/* ==========================================================================
   HDMOOC — Kỹ năng Help Desk cho Người mới Bắt đầu
   Bộ style dùng chung cho toàn bộ website
   ========================================================================== */

/* ---------- Biến & Reset ---------- */
:root {
  --primary: #2453e6;
  --primary-dark: #1a3fb8;
  --primary-deep: #12309c;
  --primary-soft: #e9efff;
  --navy: #0b1b3a;
  --navy-2: #14307a;
  --accent: #ffb020;
  --accent-soft: #fff3d6;
  --bg: #f4f7fd;
  --card: #ffffff;
  --text: #1e2a44;
  --muted: #5b6b8c;
  --border: #e3e9f4;
  --success: #16a34a;
  --success-soft: #e7f7ee;
  --danger: #dc2626;
  --danger-soft: #fdeaea;
  --warn: #d97706;
  --warn-soft: #fdf1e0;
  --radius: 14px;
  --radius-lg: 20px;
  --shadow: 0 4px 18px rgba(15, 30, 70, 0.08);
  --shadow-lg: 0 16px 44px rgba(15, 30, 70, 0.16);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: none; }
::selection { background: var(--primary); color: #fff; }

.container { max-width: 1180px; margin: 0 auto; padding: 0 22px; }

/* ---------- Nút ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 24px; border-radius: 999px; border: 2px solid transparent;
  font: inherit; font-weight: 600; font-size: 15px; cursor: pointer;
  transition: all .18s ease; white-space: nowrap; line-height: 1.3;
}
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 6px 16px rgba(36, 83, 230, .32); }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); }
.btn-outline { background: transparent; border-color: var(--border); color: var(--text); }
.btn-outline:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-soft); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #12813b; }
.btn-ghost { background: rgba(255,255,255,.12); border-color: rgba(255,255,255,.45); color: #fff; }
.btn-ghost:hover { background: rgba(255,255,255,.22); }
.btn-sm { padding: 8px 18px; font-size: 13.5px; }
.btn-lg { padding: 15px 34px; font-size: 16.5px; }
.btn[disabled] { opacity: .45; cursor: not-allowed; transform: none !important; }

/* ---------- Card ---------- */
.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); box-shadow: var(--shadow);
}

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 60;
  background: rgba(255,255,255,.92); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; gap: 26px; height: 66px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 20px; color: var(--navy); }
.brand svg { width: 34px; height: 34px; }
.brand em { font-style: normal; color: var(--primary); }
.main-nav { display: flex; gap: 4px; margin-left: 6px; }
.main-nav a {
  padding: 8px 14px; border-radius: 999px; color: var(--muted);
  font-weight: 600; font-size: 14.5px; transition: all .15s;
}
.main-nav a:hover { color: var(--primary); background: var(--primary-soft); }
.main-nav a.active { color: #fff; background: var(--primary); }
.header-right { margin-left: auto; display: flex; align-items: center; gap: 14px; }
.progress-pill {
  position: relative; width: 120px; height: 32px; border-radius: 999px;
  background: var(--border); overflow: hidden; display: flex; align-items: center;
  justify-content: center; flex: none;
}
.pp-fill { position: absolute; inset: 0; width: 0%; background: linear-gradient(90deg, var(--primary), #5b86ff); transition: width .4s; }
.pp-text { position: relative; z-index: 1; font-size: 12.5px; font-weight: 700; color: var(--navy); }
.nav-toggle { display: none; background: none; border: 1.5px solid var(--border); border-radius: 10px; font-size: 20px; padding: 4px 10px; cursor: pointer; color: var(--navy); }

