/* ==========================================================================
   SmartQuantAI — Landing site styles
   Theme: deep navy (#0B1E3F) -> cyan (#22D3EE) gradient accents
   Dependency-free, system font stack only.
   ========================================================================== */

:root {
  --navy-900: #0B1E3F;
  --navy-800: #0F2950;
  --navy-700: #143461;
  --navy-600: #1C4178;
  --cyan: #22D3EE;
  --cyan-soft: #67E8F9;
  --ink: #E6EDF7;
  --ink-dim: #A8B6CC;
  --ink-faint: #7E8CA6;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-2: rgba(255, 255, 255, 0.07);
  --border: rgba(255, 255, 255, 0.10);
  --green: #34D399;
  --green-bg: rgba(52, 211, 153, 0.14);
  --amber: #FBBF24;
  --amber-bg: rgba(251, 191, 36, 0.14);
  --radius: 14px;
  --max-width: 1120px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Microsoft JhengHei",
    sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(34, 211, 238, 0.10), transparent 60%),
    linear-gradient(180deg, var(--navy-900) 0%, #081730 100%);
  background-attachment: fixed;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ---------------------------- Header ------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 30, 63, 0.72);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}

.brand {
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.2px;
  background: linear-gradient(90deg, var(--cyan), var(--cyan-soft));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.nav {
  display: flex;
  align-items: center;
  gap: 18px;
}

.nav-link {
  color: var(--ink-dim);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.15s ease;
}

.nav-link:hover {
  color: var(--ink);
}

/* ---------------------------- Language switch ---------------------------- */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
}

.lang-btn {
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--ink-dim);
  background: transparent;
  border: none;
  border-radius: 999px;
  padding: 6px 12px;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
  white-space: nowrap;
}

.lang-btn:hover {
  color: var(--ink);
}

.lang-btn.is-active {
  background: linear-gradient(90deg, var(--cyan), var(--cyan-soft));
  color: var(--navy-900);
}

/* ---------------------------- Hero --------------------------------------- */
.hero {
  position: relative;
  padding: 96px 0 80px;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(620px 320px at 12% 20%, rgba(34, 211, 238, 0.12), transparent 60%),
    radial-gradient(520px 280px at 90% 10%, rgba(34, 211, 238, 0.08), transparent 60%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  max-width: 820px;
}

.hero-tagline {
  display: inline-block;
  margin: 0 0 18px;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  color: var(--cyan);
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
}

.hero-headline {
  margin: 0 0 20px;
  font-size: clamp(2rem, 5vw, 3.1rem);
  line-height: 1.15;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: linear-gradient(180deg, #ffffff 0%, #C8E9F4 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub {
  margin: 0 0 32px;
  font-size: clamp(1rem, 2.2vw, 1.15rem);
  color: var(--ink-dim);
  max-width: 680px;
}

/* ---------------------------- Buttons ------------------------------------ */
.btn {
  display: inline-block;
  font-family: inherit;
  font-weight: 700;
  font-size: 1rem;
  padding: 14px 28px;
  border-radius: 999px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.12s ease, box-shadow 0.15s ease, background 0.15s ease;
  text-align: center;
}

.btn-primary {
  color: var(--navy-900);
  background: linear-gradient(90deg, var(--cyan), var(--cyan-soft));
  box-shadow: 0 10px 30px rgba(34, 211, 238, 0.22);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 38px rgba(34, 211, 238, 0.32);
}

.btn-secondary {
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 0.12);
}

/* ---------------------------- Sections ----------------------------------- */
.section-heading {
  text-align: center;
  font-size: clamp(1.5rem, 3.5vw, 2.1rem);
  font-weight: 800;
  margin: 0 0 40px;
  color: var(--ink);
}

.features {
  padding: 72px 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(34, 211, 238, 0.4);
}

.feature-title {
  margin: 14px 0 10px;
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--ink);
}

.feature-body {
  margin: 0;
  color: var(--ink-dim);
  font-size: 0.96rem;
}

/* ---------------------------- Badges ------------------------------------- */
.badge {
  display: inline-block;
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.4px;
  text-transform: uppercase;
  padding: 5px 12px;
  border-radius: 999px;
}

.badge--available {
  color: var(--green);
  background: var(--green-bg);
  border: 1px solid rgba(52, 211, 153, 0.35);
}

.badge--soon {
  color: var(--amber);
  background: var(--amber-bg);
  border: 1px solid rgba(251, 191, 36, 0.35);
}

/* ---------------------------- Downloads ---------------------------------- */
.downloads {
  padding: 72px 0 96px;
}

.download-intro {
  text-align: center;
  color: var(--ink-dim);
  margin: -20px 0 40px;
  font-size: 1.05rem;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 760px;
  margin: 0 auto;
}

.download-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 28px;
  text-align: center;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.download-card:hover {
  transform: translateY(-4px);
  border-color: rgba(34, 211, 238, 0.4);
}

.download-card-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.download-title {
  margin: 0 0 8px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--ink);
}

.download-desc {
  margin: 0 0 22px;
  color: var(--ink-dim);
  font-size: 0.95rem;
  min-height: 2.8em;
}

.version-note {
  text-align: center;
  margin: 40px 0 0;
  color: var(--ink-faint);
  font-size: 0.9rem;
}

/* ---------------------------- Footer ------------------------------------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  background: rgba(8, 23, 48, 0.6);
}

.footer-text {
  margin: 0;
  text-align: center;
  color: var(--ink-faint);
  font-size: 0.88rem;
}

/* ---------------------------- Responsive --------------------------------- */
@media (max-width: 860px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
  .download-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .header-inner {
    height: auto;
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    padding-top: 14px;
    padding-bottom: 14px;
  }
  .nav {
    width: 100%;
    justify-content: space-between;
    gap: 10px;
  }
  .lang-btn {
    padding: 6px 9px;
    font-size: 0.76rem;
  }
  .hero {
    padding: 64px 0 56px;
  }
}

/* ---------------------------- Reduced motion ----------------------------- */
@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}