/* ============================================================
   B-SIC — Beta Silicon Carbide  (modernised)
   ============================================================ */

/* ── Design tokens ────────────────────────────────────────── */
:root {
  --teal:        #3dc9b3;
  --teal-dark:   #2ba895;
  --teal-dim:    rgba(61,201,179,.12);
  --dark:        #0d1117;
  --surface:     #161b27;
  --surface-t:   #686869;
  --nav-h:       56px;

  --text:        #111827;
  --text-mid:    #374151;
  --text-muted:  #6b7280;
  --border:      #e5e7eb;
  --bg-soft:     #f8fafc;

  --radius-sm:   6px;
  --radius:      12px;
  --radius-lg:   18px;
  --shadow-sm:   0 1px 4px rgba(0,0,0,.07);
  --shadow:      0 4px 20px rgba(0,0,0,.09);
  --shadow-lg:   0 12px 40px rgba(0,0,0,.14);

  --font-en:     'Inter', 'Helvetica Neue', Arial, sans-serif;
  --font-cn:     'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-tw:     'Noto Sans TC', 'PingFang TC', 'Microsoft JhengHei', sans-serif;
}

/* ── Reset ────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-en);
  color: var(--text);
  background: #fff;
  line-height: 1.7;
  padding-top: var(--nav-h);       /* offset for sticky nav */
}

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

a { color: var(--teal); text-decoration: none; transition: color .25s; }
a:hover, a:focus { color: var(--teal-dark); }

/* ── Font family per language ─────────────────────────────── */
html.lang-zh-cn body { font-family: var(--font-cn); }
html.lang-zh-tw body { font-family: var(--font-tw); }

/* ── Language visibility ──────────────────────────────────── */
.t { display: none; }

html.lang-en    .t.en    { display: inline; }
html.lang-zh-cn .t.zh-cn { display: inline; }
html.lang-zh-tw .t.zh-tw { display: inline; }

/* ── Layout ───────────────────────────────────────────────── */
.container {
  width: 100%;
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.text-center { text-align: center; }
.text-left   { text-align: left;   }

.section-padding { padding: 5rem 0; }

/* ── Navigation ───────────────────────────────────────────── */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  z-index: 9999;
  background: rgba(13,17,23,.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(255,255,255,.06);
}

.nav-inner {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--teal);
  letter-spacing: .04em;
}
.nav-brand:hover { color: #fff; }

.lang-switcher {
  display: flex;
  align-items: center;
  gap: .25rem;
  background: rgba(255,255,255,.07);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 99px;
  padding: .2rem .35rem;
}

.lang-btn {
  background: none;
  border: none;
  color: rgba(255,255,255,.5);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .05em;
  cursor: pointer;
  padding: .3rem .65rem;
  border-radius: 99px;
  transition: color .2s, background .2s;
  line-height: 1;
}
.lang-btn:hover  { color: #fff; }
.lang-btn.active {
  background: var(--teal);
  color: #fff;
}

/* ── Hero ─────────────────────────────────────────────────── */
.facade {
  position: relative;
  background: url('../img/top-bg.png') no-repeat center center / cover;
  padding: 7rem 0 10rem;
  min-height: 480px;
  display: flex;
  align-items: center;
  overflow: hidden;
}

/* Dark gradient overlay */
.facade::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    160deg,
    rgba(13,17,23,.82) 0%,
    rgba(13,17,23,.65) 60%,
    rgba(61,201,179,.18) 100%
  );
}

/* Subtle teal glow bottom-right */
.facade::after {
  content: '';
  position: absolute;
  bottom: -80px; right: -80px;
  width: 400px; height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(61,201,179,.25) 0%, transparent 70%);
  pointer-events: none;
}

.facade .container { position: relative; }

.facade-inner { padding-top: 1rem; }

.facade h1 {
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 800;
  letter-spacing: clamp(4px, 2vw, 16px);
  color: #fff;
  line-height: 1.1;
  text-transform: uppercase;
  margin-bottom: 1.1rem;
}