/* ---------- Hero ---------- */
.hero {
  position: relative; overflow: hidden; color: #fff;
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-2) 48%, #1d47c9 100%);
}
.hero::before, .hero::after {
  content: ""; position: absolute; border-radius: 50%; pointer-events: none;
}
.hero::before { width: 520px; height: 520px; right: -140px; top: -180px; background: radial-gradient(circle, rgba(91,134,255,.35), transparent 65%); }
.hero::after { width: 420px; height: 420px; left: -160px; bottom: -200px; background: radial-gradient(circle, rgba(255,176,32,.18), transparent 65%); }
.hero-inner { position: relative; z-index: 1; padding: 64px 0 70px; max-width: 860px; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--accent); color: #3a2a00; font-weight: 700; font-size: 12.5px;
  letter-spacing: 1.4px; text-transform: uppercase;
  padding: 7px 16px; border-radius: 999px; margin-bottom: 20px;
}
.hero h1 { font-size: clamp(30px, 4.6vw, 48px); line-height: 1.18; font-weight: 800; letter-spacing: -.5px; }
.hero h1 span { color: #ffd479; }
.hero-sub { margin: 18px 0 10px; font-size: 17.5px; color: #cfdcff; max-width: 720px; }
.hero-short {
  margin-top: 18px; padding: 16px 20px; border-left: 4px solid var(--accent);
  background: rgba(255,255,255,.08); border-radius: 0 12px 12px 0;
  font-size: 15.5px; color: #e6edff; max-width: 760px;
}
.hero-chips { display: flex; flex-wrap: wrap; gap: 10px; margin: 24px 0 30px; }
.chip {
  display: inline-flex; align-items: center; gap: 7px; font-size: 13.5px; font-weight: 600;
  padding: 7px 15px; border-radius: 999px;
  background: rgba(255,255,255,.1); border: 1px solid rgba(255,255,255,.25);
}
.hero-ctas { display: flex; flex-wrap: wrap; gap: 14px; }

/* ---------- Stats ---------- */
.stats-band { margin-top: -34px; position: relative; z-index: 5; padding-bottom: 8px; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.stat-card { padding: 22px 20px; text-align: center; }
.stat-card b { display: block; font-size: 30px; font-weight: 800; color: var(--primary); line-height: 1.15; }
.stat-card span { font-size: 13.5px; color: var(--muted); font-weight: 600; }

/* ---------- Sections ---------- */
.section { padding: 64px 0 10px; }
.section-head { max-width: 720px; margin-bottom: 34px; }
.section-kicker { color: var(--primary); font-weight: 700; font-size: 13px; letter-spacing: 1.6px; text-transform: uppercase; margin-bottom: 8px; }
.section-head h2 { font-size: clamp(24px, 3vw, 32px); font-weight: 800; color: var(--navy); letter-spacing: -.3px; }
.section-head p { margin-top: 10px; color: var(--muted); font-size: 16px; }

/* ---------- Outcomes ---------- */
.outcomes-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.outcome {
  display: flex; gap: 13px; align-items: flex-start;
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 17px 19px; box-shadow: var(--shadow);
}
.outcome .ic {
  flex: none; width: 30px; height: 30px; border-radius: 9px; margin-top: 2px;
  background: var(--success-soft); color: var(--success);
  display: flex; align-items: center; justify-content: center; font-weight: 800; font-size: 15px;
}
.outcome p { font-size: 15px; font-weight: 500; }

/* ---------- Curriculum ---------- */
.curriculum { display: flex; flex-direction: column; gap: 14px; }
details.module { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
details.module summary {
  list-style: none; cursor: pointer; display: flex; align-items: center; gap: 16px;
  padding: 20px 22px; transition: background .15s;
}
details.module summary::-webkit-details-marker { display: none; }
details.module summary:hover { background: var(--primary-soft); }
details.module[open] summary { border-bottom: 1px solid var(--border); background: #fafbff; }
.mod-num {
  flex: none; width: 44px; height: 44px; border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), #5b86ff); color: #fff;
  display: flex; align-items: center; justify-content: center; font-weight: 800; font-size: 18px;
}
.mod-info { flex: 1; }
.mod-info h3 { font-size: 17px; font-weight: 700; color: var(--navy); }
.mod-info span { font-size: 13px; color: var(--muted); font-weight: 600; }
.mod-chev { flex: none; color: var(--muted); font-size: 13px; transition: transform .2s; }
details.module[open] .mod-chev { transform: rotate(180deg); }
.lesson-row {
  display: flex; align-items: center; gap: 14px; padding: 13px 22px 13px 26px;
  border-bottom: 1px solid #f0f3fa; color: var(--text);
}
.lesson-row:last-child { border-bottom: none; }
.lesson-row:hover { background: var(--primary-soft); color: var(--primary); }
.lesson-idx { flex: none; width: 26px; height: 26px; border-radius: 50%; background: var(--border); color: var(--muted); font-size: 12.5px; font-weight: 700; display: flex; align-items: center; justify-content: center; }
.lesson-row .lr-title { flex: 1; font-size: 14.5px; font-weight: 500; }
.lesson-row .lr-dur { flex: none; font-size: 12.5px; color: var(--muted); font-weight: 600; }

