/* ============================================================
   Landing page — BeHocBai
   ============================================================ */

/* --- Header --- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,249,240,.85);
  backdrop-filter: blur(10px);
  border-bottom: 2px solid var(--line);
}
.site-header .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 70px;
}
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--f-display); font-weight: 800; font-size: 1.3rem; color: var(--c-primary); }
.brand .logo-dot { width: 38px; height: 38px; border-radius: 50%; background: var(--c-sun); display: grid; place-items: center; font-size: 1.3rem; box-shadow: var(--sh-sm); }
.nav-links { display: flex; gap: 26px; align-items: center; }
.nav-links a { font-weight: 600; color: var(--ink-soft); transition: color .2s; }
.nav-links a:hover { color: var(--c-primary); }
.nav-toggle { display: none; background: none; border: none; font-size: 1.6rem; cursor: pointer; }

/* --- Hero --- */
.hero { position: relative; padding: 70px 0 90px; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: 50px; align-items: center; }
.hero h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
.hero h1 .hl { color: var(--c-primary); position: relative; }
.hero h1 .hl::after {
  content: ''; position: absolute; left: 0; right: 0; bottom: 4px; height: 14px;
  background: var(--c-sun); opacity: .45; border-radius: 8px; z-index: -1;
}
.hero p.lead { font-size: 1.15rem; color: var(--ink-soft); margin: 20px 0 30px; max-width: 480px; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-blob {
  position: relative; aspect-ratio: 1; max-width: 420px; margin-left: auto;
  background: radial-gradient(circle at 30% 30%, var(--c-grape), var(--c-primary));
  border-radius: 42% 58% 63% 37% / 41% 44% 56% 59%;
  display: grid; place-items: center;
  animation: morph 8s ease-in-out infinite;
  box-shadow: var(--sh-lift);
}
.hero-blob .emoji { font-size: clamp(5rem, 14vw, 9rem); animation: bob 3s ease-in-out infinite; }
@keyframes morph {
  0%,100% { border-radius: 42% 58% 63% 37% / 41% 44% 56% 59%; }
  50% { border-radius: 58% 42% 38% 62% / 56% 59% 41% 44%; }
}
@keyframes bob { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-16px); } }

/* sao trang trí bay */
.float { position: absolute; font-size: 2rem; opacity: .8; animation: float 6s ease-in-out infinite; }
.float.f1 { top: 12%; right: 8%; animation-delay: 0s; }
.float.f2 { bottom: 18%; left: 4%; animation-delay: 1.5s; }
.float.f3 { top: 50%; right: 2%; animation-delay: 3s; }
@keyframes float { 0%,100% { transform: translateY(0) rotate(-5deg);} 50% { transform: translateY(-20px) rotate(5deg);} }

/* --- Phần game --- */
.section { padding: 70px 0; }
.section-title { text-align: center; margin-bottom: 12px; font-size: clamp(1.8rem,4vw,2.6rem); }
.section-sub { text-align: center; color: var(--ink-soft); margin-bottom: 44px; }

/* Bộ lọc theo lớp */
.grade-filter {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 10px;
  margin: -24px auto 36px; max-width: 720px;
}
.grade-chip {
  font-family: var(--f-display, inherit); font-weight: 700; font-size: 1rem;
  padding: 10px 20px; min-height: 44px; border-radius: 999px; cursor: pointer;
  background: #fff; color: var(--ink-soft, #475569);
  border: 2px solid #E2E8F0; transition: transform .15s, box-shadow .2s, background .2s, color .2s, border-color .2s;
}
.grade-chip:hover { transform: translateY(-2px); border-color: var(--c-primary, #3B82F6); }
.grade-chip.is-active {
  background: var(--c-primary, #3B82F6); color: #fff;
  border-color: var(--c-primary, #3B82F6); box-shadow: 0 6px 16px rgba(59,130,246,.3);
}

