/* Khu khoá học (/courses, /hoc-vien, /quan-tri): trang render phía máy chủ, không dùng Tailwind của SPA.
   Thiết kế ưu tiên điện thoại; cùng bảng màu với site chính. Đổi file này nhớ tăng CSS_VERSION trong functions/lib/courses/layout.ts */
:root {
  --ink: #1d1d1f; --mute: #6e6e73; --faint: #86868b; --canvas: #f5f5f7; --surface: #fff; --line: #d2d2d7;
  --accent: #0071e3; --accent-hover: #0077ed; --link: #0066cc; --eyebrow: #b64400;
  --ok: #1d8a3a; --ok-bg: #e8f6ec; --bad: #c4291c; --bad-bg: #fdecea; --warn: #9a5b00; --warn-bg: #fff4e0;
  --radius: 18px; --shadow: 2px 4px 12px rgba(0, 0, 0, .08);
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --ink: #f5f5f7; --mute: #a1a1a6; --canvas: #000; --surface: #1c1c1e; --line: #38383a; --link: #2997ff; --eyebrow: #ff9f0a;
    --ok: #5ad27a; --ok-bg: #12301b; --bad: #ff6b5e; --bad-bg: #3a1512; --warn: #ffb340; --warn-bg: #33250b;
    --shadow: 0 0 0 1px rgb(255 255 255 / .07);
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: 72px; }
body { margin: 0; background: var(--canvas); color: var(--ink); font: 17px/1.55 var(--font); -webkit-font-smoothing: antialiased; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.15; letter-spacing: -.015em; margin: 0 0 .5em; }
h1 { font-size: clamp(28px, 6vw, 44px); }
h2 { font-size: clamp(21px, 4vw, 26px); margin-top: 1.4em; }
h3 { font-size: 19px; }
img, video { max-width: 100%; }
code { font-family: var(--mono); font-size: .9em; background: rgb(127 127 127 / .12); padding: .1em .35em; border-radius: 6px; }
.i { flex: none; vertical-align: -.2em; }
.mute { color: var(--mute); }
.small { font-size: 14px; }
.center { text-align: center; }
.hp { position: absolute; left: -9999px; }

/* Khung */
.top { position: sticky; top: 0; z-index: 10; background: rgb(250 250 252 / .82); backdrop-filter: saturate(180%) blur(20px); -webkit-backdrop-filter: saturate(180%) blur(20px); border-bottom: 1px solid rgb(0 0 0 / .06); }
@media (prefers-color-scheme: dark) { .top { background: rgb(22 22 23 / .82); border-color: rgb(255 255 255 / .08); } }
.top-in { max-width: 1120px; margin: 0 auto; padding: 0 16px; height: 52px; display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.brand { font-weight: 700; letter-spacing: .08em; color: var(--ink); font-size: 14px; }
.top-nav { display: flex; align-items: center; gap: 14px; font-size: 14px; }
.top-nav a { color: var(--ink); white-space: nowrap; }
.pill { display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--line); padding: 5px 12px; border-radius: 999px; }
.pill-solid { background: var(--accent); border-color: var(--accent); color: #fff !important; }
.pill-name { max-width: 90px; overflow: hidden; text-overflow: ellipsis; }
@media (max-width: 480px) { .top-nav { gap: 10px; } .top-nav .nav-wide { display: none; } .brand { font-size: 13px; letter-spacing: .05em; } }
.wrap { max-width: 760px; margin: 0 auto; padding: 24px 16px 64px; }
.wrap-wide { max-width: 1120px; }
.foot { border-top: 1px solid var(--line); }
.foot-in { max-width: 1120px; margin: 0 auto; padding: 20px 16px 40px; display: flex; flex-wrap: wrap; gap: 8px 20px; font-size: 13px; color: var(--mute); }
.foot-in a { color: var(--mute); }

