:root {
    --bg: #F2E6CC;
    --paper: #FBF3DE;
    --soft: #E8D9B5;
    --ink: #2B1F12;
    --muted: #5A4730;
    --faint: #806B4D;
    --line: #2B1F12;
    --line-soft: #D1BF9B;
    --accent: #C7401F;
    --accent-hover: #A83216;
    --blue: #285A8E;
    --red-soft: #F4D9C8;
    --code-bg: #EEE1C4;
    --shadow: 3px 3px 0 var(--line);
    --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    color-scheme: light;
}
:root[data-theme="dark"] {
    --bg: #0E1A2E;
    --paper: #0A1424;
    --soft: #182842;
    --ink: #F2E6CC;
    --muted: #B9C6DC;
    --faint: #8798B2;
    --line: #E8D9B5;
    --line-soft: #30425E;
    --accent: #FF7464;
    --accent-hover: #FF9184;
    --blue: #79ACFF;
    --red-soft: #351C26;
    --code-bg: #111F35;
    color-scheme: dark;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--bg); }
body { margin: 0; min-width: 320px; background: var(--bg); color: var(--ink); font: 16px/1.55 var(--sans); }
button, a, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { color: inherit; }
a { color: inherit; }
button:focus-visible, a:focus-visible, summary:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
[hidden] { display: none !important; }
.skip-link { position: fixed; z-index: 100; top: -60px; left: 16px; padding: 12px; background: var(--blue); color: white; }
.skip-link:focus { top: 12px; }
.app-shell { display: grid; grid-template-columns: 236px minmax(0, 1fr); min-height: 100vh; }
.sidebar { position: sticky; top: 0; z-index: 20; display: flex; flex-direction: column; height: 100vh; padding: 24px 18px 18px; border-right: 2px solid var(--line); background: var(--paper); }
.brand { display: flex; align-items: center; gap: 11px; text-decoration: none; }
.brand-mark { width: 34px; height: 34px; color: var(--accent); }
.brand strong, .brand small { display: block; }
.brand strong { font-size: 17px; letter-spacing: -.02em; }
.brand small { color: var(--muted); font: 11px var(--mono); }
.main-nav { display: grid; gap: 6px; margin-top: 42px; }
.main-nav a { padding: 11px 12px; border: 2px solid transparent; text-decoration: none; font-size: 14px; font-weight: 650; }
.main-nav a:hover { background: var(--soft); }
.main-nav a.active { border-color: var(--line); background: var(--accent); color: var(--paper); box-shadow: 2px 2px 0 var(--line); }
.account { margin-top: auto; padding-top: 18px; border-top: 1px solid var(--line-soft); }
#login-widget { min-height: 40px; overflow: hidden; }
#login-widget iframe { max-width: 100%; }
#user-card { display: grid; grid-template-columns: 34px minmax(0, 1fr); gap: 10px; align-items: center; }
#user-card img { width: 34px; height: 34px; border: 1px solid var(--line); object-fit: cover; }
#user-card strong, #user-card small { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
#user-card strong { font-size: 13px; }
#user-card small { color: var(--muted); font-size: 11px; }
#logout { grid-column: 1 / -1; justify-self: start; }
.icon-button { padding: 4px 0; border: 0; background: transparent; color: var(--blue); cursor: pointer; font-size: 12px; }
.main-content { min-width: 0; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 18px; min-height: 66px; padding: 10px clamp(20px, 4vw, 58px); border-bottom: 2px solid var(--line); background: var(--paper); }
.breadcrumb { display: flex; gap: 10px; align-items: center; font-size: 12px; }
.breadcrumb > span { color: var(--muted); }
.breadcrumb > span::after { content: '/'; margin-left: 10px; color: var(--faint); }
.breadcrumb b { font-weight: 650; }
.menu-button { display: none; border: 2px solid var(--line); background: var(--paper); padding: 7px 10px; cursor: pointer; }
.theme-toggle { display: inline-flex; align-items: center; gap: 7px; min-height: 38px; padding: 7px 10px; border: 2px solid var(--line); background: transparent; cursor: pointer; font-size: 12px; }
.theme-toggle:hover { background: var(--soft); }
#theme-icon { color: var(--accent); font-size: 18px; }
.view, .welcome, .subscription-panel { width: min(1100px, calc(100% - 48px)); margin-inline: auto; }
.welcome { padding: 48px 0 42px; border-bottom: 1px solid var(--line-soft); }
