/* AI 科研起步 — Anthropic Research 风格：暖纸底、衬线标题、低饱和陶土橙、克制留白。
   No external fonts or assets. */

:root {
  --bg: #f7f5ef;
  --bg-soft: #efebe1;
  --card: #fdfcf8;
  --ink: #1f1e1d;
  --body: #4c4740;
  --muted: #857e72;
  --line: #e3ddd0;
  --line-strong: #d3cbba;
  --accent: #c15f3c;
  --accent-strong: #a04a2c;
  --accent-soft: #f3e5dc;
  --accent-border: #dfc1ae;
  --warn-bg: #f8f1df;
  --warn-border: #e3d3a8;
  --warn-ink: #82601c;
  --ok: #6b7f5c;
  --ok-soft: #eaede1;
  --dark: #262624;
  --radius: 14px;
  --radius-sm: 10px;
  --shadow-sm: 0 1px 2px rgba(63, 55, 40, 0.05);
  --shadow-md: 0 8px 24px -14px rgba(63, 55, 40, 0.22);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei UI",
    "Microsoft YaHei", "PingFang SC", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
  --serif: Georgia, "Times New Roman", "Source Han Serif SC", "Noto Serif SC",
    "Songti SC", "STSong", "SimSun", serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--body);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3 { font-family: var(--serif); color: var(--ink); line-height: 1.34; margin: 0; text-wrap: balance; }
h1 { font-size: clamp(1.8rem, 1.1rem + 2.5vw, 2.85rem); font-weight: 700; letter-spacing: 0.005em; }
h2 { font-size: clamp(1.32rem, 1.05rem + 0.9vw, 1.72rem); font-weight: 700; letter-spacing: 0.005em; }
h3 { font-size: 1.06rem; font-weight: 650; }
p { margin: 0; }

a { color: var(--accent-strong); text-decoration: none; }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.875em;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0.1em 0.4em;
  color: var(--ink);
}

.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  clip: rect(0 0 0 0); clip-path: inset(50%); overflow: hidden; white-space: nowrap;
}

.skip-link {
  position: absolute; left: 16px; top: -48px; z-index: 100;
  background: var(--ink); color: #fff; padding: 8px 14px; border-radius: 8px;
  transition: top 0.15s ease;
}
.skip-link:focus { top: 12px; }

/* Icons */
.icon, .icon svg { display: inline-flex; }
svg { width: 1em; height: 1em; flex: none; }

/* Layout shells */
.shell { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
.shell.narrow, .narrow { max-width: 800px; }
.section { padding: 44px 0; }

/* ============ Header ============ */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(247, 245, 239, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; gap: 20px; height: 64px; }

.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); }
.brand-mark {
  display: grid; place-items: center; width: 34px; height: 34px;
  background: var(--ink);
  color: var(--bg); border-radius: 50% 45% 52% 48% / 48% 52% 45% 55%; font-size: 16px;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-text strong { font-family: var(--serif); font-size: 0.98rem; font-weight: 700; }
.brand-text small { font-size: 0.72rem; color: var(--muted); }

.site-nav { display: flex; gap: 4px; margin-left: auto; }
.nav-link {
  padding: 7px 13px; border-radius: 99px;
  font-size: 0.9rem; color: var(--body); font-weight: 500;
  transition: color 0.15s ease, background 0.15s ease;
}
.nav-link:hover { color: var(--ink); background: var(--bg-soft); }
.nav-link.active { color: var(--accent-strong); background: var(--accent-soft); font-weight: 600; }

.nav-toggle {
  display: none; margin-left: auto;
  flex-direction: column; justify-content: center; gap: 4px;
  width: 40px; height: 40px; padding: 10px;
  background: none; border: 1px solid var(--line); border-radius: 10px; cursor: pointer;
}
.nav-toggle-bar { display: block; height: 2px; border-radius: 2px; background: var(--ink); }

/* ============ Buttons & links ============ */
.button {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 20px; border-radius: 12px;
  font-size: 0.95rem; font-weight: 600; line-height: 1.4;
  border: 1px solid transparent;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
}
.button:active { transform: translateY(1px); }
.button svg { font-size: 0.95em; }

.button.primary {
  background: var(--accent); color: #fff;
  box-shadow: var(--shadow-sm);
}
.button.primary:hover { background: var(--accent-strong); }

.button.secondary { background: var(--card); color: var(--ink); border-color: var(--line-strong); }
.button.secondary:hover { border-color: var(--accent); color: var(--accent-strong); }
.button.small { padding: 8px 14px; font-size: 0.875rem; border-radius: 10px; }

