/* 课堂宝官网 — 深色首屏 + 浅紫灰章节，对标 tnistech 排版 */
html, body { overflow-x: hidden; }

.site-header {
  background: rgba(10, 10, 18, 0.97);
  border-bottom: 1px solid rgba(139, 45, 158, 0.18);
  position: sticky;
  top: 0;
  z-index: 40;
}

.site-header__inner,
.site-wrap,
.site-footer__inner {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: 28px;
  min-height: 72px;
}

.site-logo {
  display: flex;
  align-items: center;
  color: #f9fafb;
}
.site-logo:hover { opacity: .92; }
.site-logo .ktb-lockup { height: 32px; }

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
}

.site-nav a {
  color: rgba(249, 250, 251, 0.88);
  font-size: 16px;
  font-weight: 500;
  line-height: 1;
  padding: 8px 16px;
  border-radius: 999px;
}

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

.site-nav a.is-active {
  color: #fff;
  background: var(--ktb-primary);
}

.site-header__acts {
  display: flex;
  gap: 8px;
  align-items: center;
}

.site-header__acts .ktb-btn--ghost {
  background: transparent;
  color: #f9fafb;
  border-color: rgba(255, 255, 255, 0.22);
}

.site-header__acts .ktb-btn--ghost:hover {
  background: rgba(255, 255, 255, 0.06);
  color: #fff;
}

.site-menu {
  display: none;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: transparent;
  color: #fff;
  border-radius: 10px;
  width: 40px;
  height: 40px;
}

.hero {
  position: relative;
  min-height: calc(100vh - 72px);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(139, 45, 158, 0.45), transparent 55%),
    radial-gradient(circle at 12% 80%, rgba(168, 85, 201, 0.18), transparent 40%),
    var(--ktb-dark);
  padding: 72px 0 56px;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(192, 132, 252, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(192, 132, 252, 0.07) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse at center, #000 30%, transparent 75%);
  pointer-events: none;
}

.hero__inner {
  position: relative;
  width: min(920px, calc(100% - 48px));
  margin: 0 auto;
}

.review-links {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.38);
  margin-bottom: 28px;
}

.review-links a { color: rgba(192, 132, 252, 0.85); }

.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: 999px;
  border: 1px solid rgba(192, 132, 252, 0.35);
  background: rgba(139, 45, 158, 0.2);
  color: #e9d5ff;
  font-size: 13px;
  margin-bottom: 28px;
}

.pill .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #22c55e;
  box-shadow: 0 0 8px #22c55e;
}

.hero__kicker {
  color: rgba(249, 250, 251, 0.55);
  font-size: 18px;
  margin-bottom: 8px;
}

.hero h1 {
  font-size: 52px;
  line-height: 1.18;
  color: #f9fafb;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.hero h1 span {
  color: var(--ktb-accent);
  font-weight: 500;
  padding: 0 12px;
}

.hero .lead {
  margin: 20px auto 32px;
  font-size: 16px;
  color: rgba(249, 250, 251, 0.62);
  max-width: 36em;
  line-height: 1.7;
}

.hero-acts {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 56px;
  margin-top: 64px;
  color: rgba(249, 250, 251, 0.45);
  font-size: 13px;
}

.hero-stats b {
  display: block;
  font-size: 32px;
  color: #f9fafb;
  font-weight: 600;
  letter-spacing: -0.03em;
}

.hero-stats b em {
  color: var(--ktb-accent);
  font-style: normal;
}

.section {
  padding: 88px 0;
}

.section--tint {
  background: #fff;
}

.eyebrow {
  text-align: center;
  color: var(--ktb-primary);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.22em;
  margin-bottom: 12px;
}

.section h2,
.page-hero h1 {
  text-align: center;
  font-size: 32px;
  color: var(--ktb-ink);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.section .sub,
.page-hero .sub {
  text-align: center;
  color: var(--ktb-muted);
  margin: 12px auto 40px;
  max-width: 36em;
  font-size: 16px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feat {
  padding: 28px 24px 32px;
  transition: transform var(--ktb-dur) var(--ktb-ease), box-shadow var(--ktb-dur) var(--ktb-ease);
  color: inherit;
  display: block;
}

.feat:hover {
  transform: translateY(-4px);
  box-shadow: var(--ktb-shadow-md);
  color: inherit;
}

.feat .idx {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--ktb-primary);
  font-weight: 600;
  margin-bottom: 16px;
}

.feat h3 {
  font-size: 20px;
  color: var(--ktb-ink);
  margin-bottom: 10px;
  font-weight: 600;
}

.feat p { color: var(--ktb-muted); font-size: 14px; }

.cover {
  height: 8px;
  border-radius: 999px;
  margin-bottom: 20px;
  background: linear-gradient(90deg, var(--ktb-primary), var(--ktb-accent));
}

.page-hero {
  background: var(--ktb-dark);
  padding: 72px 0 56px;
}

.page-hero h1,
.page-hero .sub {
  color: #f9fafb;
}

.page-hero .sub { color: rgba(249, 250, 251, 0.55); margin-bottom: 0; }

.page-hero .site-wrap { text-align: center; }

.prose {
  max-width: 720px;
  margin: 0 auto;
  font-size: 16px;
}

.prose p,
.prose li {
  margin-bottom: 14px;
  color: var(--ktb-body);
}

.faq {
  max-width: 760px;
  margin: 0 auto;
}

.faq details {
  background: #fff;
  border: 1px solid var(--ktb-line-tint);
  border-radius: 16px;
  padding: 16px 20px;
  margin-bottom: 10px;
}