/* ---------- Exam promo ---------- */
.exam-promo {
  display: grid; grid-template-columns: 1.6fr 1fr; gap: 0; overflow: hidden;
  background: linear-gradient(120deg, var(--primary-deep), var(--primary) 70%);
  color: #fff; border-radius: var(--radius-lg); box-shadow: var(--shadow-lg);
}
.exam-left { padding: 40px 42px; }
.exam-left h2 { font-size: 26px; font-weight: 800; margin-bottom: 8px; }
.exam-left > p { color: #cfdefd; margin-bottom: 18px; font-size: 15.5px; }
.exam-rules { list-style: none; display: grid; gap: 10px; }
.exam-rules li { display: flex; gap: 10px; align-items: flex-start; font-size: 15px; }
.exam-rules .tick { flex: none; width: 22px; height: 22px; margin-top: 2px; border-radius: 50%; background: rgba(255,255,255,.16); display: flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 800; color: #ffd479; }
.exam-right {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px;
  background: rgba(255,255,255,.07); border-left: 1px solid rgba(255,255,255,.14); padding: 30px;
}
.exam-right .big { font-size: clamp(60px, 7vw, 96px); font-weight: 800; line-height: 1; color: #ffd479; }
.exam-right .lbl { font-size: 14px; font-weight: 700; letter-spacing: 2px; text-transform: uppercase; color: #cfdefd; }
.exam-right .sub { font-size: 13px; color: #9fb6ec; margin-top: 6px; text-align: center; }

/* ---------- Audience ---------- */
.audience-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.aud-card { padding: 28px 24px; text-align: left; }
.aud-card .emo { font-size: 34px; margin-bottom: 12px; }
.aud-card h3 { font-size: 17px; font-weight: 700; color: var(--navy); margin-bottom: 8px; }
.aud-card p { font-size: 14.5px; color: var(--muted); }

/* ---------- FAQ ---------- */
.faq-list { display: flex; flex-direction: column; gap: 12px; max-width: 860px; }
details.faq { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 0 22px; box-shadow: var(--shadow); }
details.faq summary { cursor: pointer; list-style: none; font-weight: 700; font-size: 15.5px; padding: 17px 0; color: var(--navy); display: flex; justify-content: space-between; gap: 14px; }
details.faq summary::-webkit-details-marker { display: none; }
details.faq summary::after { content: "+"; color: var(--primary); font-size: 20px; font-weight: 600; flex: none; }
details.faq[open] summary::after { content: "–"; }
details.faq .faq-body { padding: 0 0 18px; color: var(--muted); font-size: 15px; }

/* ---------- CTA banner ---------- */
.cta-banner {
  margin: 70px 0 0; border-radius: var(--radius-lg); overflow: hidden; position: relative;
  background: linear-gradient(120deg, var(--navy), var(--navy-2));
  color: #fff; text-align: center; padding: 56px 30px;
}
.cta-banner h2 { font-size: clamp(24px, 3vw, 32px); font-weight: 800; margin-bottom: 10px; }
.cta-banner p { color: #c2cfe8; margin-bottom: 26px; font-size: 16px; }

/* ---------- Footer ---------- */
.site-footer { margin-top: 70px; background: var(--navy); color: #aab8d8; }
.footer-inner { padding: 46px 0 30px; display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 34px; }
.footer-inner h4 { color: #fff; font-size: 15px; margin-bottom: 12px; }
.footer-inner a { display: block; color: #aab8d8; font-size: 14px; padding: 3.5px 0; }
.footer-inner a:hover { color: #fff; }
.footer-brand { display: flex; align-items: center; gap: 10px; color: #fff; font-weight: 800; font-size: 19px; margin-bottom: 12px; }
.footer-brand svg { width: 30px; height: 30px; }
.footer-note { font-size: 13.5px; line-height: 1.7; max-width: 420px; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.12); padding: 18px 0; font-size: 13px; display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }

/* ==========================================================================
   TRANG KHÓA HỌC (course.html)
   ========================================================================== */
.course-wrap { padding: 34px 22px 70px; }
.course-top { display: flex; align-items: flex-end; justify-content: space-between; gap: 24px; flex-wrap: wrap; margin-bottom: 22px; }
.crumb { font-size: 13.5px; color: var(--muted); margin-bottom: 6px; }
.crumb a { color: var(--muted); font-weight: 600; }
.crumb a:hover { color: var(--primary); }
.course-top h1 { font-size: clamp(22px, 3vw, 30px); font-weight: 800; color: var(--navy); }
.course-progress-box { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 18px; min-width: 280px; box-shadow: var(--shadow); }
.cp-row { display: flex; justify-content: space-between; font-size: 13.5px; font-weight: 600; color: var(--muted); margin-bottom: 7px; }
.cp-row strong { color: var(--primary); font-size: 15px; }
.cp-bar { height: 9px; border-radius: 999px; background: var(--border); overflow: hidden; }
.cp-bar span { display: block; height: 100%; width: 0%; border-radius: 999px; background: linear-gradient(90deg, var(--primary), #5b86ff); transition: width .4s; }
.cp-note { font-size: 12px; color: var(--muted); margin-top: 7px; }

.course-layout { display: grid; grid-template-columns: 330px minmax(0, 1fr); gap: 24px; align-items: start; }

/* Sidebar */
.course-sidebar { position: sticky; top: 86px; max-height: calc(100vh - 110px); overflow-y: auto; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius-lg); box-shadow: var(--shadow); }
.sb-head { padding: 15px 20px 11px; font-size: 12px; font-weight: 800; letter-spacing: 1.6px; color: var(--muted); }
.sb-module { padding-bottom: 6px; }
.sb-mod-title { display: flex; align-items: center; gap: 9px; padding: 10px 18px 6px; font-size: 13px; font-weight: 700; color: var(--navy); }
.sb-mod-num { flex: none; width: 22px; height: 22px; border-radius: 7px; background: var(--primary-soft); color: var(--primary); font-size: 11.5px; font-weight: 800; display: flex; align-items: center; justify-content: center; }
.sb-lesson { display: flex; align-items: center; gap: 11px; padding: 9px 18px; color: var(--muted); border-left: 3px solid transparent; }
.sb-lesson:hover { background: var(--primary-soft); color: var(--primary); }
.sb-lesson.active { background: var(--primary-soft); color: var(--primary); border-left-color: var(--primary); font-weight: 700; }
.sb-lesson.done { color: var(--text); }
.sb-check { flex: none; width: 22px; height: 22px; border-radius: 50%; background: var(--border); color: var(--muted); font-size: 11px; font-weight: 700; display: flex; align-items: center; justify-content: center; }
.sb-lesson.done .sb-check { background: var(--success); color: #fff; }
.sb-title { flex: 1; font-size: 13.5px; line-height: 1.4; }
.sb-dur { flex: none; font-size: 11.5px; color: var(--muted); font-weight: 600; }
.quiz-link { display: block; margin: 10px 14px 16px; padding: 12px 16px; border-radius: 12px; background: linear-gradient(120deg, var(--primary-deep), var(--primary)); color: #fff; font-size: 13.5px; font-weight: 700; text-align: center; }
.quiz-link:hover { opacity: .92; }

/* Lesson panel */
.lesson-panel { padding: 34px 38px 28px; min-height: 540px; }
.lesson-kicker { font-size: 12px; font-weight: 800; letter-spacing: 1.6px; text-transform: uppercase; color: var(--primary); margin-bottom: 8px; }
.lesson-panel h2 { font-size: clamp(22px, 2.6vw, 29px); font-weight: 800; color: var(--navy); letter-spacing: -.3px; margin-bottom: 10px; }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 22px; }
.lesson-meta span { font-size: 12.5px; font-weight: 600; color: var(--muted); background: var(--bg); border: 1px solid var(--border); padding: 4px 12px; border-radius: 999px; }
.lesson-body { font-size: 16px; color: #2a3652; }
.lesson-body h3 { position: relative; font-size: 20px; font-weight: 700; color: var(--navy); margin: 30px 0 12px; padding-left: 14px; }
.lesson-body h3::before { content: ""; position: absolute; left: 0; top: 5px; bottom: 5px; width: 4px; border-radius: 4px; background: linear-gradient(var(--primary), #5b86ff); }
.lesson-body p { margin-bottom: 14px; }
.lesson-body ul, .lesson-body ol { margin: 0 0 16px 20px; display: grid; gap: 8px; }
.lesson-body li strong { color: var(--navy); }
.lesson-body table { width: 100%; border-collapse: collapse; margin: 6px 0 20px; font-size: 14.5px; background: #fff; border-radius: 12px; overflow: hidden; box-shadow: var(--shadow); }
.lesson-body th { background: var(--navy); color: #fff; text-align: left; padding: 11px 14px; font-size: 13.5px; }
.lesson-body td { padding: 11px 14px; border-bottom: 1px solid #eef2fa; vertical-align: top; }
.lesson-body tr:last-child td { border-bottom: none; }
.lesson-body code { background: var(--primary-soft); color: var(--primary-dark); font-size: 13.5px; padding: 2px 7px; border-radius: 6px; }

