:root {
  color-scheme: light;
  --bg: #f7f8fa;
  --surface: #fff;
  --ink: #202329;
  --muted: #656b75;
  --line: #e1e5eb;
  --blue: #006bd6;
  --blue-soft: #edf4fc;
  --radius: 16px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 28px; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 15px/1.65 var(--font); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-underline-offset: 4px; }
button, input, textarea { font: inherit; }
button, a, input, textarea, summary { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }
button:focus-visible, a:focus-visible, summary:focus-visible, pre:focus-visible { outline: 3px solid var(--blue); outline-offset: 5px; }
[hidden] { display: none !important; }
.site-shell { max-width: 1184px; padding: 0 40px; margin: auto; }
.header { height: 96px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 22px; font-weight: 730; letter-spacing: -.04em; text-decoration: none; white-space: nowrap; }
.brand img { border-radius: 8px; }
.brand-dot { color: var(--blue); }
nav { display: flex; align-items: center; gap: 28px; font-size: 13px; }
nav a { text-decoration: none; color: var(--muted); }
nav a:hover { color: var(--ink); }
.version-link { border-left: 1px solid var(--line); padding-left: 26px; }
.skip { position: fixed; top: 12px; left: 12px; z-index: 10; background: var(--surface); border: 1px solid var(--line); padding: 10px 14px; transform: translateY(-150%); }
.skip:focus { transform: none; }
.hero { display: grid; grid-template-columns: 1fr 1.12fr; align-items: start; gap: 72px; padding: 72px 0 80px; }
.hero-copy { padding-top: 17px; }
.eyebrow { margin: 0 0 18px; color: var(--muted); font-size: 12px; font-weight: 550; }
.hero-copy .eyebrow { display: flex; align-items: center; gap: 9px; }
.signal { width: 7px; height: 7px; border-radius: 50%; background: var(--blue); }
h1 { margin: 0; font-size: clamp(38px,4.4vw,60px); line-height: 1.28; letter-spacing: -.035em; font-weight: 720; }
.blue { color: var(--blue); }
.lead { margin: 26px 0; color: var(--muted); font-size: 16px; line-height: 1.9; }
.text-link, .text-button { display: inline-flex; align-items: center; gap: 14px; color: var(--blue); font-size: 14px; font-weight: 600; text-decoration: none; }
.text-button { border: none; background: none; padding: 8px 0; }
.text-link:hover, .text-button:hover { text-decoration: underline; }
.text-link:active, .text-button:active { opacity: .7; }
.hero-note { display: flex; gap: 16px; margin-top: 52px; color: var(--muted); font-size: 13px; line-height: 1.85; }
.hero-note p { margin: 0; }
.note-rule { width: 28px; height: 1px; margin-top: 13px; background: #9da6b2; }
.workbench { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px 30px 22px; box-shadow: 0 6px 28px rgba(32,43,61,.035); scroll-margin-top: 28px; }
.bench-heading { display: flex; justify-content: space-between; align-items: flex-start; gap: 10px; margin-bottom: 26px; }
.bench-heading .eyebrow { margin-bottom: 6px; font-size: 11px; }
h2 { margin: 0; font-size: 28px; line-height: 1.45; letter-spacing: -.015em; font-weight: 660; }
.bench-heading h2 { font-size: 22px; }
.small-note { font-size: 10px; color: var(--muted); padding-top: 2px; white-space: nowrap; }
.field { margin-bottom: 19px; }
label { display: flex; align-items: center; gap: 9px; font-size: 13px; font-weight: 570; margin-bottom: 8px; }
.field-index { font-size: 10px; color: var(--muted); font-variant-numeric: tabular-nums; }
input, textarea { display: block; width: 100%; border: 1px solid #dce1e8; border-radius: 8px; padding: 11px 13px; color: var(--ink); background: #fbfcfd; outline: none; font-size: 13px; line-height: 1.65; transition: border-color .15s, box-shadow .15s; }
textarea { min-height: 91px; resize: vertical; }
input::placeholder, textarea::placeholder { color: #858c97; opacity: 1; }
input:focus, textarea:focus { border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-soft); background: #fff; }
