:root {
    color-scheme: light;
    --ink: #171b19;
    --ink_soft: #39413d;
    --muted: #68716d;
    --paper: #ffffff;
    --paper_soft: #f3f6f4;
    --line: #d8dfdb;
    --line_dark: #aeb9b3;
    --green: #126a50;
    --green_dark: #0b4837;
    --blue: #3e67a4;
    --coral: #cf6547;
    --yellow: #c99a2e;
    --header_height: 62px;
    --content_width: 1180px;
    --reading_width: 740px;
    font-family: Aptos, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 94px; }
body {
    margin: 0;
    color: var(--ink);
    background: var(--paper);
    font-size: 16px;
    line-height: 1.76;
    text-rendering: optimizeLegibility;
}
a { color: var(--green_dark); text-decoration-thickness: 1px; text-underline-offset: 4px; }
a:hover { color: var(--coral); }
img, svg { display: block; max-width: 100%; }
button, input, select { font: inherit; }
::selection { color: #fff; background: var(--green); }

/*
 * Module purpose: keep tutorial navigation compact, bilingual, and available throughout long articles.
 * Main logic: use a translucent sticky bar, plain text navigation, and one strong map-maker command.
 * Cautions: the language switch remains an ordinary pair of crawlable links; no JavaScript is required for navigation.
 * Interactions: every localized page supplies its paired language URL and current-language state.
 */
.reading_progress {
    position: fixed;
    z-index: 80;
    inset: 0 auto auto 0;
    width: 0;
    height: 3px;
    background: var(--coral);
    transition: width 80ms linear;
}
.site_header {
    position: sticky;
    z-index: 50;
    top: 0;
    height: var(--header_height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 max(22px, calc((100vw - var(--content_width)) / 2));
    background: rgba(255, 255, 255, 0.94);
    border-bottom: 1px solid var(--line);
    backdrop-filter: blur(12px);
}
.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: var(--ink);
    font-weight: 800;
    text-decoration: none;
}
/*
 * Module purpose: keep the EasyMap master brand and Charts product label consistent across static content.
 * Main logic: size one external SVG mark and style the two-part wordmark with restrained product emphasis.
 * Cautions: the icon remains decorative; the adjacent text supplies the accessible brand identity.
 * Interactions: all generated guide, trust, and region pages use the shared brand renderers.
 */
.brand_mark {
    width: 28px;
    height: 28px;
    flex: 0 0 28px;
}
.brand_mark img { display: block; width: 100%; height: 100%; }
.brand_wordmark { display: inline-flex; align-items: baseline; gap: 6px; white-space: nowrap; }
.brand_wordmark strong { color: var(--green_dark); font-size: 17px; font-weight: 850; }
.brand_product { color: #c75f45; font-size: 12px; font-weight: 750; }
.site_actions, .site_nav, .language_switch { display: flex; align-items: center; }
.site_actions { gap: 25px; }
.site_nav { gap: 22px; font-size: 14px; }
.site_nav a { color: var(--muted); text-decoration: none; }
.site_nav a[aria-current="page"] { color: var(--ink); font-weight: 750; }
.language_switch {
    height: 30px;
    border: 1px solid var(--line);
    border-radius: 4px;
    overflow: hidden;
}
.language_switch a {
    min-width: 38px;
    padding: 3px 9px;
    color: var(--muted);
    text-align: center;
    text-decoration: none;
    font-size: 12px;
}
.language_switch a + a { border-left: 1px solid var(--line); }
.language_switch a[aria-current="true"] { color: #fff; background: var(--ink); }
.tool_link {
    display: inline-flex;
    align-items: center;
    min-height: 36px;
    padding: 7px 14px;
    color: #fff !important;
    background: var(--ink);
    border: 1px solid var(--ink);
    border-radius: 4px;
    font-weight: 750;
}
.tool_link:hover { background: var(--green_dark); border-color: var(--green_dark); }

/*
 * Module purpose: establish the world map as the first-viewport identity of the tutorial system.
 * Main logic: use one real EasyMap world choropleth as a full-bleed background with a solid translucent veil and restrained editorial typography.
 * Cautions: the map remains visible enough to identify countries; text never sits inside a floating card or depends on decorative gradients.