.button.light { background: var(--card); color: var(--ink); }
.button.light:hover { background: var(--accent-soft); }

.button-row { display: flex; flex-wrap: wrap; gap: 12px; }

.text-link { display: inline-flex; align-items: center; gap: 5px; font-weight: 600; font-size: 0.95rem; }
.text-link:hover { text-decoration: underline; text-underline-offset: 3px; }
.text-link svg { font-size: 0.8em; opacity: 0.7; }

.vpn-badge {
  display: inline-block;
  margin-left: 0.45em;
  padding: 0.1em 0.62em;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  border-radius: 999px;
  background: rgba(193, 95, 60, 0.1);
  color: #a34c2c;
  border: 1px solid rgba(193, 95, 60, 0.35);
  white-space: nowrap;
  vertical-align: 0.12em;
}
.button .vpn-badge { background: rgba(255, 255, 255, 0.85); }
.source-card h3 .vpn-badge { font-size: 0.62rem; }

.card-link {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 0.9rem; font-weight: 600; color: var(--accent-strong); margin-top: auto;
}
.card-link svg { font-size: 0.85em; transition: transform 0.15s ease; }
.card-link:hover svg { transform: translateX(3px); }

/* ============ Eyebrow / headings ============ */
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.8rem; font-weight: 650; color: var(--accent-strong);
  letter-spacing: 0.04em; margin-bottom: 14px;
}
.eyebrow.light { color: #d8a389; }
.eyebrow-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); }

.section-heading { max-width: 640px; margin-bottom: 32px; }
.section-heading p:not(.eyebrow) { margin-top: 10px; color: var(--body); }

.section-heading.with-action {
  max-width: none; display: flex; align-items: flex-end; justify-content: space-between;
  gap: 24px; flex-wrap: wrap;
}
.section-heading.with-action > div { max-width: 640px; }

/* ============ Home hero ============ */
.hero {
  position: relative; overflow: hidden;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--line);
}
.hero::before {
  content: ""; position: absolute; width: 240px; height: 200px;
  right: -60px; top: -70px; background: var(--accent-soft);
  border-radius: 58% 42% 55% 45% / 55% 48% 52% 45%;
}
.hero::after {
  content: ""; position: absolute; width: 90px; height: 84px;
  right: 16%; bottom: -30px; background: var(--ok-soft);
  border-radius: 45% 55% 62% 38% / 52% 44% 56% 48%;
}
.hero .shell { position: relative; z-index: 1; }
.hero-grid {
  display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.85fr);
  gap: 56px; align-items: center; padding-top: 72px; padding-bottom: 76px;
}
.hero-copy h1 { margin-bottom: 18px; }
.hero-lead { font-size: 1.08rem; max-width: 34em; margin-bottom: 28px; }
.hero-note {
  display: flex; align-items: center; gap: 8px;
  margin-top: 22px; font-size: 0.85rem; color: var(--muted);
}
.hero-note svg { color: var(--ok); font-size: 1.1em; }

.hero-panel {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px 26px 18px;
  box-shadow: var(--shadow-md);
}
.panel-label { font-size: 0.8rem; font-weight: 650; color: var(--muted); letter-spacing: 0.05em; margin-bottom: 6px; }

.route-steps { list-style: none; margin: 0; padding: 0; }
.route-steps li {
  position: relative; display: flex; gap: 14px; align-items: flex-start;
  padding: 14px 0;
}
.route-steps li + li { border-top: 1px dashed var(--line); }
.route-icon {
  display: grid; place-items: center; width: 38px; height: 38px; flex: none;
  border-radius: 12px; background: var(--accent-soft); color: var(--accent-strong);
  font-size: 18px; margin-top: 2px;
}
.route-steps strong { display: block; color: var(--ink); font-size: 0.98rem; font-weight: 650; }
.route-steps small { color: var(--muted); font-size: 0.83rem; }

/* ============ Feature cards ============ */
.feature-grid { display: grid; gap: 18px; }
.feature-grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.feature-card {
  display: flex; flex-direction: column; gap: 10px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.15s ease;
}
.feature-card:hover { border-color: var(--accent-border); box-shadow: var(--shadow-md); transform: translateY(-2px); }
.feature-card p { font-size: 0.93rem; margin-bottom: 6px; }

