:root {
  --teal-950: #0b3132;
  --teal-900: #0f3d3e;
  --teal-800: #17605e;
  --teal-700: #247a73;
  --mint-600: #4ea994;
  --mint-500: #72c6b1;
  --mint-300: #b9e2d7;
  --mint-200: #d8eee8;
  --mint-100: #eaf7f3;
  --mint-50: #f4fbf8;
  --paper: #ffffff;
  --ink: #173f3d;
  --muted: #667a76;
  --line: #cfe2dc;
  --amber: #9b6414;
  --amber-soft: #fff3df;
  --sky: #315d70;
  --sky-soft: #e9f3f7;
  --coral: #855044;
  --coral-soft: #fff0ed;
  --highlight: #fff1b8;
  --sidebar: 282px;
  --topbar: 68px;
  --radius: 8px;
  --shadow-soft: 0 12px 32px rgba(15, 61, 62, 0.08);
  --font: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--topbar) + 22px); }
body { margin: 0; min-width: 320px; color: var(--ink); background: var(--mint-50); font: 16px/1.78 var(--font); }
body.drawer-open { overflow: hidden; }
a { color: inherit; }
button, input { font: inherit; letter-spacing: 0; }
input[type="search"]::-webkit-search-cancel-button { display: none; -webkit-appearance: none; }
button, a { -webkit-tap-highlight-color: transparent; }
button:focus-visible, a:focus-visible, input:focus-visible, [tabindex="0"]:focus-visible, summary:focus-visible { outline: 3px solid rgba(78, 169, 148, 0.36); outline-offset: 2px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

.reading-progress { position: fixed; z-index: 80; inset: 0 0 auto; height: 3px; background: rgba(15, 61, 62, 0.08); }
.reading-progress span { display: block; width: 0; height: 100%; background: var(--mint-600); transition: width 100ms linear; }

.course-brand { display: flex; align-items: center; gap: 10px; color: var(--teal-950); text-decoration: none; min-width: 0; }
.course-brand > span:last-child { min-width: 0; display: grid; line-height: 1.2; }
.course-brand strong { font-size: 15px; }
.course-brand small { color: var(--muted); font-size: 11px; margin-top: 3px; }
.brand-mark { display: grid; place-items: center; width: 40px; height: 40px; flex: 0 0 40px; border-radius: 8px; color: white; background: var(--teal-900); box-shadow: 0 6px 18px rgba(15,61,62,.16); }
.brand-mark svg { width: 20px; height: 20px; }

.chapter-sidebar { position: fixed; z-index: 20; inset: 0 auto 0 0; width: var(--sidebar); overflow: auto; padding: 22px 18px 28px; border-right: 1px solid var(--line); background: rgba(255,255,255,.96) url("design/pattern.svg") right top / 190px auto no-repeat; }
.chapter-context { display: grid; gap: 5px; margin: 24px -2px 20px; padding: 14px 13px; border: 1px solid var(--mint-200); border-radius: var(--radius); background: rgba(234,247,243,.74); }
.chapter-context span { color: var(--teal-700); font-size: 11px; font-weight: 800; }
.chapter-context strong { font-size: 13px; line-height: 1.45; overflow-wrap: anywhere; }
.nav-label, .course-group-label { margin: 0 0 8px; color: var(--muted); font-size: 11px; font-weight: 800; }
.chapter-nav { display: grid; gap: 2px; }
.chapter-link { display: grid; grid-template-columns: 24px minmax(0,1fr); gap: 8px; align-items: start; min-height: 40px; padding: 9px 8px; border-radius: 7px; color: #526965; text-decoration: none; font-size: 12.5px; line-height: 1.45; transition: background-color .16s ease, color .16s ease; }
.chapter-link > span { color: #8aa19c; font-variant-numeric: tabular-nums; font-size: 10px; padding-top: 2px; }
.chapter-link:hover, .chapter-link.active { color: var(--teal-900); background: var(--mint-100); }
.chapter-link.active { font-weight: 700; box-shadow: inset 3px 0 var(--mint-600); }

