:root {
  --navy-950: #061426;
  --navy-900: #091d34;
  --navy-800: #102b49;
  --teal-700: #087b78;
  --teal-600: #0d918c;
  --teal-100: #dff4f1;
  --gold-500: #d2a856;
  --gold-100: #f4e7c8;
  --paper: #f6f7f8;
  --surface: #fff;
  --ink: #13273d;
  --muted: #627185;
  --line: #dfe5e9;
  --shadow: 0 22px 60px rgba(9, 29, 52, 0.1);
  --sidebar-width: 306px;
  --reading-scale: 1;
  color-scheme: light;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.65 "Segoe UI", Arial, sans-serif; }
button, select { font: inherit; }
button { color: inherit; }
.skip-link { position: fixed; z-index: 100; top: 12px; left: 12px; transform: translateY(-150%); padding: 10px 16px; border-radius: 8px; background: #fff; color: var(--navy-900); box-shadow: var(--shadow); }
.skip-link:focus { transform: none; }
.app-shell { min-height: 100vh; }

.sidebar { position: fixed; inset: 0 auto 0 0; z-index: 30; display: flex; width: var(--sidebar-width); flex-direction: column; overflow: hidden; background: var(--navy-950); color: #fff; }
.brand-block { display: flex; align-items: center; gap: 13px; min-height: 86px; padding: 18px 24px; border-bottom: 1px solid rgba(255,255,255,.1); }
.brand-mark { display: grid; width: 46px; height: 46px; flex: 0 0 46px; place-items: center; border: 1px solid rgba(210,168,86,.58); border-radius: 13px; background: linear-gradient(145deg, rgba(210,168,86,.17), transparent); }
.brand-mark svg { width: 29px; fill: none; stroke: var(--gold-500); stroke-linejoin: round; stroke-width: 1.5; }
.eyebrow, .brand-block p, .sidebar-footer p { margin: 0; }
.eyebrow { color: rgba(255,255,255,.62); font-size: .73rem; font-weight: 700; letter-spacing: .09em; line-height: 1.35; text-transform: uppercase; }

.course-progress { margin: 20px 20px 9px; padding: 14px 15px; border: 1px solid rgba(255,255,255,.08); border-radius: 12px; background: rgba(255,255,255,.045); }
.progress-copy { display: flex; align-items: center; justify-content: space-between; color: rgba(255,255,255,.66); font-size: .8rem; }
.progress-copy strong { color: #fff; font-size: .82rem; }
.progress-track { height: 5px; margin-top: 10px; overflow: hidden; border-radius: 99px; background: rgba(255,255,255,.11); }
.progress-track span { display: block; width: 6.67%; height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--gold-500), #f0ce86); }

.lesson-navigation { min-height: 0; flex: 1 1 auto; padding: 13px 11px 20px; overflow-y: auto; scrollbar-color: rgba(255,255,255,.16) transparent; scrollbar-width: thin; }
.navigation-title { margin: 0 13px 9px; color: rgba(255,255,255,.47); font-size: .75rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; }
.lesson-list { margin: 0; padding: 0 4px 6px; list-style: none; }
.lesson-link { display: grid; grid-template-columns: 28px 1fr 18px; gap: 7px; align-items: start; width: 100%; margin: 2px 0; padding: 10px 9px; border: 0; border-radius: 10px; background: transparent; color: rgba(255,255,255,.67); text-align: left; cursor: pointer; }
.lesson-link:hover, .lesson-link:focus-visible { background: rgba(255,255,255,.065); color: #fff; outline: none; }
.lesson-link.active { background: linear-gradient(90deg, rgba(13,145,140,.3), rgba(13,145,140,.1)); color: #fff; }
.lesson-number { color: rgba(255,255,255,.38); font-size: .75rem; font-weight: 700; letter-spacing: .05em; line-height: 1.7; }
.lesson-link.active .lesson-number { color: #6ee0d8; }
.lesson-name { font-size: .84rem; font-weight: 600; line-height: 1.42; }
.lesson-status { display: grid; width: 18px; height: 18px; place-items: center; margin-top: 1px; border-radius: 50%; color: rgba(255,255,255,.34); }
.lesson-link.active .lesson-status { background: var(--teal-600); color: #fff; }
.lesson-skeleton { height: 54px; margin: 6px 5px; border-radius: 10px; background: linear-gradient(90deg,rgba(255,255,255,.03),rgba(255,255,255,.075),rgba(255,255,255,.03)); background-size: 220% 100%; animation: shimmer 1.5s infinite; }