h1 { margin: 0; font-size: clamp(34px, 4.5vw, 52px); line-height: 1.1; letter-spacing: -.045em; }
.lead { max-width: 680px; margin: 20px 0; color: var(--muted); font-size: 17px; line-height: 1.65; }
.text-link { display: inline-flex; gap: 18px; align-items: center; color: var(--blue); font-size: 14px; font-weight: 700; text-decoration: none; }
.text-link:hover { text-decoration: underline; text-underline-offset: 4px; }
.subscription-panel { display: grid; grid-template-columns: 30px 1fr auto; gap: 16px; align-items: center; margin-top: 26px; padding: 16px 18px; border: 2px solid var(--line); background: var(--red-soft); box-shadow: var(--shadow); }
.lock-icon { color: var(--accent); }
.subscription-panel strong { font-size: 14px; }
.subscription-panel p { margin: 4px 0 0; color: var(--muted); font-size: 12px; }
.subscription-actions { display: flex; gap: 9px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 42px; padding: 9px 14px; border: 2px solid var(--line); background: var(--paper); box-shadow: 2px 2px 0 var(--line); cursor: pointer; text-decoration: none; font-size: 12px; font-weight: 700; }
.button:hover:not(:disabled) { box-shadow: 4px 4px 0 var(--line); }
.button:active:not(:disabled) { transform: translate(2px, 2px); box-shadow: none; }
.button:disabled { cursor: default; opacity: .6; }
.button-red { background: var(--accent); color: #FFF8E8; }
.button-red:hover { background: var(--accent-hover); }
.button-blue { background: var(--blue); color: #FFF8E8; }
.button-quiet { background: var(--paper); color: var(--ink); }
.view { padding: 38px 0 54px; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 24px; }
h2 { margin: 0; font-size: clamp(26px, 3vw, 34px); letter-spacing: -.035em; }
.section-meta { color: var(--muted); font: 12px var(--mono); }
.module-block { margin-bottom: 16px; border: 2px solid var(--line); background: var(--paper); box-shadow: var(--shadow); }
.module-block > summary { display: flex; align-items: center; gap: 12px; padding: 16px 18px; cursor: pointer; list-style: none; font-size: 15px; font-weight: 750; }
.module-block > summary::-webkit-details-marker { display: none; }
.module-block > summary::after { content: '+'; margin-left: auto; color: var(--accent); font: 22px var(--mono); }
.module-block[open] > summary::after { content: '−'; }
.module-block > summary .module-number { color: var(--accent); font: 12px var(--mono); }
.module-block > summary .module-count { margin-left: auto; color: var(--muted); font: 11px var(--mono); font-weight: 400; }
.module-block > summary::after { margin-left: 0; }
.module-lessons { border-top: 1px solid var(--line-soft); }
.lesson-row { display: grid; grid-template-columns: 30px 1fr auto; gap: 13px; align-items: center; width: 100%; padding: 15px 18px; border: 0; border-bottom: 1px solid var(--line-soft); background: transparent; text-align: left; cursor: pointer; }
.module-lessons .lesson-row:last-child { border-bottom: 0; }
.lesson-row:hover { background: var(--soft); }
.lesson-status { display: grid; place-items: center; width: 26px; height: 26px; border: 2px solid var(--line-soft); color: var(--blue); }
.lesson-status.done { border-color: var(--line); background: var(--blue); color: #FFF8E8; }
.lesson-status.is-locked { color: var(--accent); }
.lesson-meta { min-width: 0; }
.lesson-meta strong, .lesson-meta small { display: block; }
.lesson-meta strong { font-size: 14px; line-height: 1.45; }
.lesson-meta small { margin-top: 4px; color: var(--muted); font-size: 11px; line-height: 1.45; }
.lesson-order { color: var(--faint); font: 11px var(--mono); }
.back-button { margin-bottom: 24px; padding: 0; border: 0; background: transparent; color: var(--blue); cursor: pointer; font-size: 13px; }
.lesson-article { max-width: 900px; margin: 0 auto; padding: clamp(22px, 4vw, 50px); border: 2px solid var(--line); background: var(--paper); box-shadow: var(--shadow); }
.article-header { padding-bottom: 16px; border-bottom: 1px solid var(--line-soft); }
.article-meta { margin: 0 0 10px; color: var(--muted); font-size: 12px; }