/* Khối */
.card { background: var(--surface); border-radius: var(--radius); box-shadow: var(--shadow); padding: 20px; margin: 16px 0; }
.card > h2:first-child, .card > summary + h2 { margin-top: 0; }
.card summary { cursor: pointer; }
.hero { padding: 8px 0 12px; }
.eyebrow { color: var(--eyebrow); font-weight: 600; font-size: 14px; margin: 0 0 6px; }
.lead { font-size: 19px; color: var(--mute); margin: 0 0 12px; }
.grid { display: grid; gap: 14px; }
@media (min-width: 700px) { .grid { grid-template-columns: repeat(2, 1fr); } }
.course-card { display: block; color: var(--ink); margin: 0; transition: box-shadow .2s; }
a.course-card:hover { text-decoration: none; box-shadow: 2px 4px 18px rgba(0, 0, 0, .16); }
.course-card h2, .course-card h3 { margin-top: 0; }
.price { font-weight: 700; font-size: 18px; margin: 8px 0 0; }
.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.stack { display: flex; flex-direction: column; gap: 14px; }
.plain { list-style: none; padding: 0; }
.plain li { padding: 6px 0; border-bottom: 1px solid var(--line); font-size: 15px; }

/* Nút, ô nhập */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 46px; padding: 0 20px; border-radius: 999px; border: 0; background: var(--accent); color: #fff; font: 600 16px/1.2 var(--font); text-align: center; cursor: pointer; text-decoration: none !important; }
.btn:hover { background: var(--accent-hover); }
.btn-ghost { background: transparent; color: var(--link); box-shadow: inset 0 0 0 1px var(--line); }
.btn-ghost:hover { background: rgb(127 127 127 / .08); }
.btn-danger { background: var(--bad); }
.btn-block { width: 100%; }
.btn-sm { min-height: 36px; padding: 0 14px; font-size: 14px; }
form.inline { display: inline; }
.field { display: flex; flex-direction: column; gap: 6px; }
.field-label { font-weight: 600; font-size: 15px; }
.field-hint { font-size: 13px; color: var(--mute); }
input, select, textarea { font: 16px var(--font); color: var(--ink); background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 11px 14px; min-height: 46px; width: 100%; }
.row input, .row select { width: auto; flex: 1 1 180px; }
textarea { font-family: var(--mono); }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; border-color: transparent; }
.auth { max-width: 440px; margin: 24px auto; }

/* Thông báo, nhãn */
.notice { max-width: 1088px; margin: 12px auto; padding: 12px 16px; border-radius: 12px; font-size: 15px; }
body > .notice { margin: 12px 16px; }
@media (min-width: 1120px) { body > .notice { margin: 12px auto; } }
.notice-ok { background: var(--ok-bg); color: var(--ok); }
.notice-error { background: var(--bad-bg); color: var(--bad); }
.tag { display: inline-block; font-size: 12px; font-weight: 600; padding: 2px 8px; border-radius: 999px; background: rgb(127 127 127 / .14); color: var(--mute); white-space: nowrap; }
.tag-ok { background: var(--ok-bg); color: var(--ok); }
.tag-bad { background: var(--bad-bg); color: var(--bad); }
.tag-warn { background: var(--warn-bg); color: var(--warn); }
.ok-line { color: var(--ok); font-weight: 600; display: flex; gap: 8px; align-items: center; }

/* Thanh tiến độ */
.bar { height: 8px; border-radius: 99px; background: rgb(127 127 127 / .18); overflow: hidden; }
.bar span { display: block; height: 100%; background: var(--ok); border-radius: 99px; }
.bar-label { font-size: 13px; color: var(--mute); margin: 6px 0 0; }

/* Trang khoá học */
.course-top { display: grid; gap: 16px; }
@media (min-width: 900px) { .course-top { grid-template-columns: 1fr 340px; align-items: start; } .cta { position: sticky; top: 72px; } }
.cta { background: var(--surface); border-radius: var(--radius); box-shadow: var(--shadow); padding: 20px; display: flex; flex-direction: column; gap: 10px; }
.price-big { font-size: 32px; font-weight: 700; margin: 0; letter-spacing: -.02em; }
.code-box summary { font-size: 15px; color: var(--link); display: flex; gap: 6px; align-items: center; padding: 6px 0; }
.code-box form { margin-top: 8px; }
.ticks { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.ticks li { display: flex; gap: 10px; align-items: flex-start; }
.ticks .i { color: var(--ok); margin-top: 4px; }
.syllabus { margin-top: 8px; }
.chapter { background: var(--surface); border-radius: var(--radius); box-shadow: var(--shadow); margin: 12px 0; overflow: hidden; }
.chapter summary { list-style: none; display: grid; grid-template-columns: 1fr auto; gap: 2px 12px; padding: 16px 20px; cursor: pointer; }
.chapter summary::-webkit-details-marker { display: none; }
.ch-n { font-size: 13px; color: var(--eyebrow); font-weight: 600; grid-column: 1; }
.ch-t { font-weight: 600; font-size: 18px; grid-column: 1; }
.ch-c { grid-row: 1 / 3; grid-column: 2; align-self: center; font-size: 14px; color: var(--mute); }
.ch-sum { padding: 0 20px; margin: 0 0 8px; }
.lessons { list-style: none; margin: 0; padding: 0 0 8px; }
.lessons a { display: flex; gap: 12px; align-items: center; padding: 12px 20px; color: var(--ink); border-top: 1px solid var(--line); min-height: 52px; }
.lessons a:hover { background: rgb(127 127 127 / .06); text-decoration: none; }
.l-ic { color: var(--mute); display: inline-flex; }
.is-done .l-ic { color: var(--ok); }
.l-t { flex: 1; }
.l-m { font-size: 13px; color: var(--mute); white-space: nowrap; display: flex; gap: 6px; align-items: center; }