.sidebar-reference-link { display: grid; grid-template-columns: 32px 1fr; gap: 10px; align-items: center; width: calc(100% - 8px); margin: 10px 4px 2px; padding: 11px 10px; border: 1px solid rgba(210,168,86,.2); border-radius: 11px; background: rgba(210,168,86,.06); color: rgba(255,255,255,.73); text-align: left; cursor: pointer; }
.sidebar-reference-link span { display: grid; width: 30px; height: 30px; place-items: center; border-radius: 9px; background: rgba(210,168,86,.14); color: #f0ce86; font: 700 .78rem Georgia,serif; }
.sidebar-reference-link strong { font-size: .78rem; line-height: 1.35; }
.sidebar-reference-link:hover, .sidebar-reference-link:focus-visible { border-color: rgba(210,168,86,.48); background: rgba(210,168,86,.12); color: #fff; outline: none; }
.sidebar-reference-link.active { border-color: rgba(13,145,140,.6); background: linear-gradient(90deg,rgba(13,145,140,.32),rgba(13,145,140,.1)); color: #fff; }
.sidebar-reference-link.active span { background: var(--teal-600); color: #fff; }
.sidebar-footer { margin-top: auto; padding: 15px 24px 20px; border-top: 1px solid rgba(255,255,255,.08); color: rgba(255,255,255,.42); font-size: .72rem; line-height: 1.45; }
.sidebar-footer span { display: block; margin-top: 5px; }

.workspace { min-height: 100vh; margin-left: var(--sidebar-width); }
.topbar { position: sticky; top: 0; z-index: 20; display: flex; height: 66px; align-items: center; justify-content: space-between; padding: 0 clamp(20px,4vw,58px); border-bottom: 1px solid rgba(19,39,61,.08); background: rgba(246,247,248,.91); backdrop-filter: blur(15px); }
.breadcrumbs { display: flex; align-items: center; gap: 9px; color: var(--muted); font-size: .85rem; }
.breadcrumbs strong { color: var(--ink); }
.breadcrumbs svg { width: 13px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; }
.topbar-actions { display: flex; gap: 7px; }
.icon-button, .text-button { display: grid; width: 38px; height: 38px; place-items: center; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); cursor: pointer; }
.icon-button:hover, .text-button:hover, .icon-button:focus-visible, .text-button:focus-visible { border-color: var(--teal-600); outline: 3px solid rgba(13,145,140,.13); }
.icon-button svg { width: 19px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.8; }
.text-button { font: 700 .86rem Georgia, serif; }
.menu-button { display: none; }

main { width: min(1120px, calc(100% - 48px)); margin: 0 auto; padding: 34px 0 80px; }
.course-intro { position: relative; display: flex; min-height: 270px; align-items: center; justify-content: center; overflow: hidden; padding: clamp(31px,4.5vw,52px) clamp(54px,8vw,108px); border-radius: 22px; background: radial-gradient(circle at 86% 28%,rgba(13,145,140,.25),transparent 24%),linear-gradient(120deg,var(--navy-950),var(--navy-800)); box-shadow: var(--shadow); color: #fff; text-align: center; }
.course-intro::after { position: absolute; right: 17%; bottom: -58px; width: 200px; height: 200px; border: 1px solid rgba(210,168,86,.18); border-radius: 50%; content: ""; }
.intro-copy { position: relative; z-index: 2; width: min(860px,100%); }
.cover-institution { margin: 0 0 6px; color: rgba(255,255,255,.75); font-size: clamp(.72rem,1.3vw,.88rem); font-weight: 650; letter-spacing: .045em; }
.school-label { margin: 0 0 19px; color: #79d8d2; font-size: .76rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; }
.course-intro h1 { max-width: 820px; margin: 0 auto; font: 500 clamp(1.48rem,2.5vw,2.18rem)/1.2 Georgia,"Times New Roman",serif; letter-spacing: -.018em; }
.cover-page-navigation { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; width: min(650px,100%); margin: 26px auto 0; }
.cover-page-link { display: flex; min-height: 43px; align-items: center; gap: 10px; padding: 9px 14px; border: 1px solid rgba(255,255,255,.17); border-radius: 11px; background: rgba(255,255,255,.075); color: rgba(255,255,255,.84); cursor: pointer; backdrop-filter: blur(8px); }
