/* =========================================
   吕箐翎 — AI-Era Knowledge Interface
   Baseline: Pico CSS v2
   Overrides: identity + GEO architecture
   Target era: 2029-2031
   ========================================= */

/* ---- Identity Overrides ---- */
:root {
  --pico-font-family: -apple-system, BlinkMacSystemFont, 'SF Pro SC', 'PingFang SC', 'Noto Sans SC', system-ui, sans-serif;
  --pico-font-family-monospace: ui-monospace, 'SF Mono', 'JetBrains Mono', 'Noto Sans Mono', monospace;
  --pico-border-radius: 0;
  --pico-form-element-border-width: 1px;
  --pico-spacing: 1rem;
  --container-max: 1120px;
}

/* Dark scheme overrides */
[data-theme="dark"], :root:not([data-theme="light"]) {
  --pico-background-color: #0a0a0a;
  --pico-color: #e4e2de;
  --pico-muted-color: #8a8783;
  --pico-muted-border-color: #1c1c1c;
  --pico-primary: #e4e2de;
  --pico-primary-hover: #ffffff;
  --pico-table-border-color: #1c1c1c;
  --pico-card-background-color: #101010;
  --pico-card-border-color: #1c1c1c;
  --pico-divider-color: #1c1c1c;
  --pico-h1-color: #e4e2de;
  --pico-h2-color: #e4e2de;
  --pico-h3-color: #e4e2de;
  --pico-text-selection-color: rgba(228,226,222,0.15);
  --pico-mark-background-color: transparent;
  --pico-mark-color: inherit;
}

/* ---- Layout ---- */
body > header,
body > footer,
body > main {
  --pico-block-spacing-vertical: 0;
  padding: 0;
}
.container {
  max-width: var(--container-max);
  padding: 0 28px;
}

/* ---- Header ---- */
body > header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10,10,10,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--pico-muted-border-color);
  padding: 0;
}
body > header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 48px;
}
body > header a { text-decoration: none; }
.header-brand { font-size: 14px; font-weight: 500; color: var(--pico-color); }
header nav { display: flex; gap: 20px; }
header nav a { font-size: 12px; color: var(--pico-muted-color); padding: 0; background: none; }
header nav a:hover, header nav a[aria-current="page"] { color: var(--pico-color); }
.mobile-menu-toggle { display: none; background: none; border: none; color: var(--pico-color); font-size: 18px; cursor: pointer; }

/* ---- Hero (Home) ---- */
.hero-section {
  min-height: 70vh;
  display: flex;
  align-items: center;
  padding: 120px 0 0;
}
.hero-tag {
  font-family: var(--pico-font-family-monospace);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pico-muted-color);
  margin-bottom: 20px;
}
.hero-name {
  font-size: clamp(56px, 12vw, 110px);
  font-weight: 500;
  line-height: 1.0;
  letter-spacing: -0.03em;
  margin-bottom: 4px;
}
.hero-subtitle {
  font-size: clamp(16px, 1.6vw, 21px);
  color: var(--pico-muted-color);
  margin-bottom: 48px;
}
.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  background: var(--pico-muted-border-color);
  max-width: 640px;
  margin-bottom: 48px;
}
.hero-stat {
  background: var(--pico-card-background-color);
  padding: 20px;
}
.hero-stat strong {
  font-size: clamp(26px, 3.2vw, 38px);
  font-weight: 500;
  display: block;
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.hero-stat small {
  font-family: var(--pico-font-family-monospace);
  font-size: 10px;
  color: var(--pico-muted-color);
  display: block;
  margin-top: 4px;
}
.hero-desc {
  max-width: 580px;
  color: var(--pico-muted-color);
  line-height: 1.8;
  margin-bottom: 36px;
}
.hero-actions { display: flex; gap: 10px; flex-wrap: wrap; }

/* ---- Page Hero (subpages) ---- */
.page-hero {
  padding: 120px 0 0;
}
.page-hero .mono-label {
  font-family: var(--pico-font-family-monospace);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pico-muted-color);
  margin-bottom: 12px;
}
.page-hero h1 {
  font-size: clamp(36px, 5vw, 60px);
  font-weight: 500;
  line-height: 1.05;
}

/* ---- Sections ---- */
section { padding: 80px 0; }
.section-header { margin-bottom: 40px; }
.section-header h2 {
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 500;
  letter-spacing: -0.01em;
}

/* ---- Grids ---- */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--pico-muted-border-color); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--pico-muted-border-color); }
.grid-2 > *, .grid-3 > * { background: var(--pico-background-color); padding: 32px; }
.grid-2.sidebar-layout { grid-template-columns: 1fr 240px; }

/* ---- Cards in grid ---- */
.grid-2 h3, .grid-3 h3 {
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 8px;
}
.grid-2 p, .grid-3 p {
  font-size: 13px;
  color: var(--pico-muted-color);
  line-height: 1.75;
}
.grid-meta {
  font-family: var(--pico-font-family-monospace);
  font-size: 10px;
  color: var(--pico-muted-color);
  margin-bottom: 6px;
}