.page-shell { min-height: 100vh; margin-left: var(--sidebar); }
.chapter-sidebar, .page-shell { transition: transform .2s ease, margin-left .2s ease; }
body.focus-mode .chapter-sidebar { transform: translateX(-100%); }
body.focus-mode .page-shell { margin-left: 0; }
body.focus-mode .lesson-content { width: min(100%, 980px); }
.topbar { position: sticky; z-index: 15; top: 0; min-height: var(--topbar); display: grid; grid-template-columns: auto minmax(260px, 560px) auto; align-items: center; justify-content: center; gap: 12px; padding: 10px 24px; border-bottom: 1px solid rgba(207,226,220,.9); background: rgba(244,251,248,.92); backdrop-filter: blur(14px); }
.topbar-actions { display: flex; gap: 8px; }
.tool-button, .close-button, .search-step, .search-clear { display: inline-flex; align-items: center; justify-content: center; gap: 7px; min-height: 44px; border: 1px solid var(--line); border-radius: 8px; color: var(--teal-900); background: var(--paper); cursor: pointer; text-decoration: none; font-weight: 750; transition: border-color .16s ease, background-color .16s ease, box-shadow .16s ease, transform .16s ease; }
.tool-button { padding: 0 13px; white-space: nowrap; }
.tool-button.icon-only { width: 44px; padding: 0; }
.tool-button svg, .close-button svg { width: 18px; height: 18px; }
.tool-button:hover, .close-button:hover { border-color: var(--mint-500); background: var(--mint-100); box-shadow: 0 7px 18px rgba(15,61,62,.08); transform: translateY(-1px); }
.mobile-only { display: none; }
.page-search { min-height: 44px; display: grid; grid-template-columns: 20px minmax(0,1fr) auto 32px 32px 32px; gap: 5px; align-items: center; padding: 0 7px 0 12px; border: 1px solid var(--line); border-radius: 8px; background: var(--paper); }
.page-search > svg { width: 17px; color: var(--muted); }
.page-search input { min-width: 0; width: 100%; border: 0; outline: 0; color: var(--ink); background: transparent; }
.page-search input::placeholder { color: #8ba09c; }
#searchStatus { color: var(--muted); white-space: nowrap; font-size: 11px; }
.search-step, .search-clear { display: none; width: 32px; min-height: 32px; border: 0; background: transparent; }
.page-search.has-results .search-step, .page-search.has-query .search-clear { display: inline-flex; }
.search-step svg, .search-clear svg { width: 16px; height: 16px; }

.lesson-content { width: min(100%, 900px); margin: 0 auto; padding: 44px 34px 84px; }
.lesson-header { position: relative; overflow: hidden; margin: 0 0 38px; padding: 34px 36px 30px; border: 1px solid var(--mint-200); border-radius: var(--radius); background: var(--paper) url("design/pattern.svg") right top / 260px auto no-repeat; box-shadow: var(--shadow-soft); }
.lesson-header::after { content: ""; position: absolute; inset: auto 0 0; height: 4px; background: linear-gradient(90deg, var(--teal-900), var(--mint-500), #d3a344); }
.lesson-kicker { display: flex; gap: 8px; align-items: center; margin-bottom: 14px; color: var(--teal-700); font-size: 12px; font-weight: 800; }
.lesson-kicker span:first-child { padding: 3px 7px; border-radius: 5px; color: white; background: var(--teal-900); }
h1 { max-width: 720px; margin: 0; color: var(--teal-950); font-size: 31px; line-height: 1.28; letter-spacing: 0; overflow-wrap: anywhere; }
.lesson-lead { max-width: 760px; margin: 17px 0 0; color: #45615d; font-size: 16px; line-height: 1.78; }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 16px; margin-top: 20px; color: var(--muted); font-size: 12px; }
.lesson-meta span { display: inline-flex; align-items: center; gap: 6px; }
.lesson-meta svg { width: 15px; height: 15px; color: var(--mint-600); }
.lesson-status { font-weight: 750; }
.lesson-status.is-complete { color: var(--teal-700); }
.lesson-quick-nav { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 20px; padding-top: 17px; border-top: 1px solid var(--mint-200); }
.lesson-quick-nav a { display: inline-flex; align-items: center; gap: 6px; min-height: 35px; padding: 6px 9px; border: 1px solid var(--line); border-radius: 7px; color: #3f625e; background: rgba(244,251,248,.88); text-decoration: none; font-size: 12px; font-weight: 750; transition: border-color .16s ease, background-color .16s ease, transform .16s ease; }
.lesson-quick-nav a:hover { border-color: var(--mint-500); color: var(--teal-900); background: var(--mint-100); transform: translateY(-1px); }
.lesson-quick-nav svg { width: 15px; height: 15px; color: var(--mint-600); }

