/* ===== 4F Hackathon LMS — style ===== */
:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --surface-2: #eef2f7;
  --text: #1c2733;
  --text-soft: #5b6b7c;
  --border: #dce3ec;
  --primary: #1a4d7a;
  --primary-soft: #e7f0f8;
  --accent: #f0ad4e;
  --green: #2e9e5b;
  --green-soft: #e3f4ea;
  --shadow: 0 1px 3px rgba(20,40,70,.08), 0 6px 20px rgba(20,40,70,.06);
  --radius: 14px;
  --topbar-h: 58px;
  --sidebar-w: 300px;
  --mono: ui-monospace, "Cascadia Code", "Consolas", monospace;
  --sans: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
}
[data-theme="dark"] {
  --bg: #0f151c;
  --surface: #172230;
  --surface-2: #1e2b3a;
  --text: #e6edf5;
  --text-soft: #9fb0c2;
  --border: #2a3a4d;
  --primary: #5aa6e0;
  --primary-soft: #16324a;
  --accent: #e6a648;
  --green: #4cc47e;
  --green-soft: #14312e;
  --shadow: 0 1px 3px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.35);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: var(--sans); font-size: 16px; line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== Topbar ===== */
.topbar {
  position: sticky; top: 0; z-index: 50;
  height: var(--topbar-h); display: flex; align-items: center; gap: 14px;
  padding: 0 16px; background: var(--surface); border-bottom: 1px solid var(--border);
  box-shadow: 0 1px 0 rgba(0,0,0,.02);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: grid; place-items: center; width: 34px; height: 34px; border-radius: 9px;
  background: linear-gradient(135deg, var(--primary), #2f6da3); color: #fff; font-weight: 800; font-size: 14px;
}
.brand-text { font-size: 15px; letter-spacing: .2px; }
.search-wrap { position: relative; flex: 1; max-width: 460px; margin: 0 auto; }
#searchInput {
  width: 100%; height: 38px; padding: 0 14px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--surface-2); color: var(--text);
  font-size: 14px; font-family: var(--sans); outline: none;
}
#searchInput:focus { border-color: var(--primary); background: var(--surface); }
.search-results {
  position: absolute; top: 44px; left: 0; right: 0; max-height: 60vh; overflow-y: auto;
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
  box-shadow: var(--shadow); padding: 6px;
}
.search-results .sr-item { display: block; padding: 8px 10px; border-radius: 8px; color: var(--text); }
.search-results .sr-item:hover, .search-results .sr-item.active { background: var(--primary-soft); text-decoration: none; }
.search-results .sr-course { font-size: 11px; color: var(--text-soft); text-transform: uppercase; letter-spacing: .5px; }
.search-results .sr-empty { padding: 12px; color: var(--text-soft); font-size: 14px; }

.topbar-actions { display: flex; align-items: center; gap: 12px; }
.icon-btn {
  display: grid; place-items: center; width: 38px; height: 38px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--surface-2); color: var(--text);
  font-size: 17px; cursor: pointer; transition: background .15s;
}
.icon-btn:hover { background: var(--primary-soft); }
.menu-btn { display: none; }

/* Vòng tiến độ tổng */
.overall-progress { position: relative; width: 40px; height: 40px; display: grid; place-items: center; }
.overall-progress .ring { width: 40px; height: 40px; transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: var(--surface-2); stroke-width: 3.2; }
.ring-fg { fill: none; stroke: var(--green); stroke-width: 3.2; stroke-linecap: round;
  stroke-dasharray: 97.4; stroke-dashoffset: 97.4; transition: stroke-dashoffset .5s ease; }
#overallPct { position: absolute; font-size: 10px; font-weight: 700; color: var(--text-soft); }

/* ===== Layout ===== */
.layout { display: flex; align-items: flex-start; }
.sidebar {
  position: sticky; top: var(--topbar-h); width: var(--sidebar-w); flex: 0 0 var(--sidebar-w);
  height: calc(100vh - var(--topbar-h)); overflow-y: auto;
  background: var(--surface); border-right: 1px solid var(--border); padding: 16px 12px;
}
.sidebar:empty { display: none; }
.main { flex: 1; min-width: 0; padding: 28px clamp(16px, 5vw, 64px) 80px; }
.sidebar-scrim { display: none; }