/* Bài học */
.crumbs { font-size: 14px; color: var(--mute); margin: 0 0 12px; }
.lesson-grid { display: grid; gap: 16px; }
@media (min-width: 900px) { .lesson-grid { grid-template-columns: 300px minmax(0, 1fr); gap: 32px; } .side { position: sticky; top: 68px; max-height: calc(100vh - 84px); overflow: auto; } }
.lesson-main { min-width: 0; max-width: 720px; }
.side-box { background: var(--surface); border-radius: var(--radius); box-shadow: var(--shadow); padding: 4px 0; }
.side-box > summary { padding: 12px 16px; font-weight: 600; display: flex; gap: 8px; align-items: center; cursor: pointer; }
.side-box .bar, .side-box .bar-label { margin-left: 16px; margin-right: 16px; }
.side-list ol { list-style: none; margin: 0; padding: 0; }
.side-ch { font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: .04em; color: var(--mute); margin: 14px 16px 4px; }
.side-list a { display: flex; gap: 8px; padding: 8px 16px; font-size: 14px; color: var(--ink); line-height: 1.35; }
.side-list a:hover { background: rgb(127 127 127 / .07); text-decoration: none; }
.side-list a.is-current { background: rgb(0 113 227 / .1); color: var(--link); font-weight: 600; }
.side-list a.is-done .l-ic { color: var(--ok); }
.video { position: relative; margin: 8px 0 20px; border-radius: 14px; overflow: hidden; background: #000; }
.video video { display: block; width: 100%; aspect-ratio: 16 / 9; }
.wm { position: absolute; right: 12px; top: 10px; font-size: 12px; color: rgb(255 255 255 / .35); pointer-events: none; user-select: none; }
.toc { background: var(--surface); border-radius: 14px; padding: 12px 16px; margin: 0 0 16px; box-shadow: var(--shadow); font-size: 15px; }
.toc summary { font-weight: 600; cursor: pointer; }
.toc ol { margin: 8px 0 0; padding-left: 20px; }
.outline { list-style: none; padding: 0; margin: 4px 0 0; }
.outline li { padding: 6px 0; color: var(--mute); display: flex; gap: 8px; align-items: center; }
.lock-box { border: 1px solid var(--line); }
.lock-title { font-weight: 700; display: flex; gap: 8px; align-items: center; font-size: 18px; }
.done-form { margin: 28px 0 8px; }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 28px; }
.pager a { display: flex; align-items: center; gap: 10px; padding: 14px; border-radius: 14px; background: var(--surface); box-shadow: var(--shadow); color: var(--ink); font-size: 14px; line-height: 1.3; }
.pager a:hover { text-decoration: none; }
.pager small { display: block; color: var(--mute); font-size: 12px; margin-bottom: 2px; }
.pager-next { justify-content: flex-end; text-align: right; grid-column: 2; }
@media (max-width: 520px) { .pager { grid-template-columns: 1fr; } .pager-next { grid-column: 1; } }