.callout { display: flex; gap: 12px; background: var(--primary-soft); border-left: 4px solid var(--primary); border-radius: 0 12px 12px 0; padding: 15px 18px; margin: 18px 0; font-size: 15px; }
.callout.warn { background: var(--warn-soft); border-left-color: var(--warn); }
.callout .c-ic { flex: none; font-size: 18px; }

.keypoints { background: linear-gradient(120deg, #f2fbf5, #e7f7ee); border: 1px solid #bfe8cd; border-radius: var(--radius); padding: 20px 22px; margin: 28px 0 8px; }
.keypoints h4 { font-size: 14px; font-weight: 800; color: var(--success); letter-spacing: .6px; text-transform: uppercase; margin-bottom: 10px; }
.keypoints ul { margin: 0 0 0 18px; display: grid; gap: 7px; font-size: 15px; }

.dialogue { display: flex; flex-direction: column; gap: 10px; margin: 18px 0 22px; }
.msg { max-width: 82%; padding: 11px 16px; border-radius: 16px; font-size: 14.5px; line-height: 1.55; }
.msg b { display: block; font-size: 11.5px; letter-spacing: .8px; text-transform: uppercase; margin-bottom: 3px; opacity: .75; }
.msg.user { align-self: flex-start; background: var(--bg); border: 1px solid var(--border); border-bottom-left-radius: 4px; }
.msg.tech { align-self: flex-end; background: var(--primary); color: #fff; border-bottom-right-radius: 4px; }
.msg.tech b { color: #cfdcff; }

.note-example { border-radius: 12px; padding: 15px 18px; font-size: 14.5px; margin: 8px 0; line-height: 1.6; }
.note-example.good { background: var(--success-soft); border: 1px dashed #9fd8b4; }
.note-example.bad { background: var(--danger-soft); border: 1px dashed #f2b8b8; }
.note-example .tag { display: inline-block; font-size: 11px; font-weight: 800; letter-spacing: 1px; text-transform: uppercase; margin-bottom: 6px; }
.note-example.good .tag { color: var(--success); }
.note-example.bad .tag { color: var(--danger); }

.lesson-footer { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-top: 30px; padding-top: 22px; border-top: 1px solid var(--border); }
.complete-btn { background: #fff; border: 2px solid var(--success); color: var(--success); }
.complete-btn:hover { background: var(--success-soft); }
.complete-btn.done { background: var(--success); color: #fff; }
.lesson-done-note { margin-top: 14px; font-size: 13.5px; color: var(--success); font-weight: 600; }

/* ==========================================================================
   TRANG BÀI KIỂM TRA (quiz.html)
   ========================================================================== */
.quiz-wrap { padding: 40px 22px 70px; max-width: 1080px; }
.quiz-intro { padding: 44px 46px; }
.quiz-intro .q-emo { font-size: 44px; margin-bottom: 10px; }
.quiz-intro h1 { font-size: clamp(24px, 3vw, 32px); font-weight: 800; color: var(--navy); margin-bottom: 8px; }
.quiz-intro > p { color: var(--muted); font-size: 16px; max-width: 700px; }
.quiz-rules { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; margin: 26px 0; }
.qr-item { display: flex; gap: 12px; align-items: flex-start; background: var(--bg); border: 1px solid var(--border); border-radius: 12px; padding: 14px 16px; font-size: 14.5px; }
.qr-item .ic { flex: none; width: 34px; height: 34px; border-radius: 10px; background: var(--primary-soft); display: flex; align-items: center; justify-content: center; font-size: 16px; }
.qr-item b { display: block; color: var(--navy); font-size: 14.5px; }
.qr-item span { color: var(--muted); font-size: 13.5px; }
.quiz-best { margin-top: 4px; font-size: 14px; color: var(--muted); }
.quiz-best b { color: var(--primary); }

