/* Reset + nền tảng */
*, *::before, *::after { box-sizing: border-box; }
html { font-size: 16px; -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; font-family: var(--font-body); font-size: var(--text-body); line-height: 1.55; color: var(--c-text); background: var(--c-bg); -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, h4, p, figure { margin: 0; }
h1, h2, h3, h4 { font-family: var(--font-heading); font-weight: 700; line-height: 1.3; color: var(--c-text); }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; border: 0; background: none; padding: 0; }
svg { flex: none; }
i.sep { font-style: normal; opacity: .55; margin: 0 8px; }

.container { width: min(100% - (var(--container-gutter) * 2), var(--container-max)); margin-inline: auto; }
.sr-only { position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.skip-link { position: fixed; left: 12px; top: -60px; z-index: 300; background: var(--c-navy); color: #fff; padding: 10px 16px; border-radius: var(--radius-sm); transition: top var(--t-fast); }
.skip-link:focus { top: 12px; }
.ico { width: 1em; height: 1em; display: inline-block; vertical-align: -.125em; }

/* focus bàn phím nhìn thấy rõ */
:focus { outline: none; }
:focus-visible { outline: 3px solid var(--c-focus); outline-offset: 2px; border-radius: 3px; }

/* nút */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; height: 40px; padding: 0 20px; border-radius: var(--radius-sm); font-weight: 700; font-size: 14px; transition: background-color var(--t-fast) ease, box-shadow var(--t-fast) ease, transform var(--t-fast) ease; }
.btn--primary { background: var(--c-blue); color: #fff; }
.btn--primary:hover, .btn--primary.is-hover { background: var(--c-blue-dark); box-shadow: 0 4px 12px rgba(11, 94, 215, .35); }
.btn--gold { background: var(--c-gold); color: #3b2a00; }
.btn--gold:hover, .btn--gold.is-hover { background: #f0ac10; box-shadow: 0 4px 12px rgba(240, 172, 16, .4); }
.btn .ico { width: 16px; height: 16px; transition: transform var(--t-fast) ease; }
.btn--gold:hover .ico { transform: translateX(3px); }
.btn:active { transform: translateY(1px); }

.chip { display: inline-flex; align-items: center; gap: 6px; height: 24px; padding: 0 10px; border-radius: 4px; background: #0a62d6; color: #fff; font: 700 11.5px/1 var(--font-heading); text-transform: uppercase; letter-spacing: .02em; transition: background-color var(--t-fast) ease; }
.chip .ico { width: 13px; height: 13px; }
.chip:hover { background: #084eae; }
.chip--orange { background: var(--c-orange); }
.chip--orange:hover { background: #dc7d0c; }

.meta { display: flex; flex-wrap: wrap; align-items: center; gap: 4px 14px; font-size: var(--text-meta); color: var(--c-muted); }
.meta__item { display: inline-flex; align-items: center; gap: 6px; }
.meta .ico { width: 14px; height: 14px; color: var(--c-text-soft); }

.toast { position: fixed; left: 50%; bottom: 28px; transform: translate(-50%, 20px); z-index: 400; background: #0b2c5e; color: #fff; padding: 11px 20px; border-radius: 999px; font-size: 14px; box-shadow: var(--shadow-lg); opacity: 0; transition: opacity var(--t-base) var(--ease), transform var(--t-base) var(--ease); }
.toast.is-show { opacity: 1; transform: translate(-50%, 0); }
.back-top { position: fixed; right: 22px; bottom: 22px; z-index: 90; width: 44px; height: 44px; border-radius: 50%; background: var(--c-blue); color: #fff; display: grid; place-items: center; box-shadow: var(--shadow-lg); opacity: 0; transform: translateY(12px); transition: opacity var(--t-base) var(--ease), transform var(--t-base) var(--ease), background-color var(--t-fast) ease; }
.back-top .ico { width: 22px; height: 22px; }
.back-top.is-show { opacity: 1; transform: none; }
.back-top:hover { background: var(--c-blue-dark); }
.back-top[hidden] { display: none; }

/* hiện dần khi cuộn (JS thêm .js-reveal rồi .is-in) */
.js-reveal { opacity: 0; transform: translateY(20px); transition: opacity var(--t-slow) var(--ease), transform var(--t-slow) var(--ease); transition-delay: var(--reveal-delay, 0s); }
.js-reveal.is-in { opacity: 1; transform: none; }