/* =============================================
   CSS VARIABLES
   ============================================= */
:root {
  --bg:           #111214;
  --bg-section:   #16181b;
  --bg-stripe:    #13151a;
  --border:       #252830;
  --text:         #e8e9eb;
  --text-muted:   #8a8f9a;
  --accent:       #cc0000;   /* YouTube red, kept subtle */
  --accent-hover: #e50000;
  --link:         #c8cdd8;
  --link-hover:   #ffffff;
  --font:         -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --radius:       6px;
  --max-w:        1060px;
  --max-w-prose:  700px;
}

/* =============================================
   RESET & BASE
   ============================================= */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

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

/* =============================================
   LAYOUT HELPER
   ============================================= */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* =============================================
   HEADER / NAV
   ============================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(17, 18, 20, 0.95);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(6px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 58px;
  gap: 16px;
}

/* Brand */
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-size: 15px;
  font-weight: 600;
  flex-shrink: 0;
  white-space: nowrap;
}
.brand:hover { color: var(--text); }

.brand-logo {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  object-fit: cover;
}

/* Nav links */
.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  flex-shrink: 0;
}

.main-nav a {
  font-size: 13.5px;
  color: var(--text-muted);
  white-space: nowrap;
}
.main-nav a:hover { color: var(--text); }

/* =============================================
   BUTTON
   ============================================= */
.btn-primary {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  padding: 11px 24px;
  border-radius: var(--radius);
  white-space: nowrap;
  transition: background 0.15s, transform 0.1s;
}
.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
  transform: translateY(-1px);
}
.btn-primary:active {
  transform: translateY(0);
}

/* =============================================
   HERO SECTION
   ============================================= */
.hero {
  padding: 72px 0 56px;
  background: var(--bg);
}

.hero-inner {
  display: flex;
  align-items: center;
  gap: 56px;
}

.hero-text {
  flex: 1 1 0;
  min-width: 0;
}

.hero-title {
  font-size: clamp(24px, 4vw, 38px);
  font-weight: 700;
  line-height: 1.2;
  color: #fff;
  margin-bottom: 10px;
}

.hero-tagline {
  font-size: 17px;
  color: var(--text-muted);
  margin-bottom: 18px;
}

.hero-desc {
  font-size: 15px;
  color: var(--text-muted);
  max-width: 520px;
  margin-bottom: 32px;
  line-height: 1.7;
}

.hero-img-wrap {
  flex: 0 0 auto;
}

.hero-img {
    width: min(220px, 80vw);
    border-radius: 16px;
    border: 1px solid var(--border);
    box-shadow: 0 4px 24px rgba(0,0,0,0.5);
}

/* =============================================
   BANNER IMAGE
   ============================================= */
.banner-section {
  padding: 0 0 48px;
  background: var(--bg);
}

.banner-img {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--border);
}

/* =============================================
   HOW IT WORKS
   ============================================= */
.how-section {
  padding: 56px 0;
  background: var(--bg-stripe);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 28px;
}

.how-img {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--border);
}

/* =============================================
   FEATURE SCREENSHOTS
   ============================================= */
.features-section {
  padding: 56px 0;
  background: var(--bg);
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.feat-item {}

.feat-img {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--border);
}

/* =============================================
   CTA STRIP
   ============================================= */
.cta-strip {
  padding: 52px 0;
  background: var(--bg-stripe);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}

.cta-text {
  font-size: 20px;
  font-weight: 600;
  color: var(--text);
}

/* =============================================
   PRIVACY POLICY
   ============================================= */
.privacy-section {
  padding: 72px 0 80px;
  background: var(--bg);
}

.privacy-content {
  max-width: var(--max-w-prose);
}

.privacy-content h1 {
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
}

.policy-meta {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 28px;
}

.privacy-content h2 {
  font-size: 17px;
  font-weight: 600;
  color: var(--text);
  margin-top: 8px;
  margin-bottom: 12px;
}

.privacy-content p {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 14px;
}

.section-rule {
  border: none;
  border-top: 1px solid var(--border);
  margin: 32px 0 28px;
}

.email-link {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.email-link:hover {
  color: var(--accent-hover);
}

/* =============================================
   FOOTER
   ============================================= */
.site-footer {
  background: var(--bg-stripe);
  border-top: 1px solid var(--border);
  padding: 32px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13.5px;
  color: var(--text-muted);
}

.footer-logo {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  opacity: 0.7;
}

.footer-copy {
  font-size: 13px;
  color: var(--text-muted);
}

.footer-nav {
  display: flex;
  gap: 20px;
}
.footer-nav a {
  font-size: 13px;
  color: var(--text-muted);
}
.footer-nav a:hover { color: var(--text); }

/* =============================================
   RESPONSIVE – TABLET
   ============================================= */
@media (max-width: 768px) {
  .hero-inner {
    flex-direction: column;
    gap: 36px;
  }

  .hero-img {
    width: 180px;
  }

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

  .cta-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
}

/* =============================================
   RESPONSIVE – MOBILE
   ============================================= */
@media (max-width: 480px) {
    .brand-name {
        font-size: 12px;
        /* cắt bớt nếu vẫn tràn */
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
        max-width: 160px;
    }

  .main-nav {
    gap: 16px;
  }

  .hero {
    padding: 48px 0 40px;
  }

  .hero-title {
    font-size: 22px;
  }

  .cta-text {
    font-size: 17px;
  }

  .privacy-content h1 {
    font-size: 22px;
  }
}