/* NASOFT: hệ thiết kế dùng chung. Tiết chế: mực lam làm nền chữ, xanh lá cho khối phụ,
   cam chỉ dùng làm điểm nhấn và nút chính. Lưới 8px, đường kẻ mảnh, một họ chữ. */
:root {
  --navy: #0f2a44;
  --green: #2e9e5b;
  --green-soft: #e8f3ec;
  --orange: #ee7d2c;
  --orange-deep: #c9621a;
  --white: #ffffff;
  --r-lg: 28px;
  --r-md: 18px;
  --r-sm: 12px;
  --max: 1160px;
  --bg: #f6f8f4;
  --surface: #ffffff;
  --wash: #e7f3ea;
  --ink: #0f2a44;
  --ink-2: #4d6178;
  --ink-3: #7b8ca0;
  --line: #dce6de;
  --accent-ink: #1f7a45;
  --accent-soft: #e7f3ea;
  --head-bg: rgba(246, 248, 244, .86);
  --cta-bg: #0f2a44;
  --cta-bg-2: #16385a;
  --cta-ink: #ffffff;
  --hero-bg: #f6f8f4;
  --panel-bg: #e7f3ea;
  --hero-ink: #0f2a44;
  --hero-ink-2: #4d6178;
  --hero-line: #dce6de;
  --hero-check: #2e9e5b;
  --hero-chip: #ffffff;
  --tag-ink: #c9621a;
  --band-bg: #ee7d2c;
  --band-ink: #ffffff;
  --band-ink-2: rgba(255, 255, 255, .88);
  --band-line: rgba(255, 255, 255, .32);
  --shots-a: #e7f3ea;
  --shots-b: #e9eff5;
  --foot-bg: #eef2ec;
  --foot-ink: #4d6178;
  --foot-strong: #0f2a44;
  --foot-line: #dce6de;
  --shadow: rgba(15, 42, 68, .22);
  color-scheme: light;
}
/* Giao diện tối: bộ mực lam. Theo máy người xem, hoặc theo nút đổi ở đầu trang. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0b1f33;
    --surface: #112a44;
    --wash: #0f2a44;
    --ink: #eef3f8;
    --ink-2: #a9b8c8;
    --ink-3: #7f93a8;
    --line: rgba(255, 255, 255, .11);
    --accent-ink: #6fd39a;
    --accent-soft: rgba(46, 158, 91, .18);
    --head-bg: rgba(11, 31, 51, .86);
    --cta-bg: #ffffff;
    --cta-bg-2: #e7f3ea;
    --cta-ink: #0f2a44;
    --hero-bg: #0f2a44;
    --panel-bg: #0f2a44;
    --hero-ink: #ffffff;
    --hero-ink-2: rgba(255, 255, 255, .74);
    --hero-line: rgba(255, 255, 255, .14);
    --hero-check: #6fd39a;
    --hero-chip: rgba(255, 255, 255, .06);
    --tag-ink: #ffb47d;
    --band-bg: #0a1b2d;
    --band-ink: #ffffff;
    --band-ink-2: rgba(255, 255, 255, .66);
    --band-line: rgba(255, 255, 255, .14);
    --shots-a: #0f2a44;
    --shots-b: #13314f;
    --foot-bg: #081827;
    --foot-ink: rgba(255, 255, 255, .72);
    --foot-strong: #ffffff;
    --foot-line: rgba(255, 255, 255, .14);
    --shadow: rgba(0, 0, 0, .4);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0b1f33;
  --surface: #112a44;
  --wash: #0f2a44;
  --ink: #eef3f8;
  --ink-2: #a9b8c8;
  --ink-3: #7f93a8;
  --line: rgba(255, 255, 255, .11);
  --accent-ink: #6fd39a;
  --accent-soft: rgba(46, 158, 91, .18);
  --head-bg: rgba(11, 31, 51, .86);
  --cta-bg: #ffffff;
  --cta-bg-2: #e7f3ea;
  --cta-ink: #0f2a44;
  --hero-bg: #0f2a44;
  --panel-bg: #0f2a44;
  --hero-ink: #ffffff;
  --hero-ink-2: rgba(255, 255, 255, .74);
  --hero-line: rgba(255, 255, 255, .14);
  --hero-check: #6fd39a;
  --hero-chip: rgba(255, 255, 255, .06);
  --tag-ink: #ffb47d;
  --band-bg: #0a1b2d;
  --band-ink: #ffffff;
  --band-ink-2: rgba(255, 255, 255, .66);
  --band-line: rgba(255, 255, 255, .14);
  --shots-a: #0f2a44;
  --shots-b: #13314f;
  --foot-bg: #081827;
  --foot-ink: rgba(255, 255, 255, .72);
  --foot-strong: #ffffff;
  --foot-line: rgba(255, 255, 255, .14);
  --shadow: rgba(0, 0, 0, .4);
  color-scheme: dark;
}
/* Logo đổi theo nền */
.for-dark { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .for-dark { display: block; }
  :root:not([data-theme="light"]) .for-light { display: none; }
}
:root[data-theme="dark"] .for-dark { display: block; }
:root[data-theme="dark"] .for-light { display: none; }
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before { transition: none !important; } }
body { margin: 0; background: var(--bg); color: var(--ink); font: 400 18px/1.7 "Be Vietnam Pro", system-ui, sans-serif; -webkit-font-smoothing: antialiased; }
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; }
:focus-visible { outline: 2px solid var(--orange); outline-offset: 4px; border-radius: 6px; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
@media (max-width: 560px) { .wrap { padding: 0 16px; } }