/* Nội dung bài (Markdown) */
.prose { font-size: 17px; line-height: 1.7; overflow-wrap: anywhere; }
.prose h2 { font-size: 24px; margin: 1.8em 0 .5em; }
.prose h3 { font-size: 19px; margin: 1.5em 0 .4em; }
.prose p, .prose ul, .prose ol { margin: 0 0 1em; }
.prose li { margin: .3em 0; }
.prose li > p { margin: 0; }
.prose blockquote { margin: 1.2em 0; padding: 12px 16px; border-left: 3px solid var(--accent); background: rgb(0 113 227 / .06); border-radius: 0 12px 12px 0; }
.prose blockquote p:last-child { margin: 0; }
.prose pre { position: relative; background: #1d1d1f; color: #f5f5f7; padding: 16px; padding-top: 40px; border-radius: 14px; overflow-x: auto; font-size: 14px; line-height: 1.55; margin: 1.2em 0; white-space: pre-wrap; }
@media (prefers-color-scheme: dark) { .prose pre { background: #2c2c2e; } }
.prose pre code { background: none; padding: 0; font-size: inherit; color: inherit; }
.copy { position: absolute; top: 8px; right: 8px; font: 600 12px var(--font); background: rgb(255 255 255 / .14); color: #fff; border: 0; border-radius: 8px; padding: 5px 10px; cursor: pointer; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 2em 0; }
.prose img { border-radius: 12px; }
.doc-table, .table { overflow-x: auto; -webkit-overflow-scrolling: touch; margin: 1em 0; }
table { border-collapse: collapse; width: 100%; font-size: 15px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-size: 13px; color: var(--mute); font-weight: 600; white-space: nowrap; }
.doc-callout { border-left-color: var(--eyebrow) !important; }
.doc-callout::before { content: attr(data-label); display: block; font-weight: 700; font-size: 14px; margin-bottom: 4px; }
.doc-steps, .doc-timeline { padding-left: 22px; }
.doc-step-title, .doc-timeline-title, .doc-card-title, .doc-flow-title { font-weight: 600; margin: 0; }
.doc-step-desc, .doc-timeline-desc, .doc-card-desc, .doc-flow-desc { color: var(--mute); margin: 0 0 .6em; }
.doc-checklist { list-style: none; padding: 0; }
.doc-checklist li::before { content: ""; display: inline-block; width: 14px; height: 14px; border: 2px solid var(--ok); border-radius: 4px; margin-right: 10px; vertical-align: -2px; }
.doc-cards, .doc-stats, .doc-flow { display: grid; gap: 10px; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); margin: 1em 0; }
.doc-card, .doc-stat, .doc-flow-step { background: var(--surface); box-shadow: var(--shadow); border-radius: 14px; padding: 14px; }
.doc-flow-arrow { display: none; }
.doc-stat-value { font-size: 26px; font-weight: 700; margin: 0; }

/* Thanh toán */
.pay { max-width: 520px; margin: 0 auto; text-align: center; }
.qr { display: block; margin: 16px auto; width: min(320px, 100%); height: auto; border-radius: 14px; background: #fff; }
.pay-info { display: grid; grid-template-columns: auto 1fr; gap: 8px 16px; text-align: left; margin: 16px 0; font-size: 15px; }
.pay-info dt { color: var(--mute); }
.pay-info dd { margin: 0; overflow-wrap: anywhere; }
.code { font-family: var(--mono); letter-spacing: .05em; }
.big { font-size: 20px; }
.wait { display: flex; gap: 8px; align-items: center; justify-content: center; color: var(--mute); }
.wait .i { animation: spin 2s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* Quản trị */
.tabs, .chips { display: flex; gap: 6px; overflow-x: auto; margin: 0 0 16px; padding-bottom: 4px; -webkit-overflow-scrolling: touch; }
.tabs a, .chips a { white-space: nowrap; padding: 7px 14px; border-radius: 999px; background: var(--surface); box-shadow: var(--shadow); color: var(--ink); font-size: 14px; }
.tabs a.is-current, .chips a.is-current { background: var(--ink); color: var(--canvas); }
.tabs a:hover, .chips a:hover { text-decoration: none; }
.stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; margin: 0 0 16px; }
@media (min-width: 800px) { .stats { grid-template-columns: repeat(4, 1fr); } }
.stat { background: var(--surface); box-shadow: var(--shadow); border-radius: 16px; padding: 14px 16px; color: var(--ink); display: block; }
.stat:hover { text-decoration: none; }
.stat b { display: block; font-size: 22px; letter-spacing: -.02em; }
.stat span { font-size: 13px; color: var(--mute); }
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 12px; }
.filters input { flex: 1 1 220px; width: auto; }
.filters select { width: auto; flex: 0 1 auto; }
tr.is-off { opacity: .5; }
.codes-new textarea { width: 100%; }