/* ---- Case list ---- */
.case-row {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 20px;
  padding: 24px 0;
  border-bottom: 1px solid var(--pico-muted-border-color);
}
.case-row:first-child { border-top: 2px solid var(--pico-color); }
.case-row-year {
  font-family: var(--pico-font-family-monospace);
  font-size: 12px;
  color: var(--pico-muted-color);
}
.case-row h3 { font-size: 15px; font-weight: 500; margin-bottom: 4px; }
.case-row p { font-size: 13px; color: var(--pico-muted-color); line-height: 1.7; }

/* ---- Case detail ---- */
.case-detail-grid { display: grid; grid-template-columns: 1fr 220px; gap: 48px; }
.case-summary {
  font-size: 16px;
  line-height: 1.7;
  padding: 20px 24px;
  background: var(--pico-card-background-color);
  border-left: 2px solid var(--pico-color);
  margin: 24px 0;
}
.case-sidebar {}
.case-sidebar dt {
  font-family: var(--pico-font-family-monospace);
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--pico-muted-color);
  margin-top: 20px;
  margin-bottom: 4px;
}
.case-sidebar dt:first-child { margin-top: 0; }
.case-sidebar dd { font-size: 14px; color: var(--pico-muted-color); line-height: 1.6; }

/* ---- Contact ---- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--pico-muted-border-color); border: 1px solid var(--pico-muted-border-color); }
.contact-grid > * { padding: 40px 32px; }
.contact-info { background: var(--pico-background-color); }
.contact-cta { background: var(--pico-color); color: var(--pico-background-color); display: flex; flex-direction: column; justify-content: center; }
.contact-cta h3 { font-size: 20px; font-weight: 500; margin-bottom: 10px; color: inherit; }
.contact-cta p { font-size: 13px; opacity: 0.6; line-height: 1.8; margin-bottom: 20px; }
.contact-cta a { color: inherit; border-color: rgba(0,0,0,0.2); }
.contact-cta a:hover { background: var(--pico-background-color); color: var(--pico-color); }
.contact-row { display: flex; padding: 12px 0; border-bottom: 1px solid var(--pico-muted-border-color); gap: 16px; }
.contact-row:first-child { border-top: 1px solid var(--pico-muted-border-color); }
.contact-row strong { font-family: var(--pico-font-family-monospace); font-size: 10px; text-transform: uppercase; letter-spacing: 0.04em; min-width: 56px; font-weight: 500; color: var(--pico-muted-color); }
.contact-row span { font-size: 14px; color: var(--pico-muted-color); }

/* ---- FAQ ---- */
.faq-list { border-top: 1px solid var(--pico-muted-border-color); }
.faq-item { border-bottom: 1px solid var(--pico-muted-border-color); padding: 20px 0; }
.faq-q {
  font-size: 15px; font-weight: 500; cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
  -webkit-user-select: none; user-select: none;
}
.faq-q::after { content: '+'; font-size: 16px; color: var(--pico-muted-color); }
.faq-item.open .faq-q::after { content: '−'; }
.faq-a { font-size: 14px; color: var(--pico-muted-color); line-height: 1.8; margin-top: 0; max-height: 0; overflow: hidden; transition: max-height 0.25s ease; }
.faq-item.open .faq-a { max-height: 600px; margin-top: 12px; }

/* ---- Trust strip ---- */
.trust-strip { border-top: 1px solid var(--pico-muted-border-color); border-bottom: 1px solid var(--pico-muted-border-color); }
.trust-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.trust-cell { padding: 24px 16px; text-align: center; border-right: 1px solid var(--pico-muted-border-color); }
.trust-cell:last-child { border-right: none; }
.trust-cell strong { font-size: 26px; font-weight: 500; display: block; line-height: 1.1; }
.trust-cell small { font-family: var(--pico-font-family-monospace); font-size: 10px; color: var(--pico-muted-color); display: block; margin-top: 4px; }

/* ---- Footer ---- */
body > footer {
  padding: 0;
  border-top: 1px solid var(--pico-muted-border-color);
  background: transparent;
  margin-bottom: 0;
}
body > footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 28px;
  flex-wrap: wrap;
  gap: 12px;
}
body > footer small {
  font-size: 11px;
  color: var(--pico-muted-color);
}
.footer-links { display: flex; gap: 16px; }
.footer-links a { font-size: 11px; color: var(--pico-muted-color); padding: 0; background: none; }

/* ---- Responsive ---- */
@media (max-width: 900px) {
  .grid-2, .grid-3, .grid-2.sidebar-layout { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .case-detail-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .hero-stats { grid-template-columns: 1fr 1fr; }
  .trust-grid { grid-template-columns: repeat(2, 1fr); }
  .trust-cell:nth-child(2) { border-right: none; }
  header nav { display: none; }
  header nav.open { display: flex; flex-direction: column; position: absolute; top: 48px; left: 0; right: 0; background: var(--pico-background-color); border-bottom: 1px solid var(--pico-muted-border-color); padding: 12px 28px; gap: 12px; }
  .mobile-menu-toggle { display: block; }
  .case-row { grid-template-columns: 1fr; gap: 4px; }
}