*,
*::before,
*::after {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  height: 100%;
  font-family: "Inter", system-ui, sans-serif;
  background: #050b1a;
}

/* HEADER */
.site-header {
  position: fixed;
  top: 24px;
  left: 24px;
  z-index: 10;
}

.site-header img {
  width: 120px;
  height: auto;
  display: block;
}

/* HERO */
.hero {
  position: relative;
  height: 100vh;
  overflow: hidden;
}

/* SLIDES WRAPPER */
.hero-slides {
  position: absolute;
  inset: 0;
  z-index: 0;
}

/* SINGLE SLIDE */
.hero-slide {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0;
  transform: scale(1.05);
  transition: opacity 1.2s ease, transform 6s linear;
}

/* ACTIVE */
.hero-slide.active {
  opacity: 1;
  transform: scale(1.12);
}

/* DARK OVERLAY */
.hero::after {
   content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    rgba(5,11,26,.45),
    rgba(5,11,26,.85)
  );

  z-index: 1;        /* ✅ thấp hơn footer */
  pointer-events: none;
}

/* CONTENT */
.countries {
  position: relative;
  z-index: 2;
  height: 100%;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  align-items: center;
  padding: 0 6vw;
}

.country {
  text-align: center;
  color: #fff;
}

.country h2 {
  font-size: 40px;
  margin-bottom: 10px;
}

.country p {
  font-size: 15px;
  opacity: .85;
  margin-bottom: 24px;
}

/* BUTTON */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border: 1px solid rgba(255,255,255,.7);
  color: #fff;
  text-decoration: none;
  font-size: 13px;
  letter-spacing: .08em;
  text-transform: uppercase;
  transition: all .35s ease;
}

.btn:hover {
  background: #fff;
  color: #050b1a;
}

/* FOOTER */
.site-footer {
    position: fixed;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 12px;
  color: rgba(255,255,255,.5);
  z-index: 20; 
  padding-bottom: env(safe-area-inset-bottom);
}

/* RESPONSIVE */
@media (max-width: 900px) {
  .countries {
    grid-template-columns: 1fr;
    gap: 48px;
    padding-top: 100px;
  }
}

@media (max-width: 768px) {

  /* HERO HEIGHT */
  .hero {
    height: auto;
    min-height: 100vh;
  }

  /* BACKGROUND SCALE */
  .hero-slide {
    background-position: center top;
    transform: scale(1.02);
  }

  /* CONTENT STACK */
  .countries {
    grid-template-columns: 1fr;
    gap: 32px;
    padding: 120px 6vw 120px;
    align-items: start;
  }

  /* COUNTRY CARD */
  .country {
    background: transparent;
    border-radius: 14px;
    padding: 28px 20px;
  }

  .country h2 {
    font-size: 28px;
  }

  .country p {
    font-size: 14px;
    line-height: 1.5;
  }

  /* BUTTON – DỄ BẤM */
  .btn {
    width: 100%;
    padding: 14px 0;
    font-size: 13px;
  }

}