/* ===== Sidebar nội dung ===== */
.sb-course-head { padding: 6px 10px 14px; }
.sb-course-head .sb-back { font-size: 13px; color: var(--text-soft); display: inline-flex; gap: 5px; align-items: center; }
.sb-course-head h3 { margin: 10px 0 8px; font-size: 16px; line-height: 1.3; }
.sb-progress-bar { height: 7px; border-radius: 5px; background: var(--surface-2); overflow: hidden; }
.sb-progress-bar > span { display: block; height: 100%; background: var(--green); border-radius: 5px; transition: width .4s; }
.sb-progress-label { font-size: 12px; color: var(--text-soft); margin-top: 6px; }
.sb-list { list-style: none; margin: 8px 0 0; padding: 0; }
.sb-list li a {
  display: flex; align-items: center; gap: 9px; padding: 9px 10px; border-radius: 9px;
  color: var(--text); font-size: 14px; line-height: 1.35;
}
.sb-list li a:hover { background: var(--surface-2); text-decoration: none; }
.sb-list li a.active { background: var(--primary-soft); color: var(--primary); font-weight: 600; }
.sb-check {
  flex: 0 0 18px; width: 18px; height: 18px; border-radius: 50%; border: 2px solid var(--border);
  display: grid; place-items: center; font-size: 11px; color: transparent;
}
.sb-list li.done .sb-check { background: var(--green); border-color: var(--green); color: #fff; }
.sb-num { flex: 0 0 auto; color: var(--text-soft); font-size: 12px; font-variant-numeric: tabular-nums; }
.sb-list li.done .sb-title { color: var(--text-soft); }

/* ===== Home ===== */
.hero { margin-bottom: 28px; }
.hero h1 { font-size: clamp(24px, 4vw, 34px); margin: 0 0 8px; letter-spacing: -.5px; }
.hero p { color: var(--text-soft); margin: 0; max-width: 60ch; }
.hero-stats { display: flex; gap: 22px; margin-top: 18px; flex-wrap: wrap; }
.hero-stats .stat { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 12px 18px; box-shadow: var(--shadow); }
.hero-stats .stat b { display: block; font-size: 22px; color: var(--primary); }
.hero-stats .stat span { font-size: 12px; color: var(--text-soft); }

.section-title { font-size: 14px; text-transform: uppercase; letter-spacing: 1px; color: var(--text-soft); margin: 32px 0 14px; }
.course-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 18px; }
.course-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px; box-shadow: var(--shadow); cursor: pointer; transition: transform .15s, box-shadow .15s;
  display: flex; flex-direction: column; gap: 12px;
}
.course-card:hover { transform: translateY(-3px); box-shadow: 0 8px 30px rgba(20,40,70,.14); }
.course-card .cc-top { display: flex; align-items: center; gap: 12px; }
.course-card .cc-icon { font-size: 30px; }
.course-card .cc-level {
  font-size: 11px; font-weight: 700; letter-spacing: .5px; padding: 3px 9px; border-radius: 20px;
  background: var(--primary-soft); color: var(--primary); margin-left: auto;
}
.course-card h3 { margin: 0; font-size: 18px; line-height: 1.3; }
.course-card p { margin: 0; color: var(--text-soft); font-size: 14px; flex: 1; }
.cc-meta { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--text-soft); }
.cc-bar { height: 6px; border-radius: 4px; background: var(--surface-2); overflow: hidden; }
.cc-bar > span { display: block; height: 100%; background: var(--green); transition: width .4s; }
.cc-done-badge { color: var(--green); font-weight: 700; }
.res-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.res-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 16px;
  cursor: pointer; display: flex; gap: 12px; align-items: flex-start; transition: background .15s;
}
.res-card:hover { background: var(--surface-2); }
.res-card .rc-icon { font-size: 24px; }
.res-card h4 { margin: 0 0 4px; font-size: 15px; }
.res-card p { margin: 0; font-size: 13px; color: var(--text-soft); }

.hero-cta { display: flex; gap: 12px; margin-top: 18px; flex-wrap: wrap; }

/* ===== Roadmap ===== */
.roadmap-wrap { max-width: 900px; margin: 0 auto; }
.roadmap-steps { display: flex; flex-direction: column; gap: 16px; }
.rm-step { display: flex; gap: 16px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); }
.rm-step-no { flex: 0 0 40px; width: 40px; height: 40px; border-radius: 50%; display: grid; place-items: center; font-weight: 800; font-size: 18px; background: var(--primary); color: #fff; }
.rm-step-body { flex: 1; min-width: 0; }
.rm-step-head { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.rm-step-head .cc-icon { font-size: 24px; }
.rm-step-head h3 { margin: 0; font-size: 18px; }
.rm-step-head .cc-level { margin-left: auto; }
.rm-outcome { margin: 6px 0 12px; color: var(--text-soft); font-size: 14.5px; }
.rm-step-meta { font-size: 12px; color: var(--text-soft); margin: 8px 0 14px; }
.rm-kit { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); }
.rm-kit p { margin: 0 0 14px; color: var(--text-soft); }
.rm-kit .res-grid { margin-top: 16px; }
.btn.big { font-size: 15px; padding: 13px 22px; }
.rm-guide { margin-top: 28px; background: var(--primary-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 8px 22px 18px; }
.rm-guide ul { margin: 0; padding-left: 1.2em; }
.rm-guide li { margin: .5em 0; font-size: 14.5px; }

