/* ==========================================================================
   Base — reset + typography + tiện ích nhỏ
   ========================================================================== */
*,
*::before,
*::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--fs-md);
  line-height: var(--lh-normal);
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 { margin: 0; line-height: var(--lh-tight); font-weight: var(--fw-semibold); }
h1 { font-size: var(--fs-3xl); }
h2 { font-size: var(--fs-2xl); }
h3 { font-size: var(--fs-xl); }
h4 { font-size: var(--fs-lg); }
p { margin: 0; }

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

img, svg { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }

:focus-visible { outline: none; box-shadow: var(--focus-ring); border-radius: var(--radius-sm); }

table { border-collapse: collapse; width: 100%; }

/* ---- Tiện ích ---- */
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}
.text-muted { color: var(--color-text-2); }
.text-subtle { color: var(--color-text-3); }
.text-sm { font-size: var(--fs-sm); }
.text-xs { font-size: var(--fs-xs); }
.text-right { text-align: right; }
.text-center { text-align: center; }
.fw-medium { font-weight: var(--fw-medium); }
.fw-semibold { font-weight: var(--fw-semibold); }
.mono { font-family: var(--font-mono); font-size: var(--fs-sm); }
.nowrap { white-space: nowrap; }
.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.stack { display: flex; flex-direction: column; gap: var(--sp-4); }
.stack-sm { display: flex; flex-direction: column; gap: var(--sp-2); }
.row { display: flex; align-items: center; gap: var(--sp-3); flex-wrap: wrap; }
.row-between { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-3); flex-wrap: wrap; }
.grow { flex: 1 1 auto; min-width: 0; }
.hidden { display: none !important; }

.mt-2 { margin-top: var(--sp-2); }
.mt-4 { margin-top: var(--sp-4); }
.mt-6 { margin-top: var(--sp-6); }
.mb-4 { margin-bottom: var(--sp-4); }