/* ============================================================
   THEME.CSS — Biến CSS + base style dùng chung cho mọi page
   ============================================================ */
:root {
  --brand:        #F5A623;
  --brand-dark:   #D4880F;
  --brand-light:  #FDE68A;
  --brand-cream:  #FFF8E1;
  --ink:          #2E1700;
  --body:         #444444;
  --muted:        #777777;
  --urgent:       #E74C3C;
  --success:      #27AE60;
  --container:    1140px;
}

html { scroll-behavior: smooth; }
body { color: var(--body); font-family: 'Be Vietnam Pro', Roboto, system-ui, sans-serif; }

/* Section anchor offset cho sticky header */
section[id] { scroll-margin-top: 90px; }

/* Số decorative lớn phía sau (01, 02, 03...) */
.deco-num {
  font-weight: 800;
  color: var(--brand-light);
  line-height: 1;
  opacity: .55;
  user-select: none;
}

/* Heading có gạch chân vàng */
.title-underline { position: relative; display: inline-block; }
.title-underline::after {
  content: '';
  position: absolute;
  left: 50%; transform: translateX(-50%);
  bottom: -12px;
  width: 70px; height: 4px;
  background: var(--brand);
  border-radius: 2px;
}

/* Animation fade-up khi cuộn tới */
.reveal { opacity: 0; transform: translateY(24px); transition: all .6s ease; }
.reveal.in { opacity: 1; transform: none; }