--line);border-radius:14px;background:#fff;padding:1rem}.lesson-exercise h4,.lesson-case h4,.lesson-reveal-body h4{margin:0 0 .5rem;font-family:var(--font);color:var(--ink)}.lesson-case-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:1rem;margin:.75rem 0 .5rem}.lesson-sheet{margin:.9rem 0 .3rem}.lesson-sheet-title{font-weight:600;color:var(--ink);margin-bottom:.5rem}.lesson-sheet-wrap{overflow:auto;border:1px solid var(--line);border-radius:12px;background:#fff}.lesson-sheet-table{width:100%;border-collapse:collapse;min-width:560px;font-size:.88rem}.lesson-sheet-table th,.lesson-sheet-table td{padding:.55rem .6rem;border-right:1px solid #e5e0d5;border-bottom:1px solid #e5e0d5;white-space:nowrap}.lesson-sheet-table th{background:#eef5ef;color:var(--ink);text-align:left;font-weight:700}.lesson-reveal{margin-top:.85rem}.lesson-reveal-body{margin-top:.75rem;padding:.85rem 1rem;border-radius:12px;background:#f7faf7;border:1px dashed var(--line)}.lesson-check-dot{width:.7rem;height:.7rem;margin-top:.4rem;border-radius:50%;border:2px solid var(--accent);flex-shrink:0}.lesson-quiz{border:1px solid var(--line);border-radius:14px;padding:1rem;background:#fff}.lesson-quiz-q{font-weight:600;color:var(--ink);margin-bottom:.75rem}@keyframes lesson-pop{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}@media(max-width:640px){.topbar-inner{align-items:flex-start}.nav-toggle{display:inline-flex}.nav{display:none;width:100%;flex-direction:column;align-items:flex-start;gap:.5rem;padding-top:.75rem}.nav.nav-open{display:flex}.site-footer-grid,.course-filters,.landing-grid-two,.landing-grid-three{grid-template-columns:1fr}.landing-hero{padding:2rem 1.2rem;border-radius:20px}.course-focus-hero{padding:1.4rem 1.2rem}.landing-hero:before{width:72%;right:-20%}.landing-hero:after{width:52%;height:24%;right:-6%;bottom:7%}.score-hero .score{font-size:2.5rem}.lesson-layout{grid-template-columns:1fr}.lesson-toc{position:static}.lesson-key-row{grid-template-columns:1fr}.layout-flow .lesson-diagram-nodes{flex-direction:column}.layout-flow .lesson-arrow:before{content:"↓"}}