.cover-page-link:first-child { justify-content: flex-start; text-align: left; }
.cover-page-link:last-child { justify-content: flex-end; text-align: right; }
.cover-page-link strong { font-size: .82rem; letter-spacing: .015em; }
.cover-page-link span { color: #76d9d3; font-size: 1rem; transition: transform 160ms ease; }
.cover-page-link:hover, .cover-page-link:focus-visible, .cover-page-link.active { border-color: rgba(118,217,211,.55); background: rgba(13,145,140,.24); color: #fff; outline: none; }
.cover-page-link:first-child:hover span, .cover-page-link:first-child:focus-visible span { transform: translateX(-3px); }
.cover-page-link:last-child:hover span, .cover-page-link:last-child:focus-visible span { transform: translateX(3px); }
.intro-monogram { position: absolute; z-index: 1; right: -18px; bottom: -27px; display: grid; width: 150px; height: 150px; place-items: center; border: 1px solid rgba(210,168,86,.32); border-radius: 50%; color: rgba(210,168,86,.5); font: 2.15rem Georgia,serif; letter-spacing: .08em; opacity: .72; }
.intro-monogram::before { position: absolute; inset: 9px; border: 1px solid rgba(255,255,255,.08); border-radius: inherit; content: ""; }
.intro-monogram svg { position: absolute; inset: 15px; width: 120px; fill: none; stroke: rgba(210,168,86,.25); stroke-width: 1; }

.lesson-heading { display: grid; grid-template-columns: 80px 1fr; gap: 23px; align-items: center; margin: 44px 0 25px; }
.lesson-index { display: grid; min-height: 72px; place-content: center; border-right: 1px solid var(--line); text-align: center; }
.lesson-index span { color: var(--teal-700); font: 2.1rem/1 Georgia,serif; }
.lesson-index small { margin-top: 5px; color: var(--muted); font-size: .7rem; font-weight: 700; letter-spacing: .07em; text-transform: uppercase; }
.eyebrow.accent { color: var(--teal-700); }
.lesson-heading h2 { margin: 6px 0 0; font: 500 clamp(1.55rem,2.7vw,2.3rem)/1.25 Georgia,"Times New Roman",serif; }
.supplementary-heading { margin: 45px auto 0; text-align: center; }
.supplementary-heading h2 { margin: 7px 0 0; color: var(--navy-900); font: 500 clamp(1.8rem,3vw,2.65rem)/1.2 Georgia,"Times New Roman",serif; }
.lesson-overview { display: grid; grid-template-columns: minmax(0,1.2fr) minmax(320px,.8fr); gap: 16px; }
.goal-card, .plan-card { border: 1px solid var(--line); border-radius: 16px; background: var(--surface); }
.goal-card { display: grid; grid-template-columns: 52px 1fr; gap: 18px; align-items: start; padding: 25px; border-left: 4px solid var(--teal-600); }
.card-icon { display: grid; width: 48px; height: 48px; place-items: center; border-radius: 13px; background: var(--teal-100); color: var(--teal-700); }
.card-icon svg { width: 26px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.7; }
.card-label { margin: 0 0 7px; color: var(--teal-700); font-size: .75rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.goal-card p:last-child { margin: 0; font-size: .98rem; line-height: 1.62; }
.plan-card { padding: 23px 25px; }
.plan-card ol { display: grid; gap: 8px; margin: 12px 0 0; padding: 0; counter-reset: plan; list-style: none; }
.plan-card li { display: grid; grid-template-columns: 25px 1fr; gap: 8px; align-items: start; color: #415166; font-size: .9rem; line-height: 1.45; counter-increment: plan; }
.plan-card li::before { display: grid; width: 21px; height: 21px; place-items: center; border-radius: 6px; background: var(--gold-100); color: #8c6725; content: counter(plan); font-size: .69rem; font-weight: 800; }

.media-strip { display: grid; grid-template-columns: 46px 1fr auto auto; gap: 15px; align-items: center; margin-top: 16px; padding: 16px 20px; border: 1px solid var(--line); border-radius: 14px; background: linear-gradient(100deg,var(--surface),color-mix(in srgb,var(--teal-100) 48%,#fff)); }
