/* ==========================================================================
   High Yibo Media — Editorial Authority design system v3.0
   极简权威风（对标 Jounce Media）：浅灰白底 + 近黑文字 + 靛蓝强调 +
   Raleway 字体 + 全大写标题 + 深色 Hero/Footer + 胶囊按钮
   ========================================================================== */

:root {
  /* Color palette */
  --bg: #F7F7F7;             /* page background */
  --surface: #FFFFFF;        /* cards */
  --surface-hover: #F1F1F1;
  --ink: #111111;            /* primary text */
  --ink-soft: #333333;
  --muted: #777777;          /* secondary */
  --faint: #9A9A9A;

  --dark: #121212;           /* dark hero / footer */
  --dark-2: #1E1E1E;

  --brand: #3D5AFE;          /* indigo accent */
  --brand-ink: #2A3EB1;      /* hover */
  --accent-100: #E8EAF6;     /* brand tint */

  --cta: #111111;            /* primary button (dark) */
  --cta-hover: #000000;

  --line: #EEEEEE;
  --line-strong: #D9D9D9;

  --success: #1B5E20;
  --danger: #C9342A;

  /* Type */
  --font-sans: "Raleway", "Inter", -apple-system, BlinkMacSystemFont,
    "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

  /* Spacing (4px base) */
  --s1: 0.25rem; --s2: 0.5rem; --s3: 0.75rem; --s4: 1rem;
  --s5: 1.5rem; --s6: 2rem; --s7: 3rem; --s8: 4rem; --s9: 6rem;

  /* Layout */
  --container: 1200px;
  --radius-sm: 0.5rem;
  --radius: 1rem;            /* large rounded containers (Jounce signature) */
  --radius-lg: 1.25rem;
  --radius-pill: 100vh;      /* pill buttons */
  --shadow: 0 1px 3px rgba(0,0,0,0.06);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

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

img { max-width: 100%; display: block; }

a { color: var(--brand-ink); text-decoration: none; transition: color 0.15s ease; }
a:hover { color: var(--brand); }

/* 全大写标题 — Jounce 招牌 */
h1, h2, h3, h4 {
  font-family: var(--font-sans);
  color: var(--ink);
  font-weight: 700;
  line-height: 1.15;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

h1 { font-size: clamp(2.25rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.75rem, 3.5vw, 2.4rem); margin-bottom: var(--s6); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.05rem; }

p { margin-bottom: var(--s4); }

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--s6);
}

.section { padding: var(--s8) 0; }

.section--alt {
  background: var(--surface);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

/* ==========================================================================
   Utility
   ========================================================================== */

.eyebrow {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--brand);
  margin-bottom: var(--s4);
}

.lead {
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 640px;
}

.text-center { text-align: center; }
.mx-auto { margin-left: auto; margin-right: auto; }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* ==========================================================================
   Buttons — pill, uppercase (Jounce signature)
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-pill);
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.85rem;
  line-height: 1;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease,
    transform 0.15s ease;
  text-decoration: none;
  white-space: nowrap;
}

.btn:focus-visible {
  outline: 3px solid rgba(61, 90, 254, 0.35);
  outline-offset: 2px;
}

.btn--primary {
  background: var(--cta);
  color: #fff;
}
.btn--primary:hover {
  background: var(--cta-hover);
  color: #fff;
  transform: translateY(-1px);
}

.btn--cta {
  background: var(--brand);
  color: #fff;
}
.btn--cta:hover {
  background: var(--brand-ink);
  color: #fff;
  transform: translateY(-1px);
}

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

/* 深色区块（hero / page-hero）内的 ghost 按钮：黑底上用白字白边 */
.hero .btn--ghost,
.page-hero .btn--ghost {
  color: #fff;
  border-color: rgba(255, 255, 255, 0.45);
}
.hero .btn--ghost:hover,
.page-hero .btn--ghost:hover {
  color: #fff;
  border-color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