.content-section { margin: 0 0 42px; scroll-margin-top: calc(var(--topbar) + 18px); }
h2 { display: grid; grid-template-columns: 5px minmax(0,1fr); gap: 13px; align-items: stretch; margin: 0 0 19px; color: var(--teal-950); font-size: 22px; line-height: 1.45; letter-spacing: 0; }
h2::before { content: ""; border-radius: 3px; background: var(--mint-500); }
h3 { margin: 28px 0 10px; color: var(--teal-800); font-size: 18px; line-height: 1.5; letter-spacing: 0; }
h4 { margin: 21px 0 8px; color: #3c625e; font-size: 16px; line-height: 1.5; letter-spacing: 0; }
p { margin: 9px 0 13px; }
.content-section > p, .answer-body > p { text-wrap: pretty; }
strong { color: var(--teal-950); font-weight: 800; }
em { color: #5c6f6c; }
code { display: inline; padding: 2px 5px; border: 1px solid #d8e5e1; border-radius: 5px; color: #104e4d; background: #f1f7f5; font: .92em/1.5 "SFMono-Regular", Consolas, "Microsoft YaHei", monospace; overflow-wrap: anywhere; }
code .code-emphasis { color: #0a3031; font-weight: 850; }
code .code-highlight { padding: 0 2px; color: #0a3031; background: #cceadf; font-weight: 850; }
pre { margin: 16px 0 22px; padding: 16px 18px; overflow: auto; border: 1px solid #254d4b; border-radius: 8px; color: #eaf7f3; background: var(--teal-950); font: 14px/1.65 "SFMono-Regular", Consolas, "Microsoft YaHei", monospace; }
pre code { padding: 0; border: 0; color: inherit; background: transparent; }
.key-highlight { padding: 1px 3px; border-radius: 3px; color: #5d4600; background: linear-gradient(180deg, transparent 8%, var(--highlight) 8%, var(--highlight) 93%, transparent 93%); font-weight: 750; }
.search-mark { padding: 1px 2px; border-radius: 3px; color: #352800; background: #ffd766; box-shadow: 0 0 0 2px rgba(255,215,102,.22); }
.search-mark.current { color: white; background: var(--teal-800); box-shadow: 0 0 0 3px rgba(78,169,148,.24); }

ul, ol { margin: 10px 0 17px; padding-left: 1.55em; }
li { margin: 5px 0; padding-left: 3px; }
li::marker { color: var(--mint-600); font-weight: 800; }
ul ul, ol ul, ul ol, ol ol { margin: 5px 0 8px; }
.checklist { list-style: none; padding-left: 0; }
.checklist li { padding: 0; }
.checklist label { display: grid; grid-template-columns: 20px minmax(0,1fr); gap: 9px; align-items: start; }
.checklist input { width: 17px; height: 17px; margin: 5px 0 0; accent-color: var(--teal-700); }