.media-icon { display: grid; width: 43px; height: 43px; place-items: center; border-radius: 12px; background: var(--navy-900); color: #fff; }
.media-icon svg { width: 23px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.7; }
.media-strip p { margin: 0 0 1px; }
.media-strip strong { display: block; color: var(--navy-900); font-size: .93rem; }
.media-strip div > span { display: block; color: var(--muted); font-size: .78rem; }
.status-pill { padding: 5px 9px; border-radius: 99px; background: var(--gold-100); color: #7c5a1d; font-size: .72rem; font-weight: 800; }
.media-action { padding: 8px 12px; border-radius: 9px; background: var(--teal-600); color: #fff; font-size: .8rem; font-weight: 700; text-decoration: none; }
.video-player { grid-column: 1 / -1; width: 100%; margin-top: 3px; overflow: hidden; border-radius: 13px; background: #061426; box-shadow: 0 12px 30px rgb(7 24 45 / 14%); aspect-ratio: 16 / 9; }
.video-player iframe, .video-player video { display: block; width: 100%; height: 100%; border: 0; background: #000; }
.video-player-message { display: grid; height: 100%; place-content: center; gap: 10px; padding: 30px; color: #fff; text-align: center; }
.video-player-message a { color: #7fe1dd; font-weight: 700; }

.section-tabs { display: flex; gap: 3px; margin-top: 30px; overflow-x: auto; border-bottom: 1px solid var(--line); }
.section-tab { position: relative; min-width: max-content; padding: 13px 18px; border: 0; background: transparent; color: var(--muted); font-size: .87rem; font-weight: 700; }
.section-tab.active { color: var(--navy-900); }
.section-tab.active::after { position: absolute; right: 12px; bottom: -1px; left: 12px; height: 3px; border-radius: 3px 3px 0 0; background: var(--teal-600); content: ""; }
.section-tab { cursor: pointer; }
.section-tab:hover, .section-tab:focus-visible { color: var(--teal-700); outline: none; }
.tab-count { display: inline-grid; min-width: 22px; height: 20px; place-items: center; margin-left: 4px; padding: 0 5px; border-radius: 99px; background: var(--teal-100); color: var(--teal-700); font-size: .69rem; }
.reading-surface { width: min(900px,100%); margin: 0 auto; padding: 46px 0 20px; font-size: calc(1rem * var(--reading-scale)); }
.reading-surface h3 { position: relative; margin: 2.15em 0 .8em; padding-left: 15px; color: var(--navy-900); font: 600 clamp(1.18em,2vw,1.42em)/1.35 Georgia,"Times New Roman",serif; letter-spacing: -.008em; }
.reading-surface h3::before { position: absolute; top: .14em; bottom: .12em; left: 0; width: 3px; border-radius: 99px; background: linear-gradient(var(--teal-600),var(--gold-500)); content: ""; }
.reading-surface h3:first-child { margin-top: 0; }
.reading-surface p { margin: 0 0 1.12em; color: #344a60; line-height: 1.8; text-wrap: pretty; }
.static-page-intro { margin-bottom: 30px; color: var(--muted); text-align: center; }
.author-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(210px,1fr)); gap: 16px; margin-top: 38px; }
.author-card { overflow: hidden; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); text-align: center; box-shadow: 0 10px 28px rgba(9,29,52,.06); }
.author-photo { display: block; width: 100%; aspect-ratio: 1 / 1; object-fit: cover; background: linear-gradient(145deg,var(--navy-900),var(--teal-700)); }
.author-initials { display: grid; place-items: center; color: rgba(255,255,255,.9); font: 500 2.2rem Georgia,serif; letter-spacing: .06em; }
.author-card-body { padding: 18px 15px 20px; }
.author-card h3 { margin: 0 0 6px; font: 600 1.04rem/1.3 Georgia,serif; }
.author-degree { display: block; color: var(--muted); font-size: .8rem; line-height: 1.5; }
.author-degree.pending { color: #9a7635; font-style: italic; }
.reference-list { display: grid; gap: 13px; margin: 0; padding-left: 1.9rem; }
.reference-list li { padding-left: 7px; color: #33475c; line-height: 1.68; }
.reference-list li::marker { color: var(--teal-700); font-weight: 800; }