.article-tags { display: flex; flex-wrap: wrap; gap: 7px; }
.article-tags span { color: var(--faint); font: 10px var(--mono); }
.article-tags span:not(:last-child)::after { content: ' /'; }
.markdown-body { font-size: 16px; line-height: 1.8; }
.markdown-body h1 { margin: 28px 0 22px; font-size: clamp(28px, 4vw, 40px); line-height: 1.18; }
.markdown-body h2 { margin: 38px 0 14px; font-size: 23px; line-height: 1.3; }
.markdown-body h3 { margin: 30px 0 12px; font-size: 18px; line-height: 1.4; }
.markdown-body p, .markdown-body li { color: var(--ink); }
.markdown-body a { color: var(--blue); text-underline-offset: 3px; overflow-wrap: anywhere; }
.markdown-body code { padding: .12em .32em; background: var(--code-bg); font: .88em var(--mono); overflow-wrap: anywhere; }
.markdown-body pre { overflow-x: auto; padding: 18px; border: 2px solid var(--line); background: var(--code-bg); }
.markdown-body pre code { display: block; padding: 0; background: transparent; font-size: 13px; line-height: 1.65; overflow-wrap: normal; }
.markdown-body table { display: block; max-width: 100%; margin: 22px 0; border-collapse: collapse; overflow-x: auto; font-size: 14px; }
.markdown-body th, .markdown-body td { min-width: 110px; padding: 10px 12px; border: 1px solid var(--line-soft); text-align: left; }
.markdown-body th { background: var(--soft); }
.markdown-body blockquote { margin-left: 0; padding-left: 18px; border-left: 3px solid var(--accent); }
.markdown-body img { max-width: 100%; }
:root[data-theme="dark"] .hljs { color: var(--ink); }
:root[data-theme="dark"] .hljs-keyword, :root[data-theme="dark"] .hljs-selector-tag, :root[data-theme="dark"] .hljs-literal { color: #FF9184; }
:root[data-theme="dark"] .hljs-string, :root[data-theme="dark"] .hljs-attr, :root[data-theme="dark"] .hljs-template-variable { color: #A7D8A0; }
:root[data-theme="dark"] .hljs-title, :root[data-theme="dark"] .hljs-name, :root[data-theme="dark"] .hljs-type { color: #79ACFF; }
:root[data-theme="dark"] .hljs-comment, :root[data-theme="dark"] .hljs-quote { color: #8798B2; }
.completion-box { display: flex; align-items: center; justify-content: space-between; gap: 20px; margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--line-soft); }
.completion-box strong { font-size: 14px; }
.completion-box p { margin: 4px 0 0; color: var(--muted); font-size: 12px; }
.locked-lesson { padding: 28px 0; text-align: center; }
.locked-lesson .large-lock { display: block; margin-bottom: 22px; color: var(--accent); }
.locked-lesson .large-lock svg { width: 44px; height: 44px; }
.locked-lesson h2 { font-size: 28px; }
.locked-lesson p:not(.article-meta) { margin: 16px auto 24px; color: var(--muted); }
.locked-lesson .button { margin: 4px; }
.progress-number { text-align: right; }
.progress-number strong, .progress-number span { display: block; }
.progress-number strong { color: var(--blue); font: 30px var(--mono); }
.progress-number span { color: var(--muted); font-size: 11px; }
.dashboard-grid { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 20px; }
.graph-notebook, .progress-notes > section, .tag-lessons { border: 2px solid var(--line); background: var(--paper); box-shadow: var(--shadow); }
.graph-header { display: flex; justify-content: space-between; gap: 14px; padding: 18px 20px 14px; }
.graph-header h3, .progress-notes h3 { margin: 0; font-size: 16px; }
.graph-hint { max-width: 190px; color: var(--faint); font-size: 10px; line-height: 1.5; text-align: right; }
.graph-stage { height: 450px; overflow: hidden; border-block: 1px solid var(--line-soft); cursor: grab; }
.graph-stage:active { cursor: grabbing; }
.graph-stage canvas { display: block; }
.graph-legend { display: flex; flex-wrap: wrap; gap: 14px; padding: 13px 20px; }
.graph-legend span { display: flex; align-items: center; gap: 6px; color: var(--muted); font-size: 10px; }
.graph-legend i { width: 8px; height: 8px; }
.graph-legend .learned { background: #285A8E; }
.graph-legend .partial { background: #79ACFF; }
.graph-legend .unlearned { background: #B9C6DC; }
.graph-legend .locked { background: #806B4D; }