.lead { margin: 18px 0 24px; padding: 16px 18px; border-left: 4px solid var(--mint-600); border-radius: 0 7px 7px 0; color: #315e5a; background: var(--mint-100); }
.callout { display: grid; grid-template-columns: 40px minmax(0,1fr); gap: 13px; margin: 18px 0 23px; padding: 16px 18px; border: 1px solid; border-radius: var(--radius); }
.callout p { margin: 0; }
.callout-label { margin-bottom: 3px !important; font-size: 11px; font-weight: 850; }
.callout-icon { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 7px; background: rgba(255,255,255,.72); }
.callout-icon svg { width: 19px; height: 19px; }
.callout-key { border-color: #b7ddd3; color: #234f4b; background: #eaf7f3; }
.callout-key .callout-icon, .callout-key .callout-label { color: var(--teal-700); }
.callout-caution { border-color: #efd5ad; color: #69481b; background: var(--amber-soft); }
.callout-caution .callout-icon, .callout-caution .callout-label { color: var(--amber); }
.callout-reading { border-color: #c8dce5; color: #294f60; background: var(--sky-soft); }
.callout-reading .callout-icon, .callout-reading .callout-label { color: var(--sky); }
.callout-writing { border-color: #ebccc5; color: #70483f; background: var(--coral-soft); }
.callout-writing .callout-icon, .callout-writing .callout-label { color: var(--coral); }

.table-wrap { width: 100%; margin: 17px 0 25px; overflow: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); box-shadow: 0 7px 20px rgba(15,61,62,.045); }
table { width: 100%; border-collapse: collapse; font-size: 14px; line-height: 1.58; }
th, td { min-width: 120px; padding: 11px 13px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; overflow-wrap: anywhere; }
th:last-child, td:last-child { border-right: 0; }
tr:last-child td { border-bottom: 0; }
th { color: var(--teal-950); background: var(--mint-200); font-weight: 800; }
tbody tr:nth-child(even), table tr:nth-child(odd):not(:first-child) { background: #f9fcfb; }

.answer-reveal { margin: 22px 0 0; overflow: hidden; border: 1px solid #bcdad2; border-radius: var(--radius); background: var(--paper); }
.answer-reveal > summary { display: grid; grid-template-columns: 34px minmax(0,1fr) 20px; gap: 10px; align-items: center; min-height: 52px; padding: 9px 13px; list-style: none; color: var(--teal-900); background: var(--mint-100); cursor: pointer; font-weight: 800; }
.answer-reveal > summary::-webkit-details-marker { display: none; }
.answer-summary-icon { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 7px; color: white; background: var(--teal-800); }
.answer-summary-icon svg, .answer-chevron { width: 17px; height: 17px; }
.answer-chevron { transition: transform .18s ease; }
.answer-reveal[open] .answer-chevron { transform: rotate(180deg); }
.answer-body { padding: 15px 18px 18px; }

.lesson-completion { display: grid; grid-template-columns: minmax(0,1fr) auto; gap: 24px; align-items: center; margin: 52px 0 0; padding: 25px 26px; border: 1px solid var(--mint-300); border-radius: var(--radius); background: var(--mint-100); }
.lesson-completion > div > span { color: var(--teal-700); font-size: 11px; font-weight: 850; }
.lesson-completion h2 { display: block; margin: 3px 0 5px; font-size: 19px; }
.lesson-completion h2::before { content: none; }
.lesson-completion p { margin: 0; color: var(--muted); font-size: 13px; }
.completion-button { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; padding: 0 14px; border: 1px solid var(--teal-800); border-radius: 8px; color: white; background: var(--teal-800); cursor: pointer; font: 750 13px/1.35 var(--font); }
.completion-button:hover { background: var(--teal-900); }
.completion-button[aria-pressed="true"] { color: var(--teal-900); background: white; }
.completion-button svg { width: 18px; height: 18px; }

.lesson-pager { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 12px; margin-top: 54px; padding-top: 24px; border-top: 1px solid var(--line); }
.pager-link { display: flex; align-items: center; gap: 12px; min-height: 72px; padding: 12px 14px; border: 1px solid var(--line); border-radius: var(--radius); color: var(--teal-900); background: var(--paper); text-decoration: none; transition: border-color .16s ease, box-shadow .16s ease, transform .16s ease; }
.pager-link.next { justify-content: flex-end; text-align: right; grid-column: 2; }
.pager-link:hover { border-color: var(--mint-500); box-shadow: var(--shadow-soft); transform: translateY(-2px); }
.pager-link svg { width: 19px; height: 19px; flex: 0 0 auto; }
.pager-link span { display: grid; min-width: 0; }
.pager-link small { color: var(--muted); }
.pager-link strong { font-size: 13px; line-height: 1.45; overflow-wrap: anywhere; }