.content-list { display: grid; gap: 8px; margin: .25em 0 1.55em; padding: 0; color: #334a60; list-style: none; }
.content-list li { position: relative; padding: 10px 14px 10px 38px; border: 1px solid color-mix(in srgb,var(--line) 84%,var(--teal-600)); border-radius: 10px; background: color-mix(in srgb,var(--surface) 92%,var(--teal-100)); line-height: 1.62; }
.content-list li::before { position: absolute; top: 1.02em; left: 16px; width: 8px; height: 8px; border: 2px solid var(--teal-600); border-radius: 50%; background: var(--surface); content: ""; }
.figure-note { margin: 26px 0; padding: 18px 21px; border: 1px dashed #b7c4cd; border-radius: 12px; background: #f9fbfc; }
.figure-note strong { display: block; color: var(--navy-900); font: 500 1rem Georgia,serif; }
.figure-note span { color: var(--muted); font-size: .86rem; }
.figure-caption { margin: -12px auto 30px !important; color: var(--muted) !important; font: italic .92rem/1.55 Georgia,"Times New Roman",serif; text-align: center; }
.table-scroll { margin: 30px 0 34px; overflow-x: auto; border: 1px solid var(--line); border-radius: 15px; background: var(--surface); box-shadow: 0 12px 32px rgba(9,29,52,.07); }
.content-table { width: 100%; min-width: 560px; margin: 0; border-collapse: separate; border-spacing: 0; background: var(--surface); font-size: .88em; }
.content-table td { padding: 13px 15px; border: 0; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); color: #354a5f; vertical-align: middle; line-height: 1.55; }
.content-table tr:first-child td { background: linear-gradient(110deg,var(--navy-900),var(--navy-800)); color: #fff; font-weight: 700; }
.content-table tr:nth-child(even):not(:first-child) td { background: color-mix(in srgb,var(--teal-100) 28%,#fff); }
.content-table tr:last-child td { border-bottom: 0; }
.content-table td:last-child { border-right: 0; }
.content-table td:first-child { font-weight: 650; }
.content-image { display: block; max-width: 75%; height: auto; margin: 30px auto 24px; padding: 8px; border: 1px solid var(--line); border-radius: 15px; background: #fff; box-shadow: 0 16px 38px rgba(9,29,52,.09); }
.section-kicker { margin: 0 0 8px !important; color: var(--teal-700) !important; font-size: .75rem !important; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.section-intro { margin-bottom: 28px !important; color: var(--muted) !important; }
.student-panel { margin: 0 0 22px; padding: 20px; border: 1px solid var(--line); border-radius: 15px; background: var(--surface); }
.student-panel-header { display: flex; align-items: start; justify-content: space-between; gap: 16px; margin-bottom: 14px; }
.student-panel-header h3 { margin: 0 0 3px; font: 500 1.15rem/1.35 Georgia,"Times New Roman",serif; }
.student-panel-header p { margin: 0; color: var(--muted); font-size: .83rem; line-height: 1.5; }
.required-note { flex: 0 0 auto; color: #a14437; font-size: .72rem; font-weight: 700; }
.student-fields { display: grid; grid-template-columns: minmax(0,1.5fr) minmax(150px,.5fr); gap: 12px; }
.form-field { display: grid; gap: 6px; }
.form-field label { color: var(--navy-900); font-size: .8rem; font-weight: 700; }
.form-field input, .answer-field { width: 100%; border: 1px solid #cfd8de; border-radius: 10px; background: #fff; color: #17283a; font: inherit; }
.form-field input { height: 44px; padding: 8px 12px; }
.form-field input:focus, .answer-field:focus { border-color: var(--teal-600); outline: 3px solid color-mix(in srgb,var(--teal-600) 15%,transparent); }
.form-field input.invalid { border-color: #b84b3d; background: #fff8f7; }
.answer-field { display: block; min-height: 150px; margin-top: 14px; padding: 13px 14px; line-height: 1.6; resize: vertical; }
.answer-label { display: block; margin-top: 17px; color: var(--navy-900); font-size: .82rem; font-weight: 800; }
.answer-saved { display: block; min-height: 18px; margin-top: 5px; color: var(--teal-700); font-size: .72rem; }
.section-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 9px; margin: 0 0 20px; }