 * Interactions: index and article headers share the same optimized static image and vary only in height and copy.
 */
.guide_hero, .article_header {
    position: relative;
    isolation: isolate;
    min-height: min(650px, calc(100vh - var(--header_height)));
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    overflow: hidden;
    padding: 86px max(22px, calc((100vw - var(--content_width)) / 2)) 76px;
    color: #fff;
    background: #172229 url("./world_map_cover.png?v=20260727_7") center center / cover no-repeat;
}
.article_header { min-height: 470px; padding-bottom: 62px; }
.guide_hero::before, .article_header::before {
    content: "";
    position: absolute;
    z-index: -1;
    inset: 0;
    background: rgba(8, 20, 16, 0.73);
}
.hero_copy { max-width: 850px; }
.eyebrow {
    margin: 0 0 14px;
    color: #bde7d6;
    font-size: 12px;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0;
}
h1, h2, h3, .display_type {
    font-family: "Iowan Old Style", "Noto Serif SC", "Source Han Serif SC", "Songti SC", Georgia, serif;
    letter-spacing: 0;
}
h1 { margin: 0; font-size: clamp(42px, 6.1vw, 76px); line-height: 1.04; }
.article_header h1 { max-width: 950px; font-size: clamp(38px, 5vw, 62px); }
.lead {
    max-width: 760px;
    margin: 22px 0 0;
    color: rgba(255, 255, 255, 0.84);
    font-size: 18px;
    line-height: 1.7;
}
.hero_meta {
    max-width: var(--content_width);
    display: flex;
    flex-wrap: wrap;
    gap: 10px 24px;
    margin-top: 34px;
    color: rgba(255, 255, 255, 0.68);
    font-size: 12px;
}
.hero_meta span { display: inline-flex; align-items: center; gap: 8px; }
.hero_meta span::before { content: ""; width: 5px; height: 5px; background: #74c8a8; border-radius: 50%; }
.breadcrumbs {
    position: absolute;
    z-index: 4;
    top: 24px;
    left: max(22px, calc((100vw - var(--content_width)) / 2));
    max-width: calc(100vw - 44px);
    margin: 0;
    color: rgba(255, 255, 255, 0.72);
    font-size: 13px;
}
.breadcrumbs a { color: inherit; }

/*
 * Module purpose: turn the tutorial home into a clear learning sequence instead of a grid of interchangeable cards.
 * Main logic: introduce the path once, feature the quickest workflow, then list remaining lessons as numbered full-width rows.
 * Cautions: repeated items stay unframed and scan well on small screens; color is used only as a categorical accent.
 * Interactions: every row is a normal internal link and carries metadata used by both readers and search crawlers.
 */
.guide_intro {
    max-width: var(--content_width);
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(260px, 0.65fr);
    gap: 80px;
    margin: 0 auto;
    padding: 82px 22px 64px;
}
.section_kicker { margin: 0 0 10px; color: var(--green); font-size: 12px; font-weight: 800; text-transform: uppercase; }
.guide_intro h2 { margin: 0; font-size: clamp(31px, 4vw, 48px); line-height: 1.18; }
.guide_intro p { margin: 18px 0 0; color: var(--ink_soft); }
.guide_facts { margin: 0; padding: 0; border-top: 1px solid var(--line_dark); }
.guide_facts div { display: grid; grid-template-columns: 88px 1fr; gap: 14px; padding: 14px 0; border-bottom: 1px solid var(--line); }
.guide_facts dt { color: var(--muted); font-size: 13px; }
.guide_facts dd { margin: 0; font-weight: 700; }
.course_index { max-width: var(--content_width); margin: 0 auto; padding: 0 22px 96px; }
.course_heading { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 20px; }
.course_heading h2 { margin: 0; font-size: 30px; }
.course_heading p { margin: 0; color: var(--muted); font-size: 13px; }
.course_list { border-top: 1px solid var(--line_dark); }
.course_row {
    display: grid;
    grid-template-columns: 74px minmax(0, 1.2fr) minmax(240px, 0.8fr) 34px;
    gap: 28px;
    align-items: center;
    min-height: 152px;
    padding: 26px 4px;
    color: var(--ink);
    border-bottom: 1px solid var(--line);
    text-decoration: none;
