@import url("https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;500;600;700;800&display=swap");

/* Việt Nam Quan Sát — phong cảnh (sáng, bình minh) */
:root {
  --sky: #e8f2f8;
  --sky2: #dceaf3;
  --paper: #fafcfd;
  --ink: #153243;
  --ink-soft: #3d5a6b;
  --accent: #1d7a8c;
  --accent2: #0f5c6e;
  --sun: #e8a87c;
  --sun-soft: #f4d4bc;
  --line: rgba(21, 50, 67, 0.12);
  --shadow: 0 20px 50px rgba(21, 50, 67, 0.1);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --r: clamp(14px, 2vw, 22px);
  --font: "Be Vietnam Pro", "Segoe UI", system-ui, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.65;
  color: var(--ink);
  background: linear-gradient(180deg, var(--sky) 0%, var(--paper) 38%, var(--paper) 100%);
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent);
  text-underline-offset: 3px;
}

:focus-visible {
  outline: 2px solid var(--sun);
  outline-offset: 3px;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0;
  padding: 12px 16px;
  background: var(--ink);
  color: var(--paper);
  z-index: 9999;
}

.skip:focus {
  left: 12px;
  top: 12px;
}

.shell {
  width: min(1180px, 100% - 32px);
  margin-inline: auto;
}

/* Header */
.top {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 252, 253, 0.88);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 4px 24px rgba(21, 50, 67, 0.04);
}

.top__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.brand__dot {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: linear-gradient(145deg, var(--accent), var(--accent2));
  box-shadow: 0 8px 24px rgba(29, 122, 140, 0.35);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand__text strong {
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand__text span {
  font-size: 0.72rem;
  opacity: 0.72;
  font-weight: 500;
  color: var(--ink-soft);
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: none;
  border-radius: 12px;
  background: var(--sky2);
  cursor: pointer;
  border: 1px solid var(--line);
}

.nav-toggle span {
  display: block;
  height: 2px;
  margin: 0 10px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.25s var(--ease), opacity 0.2s;
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

.nav {
  display: none;
  flex-wrap: wrap;
  gap: 6px;
  justify-content: flex-end;
}

.nav a {
  text-decoration: none;
  color: var(--ink);
  font-weight: 600;
  font-size: 0.88rem;
  padding: 8px 14px;
  border-radius: 999px;
  transition: background 0.2s var(--ease);
}

.nav a:hover {
  background: var(--sky2);
}

@media (min-width: 880px) {
  .nav-toggle {
    display: none;
  }

  .nav {
    display: flex;
  }
}

@media (max-width: 879px) {
  .nav.is-open {
    display: flex;
    position: absolute;
    left: 16px;
    right: 16px;
    top: calc(100% + 8px);
    padding: 16px;
    flex-direction: column;
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: var(--r);
    box-shadow: var(--shadow);
  }

  .top {
    position: relative;
  }
}

/* Hero */
.hero {
  position: relative;
  padding: clamp(36px, 7vw, 80px) 0 clamp(32px, 6vw, 64px);
  overflow: hidden;
}

.hero__mesh {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 55% at 15% 20%, rgba(232, 168, 124, 0.22), transparent),
    radial-gradient(ellipse 50% 45% at 90% 10%, rgba(29, 122, 140, 0.12), transparent);
  pointer-events: none;
}

.hero__grid {
  position: relative;
  display: grid;
  gap: clamp(28px, 5vw, 48px);
  align-items: center;
}

@media (min-width: 960px) {
  .hero__grid {
    grid-template-columns: 1fr 1.02fr;
    gap: 40px;
  }
}

.hero__title {
  font-size: clamp(2rem, 4.8vw, 3.15rem);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.035em;
  margin: 0 0 1.25rem;
  color: var(--ink);
  max-width: 18ch;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent2);
  margin: 0 0 1rem;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(29, 122, 140, 0.1);
  border: 1px solid rgba(29, 122, 140, 0.15);
}