.feature-icon {
  display: grid; place-items: center; width: 42px; height: 42px;
  border-radius: 12px; background: var(--accent-soft); color: var(--accent-strong);
  font-size: 20px; margin-bottom: 6px;
}
.feature-index {
  font-size: 0.8rem; font-weight: 700; color: var(--accent);
  font-variant-numeric: tabular-nums; letter-spacing: 0.08em;
}

/* ============ CTA band ============ */
.cta-band {
  display: flex; align-items: center; justify-content: space-between; gap: 32px;
  background: var(--dark);
  color: #cfc9bd;
  border-radius: 20px; padding: 40px 44px;
}
.cta-band h2 { color: #f5f2ea; margin: 0 0 10px; }
.cta-band p:not(.eyebrow) { max-width: 44em; font-size: 0.95rem; }
.cta-band .button { flex: none; }

/* ============ Page hero (inner pages) ============ */
.page-hero {
  position: relative; overflow: hidden;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--line);
  padding: 48px 0 44px;
}
.page-hero::before {
  content: ""; position: absolute; width: 170px; height: 140px;
  right: -40px; top: -50px; background: var(--accent-soft);
  border-radius: 58% 42% 55% 45% / 55% 48% 52% 45%;
}
.page-hero .shell { position: relative; z-index: 1; }
.page-hero h1 { margin-bottom: 12px; }
.page-hero p { max-width: 40em; }

/* Step pager */
.step-pager { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-bottom: 26px; }
.pager-step {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.85rem; font-weight: 600; color: var(--muted);
}
.pager-dot {
  display: grid; place-items: center; width: 24px; height: 24px;
  border-radius: 50%; font-size: 0.72rem; font-variant-numeric: tabular-nums;
  background: var(--card); border: 1.5px solid var(--line-strong); color: var(--muted);
}
.pager-step.current { color: var(--accent-strong); }
.pager-step.current .pager-dot { background: var(--accent); border-color: var(--accent); color: #fff; }
.pager-step.done { color: var(--ok); }
.pager-step.done .pager-dot { background: var(--ok-soft); border-color: transparent; color: var(--ok); font-size: 0.8rem; }
.pager-step:hover { color: var(--ink); }

/* ============ Notices ============ */
.notice {
  background: var(--accent-soft); border: 1px solid var(--accent-border);
  border-radius: var(--radius-sm); padding: 14px 18px;
  font-size: 0.92rem; color: var(--body);
}
.notice strong { color: var(--ink); }
.notice.warning { background: var(--warn-bg); border-color: var(--warn-border); }
.notice.warning strong { color: var(--warn-ink); }

/* ============ Timeline (network steps) ============ */
.timeline { list-style: none; margin: 28px 0 0; padding: 0; }
.timeline-step { position: relative; display: flex; gap: 20px; padding: 0 0 36px; }
.timeline-step:last-child { padding-bottom: 0; }
.timeline-step::before {
  content: ""; position: absolute; left: 19px; top: 44px; bottom: 4px;
  width: 2px; background: var(--line);
}
.timeline-step:last-child::before { display: none; }
.timeline-dot {
  display: grid; place-items: center; width: 40px; height: 40px; flex: none;
  border-radius: 50%; background: var(--accent); color: #fff;
  font-weight: 700; font-size: 0.95rem;
  box-shadow: 0 0 0 5px var(--accent-soft);
}
.timeline-body {
  flex: 1; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 24px; box-shadow: var(--shadow-sm);
}
.timeline-body h2 { font-size: 1.15rem; margin-bottom: 8px; }
.timeline-body p { font-size: 0.93rem; margin-bottom: 16px; }
.timeline-body .link-row { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; }
.timeline-body .step-extra {
  margin: 14px 0 0; font-size: 0.85rem; color: var(--muted);
  border-top: 1px dashed var(--line); padding-top: 12px;
}
.timeline-body .step-extra .text-link { font-size: 0.85rem; margin-left: 6px; }

/* ============ Checkpoint ============ */
.checkpoint {
  background: var(--card); border: 1px solid var(--line); border-radius: 20px;
  padding: 32px 34px; box-shadow: var(--shadow-md);
}
.checkpoint h2 { margin-bottom: 18px; }
.check-list { list-style: none; margin: 0 0 26px; padding: 0; display: grid; gap: 10px; }
.check-list li {
  display: flex; align-items: flex-start; gap: 10px;
  font-size: 0.95rem;
}
.check-list svg {
  color: var(--ok); background: var(--ok-soft); border-radius: 50%;
  padding: 3px; font-size: 1.15rem; margin-top: 3px;
}