.btn--lg { padding: 0.95rem 2rem; font-size: 0.9rem; }

/* ==========================================================================
   Header / Nav — light, minimal
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--ink);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.brand__mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--brand);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 0.9rem;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--s5);
  list-style: none;
}

.nav__links a {
  color: var(--ink-soft);
  font-weight: 600;
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.nav__links a:hover { color: var(--brand); }
.nav__links a.is-active { color: var(--brand); }

.nav__cta { display: flex; align-items: center; gap: var(--s3); }

.nav__toggle {
  display: none;
  background: none;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  width: 40px; height: 40px;
  cursor: pointer;
  align-items: center; justify-content: center;
}

.nav__toggle span {
  display: block; width: 18px; height: 2px;
  background: var(--ink); margin: 2px 0; border-radius: 2px;
}

/* ==========================================================================
   Hero — dark block, centered, uppercase headline (Jounce signature)
   ========================================================================== */

.hero {
  position: relative;
  overflow: hidden;
  background: var(--dark);
  color: #fff;
  padding: var(--s9) 0;
  text-align: center;
}

.hero__grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--s5);
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.85);
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: var(--radius-pill);
  padding: 0.4rem 1.2rem;
  margin-bottom: var(--s4);
}

.hero h1 {
  color: #fff;
  max-width: 900px;
  margin: 0 auto var(--s4);
  font-weight: 800;
}

.hero h1 .accent { color: #fff; }

.hero__sub {
  font-size: 1.15rem;
  color: rgba(255,255,255,0.75);
  margin-bottom: var(--s6);
  max-width: 620px;
  margin-left: auto;
  margin-right: auto;
}

.hero__actions { display: flex; gap: var(--s3); flex-wrap: wrap; justify-content: center; }

.hero__proof {
  display: flex;
  gap: var(--s6);
  margin-top: var(--s6);
  flex-wrap: wrap;
  justify-content: center;
}

.hero .stat__num {
  font-family: var(--font-sans);
  font-size: 1.9rem;
  font-weight: 800;
  color: #fff;
}
.hero .stat__label {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.6);
}

.hero__visual { display: none; }  /* 极简风去掉右侧卡片 */

/* ==========================================================================
   Stat (shared)
   ========================================================================== */

.stat__num {
  font-family: var(--font-sans);
  font-size: 2rem;
  font-weight: 800;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.stat__label {
  font-size: 0.82rem;
  color: var(--muted);
}

/* ==========================================================================
   Sections / grids
   ========================================================================== */

.section-head { max-width: 640px; margin-bottom: var(--s7); }
.section-head--center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head h2 { margin-bottom: var(--s4); }

.grid { display: grid; gap: var(--s5); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--s6);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.card:hover {
  border-color: var(--line-strong);
  box-shadow: var(--shadow);
}

.card__icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  background: var(--accent-100);
  color: var(--brand);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: var(--s4);
  font-size: 1.2rem;
}

.card h3 { margin-bottom: var(--s2); }
.card p { margin-bottom: 0; color: var(--muted); font-size: 0.95rem; }

/* ==========================================================================
   Feature / split rows
   ========================================================================== */

.split { display: grid; grid-template-columns: 1fr 1fr; gap: var(--s7); align-items: center; }
.split--reverse { direction: rtl; }
.split--reverse > * { direction: ltr; }

.split__body h2 { margin-bottom: var(--s4); }

.checklist {
  list-style: none; margin-top: var(--s4);
  display: flex; flex-direction: column; gap: var(--s3);
}
.checklist li { display: flex; gap: var(--s3); align-items: flex-start; }
.checklist li::before {
  content: "";
  flex: none;
  width: 20px; height: 20px;
  border-radius: 50%;
  background: var(--accent-100);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%233D5AFE' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: center;
  margin-top: 4px;
}

.visual-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--s6);
  color: var(--ink);
}

.visual-panel h3 { color: var(--ink); margin-bottom: var(--s2); }
.visual-panel p { color: var(--muted); }

