/* Reset và kiểu chữ cơ bản. */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; background: #C9DFE4; color: var(--deep); font: 400 16px/24px var(--body); min-height: 100vh; }
img { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
h1, h2, h3, h4, p, dl, dd, figure, blockquote, ul, ol { margin: 0; padding: 0; }
ul, ol { list-style: none; }
a { color: inherit; }
[hidden] { display: none !important; }
:focus-visible { outline: 2px solid var(--deep); outline-offset: 2px; border-radius: 6px; }

h1 { font-weight: 700; letter-spacing: -.025em; line-height: 1.1; }
h2 { font-weight: 700; font-size: clamp(22px, 2.2vw, 28px); line-height: 1.25; letter-spacing: -.015em; }
h3 { font-weight: 700; font-size: 18px; line-height: 26px; letter-spacing: -.1px; }
h4 { font-weight: 600; font-size: 15px; line-height: 22px; }

.muted { color: var(--deep-soft); }
.small { font-size: 14px; line-height: 21px; }
.xs { font-size: 13px; line-height: 19px; }
.b { font-weight: 700; }
.eyebrow { font-size: 13px; line-height: 22px; font-weight: 500; letter-spacing: .7px; text-transform: uppercase; }
.num { font-variant-numeric: tabular-nums; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

.icon { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; flex: none; }
.icon.sm { width: 16px; height: 16px; }

/* Bố trí nhanh */
.row { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.row.between { justify-content: space-between; }
.row.top { align-items: flex-start; flex-wrap: nowrap; }
.row.tight { gap: 6px; }
.stack { display: grid; gap: 16px; align-content: start; }
.stack.lg { gap: 24px; }
.stack.sm { gap: 8px; }
.grow { flex: 1 1 auto; min-width: 0; }
.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 20px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; }
.split { display: grid; grid-template-columns: minmax(0, 1fr) 360px; gap: 24px; align-items: start; }
.mt { margin-top: 16px; }
.mt-lg { margin-top: 28px; }

@media (max-width: 1000px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .split { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 640px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: minmax(0, 1fr); }
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  html { scroll-behavior: auto; }
}