.quiz-topbar { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 18px; box-shadow: var(--shadow); margin-bottom: 20px; position: sticky; top: 80px; z-index: 40; }
.quiz-topbar .qt-info { font-size: 14px; color: var(--muted); font-weight: 600; }
.quiz-topbar .qt-info strong { color: var(--primary); font-size: 16px; }
.q-pages { display: flex; gap: 6px; margin-left: auto; }
.q-pages button { width: 34px; height: 34px; border-radius: 10px; border: 1.5px solid var(--border); background: #fff; font: inherit; font-size: 13px; font-weight: 700; color: var(--muted); cursor: pointer; }
.q-pages button.cur { background: var(--primary); border-color: var(--primary); color: #fff; }

.quiz-grid { display: grid; grid-template-columns: minmax(0, 1fr) 250px; gap: 20px; align-items: start; }
.quiz-questions { display: flex; flex-direction: column; gap: 18px; }
.q-card { padding: 24px 26px; }
.q-head { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.q-num { flex: none; background: var(--primary); color: #fff; font-size: 12.5px; font-weight: 800; padding: 4px 12px; border-radius: 999px; }
.q-text { font-size: 16.5px; font-weight: 700; color: var(--navy); line-height: 1.5; }
.opt { display: flex; align-items: center; gap: 13px; border: 1.8px solid var(--border); border-radius: 12px; padding: 12px 15px; margin-top: 9px; cursor: pointer; transition: all .13s; background: #fff; }
.opt:hover { border-color: #9db6f2; background: #f7faff; }
.opt input { position: absolute; opacity: 0; pointer-events: none; }
.opt-letter { flex: none; width: 28px; height: 28px; border-radius: 9px; background: var(--bg); border: 1.5px solid var(--border); color: var(--muted); font-weight: 800; font-size: 13px; display: flex; align-items: center; justify-content: center; }
.opt-text { font-size: 15px; }
.opt.picked { border-color: var(--primary); background: var(--primary-soft); }
.opt.picked .opt-letter { background: var(--primary); border-color: var(--primary); color: #fff; }
.opt.correct { border-color: var(--success); background: var(--success-soft); }
.opt.correct .opt-letter { background: var(--success); border-color: var(--success); color: #fff; }
.opt.wrong { border-color: var(--danger); background: var(--danger-soft); }
.opt.wrong .opt-letter { background: var(--danger); border-color: var(--danger); color: #fff; }

.quiz-navigator { position: sticky; top: 148px; padding: 18px; }
.quiz-navigator h4 { font-size: 13px; font-weight: 800; letter-spacing: 1px; text-transform: uppercase; color: var(--muted); margin-bottom: 12px; }
.nav-grid { display: grid; grid-template-columns: repeat(8, 1fr); gap: 6px; margin-bottom: 14px; }
.nav-grid button { aspect-ratio: 1; border-radius: 8px; border: 1.5px solid var(--border); background: #fff; font: inherit; font-size: 11.5px; font-weight: 700; color: var(--muted); cursor: pointer; padding: 0; }
.nav-grid button.answered { background: var(--primary); border-color: var(--primary); color: #fff; }
.nav-grid button.inpage { outline: 2.5px solid #9db6f2; outline-offset: 1px; }
.nav-legend { display: grid; gap: 6px; font-size: 12px; color: var(--muted); }
.nav-legend i { display: inline-block; width: 12px; height: 12px; border-radius: 4px; margin-right: 7px; vertical-align: -1px; border: 1.5px solid var(--border); background: #fff; }
.nav-legend i.a { background: var(--primary); border-color: var(--primary); }

.quiz-bottom { display: flex; align-items: center; gap: 14px; margin-top: 22px; flex-wrap: wrap; }
.quiz-bottom .page-info { font-size: 14px; color: var(--muted); font-weight: 600; margin: 0 auto; }