/* ============ Route features (setup) ============ */
.route-feature {
  display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: 36px; align-items: start;
  background: var(--card); border: 1px solid var(--line); border-radius: 20px;
  padding: 32px 36px; margin-bottom: 18px;
}
.route-feature.recommended {
  border-color: var(--accent-border);
  background: var(--card);
  box-shadow: var(--shadow-md);
}
.route-feature.muted { background: var(--bg-soft); box-shadow: none; }

.route-head { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.route-badge {
  display: inline-flex; padding: 4px 12px; border-radius: 99px;
  background: var(--accent); color: #fff; font-size: 0.78rem; font-weight: 650;
}
.route-label { font-size: 0.82rem; font-weight: 650; color: var(--muted); letter-spacing: 0.04em; }
.route-copy h2 { margin-bottom: 10px; }
.route-copy p { font-size: 0.95rem; }

.link-list {
  list-style: none; margin: 0; padding: 0;
  counter-reset: linkitem;
  display: flex; flex-direction: column;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius-sm);
  overflow: hidden;
}
.link-list li { counter-increment: linkitem; display: flex; }
.link-list li + li { border-top: 1px solid var(--line); }
.link-list .text-link {
  flex: 1; display: flex; align-items: center; gap: 10px;
  padding: 13px 16px; font-size: 0.9rem; font-weight: 550; color: var(--ink);
  transition: background 0.15s ease;
}
.link-list .text-link:hover { background: var(--accent-soft); text-decoration: none; color: var(--accent-strong); }
.link-list .text-link::before {
  content: counter(linkitem);
  display: grid; place-items: center; width: 22px; height: 22px; flex: none;
  border-radius: 50%; background: var(--accent-soft); color: var(--accent-strong);
  font-size: 0.75rem; font-weight: 700;
}
.link-list .text-link svg { margin-left: auto; }

.section .notice { margin-top: 18px; }

/* ============ Workflow (research) ============ */
.workflow-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.workflow-card {
  display: flex; flex-direction: column; gap: 12px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px; box-shadow: var(--shadow-sm);
}
.workflow-head { display: flex; align-items: baseline; gap: 12px; }
.workflow-card h2 { font-size: 1.15rem; }
.workflow-card > p { font-size: 0.92rem; }

.prompt-block {
  margin-top: auto;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  overflow: hidden; background: var(--dark);
}
.prompt-head {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 10px 14px;
  background: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.prompt-head div { display: flex; flex-direction: column; line-height: 1.35; }
.prompt-head span { font-size: 0.7rem; color: #9a938a; letter-spacing: 0.05em; }
.prompt-head strong { font-size: 0.85rem; color: #efece4; font-weight: 600; }
.copy-button {
  flex: none; padding: 6px 14px; border-radius: 8px;
  background: rgba(255, 255, 255, 0.1); color: #efece4;
  border: 1px solid rgba(255, 255, 255, 0.14);
  font-family: inherit; font-size: 0.8rem; font-weight: 600; cursor: pointer;
  transition: background 0.15s ease;
}
.copy-button:hover { background: rgba(255, 255, 255, 0.2); }
.prompt-block pre {
  margin: 0; padding: 14px 16px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.8rem; line-height: 1.7; color: #d0cabd;
  white-space: pre-wrap; word-break: break-word;
}

/* Office band */
.office-band {
  background: var(--bg-soft); border: 1px solid var(--line); border-radius: 20px;
  padding: 34px 36px;
}
.office-band .section-heading { margin-bottom: 20px; }
.chip-list { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 26px; }
.chip-list span {
  padding: 6px 14px; border-radius: 99px; font-size: 0.85rem; font-weight: 550;
  background: var(--card); border: 1px solid var(--line-strong); color: var(--body);
}