input[aria-invalid="true"], textarea[aria-invalid="true"] { border-color: #b54141; }
.field-error { margin: 5px 0 0; font-size: 12px; color: #a12f2f; }
.bench-actions { display: flex; align-items: center; justify-content: space-between; gap: 10px; padding-top: 4px; }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 19px; border-radius: 8px; border: 1px solid transparent; padding: 11px 15px; font-size: 13px; font-weight: 600; line-height: 1.5; transition: background .15s, transform .1s; }
.primary { background: var(--blue); color: #fff; }
.primary:hover { background: #005bbb; }
.button:active { transform: scale(.98); }
.button:disabled { cursor: not-allowed; opacity: .55; }
.bench-actions p { margin: 0; font-size: 10px; color: var(--muted); }
.form-status { font-size: 11px; color: var(--muted); margin: 10px 0 0; }
.form-status:empty { margin: 0; }
.section-heading { display: flex; align-items: flex-end; justify-content: space-between; gap: 24px; margin-bottom: 24px; }
.section-heading .eyebrow { margin-bottom: 10px; }
.section-heading>p { color: var(--muted); font-size: 13px; line-height: 1.85; margin: 0 0 4px; }
.ideas-section { border-top: 1px solid var(--line); padding: 46px 0 58px; }
.idea-list { display: grid; grid-template-columns: 1fr 1fr; }
.idea-pick { display: flex; align-items: center; text-align: left; gap: 18px; padding: 24px 20px 24px 0; background: transparent; color: var(--ink); border: 0; border-bottom: 1px solid var(--line); transition: background .15s; }
.idea-pick:nth-child(even) { margin-left: 30px; }
.idea-pick:hover, .idea-pick[aria-pressed="true"] { background: var(--blue-soft); }
.idea-pick:active { background: #e1edfb; }
.idea-symbol { display: flex; align-items: center; justify-content: center; height: 40px; width: 40px; flex-shrink: 0; color: var(--blue); font-size: 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; }
.idea-content { display: grid; gap: 4px; flex: 1; }
.idea-category { color: var(--muted); font-size: 10px; }
.idea-content strong { font-weight: 590; font-size: 15px; }
.idea-desc { color: var(--muted); font-size: 12px; }
.idea-action { white-space: nowrap; color: var(--muted); font-size: 11px; }
.idea-action span { margin-left: 6px; }
.method-section { display: grid; grid-template-columns: 1fr 1.12fr; gap: 72px; padding: 50px 0 64px; border-bottom: 1px solid var(--line); }
.method-intro>p:last-child { color: var(--muted); font-size: 14px; line-height: 1.85; }
.method-list { margin: 0; padding: 0; list-style: none; }
.method-list li { display: flex; gap: 22px; padding: 20px 0; border-top: 1px solid var(--line); }
.method-list li>span { color: var(--blue); font-size: 12px; font-variant-numeric: tabular-nums; padding-top: 3px; }
h3 { margin: 0 0 6px; font-size: 16px; font-weight: 600; }
.method-list p { margin: 0; color: var(--muted); font-size: 13px; }
.questions-section { display: grid; grid-template-columns: 1fr 1.12fr; gap: 72px; padding: 52px 0; }
.questions-section h2 { font-size: 24px; }
details { border-bottom: 1px solid var(--line); }
summary { display: flex; align-items: center; justify-content: space-between; padding: 15px 0; cursor: pointer; font-size: 14px; font-weight: 540; list-style: none; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; font-size: 20px; color: var(--muted); margin-left: 16px; }
details[open] summary::after { content: "−"; }
details p { margin: 0 0 18px; color: var(--muted); font-size: 13px; line-height: 1.85; max-width: 55ch; }
.closing { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 27px 0 38px; }
.closing p { margin: 0; font-size: 17px; font-weight: 540; }
.closing p span { color: var(--muted); margin-left: 10px; }
footer { display: flex; align-items: center; justify-content: space-between; gap: 16px; border-top: 1px solid var(--line); padding: 24px 0 30px; font-size: 12px; color: var(--muted); }