/* Banner tải kit trong bài học */
.kit-banner { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; background: var(--primary-soft); border: 1px solid var(--border); border-radius: 12px; padding: 12px 16px; margin-bottom: 20px; font-size: 14px; }
.kit-banner span { flex: 1; min-width: 200px; color: var(--text-soft); }
.kit-path { font-size: 13px; color: var(--text-soft); margin: 0 0 10px; }

/* ===== Trang bài học ===== */
.lesson-wrap { max-width: 820px; margin: 0 auto; }
.lesson-bc { font-size: 13px; color: var(--text-soft); margin-bottom: 10px; }
.lesson-bc a { color: var(--text-soft); }
.lesson-meta { display: flex; align-items: center; gap: 14px; font-size: 13px; color: var(--text-soft); margin-bottom: 22px; padding-bottom: 16px; border-bottom: 1px solid var(--border); }
.lesson-meta .badge { padding: 2px 9px; border-radius: 20px; background: var(--primary-soft); color: var(--primary); font-weight: 700; font-size: 11px; }

/* Prose */
.prose { font-size: 16.5px; line-height: 1.72; }
.prose > *:first-child { margin-top: 0; }
.prose h1 { font-size: 28px; line-height: 1.25; margin: 0 0 18px; letter-spacing: -.4px; }
.prose h2 { font-size: 22px; margin: 1.8em 0 .6em; padding-bottom: 6px; border-bottom: 1px solid var(--border); }
.prose h3 { font-size: 18px; margin: 1.5em 0 .5em; color: var(--text); }
.prose h4 { font-size: 16px; margin: 1.3em 0 .4em; }
.prose p { margin: .8em 0; }
.prose ul, .prose ol { padding-left: 1.5em; margin: .7em 0; }
.prose li { margin: .35em 0; }
.prose code { font-family: var(--mono); font-size: .88em; background: var(--surface-2); padding: 2px 6px; border-radius: 5px; }
.prose pre { background: var(--surface-2); border: 1px solid var(--border); border-left: 3px solid var(--primary); border-radius: 10px; padding: 14px 16px; overflow-x: auto; margin: 1em 0; }
.prose pre code { background: none; padding: 0; font-size: 13.5px; line-height: 1.55; }
.prose blockquote { margin: 1em 0; padding: 10px 18px; border-left: 4px solid var(--accent); background: color-mix(in srgb, var(--accent) 10%, transparent); border-radius: 0 8px 8px 0; color: var(--text-soft); }
.prose blockquote p { margin: .3em 0; }
.prose table { border-collapse: collapse; width: 100%; margin: 1.1em 0; font-size: 14.5px; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--border); padding: 8px 11px; text-align: left; vertical-align: top; }
.prose th { background: var(--surface-2); font-weight: 700; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 1.8em 0; }
.prose a { text-decoration: underline; text-underline-offset: 2px; }
.prose img { max-width: 100%; }

/* Nav dưới bài */
.lesson-nav { display: flex; gap: 14px; margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--border); flex-wrap: wrap; align-items: center; }
.btn {
  display: inline-flex; align-items: center; gap: 8px; padding: 11px 18px; border-radius: 11px;
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  font-size: 14px; font-weight: 600; cursor: pointer; font-family: var(--sans); transition: all .15s;
}
.btn:hover { background: var(--surface-2); text-decoration: none; }
.btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.done-toggle.is-done { background: var(--green-soft); border-color: var(--green); color: var(--green); }
.btn.ghost { border: none; background: none; color: var(--text-soft); }
.lesson-nav .spacer { flex: 1; }
.btn[disabled] { opacity: .4; pointer-events: none; }

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .menu-btn { display: grid; }
  .brand-text { display: none; }
  .sidebar {
    position: fixed; left: 0; top: var(--topbar-h); z-index: 40;
    transform: translateX(-100%); transition: transform .25s; box-shadow: var(--shadow);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar:empty { display: block; }
  .sidebar-scrim.show { display: block; position: fixed; inset: var(--topbar-h) 0 0; background: rgba(0,0,0,.4); z-index: 39; }
  .search-wrap { max-width: none; }
}
@media (max-width: 560px) {
  .hero-stats { gap: 12px; }
  .topbar { gap: 10px; padding: 0 12px; }
  .main { padding: 20px 16px 60px; }
}
/* Cuộn mượt + thanh cuộn */
.sidebar::-webkit-scrollbar, .search-results::-webkit-scrollbar { width: 8px; }
.sidebar::-webkit-scrollbar-thumb, .search-results::-webkit-scrollbar-thumb { background: var(--border); border-radius: 8px; }
mark { background: var(--accent); color: #1c2733; border-radius: 3px; padding: 0 2px; }