.section-actions.bottom { margin: 22px 0 0; }
.danger-button { min-height: 42px; padding: 9px 16px; border: 1px solid #e4c5c0; border-radius: 10px; background: #fff8f7; color: #973f33; font-weight: 700; cursor: pointer; }
.danger-button:hover, .danger-button:focus-visible { border-color: #b84b3d; outline: 3px solid rgba(184,75,61,.12); }
.task-grid { display: grid; gap: 15px; }
.task-card { padding: 24px; border: 1px solid var(--line); border-radius: 15px; background: var(--surface); box-shadow: 0 10px 28px rgba(9,29,52,.045); }
.task-header { display: grid; grid-template-columns: 42px 1fr; gap: 14px; align-items: start; }
.task-number { display: grid; width: 39px; height: 39px; place-items: center; border-radius: 11px; background: var(--teal-100); color: var(--teal-700); font-weight: 800; }
.task-card h3 { margin: 1px 0 14px; font-size: 1.16em; }
.task-body { padding-left: 56px; }
.task-body p, .task-body li { font-size: .93em; }
.quiz-shell { overflow: hidden; border: 1px solid var(--line); border-radius: 17px; background: var(--surface); box-shadow: 0 14px 38px rgba(9,29,52,.06); }
.quiz-topline { display: flex; align-items: center; justify-content: space-between; padding: 16px 20px; border-bottom: 1px solid var(--line); background: #fafbfc; color: var(--muted); font-size: .82rem; }
.quiz-progress { width: 150px; height: 5px; overflow: hidden; border-radius: 99px; background: var(--line); }
.quiz-progress span { display: block; height: 100%; border-radius: inherit; background: var(--teal-600); }
.quiz-question { padding: 28px; }
.quiz-question h3 { margin: 0 0 23px; font-size: 1.35em; }
.option-list { display: grid; gap: 10px; }
.quiz-option { display: grid; grid-template-columns: 33px 1fr; gap: 12px; align-items: center; padding: 13px 15px; border: 1px solid var(--line); border-radius: 11px; cursor: pointer; transition: 150ms ease; }
.quiz-option:hover { border-color: var(--teal-600); background: color-mix(in srgb,var(--teal-100) 38%,#fff); }
.quiz-option:has(input:checked) { border-color: var(--teal-600); background: var(--teal-100); box-shadow: 0 0 0 2px color-mix(in srgb,var(--teal-600) 18%,transparent); }
.quiz-option input { position: absolute; opacity: 0; }
.option-letter { display: grid; width: 31px; height: 31px; place-items: center; border-radius: 8px; background: #eef2f4; color: var(--navy-900); font-weight: 800; }
.quiz-option:has(input:checked) .option-letter { background: var(--teal-600); color: #fff; }
.quiz-option.correct-answer { border-color: #55a77b; background: #edf9f2; }
.quiz-option.correct-answer .option-letter { background: #248357; color: #fff; }
.quiz-option.wrong-answer { border-color: #d58e84; background: #fff3f1; }
.quiz-option.wrong-answer .option-letter { background: #b64d3e; color: #fff; }
.quiz-actions { display: flex; align-items: center; justify-content: space-between; gap: 10px; padding: 17px 20px; border-top: 1px solid var(--line); }
.primary-button, .secondary-button { min-height: 42px; padding: 9px 16px; border-radius: 10px; font-weight: 700; cursor: pointer; }
.primary-button { border: 1px solid var(--teal-600); background: var(--teal-600); color: #fff; }
.secondary-button { border: 1px solid var(--line); background: #fff; color: var(--navy-900); }
.primary-button:hover, .primary-button:focus-visible { background: var(--teal-700); outline: 3px solid color-mix(in srgb,var(--teal-600) 18%,transparent); }
.secondary-button:hover, .secondary-button:focus-visible { border-color: var(--teal-600); outline: 3px solid color-mix(in srgb,var(--teal-600) 14%,transparent); }
.primary-button:disabled, .secondary-button:disabled { cursor: not-allowed; opacity: .45; }
.quiz-note { margin: 15px 0 0 !important; padding: 12px 14px; border-radius: 10px; background: var(--gold-100); color: #6b501d !important; font-size: .82em; line-height: 1.55 !important; }