.visual-panel .mini-row {
  display: flex; justify-content: space-between; align-items: center;
  padding: var(--s3) 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.9rem;
  color: var(--muted);
}
.visual-panel .mini-row:last-child { border-bottom: none; }
.visual-panel .mini-row strong { color: var(--ink); }

.pill {
  display: inline-block;
  font-size: 0.72rem; font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.25rem 0.6rem; border-radius: 999px;
  background: var(--accent-100); color: var(--brand);
}

/* ==========================================================================
   Logos / social proof
   ========================================================================== */

.logo-strip {
  display: flex; flex-wrap: wrap;
  gap: var(--s5) var(--s6);
  align-items: center; justify-content: center;
}

.logo-strip span {
  font-weight: 700; font-size: 1rem;
  color: var(--faint); letter-spacing: 0.02em;
  white-space: nowrap;
}

/* ==========================================================================
   Case studies
   ========================================================================== */

.case-card { overflow: hidden; padding: 0; display: flex; flex-direction: column; }

.case-card__body {
  padding: var(--s5);
  display: flex; flex-direction: column; gap: var(--s3); flex: 1;
}

.case-card__tag {
  font-size: 0.72rem; font-weight: 700;
  color: var(--brand);
  text-transform: uppercase; letter-spacing: 0.08em;
}

.case-card__result {
  display: flex; gap: var(--s5);
  padding-top: var(--s4);
  border-top: 1px solid var(--line);
  margin-top: auto;
}

.case-card__result .stat__num { font-size: 1.5rem; color: var(--brand); }

/* ==========================================================================
   Article list
   ========================================================================== */

.article-card { display: flex; flex-direction: column; gap: var(--s2); }
.article-card__meta {
  font-size: 0.78rem; color: var(--faint);
  display: flex; gap: var(--s2); flex-wrap: wrap;
}
.article-card h3 a { color: var(--ink); }
.article-card h3 a:hover { color: var(--brand); }
.article-card p { margin-bottom: 0; }

/* ==========================================================================
   Forms
   ========================================================================== */

.form { display: flex; flex-direction: column; gap: var(--s4); }

.field label {
  display: block;
  font-weight: 700; color: var(--ink);
  margin-bottom: var(--s2); font-size: 0.82rem;
  text-transform: uppercase; letter-spacing: 0.05em;
}

.field input,
.field select,
.field textarea {
  width: 100%;
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.95rem; color: var(--ink);
  background: #fff;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(61, 90, 254, 0.12);
}

.field textarea { resize: vertical; min-height: 120px; }

.form__note { font-size: 0.82rem; color: var(--faint); }

.form__success {
  display: none;
  padding: var(--s4);
  background: #E8F5E9;
  border: 1px solid #C8E6C9;
  border-radius: var(--radius);
  color: var(--success);
  font-weight: 600;
}

/* ==========================================================================
   CTA band — white card on light bg
   ========================================================================== */

.cta-band {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: var(--s7) var(--s6);
  text-align: center;
}

.cta-band h2 { color: var(--ink); margin-bottom: var(--s3); }
.cta-band p { color: var(--muted); max-width: 560px; margin: 0 auto var(--s5); }
.cta-band .btn--cta { background: var(--cta); }
.cta-band .btn--cta:hover { background: var(--cta-hover); }

/* ==========================================================================
   Footer — dark block (Jounce signature)
   ========================================================================== */

.site-footer {
  background: var(--dark);
  color: #DDDDDD;
  padding: var(--s8) 0 var(--s5);
  margin-top: var(--s8);
}

.footer__grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--s6); margin-bottom: var(--s6);
}

.site-footer a { color: #DDDDDD; }
.site-footer a:hover { color: #fff; }

.footer__col h4 {
  color: #fff;
  font-size: 0.78rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.1em;
  margin-bottom: var(--s4);
}

.footer__col ul {
  list-style: none; display: flex; flex-direction: column; gap: var(--s2);
  font-size: 0.9rem;
}