/* Kết quả */
.result-hero { display: flex; gap: 34px; align-items: center; padding: 38px 42px; margin-bottom: 22px; flex-wrap: wrap; }
.score-ring { position: relative; flex: none; width: 160px; height: 160px; }
.score-ring svg { transform: rotate(-90deg); }
.score-ring .track { fill: none; stroke: var(--border); stroke-width: 13; }
.score-ring .bar { fill: none; stroke-width: 13; stroke-linecap: round; transition: stroke-dashoffset 1s ease; }
.score-ring .val { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; }
.score-ring .val b { font-size: 36px; font-weight: 800; color: var(--navy); line-height: 1; }
.score-ring .val span { font-size: 12.5px; color: var(--muted); font-weight: 700; margin-top: 4px; }
.result-info h2 { font-size: clamp(22px, 3vw, 30px); font-weight: 800; margin-bottom: 6px; }
.result-info h2.pass { color: var(--success); }
.result-info h2.fail { color: var(--danger); }
.result-info > p { color: var(--muted); font-size: 15.5px; max-width: 520px; }
.result-stats { display: flex; gap: 12px; margin: 18px 0 4px; flex-wrap: wrap; }
.rs { background: var(--bg); border: 1px solid var(--border); border-radius: 12px; padding: 10px 18px; text-align: center; min-width: 92px; }
.rs b { display: block; font-size: 21px; font-weight: 800; }
.rs span { font-size: 12px; color: var(--muted); font-weight: 600; }
.rs.ok b { color: var(--success); }
.rs.no b { color: var(--danger); }
.rs.skip b { color: var(--muted); }
.result-actions { display: flex; gap: 12px; margin-top: 18px; flex-wrap: wrap; }

.review-head { display: flex; align-items: center; justify-content: space-between; gap: 14px; margin: 34px 0 16px; flex-wrap: wrap; }
.review-head h3 { font-size: 21px; font-weight: 800; color: var(--navy); }
.review-filters { display: flex; gap: 8px; }
.review-filters button { border: 1.5px solid var(--border); background: #fff; border-radius: 999px; padding: 7px 16px; font: inherit; font-size: 13px; font-weight: 700; color: var(--muted); cursor: pointer; }
.review-filters button.on { background: var(--navy); border-color: var(--navy); color: #fff; }
.review-list { display: flex; flex-direction: column; gap: 14px; }
.rv-card { padding: 22px 24px; }
.rv-card .q-head { margin-bottom: 8px; }
.rv-status { margin-left: auto; flex: none; font-size: 12px; font-weight: 800; padding: 4px 12px; border-radius: 999px; }
.rv-status.ok { background: var(--success-soft); color: var(--success); }
.rv-status.no { background: var(--danger-soft); color: var(--danger); }
.rv-status.skip { background: var(--bg); color: var(--muted); border: 1px solid var(--border); }
.rv-explain { margin-top: 12px; background: var(--primary-soft); border-left: 3px solid var(--primary); border-radius: 0 10px 10px 0; padding: 11px 15px; font-size: 14px; color: #29408f; }
.rv-explain b { color: var(--primary-dark); }

/* ==========================================================================
   TRANG CHỨNG CHỈ (certificate.html)
   ========================================================================== */
.cert-wrap { padding: 44px 22px 70px; max-width: 940px; }
.cert-locked { text-align: center; padding: 60px 30px; }
.cert-locked .emo { font-size: 52px; margin-bottom: 12px; }
.cert-locked h1 { font-size: 26px; font-weight: 800; color: var(--navy); margin-bottom: 10px; }
.cert-locked p { color: var(--muted); max-width: 520px; margin: 0 auto 24px; }
.cert-controls { display: flex; align-items: center; gap: 16px; padding: 16px 20px; margin-bottom: 22px; flex-wrap: wrap; }
.cert-controls label { font-size: 14px; font-weight: 700; color: var(--navy); display: flex; align-items: center; gap: 12px; }
.cert-controls input { font: inherit; font-size: 15px; padding: 10px 16px; border: 1.8px solid var(--border); border-radius: 10px; min-width: 260px; outline: none; }
.cert-controls input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft); }