/* ============ Library ============ */
.library-map {
  position: relative; z-index: 5;
  margin-top: -30px;
  display: flex; flex-direction: column; gap: 10px;
}
.map-card {
  display: grid; grid-template-columns: 40px minmax(0, 1fr) 250px;
  gap: 18px; align-items: start;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius-sm);
  padding: 18px 22px; box-shadow: var(--shadow-sm);
  color: inherit; text-decoration: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.map-card:hover { border-color: var(--accent); box-shadow: var(--shadow-md); }
.map-card:hover .map-title { color: var(--accent-strong); }
.map-num {
  width: 32px; height: 32px; margin-top: 2px;
  display: grid; place-items: center;
  background: var(--ink); color: var(--bg);
  border-radius: 52% 48% 45% 55% / 48% 55% 45% 52%;
  font-family: var(--serif); font-size: 0.95rem; font-weight: 700;
}
.map-main { display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.map-title {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  font-family: var(--serif);
  font-size: 1.02rem; font-weight: 700; color: var(--ink); line-height: 1.35;
}
.map-count {
  font-family: var(--font);
  font-size: 0.72rem; font-weight: 650; color: var(--muted);
  background: var(--bg-soft); border: 1px solid var(--line);
  padding: 1px 9px; border-radius: 99px;
}
.map-what { font-size: 0.88rem; line-height: 1.65; color: var(--body); }
.map-when {
  display: flex; flex-direction: column; gap: 3px;
  font-size: 0.84rem; line-height: 1.6; color: var(--body);
  border-left: 2px solid var(--accent-border); padding-left: 14px; margin-top: 2px;
}
.map-when-label {
  font-size: 0.72rem; font-weight: 650; color: var(--accent-strong); letter-spacing: 0.06em;
}
.map-footnote { margin-top: 14px; font-size: 0.84rem; color: var(--muted); }

.library-toolbar {
  position: relative; z-index: 5;
  margin-top: 20px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px 14px; box-shadow: var(--shadow-md);
}
.search-field {
  display: flex; align-items: center; gap: 10px;
  background: var(--bg-soft); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: 0 14px;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.search-field:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(47, 107, 255, 0.15);
  background: var(--card);
}
.search-field svg { color: var(--muted); font-size: 1.05rem; }
.search-field input {
  flex: 1; border: 0; background: none; outline: none;
  padding: 12px 0; font-family: inherit; font-size: 0.95rem; color: var(--ink);
}
.search-field input::placeholder { color: var(--muted); }

.filter-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.filter-button {
  padding: 7px 15px; border-radius: 99px;
  background: var(--card); border: 1px solid var(--line-strong); color: var(--body);
  font-family: inherit; font-size: 0.85rem; font-weight: 550; cursor: pointer;
  transition: all 0.15s ease;
}
.filter-button:hover { border-color: var(--accent); color: var(--accent-strong); }
.filter-button.active {
  background: var(--ink); border-color: var(--ink); color: #fff;
}
.result-count { margin-top: 12px; font-size: 0.82rem; color: var(--muted); }

.library-content { padding-top: 40px; padding-bottom: 24px; }
.library-group { margin-bottom: 44px; }
.group-heading {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  margin-bottom: 18px;
}
.group-heading .eyebrow { margin-bottom: 6px; }
.group-count {
  flex: none; font-size: 0.8rem; font-weight: 650; color: var(--muted);
  background: var(--bg-soft); border: 1px solid var(--line);
  padding: 4px 12px; border-radius: 99px;
}

.group-note { margin-top: 4px; font-size: 0.88rem; color: var(--muted); }
.notice + .notice { margin-top: 16px; }

details.library-group {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius-sm);
  padding: 0; margin-bottom: 16px; overflow: hidden;
  scroll-margin-top: 84px;
}
details.library-group > summary {
  list-style: none; cursor: pointer; user-select: none;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 18px 22px;
}
details.library-group > summary::-webkit-details-marker { display: none; }
details.library-group > summary::after {
  content: ""; flex: none; width: 10px; height: 10px;
  border-right: 2px solid var(--muted); border-bottom: 2px solid var(--muted);
  transform: rotate(45deg); transition: transform 0.15s ease; margin-right: 4px;
}
details.library-group[open] > summary::after { transform: rotate(-135deg); }
details.library-group > summary:hover h2 { color: var(--accent-strong); }
details.library-group > summary h2 { font-size: 1.05rem; }
details.library-group[open] > summary { border-bottom: 1px solid var(--line); }
details.library-group > .source-grid { padding: 18px 22px 22px; }

