/* NicheCue — research desk, simplified
   Palette: ink navy, mist paper, cobalt signal */

:root {
  --ink: #0e1828;
  --ink-soft: #1a2a42;
  --paper: #eef2f7;
  --paper-raised: #f7f9fc;
  --line: #c5d0e0;
  --mute: #5a6b82;
  --cobalt: #2f5fff;
  --cobalt-deep: #1e45c9;
  --amber: #c47a12;
  --amber-soft: #fff4e3;
  --ok: #1f6b4a;
  --danger: #b42318;
  --radius: 6px;
  --font-display: "Instrument Serif", "Georgia", serif;
  --font-ui: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
  --shadow: 0 1px 0 rgba(14, 24, 40, 0.06), 0 8px 24px rgba(14, 24, 40, 0.06);
  --focus: 3px solid var(--cobalt);
  --max: 56rem;
  --content: 42rem;
  color-scheme: light;
}

html[lang="zh-Hans"] {
  --font-ui: "Noto Sans SC", "IBM Plex Sans", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-display: "Noto Sans SC", "Instrument Serif", "PingFang SC", "Microsoft YaHei", serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  font-family: var(--font-ui);
  font-size: 1.0625rem;
  line-height: 1.55;
  color: var(--ink);
  background:
    radial-gradient(900px 420px at 8% -8%, #dce6f8 0%, transparent 55%),
    linear-gradient(180deg, var(--paper) 0%, #e4ebf4 100%);
}

main {
  flex: 1;
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: var(--cobalt-deep);
  text-underline-offset: 0.15em;
}

a:hover {
  color: var(--cobalt);
}

:focus-visible {
  outline: var(--focus);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  inset-inline-start: 1rem;
  inset-block-start: -100%;
  z-index: 100;
  padding: 0.65rem 1rem;
  background: var(--ink);
  color: var(--paper-raised);
  border-radius: var(--radius);
  text-decoration: none;
}

.skip-link:focus {
  inset-block-start: 1rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  border-block-end: 1px solid var(--line);
}

.site-header__inner,
.site-footer__inner,
.wrap {
  width: min(100% - 2rem, var(--max));
  margin-inline: auto;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 0.85rem;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.45rem;
  text-decoration: none;
  color: var(--ink);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.brand__mark {
  display: inline-grid;
  place-items: center;
  width: 1.55rem;
  height: 1.55rem;
  border-radius: 4px;
  background: var(--ink);
  color: #f2f6ff;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
}

.brand__name {
  font-size: 1.05rem;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.15rem;
  align-items: center;
}

.nav a {
  text-decoration: none;
  color: var(--mute);
  font-size: 0.95rem;
}

.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--ink);
}

.nav__lang {
  font-weight: 500;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  min-height: 48px;
  padding: 0.65rem 1.25rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font: inherit;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: background 160ms ease, border-color 160ms ease, color 160ms ease;
}

.btn--primary {
  background: var(--cobalt);
  color: #fff;
}

.btn--primary:hover {
  background: var(--cobalt-deep);
  color: #fff;
}

.btn--ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}

.btn--ghost:hover {
  border-color: var(--ink-soft);
  background: var(--paper-raised);
}

.btn--small {
  min-height: 40px;
  padding: 0.4rem 0.85rem;
  font-size: 0.92rem;
}

/* Landing — SEO content home */
.landing {
  padding-block: 1.75rem 3rem;
}

.landing--seo {
  max-width: var(--max);
}

.landing__updated {
  margin: 0 0 1rem;
  color: var(--mute);
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

.landing__hero h1 {
  margin: 0 0 0.85rem;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(1.85rem, 4.5vw, 2.55rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  max-width: 22ch;
}

html[lang="zh-Hans"] .landing__hero h1 {
  max-width: 16em;
  letter-spacing: 0;
}

.landing__lede {
  margin: 0 0 1rem;
  color: var(--ink-soft);
  font-size: 1.12rem;
  max-width: 58ch;
}

.landing__what,
.landing__who {
  margin: 0 0 0.85rem;
  max-width: 62ch;
  color: var(--ink);
}

.landing__who {
  color: var(--mute);
  font-size: 0.98rem;
}

.landing__steps {
  list-style: none;
  margin: 1.25rem 0 1.35rem;
  padding: 0;
  display: grid;
  gap: 0.65rem;
  max-width: 40rem;
}