.drawer-backdrop { position: fixed; z-index: 50; inset: 0; opacity: 0; pointer-events: none; background: rgba(7,35,35,.38); backdrop-filter: blur(2px); transition: opacity .2s ease; }
body.drawer-open .drawer-backdrop { opacity: 1; pointer-events: auto; }
.drawer { position: fixed; z-index: 60; top: 0; bottom: 0; overflow: auto; width: min(400px, 92vw); padding: 20px 18px 32px; border-color: var(--line); background: var(--paper) url("design/pattern.svg") right top / 220px auto no-repeat; box-shadow: 0 24px 64px rgba(7,35,35,.2); transition: transform .24s ease; }
.course-drawer { right: 0; border-left: 1px solid var(--line); transform: translateX(104%); }
.chapter-drawer { left: 0; border-right: 1px solid var(--line); transform: translateX(-104%); }
body.course-drawer-open .course-drawer, body.chapter-drawer-open .chapter-drawer { transform: translateX(0); }
.drawer-head { position: sticky; z-index: 2; top: -20px; display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 76px; margin: -20px -18px 16px; padding: 16px 18px; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.94); backdrop-filter: blur(10px); }
.drawer-head > div { display: grid; }
.drawer-head small { color: var(--muted); font-size: 11px; }
.drawer-head strong { color: var(--teal-950); font-size: 17px; }
.close-button { width: 44px; padding: 0; }
.course-group { margin: 0 0 23px; }
.course-group h3 { margin: 0 0 8px; color: var(--teal-900); font-size: 15px; }
.course-group nav { display: grid; gap: 2px; }
.course-link { display: grid; grid-template-columns: 32px minmax(0,1fr); gap: 8px; align-items: center; min-height: 43px; padding: 7px 9px; border-radius: 7px; color: #506762; text-decoration: none; font-size: 13px; line-height: 1.42; }
.course-link:hover, .course-link.active { color: var(--teal-900); background: var(--mint-100); }
.course-link.active { font-weight: 750; }
.course-link-number { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 7px; color: var(--teal-700); background: var(--mint-100); font-size: 10px; font-weight: 800; }
.course-link.active .course-link-number { color: white; background: var(--teal-800); }