.facade h1 span { color: rgba(255,255,255,.45); }

.facade p {
  color: rgba(255,255,255,.75);
  font-size: clamp(.85rem, 2vw, 1.05rem);
  letter-spacing: .06em;
  margin-bottom: 0;
}

.facade-cta { margin-top: 2.75rem; }

.learn-more-btn {
  display: inline-block;
  background: var(--teal);
  color: #fff;
  padding: .9rem 2.2rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: .82rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  line-height: 1.65;
  box-shadow: 0 4px 0 var(--teal-dark), 0 8px 24px rgba(61,201,179,.3);
  transition: background .25s, transform .15s, box-shadow .15s;
}
.learn-more-btn:hover, .learn-more-btn:focus {
  background: var(--teal-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 0 #228a77, 0 12px 28px rgba(61,201,179,.35);
}

/* ── Fade-in animations ───────────────────────────────────── */
@keyframes fadeDown { from { opacity:0; transform:translateY(-22px); } to { opacity:1; transform:none; } }
@keyframes fadeUp   { from { opacity:0; transform:translateY( 22px); } to { opacity:1; transform:none; } }

.fade-in-down { animation: fadeDown .85s ease both; }
.fade-in-up   { animation: fadeUp  .85s ease .3s both; }

/* ── Section titles ───────────────────────────────────────── */
.section-title {
  display: flex;
  align-items: center;
  gap: .75rem;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: .04em;
  margin: 2.8rem 0 1.4rem;
}

.section-title::before {
  content: '';
  display: block;
  width: 4px;
  height: 1.2em;
  background: var(--teal);
  border-radius: 2px;
  flex-shrink: 0;
}

/* When centered (products section) */
.text-center .section-title {
  justify-content: center;
}
.text-center .section-title::before { display: none; }
.text-center .section-title::after {
  content: '';
  display: block;
  width: 36px;
  height: 3px;
  background: var(--teal);
  border-radius: 2px;
  margin: .6rem auto 0;
}
/* override flex for centered: stack vertically */
.text-center .section-title {
  flex-direction: column;
  gap: 0;
}

/* ── Intro section ────────────────────────────────────────── */
.intro { background: var(--bg-soft); }

.intro-content { max-width: 800px; margin: 0 auto; }

.text-block { margin-bottom: 2rem; }
.text-block p { margin-bottom: 1.1rem; }
.text-block p:last-child { margin-bottom: 0; }

p {
  color: var(--text-mid);
  font-size: 1rem;
  line-height: 1.9;
  letter-spacing: .02em;
}

.text-chn p { text-align: justify; }

/* ── Applications grid ────────────────────────────────────── */
.applications { margin-top: .5rem; }

.apps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.25rem;
}

.app-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.6rem;
  transition: border-color .25s, box-shadow .25s, transform .25s;
}
.app-card:hover {
  border-color: var(--teal);
  box-shadow: 0 0 0 3px var(--teal-dim), var(--shadow);
  transform: translateY(-3px);
}

.app-card-header {
  display: flex;
  align-items: center;
  gap: .75rem;
  margin-bottom: .75rem;
}

.app-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.9rem;
  height: 1.9rem;
  background: var(--teal);
  color: #fff;
  border-radius: 50%;
  font-size: .75rem;
  font-weight: 700;
  flex-shrink: 0;
  line-height: 1;
}

.app-card h3 {
  font-size: .95rem;
  font-weight: 700;
  color: var(--text);
  margin: 0;
}

.app-card p {
  text-align: left;
  font-size: .9rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin: 0;
}

/* ── CTA-T band ─────────────────────────────────────────────── */
.ignite-cta-t {
  background: var(--surface-t);
  padding: 4rem 1rem;
  position: relative;
  overflow: hidden;
}

/* ── CTA band ─────────────────────────────────────────────── */
.ignite-cta {
  background: var(--surface);
  padding: 4rem 1rem;
  position: relative;
  overflow: hidden;
}
.ignite-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(61,201,179,.08) 0%, transparent 60%);
  pointer-events: none;
}