.result-card { display: grid; grid-template-columns: auto 1fr auto; gap: 18px; align-items: center; margin: 0 0 20px; padding: 19px 21px; border: 1px solid color-mix(in srgb,var(--teal-600) 40%,var(--line)); border-radius: 15px; background: color-mix(in srgb,var(--teal-100) 55%,#fff); }
.result-score { display: grid; width: 72px; height: 72px; place-items: center; border-radius: 50%; background: var(--teal-600); color: #fff; font: 700 1.35rem Georgia,serif; }
.result-card h3 { margin: 0 0 3px; font-size: 1.25em; }
.result-card p { margin: 0; color: var(--muted); font-size: .86em; line-height: 1.5; }
.result-percent { color: var(--teal-700); font: 500 2rem Georgia,serif; }
.control-list { display: grid; gap: 10px; padding: 0; list-style: none; counter-reset: control; }
.control-item { display: grid; grid-template-columns: 42px 1fr; gap: 13px; align-items: start; padding: 18px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); counter-increment: control; }
.control-item::before { display: grid; width: 36px; height: 36px; place-items: center; border-radius: 10px; background: var(--navy-900); color: #fff; content: counter(control, decimal-leading-zero); font-size: .72rem; font-weight: 800; }
.control-content { min-width: 0; }
.control-question { margin: 3px 0 0 !important; color: #33475c !important; font-weight: 600; line-height: 1.55 !important; }
.control-content .answer-field { min-height: 125px; }
.empty-lesson { padding: 34px; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); text-align: center; }
.empty-lesson strong { display: block; margin-bottom: 5px; color: var(--navy-900); font: 500 1.3rem Georgia,serif; }
.print-root { display: none; }
.content-skeleton { width: 87%; height: 15px; margin: 13px 0; border-radius: 5px; background: linear-gradient(90deg,#e9edef,#f7f8f8,#e9edef); background-size: 220% 100%; animation: shimmer 1.5s infinite; }
.content-skeleton.wide { width: 100%; } .content-skeleton.short { width: 64%; }
.error-state { padding: 30px; border: 1px solid #efc8c8; border-radius: 14px; background: #fff5f5; color: #7a2626; }
.toast { position: fixed; right: 24px; bottom: 24px; z-index: 80; max-width: 340px; transform: translateY(18px); padding: 12px 16px; border-radius: 10px; background: var(--navy-950); box-shadow: var(--shadow); color: #fff; font-size: .85rem; opacity: 0; pointer-events: none; transition: 180ms ease; }
.toast.visible { transform: none; opacity: 1; }
.sidebar-backdrop { display: none; }
@keyframes shimmer { to { background-position: -220% 0; } }

@media (max-width: 980px) {
  .sidebar { transform: translateX(-100%); box-shadow: 20px 0 50px rgba(3,14,27,.2); transition: transform 220ms ease; }
  .sidebar.open { transform: none; }
  .sidebar-backdrop { position: fixed; inset: 0; z-index: 25; display: block; border: 0; background: rgba(6,20,38,.48); opacity: 0; pointer-events: none; transition: opacity 220ms ease; }
  .sidebar-backdrop.visible { opacity: 1; pointer-events: auto; }
  .workspace { margin-left: 0; }
  .menu-button { display: grid; }
  .topbar { gap: 15px; }
  .breadcrumbs { margin-right: auto; }
}

@media (max-width: 760px) {
  main { width: min(100% - 28px,680px); padding-top: 18px; }
  .topbar { height: 60px; padding: 0 14px; }
  .breadcrumbs span, .breadcrumbs svg { display: none; }
  .course-intro { min-height: 270px; padding: 29px 22px; }
  .intro-monogram { position: absolute; right: -38px; bottom: -42px; opacity: .45; }
  .course-intro h1 { max-width: 96%; font-size: clamp(1.42rem,6.5vw,1.95rem); }
  .cover-page-navigation { gap: 9px; margin-top: 22px; }
  .cover-page-link { min-height: 42px; padding: 8px 10px; }
  .cover-page-link strong { font-size: .74rem; }
  .cover-institution { line-height: 1.45; }
  .lesson-heading { grid-template-columns: 58px 1fr; gap: 14px; margin-top: 31px; }
  .lesson-index { min-height: 62px; }
  .lesson-index span { font-size: 1.7rem; }
  .lesson-overview { grid-template-columns: 1fr; }