footer .brand { font-size: 18px; color: var(--ink); }
footer p { margin: 0; }
footer>a:last-child { text-decoration: none; }
.brief-panel { border: 1px solid #bdcfea; border-radius: var(--radius); background: var(--surface); padding: 28px 30px 20px; margin: -35px 0 55px; scroll-margin-top: 28px; }
.brief-heading { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-bottom: 22px; }
.brief-heading .eyebrow { margin-bottom: 7px; }
.brief-heading h2 { font-size: 23px; }
.brief-heading p:last-child { color: var(--muted); font-size: 13px; margin: 8px 0 0; }
pre { border: 1px solid var(--line); background: #f8fafc; border-radius: 9px; padding: 22px; margin: 0; white-space: pre-wrap; overflow-wrap: anywhere; font: 13px/1.9 var(--font); max-height: 420px; overflow: auto; }
.brief-footer { display: flex; align-items: center; justify-content: space-between; gap: 18px; margin-top: 10px; }
.brief-footer p { margin: 0; color: var(--muted); font-size: 12px; }
@media (max-width: 1050px) {
  .hero, .method-section, .questions-section { gap: 38px; }
  .bench-actions { align-items: flex-start; flex-direction: column; }
  .idea-action { font-size: 0; }
  .idea-action span { font-size: 16px; }
}
@media (max-width: 740px) {
  .site-shell { padding: 0 22px; }
  .header { height: 78px; }
  .brand { font-size: 19px; gap: 8px; }
  .brand img { width: 26px; height: 26px; }
  nav { gap: 17px; font-size: 11px; }
  .version-link { padding: 0; border: 0; }
  nav a:nth-child(2) { display: none; }
  .hero { grid-template-columns: 1fr; gap: 32px; padding: 35px 0 42px; }
  .hero-copy { padding: 0; }
  h1 { font-size: 38px; line-height: 1.3; letter-spacing: -.02em; }
  .hero-copy .eyebrow { font-size: 11px; margin-bottom: 18px; }
  .lead { font-size: 14px; margin: 17px 0 16px; line-height: 1.85; }
  .desktop-break { display: none; }
  .hero-note { display: none; }
  .start-link { font-size: 13px; }
  .workbench { padding: 23px 20px 19px; }
  .bench-heading { margin-bottom: 21px; }
  .bench-heading h2 { font-size: 20px; }
  .small-note { font-size: 9px; }
  label { font-size: 12px; }
  input, textarea { font-size: 16px; }
  input::placeholder, textarea::placeholder { font-size: 12px; }
  .bench-actions { align-items: center; }
  .bench-actions .button { width: 100%; font-size: 14px; }
  .bench-actions p { font-size: 11px; }
  .ideas-section { padding: 34px 0 38px; }
  .section-heading { display: block; margin-bottom: 13px; }
  h2 { font-size: 25px; }
  .section-heading>p { margin-top: 15px; font-size: 12px; }
  .idea-list { grid-template-columns: 1fr; }
  .idea-pick { padding: 20px 0; gap: 13px; }
  .idea-pick:nth-child(even) { margin: 0; }
  .idea-content strong { font-size: 14px; }
  .idea-desc { font-size: 11px; }
  .method-section, .questions-section { grid-template-columns: 1fr; gap: 20px; padding: 34px 0; }
  .method-intro>p:last-child { font-size: 13px; }
  .method-list li { padding: 18px 0; }
  h3 { font-size: 14px; }
  .questions-section { gap: 10px; }
  .closing { display: block; padding: 18px 0 31px; }
  .closing p { font-size: 14px; margin-bottom: 12px; }
  .closing p span { margin-left: 5px; }
  .closing .text-link { font-size: 12px; }
  footer { flex-wrap: wrap; padding: 20px 0 27px; font-size: 11px; }
  footer p { display: none; }
  .brief-panel { margin: 0 0 35px; padding: 22px 20px 17px; }
  .brief-heading { align-items: flex-start; flex-direction: column; gap: 14px; }
  .brief-heading h2 { font-size: 20px; }
  .brief-heading .button { width: 100%; }
  pre { padding: 16px; font-size: 12px; max-height: 400px; }
  .brief-footer { align-items: flex-start; flex-direction: column; gap: 7px; }
}
@media (max-width: 360px) {
  .site-shell { padding: 0 16px; }
  .header { gap: 10px; }
  nav { gap: 10px; }
  h1 { font-size: 34px; }
  .small-note { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0s !important; }
}