    transition: padding 180ms ease, background 180ms ease;
}
.course_row:hover { padding-inline: 14px; color: var(--ink); background: var(--paper_soft); }
.course_number { color: var(--green); font: 700 16px/1 "Iowan Old Style", serif; }
.course_row:nth-child(2) .course_number { color: var(--blue); }
.course_row:nth-child(3) .course_number { color: var(--coral); }
.course_row h3 { margin: 0; font-size: 26px; line-height: 1.25; }
.course_row p { margin: 0; color: var(--muted); font-size: 14px; }
.course_arrow { color: var(--ink); font-size: 23px; }
.workflow_band { color: #fff; background: var(--ink); }
.workflow_inner { max-width: var(--content_width); margin: 0 auto; padding: 72px 22px; }
.workflow_inner h2 { max-width: 760px; margin: 0; font-size: clamp(30px, 4vw, 46px); }
.workflow_steps { display: grid; grid-template-columns: repeat(6, 1fr); gap: 0; margin-top: 40px; border-top: 1px solid rgba(255,255,255,.22); }
.workflow_steps span { min-height: 92px; padding: 18px 18px 0 0; color: #d7e0dc; border-right: 1px solid rgba(255,255,255,.14); font-size: 13px; }
.workflow_steps b { display: block; margin-bottom: 7px; color: #7fd0b0; font: 700 12px/1 Aptos, sans-serif; }
.workflow_link { display: inline-block; margin-top: 28px; color: #fff; font-weight: 750; }

/*
 * Module purpose: support long-form tutorials with a calm reading measure and persistent orientation.
 * Main logic: constrain prose width, keep the table of contents sticky, and use bands, tables, and figures only when they carry information.
 * Cautions: headings remain semantic and visible without JavaScript; mobile removes the sticky column rather than compressing prose.
 * Interactions: guides.js highlights matching heading anchors and updates the reading progress indicator.
 */
.article_meta_line { display: flex; flex-wrap: wrap; gap: 10px 24px; margin-top: 26px; color: rgba(255,255,255,.66); font-size: 12px; }
.article_layout {
    max-width: var(--content_width);
    display: grid;
    grid-template-columns: minmax(0, var(--reading_width)) 240px;
    justify-content: space-between;
    gap: 74px;
    margin: 0 auto;
    padding: 76px 22px 104px;
}
.article_body { min-width: 0; font-size: 16px; }
.article_body > p:first-of-type { color: var(--ink); font-size: 19px; line-height: 1.65; }
.article_body h2 { margin: 62px 0 16px; padding-top: 5px; font-size: 32px; line-height: 1.28; }
.article_body h2:first-child { margin-top: 0; }
.article_body h3 { margin: 34px 0 10px; font-size: 22px; }
.article_body p { margin: 0 0 19px; color: var(--ink_soft); }
.article_body ul { margin: 18px 0 24px; padding-left: 1.2em; }
.article_body li { margin: 8px 0; color: var(--ink_soft); }
.article_body table { width: 100%; margin: 28px 0; border-collapse: collapse; font-size: 14px; }
.article_body th, .article_body td { padding: 14px 15px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.article_body th { color: var(--ink); background: var(--paper_soft); border-top: 1px solid var(--line_dark); }
.article_body tr:last-child td { border-bottom-color: var(--line_dark); }
.map_figure { margin: 0 0 48px; overflow: hidden; background: var(--paper_soft); border: 1px solid var(--line); border-radius: 4px; }
.map_figure img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; }
.map_figure figcaption { padding: 12px 15px; color: var(--muted); border-top: 1px solid var(--line); font-size: 12px; }
.example { margin: 26px 0; padding: 20px 22px; overflow-x: auto; color: #e8f2ee; background: #1d2824; border-left: 4px solid #4daf88; border-radius: 3px; white-space: pre; font: 14px/1.74 Consolas, "Microsoft YaHei", monospace; }
.note { margin: 28px 0; padding: 18px 21px; color: #54451c; background: #fff9e8; border-left: 4px solid var(--yellow); }
.note strong { color: #403514; }
.toc { position: sticky; top: 92px; align-self: start; padding-left: 20px; border-left: 1px solid var(--line_dark); font-size: 13px; }