.landing__steps li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.75rem;
  align-items: start;
  padding: 0.85rem 1rem;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.landing__step-num {
  display: inline-grid;
  place-items: center;
  width: 1.6rem;
  height: 1.6rem;
  border-radius: 999px;
  background: var(--ink);
  color: #f2f6ff;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  flex-shrink: 0;
}

.landing__steps strong {
  display: inline;
  color: var(--ink);
}

.landing__actions {
  margin: 0 0 0.25rem;
}

.landing__section {
  margin-block-start: 2.5rem;
  padding-block-start: 2rem;
  border-block-start: 1px solid var(--line);
}

.landing__section h2 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(1.35rem, 3vw, 1.7rem);
}

.landing__section-lede {
  margin: 0 0 1.1rem;
  color: var(--mute);
  max-width: 58ch;
}

.landing__niche-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.65rem;
}

@media (min-width: 560px) {
  .landing__niche-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 900px) {
  .landing__niche-grid {
    grid-template-columns: 1fr 1fr 1fr 1fr;
  }
}

.landing__niche-card {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  min-height: 4.4rem;
  padding: 0.9rem 1rem;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 8px;
  text-decoration: none;
  color: var(--ink);
  box-shadow: var(--shadow);
  transition: border-color 160ms ease, color 160ms ease;
}

.landing__niche-card:hover {
  border-color: color-mix(in srgb, var(--cobalt) 45%, var(--line));
  color: var(--cobalt-deep);
}

.landing__niche-name {
  font-weight: 600;
  font-size: 0.98rem;
  line-height: 1.3;
}

.landing__niche-meta {
  color: var(--mute);
  font-size: 0.8rem;
  font-family: var(--font-mono);
}

.landing__more {
  margin: 1rem 0 0;
  font-size: 0.95rem;
}

.landing__faq {
  display: grid;
  gap: 0.5rem;
  max-width: 44rem;
}

.landing__faq details {
  padding: 0.75rem 1rem;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.landing__faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--ink);
}

.landing__faq details[open] summary {
  margin-bottom: 0.45rem;
}

.landing__faq p {
  margin: 0;
  color: var(--ink-soft);
  max-width: 62ch;
}

/* Tool page */
.tool-page {
  padding-block: 1.5rem 2.5rem;
}

.tool-head {
  margin-bottom: 1.25rem;
}

.tool-head h1 {
  margin: 0 0 0.25rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3vw, 2.1rem);
  font-weight: 400;
}

.tool-head__sub {
  margin: 0;
  color: var(--mute);
  font-size: 0.95rem;
}

.tool-filters {
  display: grid;
  gap: 0.75rem;
  margin-bottom: 1rem;
  padding: 1rem 1.1rem;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 10px;
}

@media (min-width: 720px) {
  .tool-filters {
    grid-template-columns: 1.4fr 1fr 1fr auto;
    align-items: end;
  }
}

.tool-filters[hidden] {
  display: none;
}

.tool-count {
  margin: 0;
  color: var(--mute);
  font-size: 0.9rem;
  font-family: var(--font-mono);
  align-self: end;
  padding-bottom: 0.85rem;
}

.freshness {
  margin: 0 0 1rem;
  color: var(--mute);
  font-size: 0.85rem;
}

.field {
  display: grid;
  gap: 0.3rem;
}

.field label {
  font-size: 0.85rem;
  font-weight: 560;
  color: var(--mute);
}

input[type="search"],
input[type="text"],
input[type="email"],
textarea,
select {
  width: 100%;
  min-height: 44px;
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  color: var(--ink);
  font: inherit;
  font-size: 1rem;
}

.panel {
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 10px;
  box-shadow: var(--shadow);
}

.topic-grid {
  display: grid;
  gap: 0.65rem;
}

@media (min-width: 640px) {
  .topic-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.topic-card {
  padding: 0.95rem 1.05rem;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.topic-card--compact {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-height: 4.5rem;
}

.topic-card h3 {
  margin: 0;
  font-size: 1.02rem;
  font-weight: 600;
  line-height: 1.3;
}