.progress-notes { display: grid; align-content: start; gap: 18px; }
.progress-notes > section { padding: 18px; }
.progress-notes h3 { margin-bottom: 18px; }
.module-progress { margin-bottom: 18px; }
.module-progress > div:first-child { display: flex; justify-content: space-between; gap: 8px; font-size: 11px; }
.module-progress span { color: var(--muted); font: 10px var(--mono); }
.progress-track { height: 5px; margin-top: 8px; border: 1px solid var(--line); }
.progress-track i { display: block; height: 100%; background: var(--blue); transition: width .4s; }
.recent-lesson { display: block; width: 100%; padding: 11px 0; border: 0; border-top: 1px solid var(--line-soft); background: transparent; text-align: left; cursor: pointer; }
.recent-lesson strong, .recent-lesson small { display: block; }
.recent-lesson strong { font-size: 11px; line-height: 1.45; }
.recent-lesson small { margin-top: 3px; color: var(--muted); font-size: 10px; }
.muted, .empty, .loading { color: var(--muted); font-size: 13px; }
.tag-lessons { display: grid; grid-template-columns: 160px 1fr; gap: 22px; margin-top: 20px; padding: 20px; }
.tag-lessons h3 { margin: 0; color: var(--blue); font: 22px var(--mono); }
.tag-lessons button { display: block; width: 100%; padding: 10px 0; border: 0; border-bottom: 1px solid var(--line-soft); background: transparent; text-align: left; cursor: pointer; font-size: 12px; }
.tag-lessons button span { margin-right: 9px; color: var(--blue); }
.graph-fallback { max-height: 450px; overflow: auto; padding: 20px; border-block: 1px solid var(--line-soft); }
.graph-fallback h4 { margin-top: 0; }
.graph-fallback ul { padding-left: 20px; }
.graph-fallback li { margin-bottom: 13px; }
.graph-fallback button { padding: 0; border: 0; background: transparent; color: var(--blue); cursor: pointer; text-align: left; }
.graph-fallback small { display: block; margin-top: 4px; color: var(--muted); }
footer { display: flex; justify-content: space-between; gap: 18px; padding: 22px clamp(20px, 4vw, 58px); border-top: 2px solid var(--line); color: var(--muted); font-size: 11px; }
footer a { color: var(--blue); text-decoration: none; }
.toast { position: fixed; z-index: 100; right: 20px; bottom: 20px; max-width: min(400px, calc(100% - 40px)); padding: 14px 16px; border: 2px solid var(--line); background: var(--paper); box-shadow: var(--shadow); color: var(--ink); font-size: 13px; }
.toast.error { border-color: var(--accent); }
.error-text { color: var(--accent); }
@media (max-width: 1000px) {
    .app-shell { grid-template-columns: 210px minmax(0, 1fr); }
    .dashboard-grid { grid-template-columns: 1fr; }
    .progress-notes { grid-template-columns: 1fr 1fr; }
    .subscription-panel { grid-template-columns: 30px 1fr; }
    .subscription-actions { grid-column: 2; }
}
@media (max-width: 720px) {
    .app-shell { display: block; }
    .sidebar { position: fixed; left: 0; width: 250px; transform: translateX(-105%); transition: transform .18s; box-shadow: 5px 0 0 rgba(0,0,0,.2); }
    .sidebar.open { transform: translateX(0); }
    .topbar { padding-inline: 14px; }
    .menu-button { display: block; }
    .breadcrumb > span { display: none; }
    #theme-label { display: none; }
    .view, .welcome, .subscription-panel { width: calc(100% - 28px); }
    .welcome { padding-top: 34px; }
    h1 { font-size: 36px; }
    .lead { font-size: 15px; }
    .view { padding-top: 28px; }
    .section-heading { align-items: start; flex-direction: column; gap: 8px; }
    .section-heading .progress-number { text-align: left; }
    .lesson-row { grid-template-columns: 28px 1fr; padding-inline: 12px; }
    .lesson-order { display: none; }
    .lesson-article { padding: 22px 16px; }
    .markdown-body { font-size: 15px; }
    .completion-box { align-items: stretch; flex-direction: column; }
    .graph-hint { display: none; }
    .graph-stage { height: 390px; }
    .progress-notes { grid-template-columns: 1fr; }
    .tag-lessons { grid-template-columns: 1fr; }
    .subscription-actions { flex-wrap: wrap; }
    footer { flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}