.toc strong { display: block; margin-bottom: 14px; color: var(--ink); }
.toc a { display: block; margin: 9px 0; color: var(--muted); text-decoration: none; transition: color 140ms ease, transform 140ms ease; }
.toc a:hover, .toc a.is_active { color: var(--green_dark); transform: translateX(3px); }
.article_cta { margin-top: 58px; padding: 35px 36px; color: #fff; background: var(--ink); }
.article_cta h2 { margin: 0 0 8px; color: #fff; }
.article_cta p { color: #d9e2de; }
.article_cta a { display: inline-block; margin-top: 8px; color: #fff; font-weight: 750; }
.article_navigation { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; margin-top: 24px; background: var(--line); border: 1px solid var(--line); }
.article_navigation a { min-height: 98px; padding: 17px 19px; color: var(--ink); background: var(--paper); text-decoration: none; }
.article_navigation a:hover { background: var(--paper_soft); }
.article_navigation small { display: block; margin-bottom: 5px; color: var(--muted); }
.article_navigation strong { font-family: "Iowan Old Style", "Noto Serif SC", "Songti SC", serif; }

/*
 * Module purpose: keep footer, motion, and responsive behavior consistent across every localized page.
 * Main logic: use progressive enhancement for reveal effects and collapse multi-column layouts at predictable content breakpoints.
 * Cautions: reduced-motion users receive no transforms; text and controls remain inside their containers at all widths.
 * Interactions: guides.js adds has_motion and is_visible classes only after the document is usable.
 */
.site_footer { padding: 34px 22px; color: var(--muted); text-align: center; background: var(--paper_soft); border-top: 1px solid var(--line); font-size: 13px; }
.has_motion [data_reveal] { opacity: 0; transform: translateY(16px); transition: opacity 480ms ease, transform 480ms ease; }
.has_motion [data_reveal].is_visible { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { animation: none !important; transition: none !important; }
    .has_motion [data_reveal] { opacity: 1; transform: none; }
}
@media (max-width: 900px) {
    .guide_intro { grid-template-columns: 1fr; gap: 36px; }
    .course_row { grid-template-columns: 54px minmax(0, 1fr) 30px; }
    .course_row p { grid-column: 2 / 3; }
    .course_arrow { grid-column: 3; grid-row: 1 / span 2; }
    .workflow_steps { grid-template-columns: repeat(2, 1fr); }
    .article_layout { grid-template-columns: minmax(0, 1fr); gap: 0; }
    .toc { display: none; }
}
@media (max-width: 680px) {
    :root { --header_height: 58px; }
    .site_header { padding-inline: 15px; }
    .site_actions { gap: 9px; }
    .site_nav a:not(.tool_link) { display: none; }
    .tool_link { min-height: 32px; padding: 5px 9px; font-size: 12px; }
    .language_switch a { min-width: 33px; padding-inline: 7px; }
    .guide_hero, .article_header { min-height: 72vh; padding: 72px 19px 50px; background-position: 54% center; }
    .article_header { min-height: 430px; }
    h1, .article_header h1 { font-size: 39px; }
    .lead { font-size: 16px; }
    .breadcrumbs { top: 18px; left: 19px; }
    .guide_intro { padding: 55px 18px 44px; }
    .course_index { padding: 0 18px 70px; }
    .course_heading { display: block; }
    .course_heading p { margin-top: 7px; }
    .course_row { grid-template-columns: 38px minmax(0, 1fr) 22px; gap: 13px; min-height: 136px; padding-block: 22px; }
    .course_row h3 { font-size: 22px; }
    .workflow_inner { padding: 54px 18px; }
    .workflow_steps { grid-template-columns: 1fr; }
    .workflow_steps span { min-height: 68px; border-right: 0; border-bottom: 1px solid rgba(255,255,255,.14); }
    .article_layout { padding: 52px 18px 72px; }
    .article_body > p:first-of-type { font-size: 17px; }
    .article_body h2 { margin-top: 48px; font-size: 27px; }
    .article_body table { display: block; overflow-x: auto; }
    .article_cta { padding: 28px 23px; }
    .article_navigation { grid-template-columns: 1fr; }
}