.games-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(250px,1fr)); gap: 22px;
}
.game-card {
  background: var(--bg-card); border-radius: var(--r-lg); padding: 26px 22px;
  box-shadow: var(--sh-md); border: 2px solid transparent;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s;
  display: flex; flex-direction: column; gap: 6px; position: relative; overflow: hidden;
}
.game-card::before {
  content: ''; position: absolute; inset: 0 0 auto 0; height: 6px; background: var(--accent, var(--c-primary));
}
.game-card:hover { transform: translateY(-6px); box-shadow: var(--sh-lift); border-color: var(--accent, var(--c-primary)); }
.game-card .ico { font-size: 2.6rem; width: 64px; height: 64px; border-radius: var(--r-md); display: grid; place-items: center; background: var(--accent-bg, #EFF6FF); margin-bottom: 8px; }
.game-card h3 { font-size: 1.25rem; }
.game-card p { color: var(--ink-soft); font-size: .95rem; flex: 1; }
.game-card .play { margin-top: 12px; font-weight: 700; font-family: var(--f-display); color: var(--accent, var(--c-primary)); display: inline-flex; align-items: center; gap: 6px; }
.game-card .play .arr { transition: transform .2s; }
.game-card:hover .play .arr { transform: translateX(5px); }

/* --- Phần lợi ích --- */
.benefits { background: linear-gradient(180deg, transparent, #FFF1DE); }
.benefit-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 28px; }
.benefit { background: var(--bg-card); border-radius: var(--r-lg); padding: 32px 26px; text-align: center; box-shadow: var(--sh-sm); }
.benefit .b-ico { font-size: 3rem; margin-bottom: 14px; }
.benefit h3 { font-size: 1.2rem; margin-bottom: 10px; }
.benefit p { color: var(--ink-soft); font-size: .96rem; }

/* --- Lời chứng thực --- */
.quotes-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(280px,1fr)); gap: 24px; }
.quote {
  background: var(--bg-card); border-radius: var(--r-lg); padding: 28px;
  box-shadow: var(--sh-md); position: relative;
}
.quote .mark { font-family: var(--f-display); font-size: 4rem; color: var(--c-sun); line-height: .6; position: absolute; top: 18px; right: 22px; opacity: .35; }
.quote p { font-style: italic; color: var(--ink); margin-bottom: 18px; }
.quote .who { display: flex; align-items: center; gap: 12px; }
.quote .who .av { width: 46px; height: 46px; border-radius: 50%; background: var(--c-mint); display: grid; place-items: center; font-size: 1.4rem; }
.quote .who b { font-family: var(--f-display); }
.quote .who span { display: block; font-size: .82rem; color: var(--ink-soft); }

/* --- CTA cuối --- */
.cta-band {
  background: linear-gradient(135deg, var(--c-primary), var(--c-grape));
  border-radius: var(--r-lg); padding: 56px 30px; text-align: center; color: #fff;
  box-shadow: var(--sh-lift); position: relative; overflow: hidden;
}
.cta-band h2 { font-size: clamp(1.8rem,4vw,2.6rem); color: #fff; margin-bottom: 12px; }
.cta-band p { opacity: .92; margin-bottom: 26px; }

/* --- Footer --- */
.site-footer { background: #1F2937; color: #D1D5DB; padding: 46px 0 30px; margin-top: 70px; }
.footer-grid { display: grid; grid-template-columns: 1fr 1.6fr; gap: 48px; margin-bottom: 30px; align-items: start; }
.site-footer h4 { color: #fff; margin-bottom: 14px; font-size: 1.05rem; }
.site-footer a { color: #9CA3AF; font-size: .92rem; line-height: 2; transition: color .2s; }
.site-footer a:hover { color: var(--c-sun); }
.footer-links { display: flex; flex-direction: column; }
.footer-links--cols { display: block; columns: 3; column-gap: 28px; }
.footer-links--cols a { display: block; break-inside: avoid; }
.footer-bottom { border-top: 1px solid #374151; padding-top: 20px; text-align: center; font-size: .86rem; color: #9CA3AF; }
.footer-bottom a { color: var(--c-sun); }

/* --- Reveal on scroll --- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* --- Responsive --- */
@media (max-width: 880px) {
  .hero-grid { grid-template-columns: 1fr; text-align: center; }
  .hero p.lead { margin-left: auto; margin-right: auto; }
  .hero-cta { justify-content: center; }
  .hero-blob { margin: 0 auto; }
  .benefit-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .footer-links--cols { columns: 2; }
  .nav-links { position: fixed; inset: 70px 0 auto 0; z-index: 99; background: var(--bg); flex-direction: column; padding: 20px; gap: 16px; border-bottom: 2px solid var(--line); max-height: calc(100vh - 70px); overflow-y: auto; transform: translateY(calc(-100% - 80px)); transition: transform .3s; }
  .nav-links.open { transform: none; }
  .nav-toggle { display: block; }
}