.ignite-btn {
  display: inline-block;
  padding: 1.1rem 3rem;
  color: #fff;
  border: 2px solid rgba(255,255,255,.3);
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: .1em;
  font-size: .85rem;
  transition: color .25s, border-color .25s, background .25s;
  position: relative;
}
.ignite-btn:hover, .ignite-btn:focus {
  color: var(--teal);
  border-color: var(--teal);
  background: rgba(61,201,179,.06);
}

/* ── Products section ─────────────────────────────────────── */
.features { background: #fff; }

.products-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.product-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.2rem;
  padding: 2.2rem 1.25rem 1.8rem;
  border-radius: var(--radius-lg);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  transition: transform .3s, box-shadow .3s, border-color .3s;
}
.product-card:hover {
  transform: translateY(-6px);
  border-color: var(--teal);
  box-shadow: 0 0 0 3px var(--teal-dim), var(--shadow-lg);
}

.product-icon {
  width: 80px;
  height: 80px;
  background: linear-gradient(135deg, var(--teal), var(--teal-dark));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px;
  box-shadow: 0 6px 20px rgba(61,201,179,.35);
  flex-shrink: 0;
}
.product-icon svg { width: 100%; height: 100%; }

.product-card h3 {
  font-size: .9rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: .05em;
  text-align: center;
  margin: 0;
  line-height: 1.4;
}
.product-card h3::after {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--teal);
  border-radius: 2px;
  margin: .6rem auto 0;
}

/* ── Footer ───────────────────────────────────────────────── */
footer {
  background: var(--dark);
  padding: 2rem 1rem;
  text-align: center;
  border-top: 1px solid rgba(255,255,255,.05);
}
footer p { margin: 0; font-size: .85rem; color: rgba(255,255,255,.35); }
footer a { color: rgba(255,255,255,.4); font-size: .85rem; }
footer a:hover, footer a:focus { color: var(--teal); }

/* ── Scroll-reveal (added by JS) ──────────────────────────── */
.reveal-hidden {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .55s ease, transform .55s ease;
}
.reveal-visible {
  opacity: 1;
  transform: none;
}

/* ── Mobile  ≤ 480px ──────────────────────────────────────── */
@media (max-width: 480px) {
  :root { --nav-h: 52px; }

  .facade { padding: 4rem 0 7rem; min-height: 320px; }
  .facade h1 { letter-spacing: 3px; }

  .learn-more-btn { padding: .8rem 1.6rem; font-size: .78rem; }

  .section-padding { padding: 3rem 0; }

  .section-title { font-size: .92rem; }

  .apps-grid { grid-template-columns: 1fr; }

  .products-grid { grid-template-columns: 1fr; gap: 1rem; }

  .ignite-btn { padding: .9rem 1.75rem; font-size: .8rem; }

  p { font-size: .93rem; }

  .lang-btn { font-size: .7rem; padding: .28rem .55rem; }
}

/* ── Tablet  481–768px ────────────────────────────────────── */
@media (min-width: 481px) and (max-width: 768px) {
  .facade { padding: 5rem 0 9rem; }
  .apps-grid { grid-template-columns: 1fr; }
  .products-grid { grid-template-columns: repeat(2, 1fr); }
  .section-padding { padding: 3.75rem 0; }
}

/* ── Desktop  ≥ 769px ─────────────────────────────────────── */
@media (min-width: 769px) {
  .facade { padding: 8rem 0 13rem; }
  .facade-inner { padding-top: 2rem; }
  .apps-grid { grid-template-columns: repeat(2, 1fr); }
  p { font-size: 1rem; }
}

/* ── Reduced motion ───────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  .fade-in-down, .fade-in-up { animation: none; opacity: 1; }
  .reveal-hidden { opacity: 1; transform: none; transition: none; }
  .product-card:hover, .app-card:hover, .learn-more-btn:hover { transform: none; }
}