.footer__brand .brand { color: #fff; margin-bottom: var(--s3); }
.footer__brand p { font-size: 0.9rem; color: #999; }

.footer__bottom {
  border-top: 1px solid rgba(255,255,255,0.12);
  padding-top: var(--s5);
  display: flex; justify-content: space-between; gap: var(--s4);
  flex-wrap: wrap;
  font-size: 0.82rem; color: #999;
}

/* ==========================================================================
   Page hero (interior)
   ========================================================================== */

.page-hero {
  padding: var(--s8) 0 var(--s6);
  background: var(--dark);
  color: #fff;
  text-align: center;
}

.page-hero h1 { color: #fff; margin-bottom: var(--s3); }
.page-hero .lead { color: rgba(255,255,255,0.7); margin: 0 auto; }

.breadcrumb {
  font-size: 0.82rem; color: var(--faint); margin-bottom: var(--s4);
}
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--brand); }

.page-hero .breadcrumb { color: rgba(255,255,255,0.5); }
.page-hero .breadcrumb a { color: rgba(255,255,255,0.6); }
.page-hero .breadcrumb a:hover { color: #fff; }

/* ==========================================================================
   Prose (article body)
   ========================================================================== */

.prose {
  max-width: 720px; margin: 0 auto;
  font-size: 1.05rem; line-height: 1.8;
}

.prose h2 { margin: var(--s6) 0 var(--s3); font-size: 1.5rem; }
.prose h3 { margin: var(--s5) 0 var(--s2); }
.prose ul, .prose ol { margin: 0 0 var(--s4) var(--s5); }
.prose li { margin-bottom: var(--s2); }
.prose blockquote {
  border-left: 4px solid var(--brand);
  padding: var(--s2) var(--s4);
  margin: var(--s5) 0;
  background: var(--accent-100);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--ink);
  font-style: italic;
}
.prose code {
  background: #EDEDED;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9em;
  color: var(--brand-ink);
}

.article-hero { max-width: 720px; margin: 0 auto; }
.article-hero__meta {
  display: flex; gap: var(--s3); color: var(--faint);
  font-size: 0.88rem; margin-bottom: var(--s4); flex-wrap: wrap;
}

/* ==========================================================================
   FAQ
   ========================================================================== */

.faq-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  margin-bottom: var(--s3);
  overflow: hidden;
}

.faq-item__q {
  width: 100%; text-align: left;
  padding: var(--s4) var(--s5);
  font-size: 1rem; font-weight: 700; color: var(--ink);
  background: none; border: none; cursor: pointer;
  display: flex; justify-content: space-between; align-items: center; gap: var(--s4);
}

.faq-item__q::after {
  content: "+"; font-size: 1.4rem; font-weight: 400;
  color: var(--muted); transition: transform 0.2s ease;
}
.faq-item.open .faq-item__q::after { transform: rotate(45deg); }

.faq-item__a { display: none; padding: 0 var(--s5) var(--s4); color: var(--muted); }
.faq-item.open .faq-item__a { display: block; }

/* ==========================================================================
   Responsive
   ========================================================================== */

@media (max-width: 960px) {
  .hero__grid, .split, .split--reverse { grid-template-columns: 1fr; }
  .split--reverse { direction: ltr; }
  .grid--3, .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .footer__grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 640px) {
  .section { padding: var(--s6) 0; }
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr; }

  .nav__links {
    position: absolute; top: 72px; left: 0; right: 0;
    background: #fff;
    flex-direction: column; align-items: stretch; gap: 0;
    padding: var(--s3) var(--s5);
    border-bottom: 1px solid var(--line);
    display: none;
  }
  .nav__links.open { display: flex; }
  .nav__links li { padding: var(--s3) 0; border-bottom: 1px solid var(--line); }
  .nav__links li:last-child { border-bottom: none; }
  .nav__cta .btn--ghost { display: none; }
  .nav__toggle { display: flex; }

  .hero { padding: var(--s6) 0; }
  .hero__proof { gap: var(--s4); }
}