.topic-card h3 a {
  text-decoration: none;
  color: var(--ink);
}

.topic-card h3 a:hover {
  color: var(--cobalt);
}

.topic-card__meta {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.65rem;
  margin: 0;
  color: var(--mute);
  font-size: 0.82rem;
}

.topic-card__meta-left {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.topic-card__meta-time {
  flex-shrink: 0;
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  white-space: nowrap;
}

.empty-state {
  padding: 2rem 1.25rem;
  text-align: center;
  color: var(--mute);
  border: 1px dashed var(--line);
  border-radius: 8px;
}

/* Detail */
.detail {
  display: grid;
  gap: 1.35rem;
}

.detail[hidden],
#library-view[hidden] {
  display: none;
}

.crumb {
  font-size: 0.95rem;
}

.crumb a {
  text-decoration: none;
}

.detail__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 1.9rem);
  font-weight: 400;
  line-height: 1.2;
}

.detail__meta {
  margin: -0.75rem 0 0;
  color: var(--mute);
  font-size: 0.92rem;
}

.detail__block h3 {
  margin: 0 0 0.65rem;
  font-size: 1.05rem;
}

.idea-list,
.source-list {
  margin: 0;
  padding-inline-start: 1.15rem;
}

.idea-list li + li,
.source-list li + li {
  margin-top: 0.45rem;
}

.outline {
  padding: 1.15rem 1.25rem 1.3rem;
}

.outline__meta {
  margin: 0 0 0.85rem;
  color: var(--mute);
  font-size: 0.9rem;
}

.outline ol {
  margin: 0;
  padding-inline-start: 1.2rem;
}

.outline li + li {
  margin-top: 0.65rem;
}

.site-footer {
  margin-top: auto;
  padding-block: 1.5rem 2rem;
  border-block-start: 1px solid var(--line);
  color: var(--mute);
  font-size: 0.9rem;
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  justify-content: space-between;
}

/* SEO article (niche guide) */
.article {
  width: min(100% - 2rem, var(--content));
  margin-inline: auto;
  padding-block: 2rem 3rem;
}

.article__meta {
  margin: 0 0 0.75rem;
  color: var(--mute);
  font-size: 0.9rem;
}

.article h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.5rem);
  font-weight: 400;
  line-height: 1.15;
}

.article .lede {
  font-size: 1.1rem;
  color: var(--ink-soft);
  margin: 0 0 1.5rem;
}

.article h2 {
  margin: 1.75rem 0 0.65rem;
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 400;
}

.article h3 {
  margin: 1.25rem 0 0.45rem;
  font-size: 1.05rem;
}

.article p,
.article li {
  max-width: 68ch;
}

.article ul,
.article ol {
  padding-inline-start: 1.2rem;
}

.article li + li {
  margin-top: 0.35rem;
}

.toc {
  margin: 0 0 1.5rem;
  padding: 0.9rem 1rem;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.toc h2 {
  margin: 0 0 0.45rem;
  font-family: var(--font-ui);
  font-size: 0.9rem;
  font-weight: 600;
}

.toc ol {
  margin: 0;
  padding-inline-start: 1.15rem;
}

.toc a {
  text-decoration: none;
}

.callout {
  margin: 1.25rem 0;
  padding: 0.9rem 1rem;
  border-left: 3px solid var(--cobalt);
  background: #eaf0ff;
  border-radius: 0 8px 8px 0;
}

.callout p {
  margin: 0;
}

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

/* Detail → structure template CTA */
.detail__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  align-items: center;
  margin-top: 0.15rem;
}

.detail__actions[hidden] {
  display: none;
}

.detail__actions-hint {
  margin: 0;
  color: var(--mute);
  font-size: 0.9rem;
}

/* Shared structure-template viewer (?id=) */
.template-page .tool-head {
  margin-bottom: 0.5rem;
}

.template-ids {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  word-break: break-all;
  color: var(--ink-soft);
}

.template-ids code {
  font-family: inherit;
  font-size: 0.92em;
  background: #e4ebf4;
  padding: 0.1em 0.4em;
  border-radius: 4px;
  margin-right: 0.25rem;
}

.angle-list {
  margin: 0;
  padding-inline-start: 1.15rem;
}

.angle-list li + li {
  margin-top: 0.45rem;
}