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

.faq p {
  margin-top: 10px;
  color: var(--ktb-body);
}

.cta-band {
  background: var(--ktb-dark);
  color: #fff;
  border-radius: 28px;
  padding: 48px 40px;
  display: flex;
  gap: 32px;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  position: relative;
  overflow: hidden;
}

.cta-band::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 80% 20%, rgba(139, 45, 158, 0.45), transparent 50%);
  pointer-events: none;
}

.cta-band > * { position: relative; }

.cta-band h2 { color: #fff; text-align: left; font-size: 28px; }

.cta-band .sub { color: rgba(255,255,255,.62); text-align: left; margin: 8px 0 0; }

.site-footer .logo-tnis {
  height: 36px;
  border-radius: 6px;
}

.site-footer {
  background: var(--ktb-dark);
  padding: 40px 0 28px;
  margin-top: 0;
  font-size: 13px;
  color: rgba(249, 250, 251, 0.5);
}

.site-footer__brand {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
  padding-bottom: 28px;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.site-footer__brand .site-logo { gap: 14px; }
.site-footer__brand .site-logo .ktb-lockup { height: 28px; }
.site-footer__brand p {
  margin: 0;
  padding-left: 20px;
  border-left: 1px solid rgba(255,255,255,.16);
  color: rgba(249,250,251,.45);
  font-size: 13px;
}

.site-footer__map {
  display: grid;
  grid-template-columns: repeat(3, minmax(88px, 0.8fr)) minmax(260px, 1.9fr) auto;
  gap: 28px 32px;
  padding: 32px 0;
}
.site-footer__map h3 {
  margin: 0 0 14px;
  font-size: 13px;
  font-weight: 600;
  color: #f9fafb;
  letter-spacing: .04em;
}
.site-footer__map a {
  display: block;
  margin: 0 0 10px;
  color: rgba(249, 250, 251, 0.62);
}
.site-footer__map a:hover { color: var(--ktb-accent); }

.site-footer__contact p {
  margin: 0 0 10px;
  line-height: 1.6;
  color: rgba(249,250,251,.62);
}
.site-footer__contact span {
  display: inline-block;
  min-width: 2.2em;
  margin-right: 8px;
  color: rgba(249,250,251,.38);
}
.site-footer__contact a {
  display: inline;
  margin: 0;
}

.site-footer__qr {
  text-align: center;
  min-width: 132px;
}
.site-footer__qr .qr {
  width: 116px;
  height: 116px;
  margin: 0 auto 10px;
  border-radius: 12px;
  background: #fff;
  border: 0;
  padding: 6px;
  box-sizing: border-box;
}
.site-footer__qr .qr svg { display: block; width: 100%; height: 100%; }
.site-footer__qr strong {
  display: block;
  color: #f9fafb;
  font-size: 13px;
}
.site-footer__qr small {
  display: block;
  margin-top: 4px;
  font-size: 12px;
  color: rgba(249,250,251,.4);
}

.site-footer__copy {
  padding-top: 20px;
  border-top: 1px solid rgba(255,255,255,.08);
  font-size: 12px;
  color: rgba(249,250,251,.38);
}
.site-footer__copy p { margin: 0; }
.site-footer__copy a { color: rgba(249,250,251,.5); margin-right: 0; }
.site-footer__copy a:hover { color: var(--ktb-accent); }
.site-footer__note { margin-top: 8px !important; }
.site-footer__review { margin-left: 8px; }
.site-footer__review a { margin-left: 8px; }

.qr {
  width: 108px;
  height: 108px;
  border: 1px solid rgba(255,255,255,.15);
  border-radius: 16px;
  display: grid;
  place-items: center;
  font-size: 12px;
  color: rgba(255,255,255,.5);
  background:
    repeating-conic-gradient(#8b2d9e 0 25%, #1a1a2e 0 50%) 0 0 / 12px 12px;
}

@media (max-width: 800px) {
  .grid-3 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 32px; }
  .hero-stats { gap: 24px; }
  .hero-stats b { font-size: 24px; }
  .site-nav { display: none; }
  .site-nav.is-open {
    display: flex;
    flex-direction: column;
    position: absolute;
    left: 0;
    right: 0;
    top: 72px;
    background: #0a0a12;
    padding: 12px 20px 16px;
    border-bottom: 1px solid rgba(139, 45, 158, 0.25);
    gap: 12px;
  }
  .site-menu { display: inline-flex; align-items: center; justify-content: center; }
  .site-header__acts .ktb-btn--ghost { display: none; }
  .section h2, .page-hero h1 { font-size: 26px; }
  .cta-band { padding: 32px 24px; }
  .site-footer__map { grid-template-columns: 1fr 1fr; }
  .site-footer__contact { grid-column: 1 / -1; }
  .site-footer__qr { grid-column: 1 / -1; padding-top: 8px; }
  .site-footer__brand p {
    padding-left: 0;
    border-left: 0;
    width: 100%;
  }
}