.index-topbar { position: sticky; z-index: 20; top: 0; display: flex; align-items: center; justify-content: space-between; gap: 20px; min-height: 72px; padding: 10px max(24px, calc((100vw - 1180px)/2)); border-bottom: 1px solid var(--line); background: rgba(255,255,255,.94); backdrop-filter: blur(14px); }
.index-search { display: grid; grid-template-columns: 19px minmax(120px, 300px) 34px; gap: 7px; align-items: center; min-height: 44px; padding-left: 12px; border: 1px solid var(--line); border-radius: 8px; background: var(--mint-50); }
.index-search > svg { width: 17px; color: var(--muted); }
.index-search input { min-width: 0; border: 0; outline: 0; background: transparent; }
.index-search button { display: grid; place-items: center; width: 34px; height: 34px; border: 0; color: var(--muted); background: transparent; cursor: pointer; }
.index-search button svg { width: 16px; }
.index-page { width: min(100% - 40px, 1180px); margin: 0 auto; padding: 34px 0 76px; }
.course-intro { position: relative; isolation: isolate; display: grid; grid-template-columns: minmax(0,1fr) 180px; gap: 30px; align-items: center; min-height: 290px; overflow: hidden; padding: 42px 48px; border-radius: var(--radius); color: white; background: var(--teal-900); box-shadow: 0 18px 44px rgba(15,61,62,.17); }
.course-intro::before { content: ""; position: absolute; z-index: -1; inset: 0 0 0 58%; background: url("design/pattern.svg") center / cover no-repeat; opacity: .2; }
.course-intro::after { content: ""; position: absolute; inset: auto 0 0; height: 5px; background: linear-gradient(90deg, var(--mint-500), #e7bc64, #e38e7e); }
.index-eyebrow { margin: 0 0 12px; color: #bfe7dc; font-size: 11px; font-weight: 850; }
.course-intro h1 { color: white; font-size: 38px; }
.course-intro-copy > p:not(.index-eyebrow) { max-width: 680px; margin: 15px 0 0; color: #d8eee8; font-size: 17px; }
.course-stats { display: flex; flex-wrap: wrap; gap: 22px; margin-top: 26px; color: #d8eee8; font-size: 12px; }
.course-stats span { display: flex; align-items: baseline; gap: 5px; }
.course-stats strong { color: white; font-size: 22px; }
.course-intro-mark { justify-self: end; display: grid; grid-template-columns: 76px 1fr; gap: 12px; align-items: center; min-width: 160px; }
.course-intro-mark > span { display: grid; place-items: center; width: 76px; height: 96px; border: 1px solid rgba(255,255,255,.38); border-radius: 8px; color: var(--teal-900); background: var(--mint-500); font: 800 54px/1 Georgia, serif; }
.course-intro-mark small { color: #d8eee8; font-weight: 750; line-height: 1.35; }
.learning-dashboard { display: grid; grid-template-columns: minmax(0,1.25fr) minmax(0,1fr); gap: 12px; margin: 22px 0 18px; }
.dashboard-progress, .dashboard-resume { min-height: 150px; padding: 22px 24px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); }
.dashboard-label { color: var(--teal-700); font-size: 10px; font-weight: 850; }
.dashboard-progress > div:first-of-type { display: flex; align-items: baseline; justify-content: space-between; gap: 14px; margin-top: 5px; }
.dashboard-progress strong { font-size: 24px; }
.dashboard-progress > div > span { color: var(--muted); font-size: 12px; font-weight: 750; }
.course-progress-track { height: 8px; overflow: hidden; margin: 12px 0 10px; border-radius: 4px; background: var(--mint-100); }
.course-progress-track span { display: block; width: 0; height: 100%; border-radius: inherit; background: var(--mint-600); transition: width .25s ease; }
.dashboard-progress p, .dashboard-resume p { margin: 0; color: var(--muted); font-size: 12px; }
.dashboard-resume { display: grid; grid-template-columns: minmax(0,1fr) auto; grid-template-rows: auto auto 1fr; column-gap: 16px; }
.dashboard-resume .dashboard-label, .dashboard-resume strong, .dashboard-resume p { grid-column: 1; }
.dashboard-resume strong { margin-top: 5px; color: var(--teal-950); font-size: 16px; line-height: 1.45; }
.resume-button { grid-column: 2; grid-row: 1 / 4; align-self: center; display: inline-flex; align-items: center; justify-content: center; gap: 7px; min-height: 44px; padding: 0 14px; border-radius: 8px; color: white; background: var(--teal-800); text-decoration: none; font-size: 13px; font-weight: 800; }
.resume-button:hover { background: var(--teal-900); }
.resume-button svg { width: 17px; height: 17px; }
.module-rail { display: grid; grid-template-columns: repeat(6, minmax(0,1fr)); gap: 7px; margin: 22px 0 48px; }