  .media-strip { grid-template-columns: 43px 1fr auto; }
  .media-action { grid-column: 2 / -1; justify-self: start; }
  .video-player { grid-column: 1 / -1; }
  .goal-card { grid-template-columns: 42px 1fr; gap: 13px; padding: 20px; }
  .card-icon { width: 41px; height: 41px; }
  .section-tab { padding-inline: 13px; }
  .reading-surface { padding-top: 34px; }
  .reading-surface h3 { padding-left: 12px; }
  .content-list li { padding: 9px 11px 9px 34px; }
  .content-list li::before { left: 13px; }
  .task-body { padding-left: 0; }
  .student-fields { grid-template-columns: 1fr; }
  .student-panel-header { flex-direction: column; gap: 5px; }
  .section-actions { align-items: stretch; flex-direction: column-reverse; }
  .section-actions button { width: 100%; }
  .quiz-question { padding: 22px 17px; }
  .quiz-actions { align-items: stretch; flex-direction: column-reverse; }
  .quiz-actions button { width: 100%; }
  .result-card { grid-template-columns: 62px 1fr; }
  .result-score { width: 60px; height: 60px; }
  .result-percent { grid-column: 2; }
  .control-item { grid-template-columns: 38px 1fr; padding: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  *,*::before,*::after { scroll-behavior: auto !important; animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

@media print {
  @page { size: A4; margin: 15mm 14mm 18mm; }
  :root { color-scheme: light; }
  body { background: #fff !important; color: #17283a !important; font: 10.5pt/1.5 Arial, sans-serif; }
  body.printing .app-shell, body.printing .toast { display: none !important; }
  body.printing .print-root { display: block !important; width: auto; margin: 0; padding: 0 0 14mm; }
  .print-header { display: grid; grid-template-columns: 42px 1fr; gap: 12px; align-items: center; padding-bottom: 10mm; border-bottom: 2px solid #0d918c; }
  .print-mark { display: grid; width: 40px; height: 40px; place-items: center; border-radius: 9px; background: #091d34 !important; color: #fff !important; font: 700 12pt Georgia,serif; print-color-adjust: exact; }
  .print-header h1 { margin: 0; color: #091d34; font: 700 15pt/1.25 Georgia,serif; }
  .print-header p { margin: 2px 0 0; color: #536273; font-size: 8.5pt; }
  .print-meta { display: grid; grid-template-columns: 1fr 1fr; gap: 4mm 8mm; margin: 8mm 0; padding: 5mm; border: 1px solid #cfd8de; border-radius: 3mm; }
  .print-meta div { min-width: 0; }
  .print-meta span { display: block; color: #687687; font-size: 7.8pt; text-transform: uppercase; }
  .print-meta strong { display: block; margin-top: 1mm; font-size: 10pt; }
  .print-summary { display: grid; grid-template-columns: repeat(3,1fr); gap: 4mm; margin-bottom: 8mm; }
  .print-stat { padding: 4mm; border-radius: 3mm; background: #edf7f6 !important; text-align: center; print-color-adjust: exact; }
  .print-stat strong { display: block; color: #087b78; font-size: 16pt; }
  .print-stat span { color: #536273; font-size: 8pt; }
  .print-section { break-inside: avoid; margin: 0 0 7mm; padding: 0 0 6mm; border-bottom: 1px solid #dfe5e9; }
  .print-section h2 { margin: 0 0 3mm; color: #091d34; font: 700 11pt/1.35 Georgia,serif; }
  .print-section p { margin: 0 0 2mm; }
  .print-answer { min-height: 14mm; padding: 4mm; border-left: 3px solid #0d918c; background: #f5f8f9 !important; white-space: pre-wrap; print-color-adjust: exact; }
  .print-question { break-inside: avoid; margin: 0 0 5mm; padding: 4mm; border: 1px solid #dfe5e9; border-radius: 2.5mm; }
  .print-question h3 { margin: 0 0 2mm; font-size: 10pt; }
  .print-question p { margin: 1mm 0; }
  .print-correct { color: #166a43; font-weight: 700; }
  .print-wrong { color: #9c3c30; font-weight: 700; }
  .print-footer { position: fixed; right: 0; bottom: -10mm; left: 0; display: flex; justify-content: space-between; padding-top: 2mm; border-top: 1px solid #dfe5e9; color: #6b7786; font-size: 7.5pt; }
  .print-page::after { content: counter(page); }
}