.certificate { background: #fdfaf1; border-radius: 8px; padding: 12px; box-shadow: var(--shadow-lg); }
.cert-inner { border: 3px solid var(--primary); outline: 1px solid var(--primary); outline-offset: -9px; border-radius: 6px; padding: 52px 48px 44px; text-align: center; position: relative; background: radial-gradient(circle at 50% 0%, #fffef9, #fdfaf1); }
.cert-brand { display: inline-flex; align-items: center; gap: 9px; font-weight: 800; font-size: 17px; color: var(--navy); margin-bottom: 26px; }
.cert-brand svg { width: 30px; height: 30px; }
.cert-label { font-size: 13px; font-weight: 800; letter-spacing: 4px; text-transform: uppercase; color: var(--primary); margin-bottom: 26px; }
.cert-present { font-size: 15px; color: var(--muted); font-style: italic; margin-bottom: 6px; }
.cert-name { font-size: clamp(30px, 5vw, 46px); font-weight: 800; font-style: italic; color: var(--navy); border-bottom: 2px solid var(--accent); display: inline-block; padding: 0 26px 6px; margin-bottom: 22px; max-width: 100%; overflow-wrap: break-word; }
.cert-course { font-size: 15px; color: var(--muted); margin-bottom: 4px; }
.cert-title { font-size: 21px; font-weight: 800; color: var(--primary-dark); margin-bottom: 14px; }
.cert-desc { font-size: 14.5px; color: var(--muted); max-width: 560px; margin: 0 auto 30px; }
.cert-meta { display: flex; justify-content: center; gap: 40px; flex-wrap: wrap; margin-bottom: 36px; }
.cert-meta > div { min-width: 130px; }
.cert-meta span { display: block; font-size: 11.5px; font-weight: 800; letter-spacing: 1.6px; text-transform: uppercase; color: var(--muted); margin-bottom: 4px; }
.cert-meta strong { font-size: 15.5px; color: var(--navy); }
.cert-signrow { display: flex; align-items: flex-end; justify-content: center; gap: 60px; flex-wrap: wrap; }
.cert-sig { text-align: center; font-size: 13px; font-weight: 700; color: var(--navy); }
.cert-sig i { display: block; width: 170px; border-top: 2px solid var(--navy); margin-bottom: 8px; padding-top: 20px; font-style: italic; font-family: Georgia, serif; font-size: 17px; color: var(--primary-dark); }
.cert-seal { flex: none; width: 84px; height: 84px; border-radius: 50%; background: linear-gradient(135deg, var(--primary), #5b86ff); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 30px; font-weight: 800; box-shadow: 0 8px 20px rgba(36,83,230,.35); border: 4px solid #e9efff; }
.cert-credit { text-align: center; font-size: 13px; color: var(--muted); margin-top: 18px; }

/* ---------- Responsive ---------- */
@media (max-width: 1020px) {
  .quiz-grid { grid-template-columns: 1fr; }
  .quiz-navigator { position: static; }
  .nav-grid { grid-template-columns: repeat(20, 1fr); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 900px) {
  .course-layout { grid-template-columns: 1fr; }
  .course-sidebar { position: static; max-height: none; }
  .outcomes-grid { grid-template-columns: 1fr; }
  .audience-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .exam-promo { grid-template-columns: 1fr; }
  .exam-right { border-left: none; border-top: 1px solid rgba(255,255,255,.14); padding: 34px; }
  .quiz-rules { grid-template-columns: 1fr; }
  .main-nav {
    display: none; position: absolute; top: 66px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--border); box-shadow: var(--shadow-lg);
    flex-direction: column; padding: 10px 18px 16px;
  }
  .main-nav.open { display: flex; }
  .nav-toggle { display: block; }
  .progress-pill { display: none; }
  .footer-inner { grid-template-columns: 1fr; gap: 22px; }
}
@media (max-width: 640px) {
  .lesson-panel { padding: 24px 20px; }
  .quiz-intro { padding: 30px 22px; }
  .result-hero { padding: 28px 22px; }
  .cert-inner { padding: 34px 18px; }
  .cert-signrow { gap: 26px; }
  .header-right .btn { display: none; }
  .q-pages { display: none; }
}

/* ---------- In ấn (chứng chỉ) ---------- */
@media print {
  .site-header, .site-footer, .cert-controls, .cert-credit, .no-print { display: none !important; }
  body { background: #fff; }
  .cert-wrap { padding: 0; max-width: 100%; }
  .certificate { box-shadow: none; }
}