.module-rail a { display: grid; grid-template-columns: 28px minmax(0,1fr); gap: 7px; align-items: center; min-height: 48px; padding: 8px 9px; border: 1px solid var(--line); border-radius: 8px; color: #4c6560; background: var(--paper); text-decoration: none; font-size: 12px; line-height: 1.3; }
.module-rail a:hover { border-color: var(--mint-500); color: var(--teal-900); background: var(--mint-100); }
.module-rail a span { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 7px; color: var(--teal-700); background: var(--mint-100); font-size: 10px; font-weight: 850; }
.module-section { margin: 0 0 56px; scroll-margin-top: 100px; }
.module-section > header { display: grid; grid-template-columns: 50px minmax(0,1fr); gap: 15px; align-items: start; margin-bottom: 18px; }
.module-number { display: grid; place-items: center; width: 48px; height: 48px; border-radius: 8px; color: white; background: var(--teal-900); font-size: 13px; font-weight: 850; }
.module-section header p { margin: 0; color: var(--mint-600); font-size: 10px; font-weight: 850; }
.module-section header h2 { display: block; margin: 1px 0 3px; font-size: 23px; }
.module-section header h2::before { content: none; }
.module-section header span { color: var(--muted); font-size: 13px; }
.chapter-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 11px; }
.chapter-card { display: grid; grid-template-columns: 42px minmax(0,1fr) 18px; gap: 11px; align-items: center; min-height: 94px; padding: 14px; border: 1px solid var(--line); border-radius: var(--radius); color: var(--ink); background: var(--paper); text-decoration: none; transition: border-color .16s ease, box-shadow .16s ease, transform .16s ease; }
.chapter-card:hover { border-color: var(--mint-500); box-shadow: var(--shadow-soft); transform: translateY(-2px); }
.chapter-card-number { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 7px; color: var(--teal-800); background: var(--mint-100); font-size: 11px; font-weight: 850; }
.chapter-card-copy { display: grid; min-width: 0; }
.chapter-card-copy strong { line-height: 1.45; overflow-wrap: anywhere; }
.chapter-card-copy small { margin-top: 5px; color: var(--muted); font-size: 11px; }
.chapter-card-status { display: inline-flex; align-items: center; gap: 5px; width: fit-content; margin-top: 8px; color: #829591; font-size: 10px; font-weight: 750; }
.chapter-card-status svg { width: 12px; height: 12px; }
.chapter-card.is-in-progress .chapter-card-status { color: var(--amber); }
.chapter-card.is-complete .chapter-card-status { color: var(--teal-700); }
.chapter-card.is-complete .chapter-card-number { color: white; background: var(--teal-700); }
.chapter-card > svg { width: 17px; color: var(--mint-600); }
.course-search-empty { padding: 48px 20px; color: var(--muted); text-align: center; }
.course-search-results { margin: 34px 0 56px; }
.course-search-results > header { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin-bottom: 15px; }
.course-search-results h2 { display: block; margin: 2px 0 0; font-size: 23px; }
.course-search-results h2::before { content: none; }
.course-search-results > header > strong { color: var(--muted); font-size: 12px; }
.search-result-list { display: grid; gap: 8px; }
.search-result { display: grid; grid-template-columns: 42px minmax(0,1fr) 18px; gap: 12px; align-items: start; padding: 15px 16px; border: 1px solid var(--line); border-radius: var(--radius); color: inherit; background: var(--paper); text-decoration: none; }
.search-result:hover { border-color: var(--mint-500); box-shadow: var(--shadow-soft); }
.search-result-number { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 7px; color: var(--teal-800); background: var(--mint-100); font-size: 10px; font-weight: 850; }
.search-result-copy { min-width: 0; }
.search-result-copy strong { display: block; line-height: 1.45; }
.search-result-copy small { display: block; margin: 2px 0 6px; color: var(--teal-700); font-weight: 750; }
.search-result-copy p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.58; }
.search-result-copy mark { padding: 0 2px; color: #5d4600; background: var(--highlight); }
.search-result > svg { width: 17px; color: var(--mint-600); margin-top: 11px; }
.course-link.is-complete .course-link-number { color: white; background: var(--teal-700); }
.index-footer { display: flex; justify-content: space-between; gap: 20px; padding: 24px max(24px, calc((100vw - 1180px)/2)); border-top: 1px solid var(--line); color: var(--muted); background: var(--paper); font-size: 12px; }