.source-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }

.source-card {
  display: flex; flex-direction: column; gap: 8px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius-sm);
  padding: 18px 18px 14px;
  transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.15s ease;
}
.source-card:hover {
  border-color: var(--accent-border); box-shadow: var(--shadow-md); transform: translateY(-2px);
}
.source-top { display: flex; align-items: center; gap: 8px; }
.source-kind { font-size: 0.75rem; font-weight: 650; color: var(--muted); letter-spacing: 0.03em; }
.source-number {
  font-size: 0.72rem; font-weight: 700; color: var(--accent-strong);
  background: var(--accent-soft); border-radius: 6px; padding: 1px 7px;
  font-variant-numeric: tabular-nums;
}
.source-status.partial {
  margin-left: auto; font-size: 0.72rem; font-weight: 650;
  color: var(--warn-ink); background: var(--warn-bg);
  border: 1px solid var(--warn-border); border-radius: 6px; padding: 1px 7px;
}
.source-card h3 { font-size: 0.98rem; line-height: 1.45; }
.source-card h3 a { color: var(--ink); }
.source-card h3 a:hover { color: var(--accent-strong); }
.source-card > p {
  font-size: 0.85rem; color: var(--body); line-height: 1.6;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.source-footer {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  margin-top: auto; padding-top: 10px; border-top: 1px solid var(--bg-soft);
}
.tag-row { display: flex; flex-wrap: wrap; gap: 6px; }
.tag-row span {
  font-size: 0.72rem; font-weight: 550; color: var(--muted);
  background: var(--bg-soft); border-radius: 6px; padding: 2px 8px;
  max-width: 12em; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.source-open {
  display: inline-flex; align-items: center; gap: 4px; flex: none;
  font-size: 0.78rem; font-weight: 600; color: var(--accent-strong);
  opacity: 0; transition: opacity 0.15s ease;
}
.source-card:hover .source-open { opacity: 1; }

.empty-state {
  text-align: center; padding: 60px 20px;
  background: var(--bg-soft); border: 1px dashed var(--line-strong); border-radius: var(--radius);
}
.empty-state h2 { margin-bottom: 8px; }

/* ============ Footer ============ */
.site-footer { border-top: 1px solid var(--line); background: var(--bg-soft); margin-top: 40px; }
.footer-inner {
  display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr) minmax(0, 1.2fr);
  gap: 40px; padding-top: 44px; padding-bottom: 44px;
}
.footer-brand strong { color: var(--ink); font-size: 1rem; }
.footer-brand p { margin-top: 8px; font-size: 0.88rem; max-width: 26em; }
.footer-title { font-size: 0.8rem; font-weight: 700; color: var(--ink); letter-spacing: 0.04em; margin-bottom: 12px; }
.footer-col { display: flex; flex-direction: column; gap: 8px; }
.footer-col a { font-size: 0.88rem; color: var(--body); }
.footer-col a:hover { color: var(--accent-strong); }
.footer-note p { font-size: 0.85rem; color: var(--muted); }

/* ============ Responsive ============ */
@media (max-width: 960px) {
  .hero-grid { grid-template-columns: 1fr; gap: 36px; padding-top: 52px; padding-bottom: 56px; }
  .feature-grid.three { grid-template-columns: 1fr; }
  .source-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .map-card { grid-template-columns: 40px minmax(0, 1fr); }
  .map-when { grid-column: 2; }
  .workflow-grid { grid-template-columns: 1fr; }
  .route-feature { grid-template-columns: 1fr; gap: 22px; padding: 26px; }
  .cta-band { flex-direction: column; align-items: flex-start; padding: 32px 28px; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 680px) {
  .section { padding: 32px 0; }
  .shell { padding: 0 18px; }

  .nav-toggle { display: flex; }
  .site-nav {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; gap: 2px; padding: 12px 18px 16px;
    background: var(--card); border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md);
  }
  .site-nav.open { display: flex; }
  .nav-link { padding: 11px 14px; border-radius: 10px; }

  .source-grid { grid-template-columns: 1fr; }
  .timeline-step { gap: 14px; }
  .timeline-dot { width: 34px; height: 34px; font-size: 0.85rem; }
  .timeline-step::before { left: 16px; }
  .timeline-body { padding: 18px; }
  .checkpoint { padding: 24px 20px; }
  .route-feature { padding: 22px 18px; }
  .office-band { padding: 26px 20px; }
  .library-map { margin-top: -22px; gap: 8px; }
  .map-card { grid-template-columns: 34px minmax(0, 1fr); gap: 12px; padding: 14px 16px; }
  .map-num { width: 28px; height: 28px; font-size: 0.85rem; }
  .map-when { grid-column: 1 / -1; margin-top: 0; }
  .library-toolbar { margin-top: 16px; padding: 14px; }
  .footer-inner { grid-template-columns: 1fr; gap: 28px; }
  .section-heading.with-action { flex-direction: column; align-items: flex-start; }
  .prompt-head { flex-wrap: wrap; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
  html { scroll-behavior: auto; }
}