/* Chữ */
.display { font-weight: 800; font-size: clamp(40px, 5.6vw, 72px); line-height: 1.04; letter-spacing: -.035em; margin: 0; }
.h2 { font-weight: 800; font-size: clamp(30px, 3.6vw, 44px); line-height: 1.12; letter-spacing: -.025em; margin: 0; }
.h3 { font-weight: 700; font-size: 22px; line-height: 1.3; letter-spacing: -.01em; margin: 0; }
.lead { font-size: 20px; line-height: 1.65; color: var(--ink-2); margin: 0; max-width: 34em; }
.muted { color: var(--ink-2); }
.small { font-size: 15px; color: var(--ink-3); }

/* Nút */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 10px; height: 52px; padding: 0 26px; border-radius: var(--r-sm); font: 600 16px/1 "Be Vietnam Pro", sans-serif; text-decoration: none; border: 0; cursor: pointer; transition: background .2s, color .2s, border-color .2s; }
.btn-primary { background: var(--orange); color: #fff; }
.btn-primary:hover { background: var(--orange-deep); }
.btn-quiet { background: var(--surface); color: var(--ink); box-shadow: inset 0 0 0 1px var(--line); }
.btn-quiet:hover { box-shadow: inset 0 0 0 1px var(--ink-3); }
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; }

/* Đầu trang */
.site-head { position: sticky; top: 0; z-index: 20; background: var(--head-bg); backdrop-filter: saturate(1.4) blur(14px); -webkit-backdrop-filter: saturate(1.4) blur(14px); border-bottom: 1px solid var(--line); }
.site-head .wrap { height: 72px; display: flex; align-items: center; justify-content: space-between; }
.site-head .logo img { height: 28px; width: auto; }
.site-head .logo { display: block; }
.site-nav { display: flex; align-items: center; gap: 32px; }
.site-nav a { text-decoration: none; font-size: 15px; font-weight: 600; color: var(--ink-2); transition: color .2s; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--ink); }
.site-nav .cta { color: var(--cta-ink); background: var(--cta-bg); padding: 10px 18px; border-radius: 999px; }
.site-nav .cta:hover, .site-nav .cta[aria-current="page"] { color: var(--cta-ink); background: var(--cta-bg-2); }
.theme-btn { width: 40px; height: 40px; border-radius: 50%; border: 0; background: transparent; color: var(--ink-2); display: grid; place-items: center; cursor: pointer; box-shadow: inset 0 0 0 1px var(--line); margin-left: -12px; }
.theme-btn:hover { color: var(--ink); }
.theme-btn .moon, :root[data-mode="dark"] .theme-btn .sun { display: none; }
:root[data-mode="dark"] .theme-btn .moon { display: block; }
@media (max-width: 720px) { .site-nav { gap: 14px; } .theme-btn { margin-left: 0; } .site-nav .opt { display: none; } }

/* Chân trang */
.site-foot { background: var(--foot-bg); color: var(--foot-ink); padding: 64px 0 40px; font-size: 15px; }
.site-foot .grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px; padding-bottom: 40px; border-bottom: 1px solid var(--foot-line); }
.site-foot img { height: 28px; width: auto; margin-bottom: 18px; }
.site-foot p { margin: 0; max-width: 26em; }
.site-foot h4 { color: var(--foot-strong); font-size: 14px; font-weight: 700; margin: 0 0 14px; letter-spacing: .02em; }
.site-foot ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.site-foot a { text-decoration: none; color: var(--foot-ink); }
.site-foot a:hover { color: var(--foot-strong); }
.site-foot .base { padding-top: 24px; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; font-size: 14px; color: var(--foot-ink); opacity: .8; }
@media (max-width: 760px) { .site-foot .grid { grid-template-columns: 1fr 1fr; } .site-foot .grid > :first-child { grid-column: 1 / -1; } }

/* Biểu tượng nét mảnh, dùng chung */
.i { width: 20px; height: 20px; flex: none; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.btn .i { width: 18px; height: 18px; }
.site-nav .cta { white-space: nowrap; }
@media (max-width: 400px) {
  .site-nav { gap: 8px; }
  .site-nav .cta { font-size: 14px; padding: 9px 14px; }
  .site-head .logo img { height: 24px; }
}

/* Chuyển ngôn ngữ */
.site-nav .lang { display: grid; place-items: center; min-width: 40px; height: 40px; padding: 0 8px; border-radius: 999px; box-shadow: inset 0 0 0 1px var(--line); font-size: 13px; font-weight: 700; letter-spacing: .04em; color: var(--ink-2); margin-left: -12px; }
.site-nav .lang:hover { color: var(--ink); box-shadow: inset 0 0 0 1px var(--ink-3); }
.site-nav .lang + .theme-btn { margin-left: -20px; }
@media (max-width: 720px) { .site-nav .lang { margin-left: 0; } .site-nav .lang + .theme-btn { margin-left: 0; } }
@media (max-width: 400px) {
  .site-nav .lang, .theme-btn { min-width: 36px; width: 36px; height: 36px; }
  .site-nav .cta { font-size: 13px; padding: 8px 12px; }
  .site-head .logo img { height: 22px; }
}
@media (max-width: 370px) { .theme-btn { display: none; } }