@media (max-width: 1040px) {
  .chapter-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .module-rail { grid-template-columns: repeat(3, minmax(0,1fr)); }
}

@media (max-width: 860px) {
  :root { --topbar: 112px; }
  .chapter-sidebar { display: none; }
  .page-shell { margin-left: 0; }
  .focus-toggle { display: none; }
  .mobile-only { display: inline-flex; }
  .topbar { grid-template-columns: minmax(0,1fr) auto; min-height: auto; padding: 9px 12px; }
  .topbar-actions { min-width: 0; }
  .topbar-actions .tool-button.mobile-only { min-width: 0; }
  .page-search { grid-column: 1 / -1; grid-row: 2; width: 100%; }
  .lesson-content { padding: 28px 18px 64px; }
  .lesson-header { padding: 27px 24px 25px; }
  h1 { font-size: 27px; }
  .course-intro { grid-template-columns: 1fr; }
  .course-intro-mark { display: none; }
  .learning-dashboard { grid-template-columns: 1fr; }
}

@media (max-width: 620px) {
  body { font-size: 15px; line-height: 1.75; }
  .tool-button { padding: 0 10px; }
  .topbar .tool-button.icon-only { display: none; }
  .lesson-content { padding: 22px 14px 54px; }
  .lesson-header { margin-bottom: 30px; padding: 24px 18px 23px; background-size: 180px auto; }
  .lesson-kicker { align-items: flex-start; flex-direction: column; }
  h1 { font-size: 24px; }
  .lesson-lead { font-size: 15px; }
  .content-section { margin-bottom: 36px; }
  .lesson-quick-nav { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); }
  .lesson-quick-nav a { justify-content: flex-start; }
  h2 { font-size: 19px; gap: 10px; }
  h3 { font-size: 17px; }
  .callout { grid-template-columns: 34px minmax(0,1fr); gap: 10px; padding: 14px; }
  .callout-icon { width: 32px; height: 32px; }
  .table-wrap { margin-left: -2px; margin-right: -2px; }
  th, td { min-width: 116px; padding: 10px; }
  .lesson-pager { grid-template-columns: 1fr; }
  .pager-link.next { grid-column: 1; }
  .lesson-completion { grid-template-columns: 1fr; padding: 20px 18px; }
  .completion-button { width: 100%; }
  .index-topbar { align-items: stretch; flex-direction: column; padding: 10px 14px; }
  .index-search { width: 100%; }
  .index-page { width: min(100% - 28px, 1180px); padding-top: 20px; }
  .course-intro { min-height: 0; padding: 28px 20px 30px; }
  .course-intro::before { inset: 0; opacity: .09; }
  .course-intro h1 { font-size: 29px; }
  .course-intro-copy > p:not(.index-eyebrow) { font-size: 15px; }
  .course-stats { gap: 12px; }
  .dashboard-progress, .dashboard-resume { padding: 18px; }
  .dashboard-resume { grid-template-columns: 1fr; }
  .dashboard-resume .dashboard-label, .dashboard-resume strong, .dashboard-resume p, .resume-button { grid-column: 1; }
  .resume-button { grid-row: auto; width: 100%; margin-top: 14px; }
  .module-rail { grid-template-columns: repeat(2, minmax(0,1fr)); margin-bottom: 38px; }
  .module-section { margin-bottom: 44px; }
  .module-section > header { grid-template-columns: 42px minmax(0,1fr); gap: 12px; }
  .module-number { width: 40px; height: 40px; }
  .module-section header h2 { font-size: 20px; }
  .chapter-grid { grid-template-columns: 1fr; }
  .chapter-card { min-height: 84px; }
  .search-result { grid-template-columns: 38px minmax(0,1fr); }
  .search-result-number { width: 36px; height: 36px; }
  .search-result > svg { display: none; }
  .index-footer { align-items: flex-start; flex-direction: column; padding: 20px 14px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; }
}

@media print {
  body { background: white; }
  .reading-progress, .chapter-sidebar, .topbar, .drawer, .drawer-backdrop, .lesson-pager { display: none !important; }
  .page-shell { margin: 0; }
  .lesson-content { width: auto; padding: 0; }
  .lesson-header { box-shadow: none; }
  .answer-reveal > summary { display: none; }
  .answer-reveal { border: 0; }
  .answer-body { display: block !important; padding: 0; }
}