.eyebrow--dark {
  color: var(--accent2);
  background: rgba(29, 122, 140, 0.08);
}

.lead {
  margin: 0 0 1.75rem;
  max-width: 52ch;
  color: var(--ink-soft);
  font-size: 1.02rem;
  line-height: 1.75;
}

.inline-code {
  font-family: ui-monospace, monospace;
  font-size: 0.88em;
  padding: 0.12em 0.45em;
  border-radius: 6px;
  background: var(--sky2);
  border: 1px solid var(--line);
  color: var(--ink);
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 22px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.92rem;
  text-decoration: none;
  transition: transform 0.2s var(--ease), box-shadow 0.2s;
}

.btn:active {
  transform: scale(0.98);
}

.btn--solid {
  background: linear-gradient(165deg, var(--accent), var(--accent2));
  color: #fff;
  box-shadow: 0 12px 32px rgba(29, 122, 140, 0.3);
}

.btn--solid:hover {
  box-shadow: 0 16px 40px rgba(29, 122, 140, 0.38);
}

.btn--line {
  border: 1px solid var(--line);
  color: var(--ink);
  background: #fff;
}

.btn--line:hover {
  background: var(--sky);
}

.hero__visual {
  position: relative;
  min-height: 260px;
}

.hero__card {
  margin: 0;
  border-radius: calc(var(--r) + 6px);
  overflow: hidden;
  border: 1px solid var(--line);
  background: #fff;
  box-shadow: var(--shadow);
}

.hero__card--main {
  max-width: 100%;
}

.hero__card--main img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  min-height: 200px;
}

.cap {
  padding: 12px 16px;
  font-size: 0.78rem;
  color: var(--ink-soft);
  border-top: 1px solid var(--line);
  background: var(--paper);
}

.hero__card--sub {
  position: absolute;
  right: 0;
  bottom: 6%;
  width: min(48%, 260px);
  z-index: 2;
  box-shadow: 0 16px 40px rgba(21, 50, 67, 0.18);
}

.hero__card--sub img {
  aspect-ratio: 1;
  object-fit: cover;
  width: 100%;
  min-height: 160px;
}

.hero__stamp {
  position: absolute;
  left: 0;
  top: 12%;
  max-width: 210px;
  padding: 14px 16px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid var(--line);
  z-index: 3;
  font-size: 0.82rem;
  line-height: 1.45;
  color: var(--ink);
  box-shadow: var(--shadow);
}

.hero__stamp strong {
  display: block;
  margin-bottom: 6px;
  color: var(--accent2);
}

@media (max-width: 959px) {
  .hero__card--sub {
    position: relative;
    bottom: auto;
    right: auto;
    width: 75%;
    margin: -36px 0 0 auto;
  }

  .hero__stamp {
    top: 6%;
  }
}

/* Hàng ảnh — 6 ô (4 cũ + 2 mới), responsive */
.photo-strip {
  padding: 0 0 clamp(28px, 5vw, 48px);
  background: var(--paper);
}

.photo-strip__inner {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

@media (min-width: 520px) {
  .photo-strip__inner {
    grid-template-columns: repeat(3, 1fr);
    gap: 11px;
  }
}

@media (min-width: 900px) {
  .photo-strip__inner {
    grid-template-columns: repeat(6, 1fr);
    gap: 12px;
  }
}

.photo-strip__img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--r);
  border: 1px solid var(--line);
  background: var(--sky2);
  box-shadow: 0 8px 24px rgba(21, 50, 67, 0.08);
}

/* Ticker */
.ticker {
  border-block: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(29, 122, 140, 0.08), rgba(232, 168, 124, 0.12));
  padding: 14px 0;
  overflow: hidden;
}

.ticker__track {
  display: flex;
  gap: 48px;
  width: max-content;
  animation: tick 26s linear infinite;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

@keyframes tick {
  to {
    transform: translateX(-50%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .ticker__track {
    animation: none;
  }
}

/* Band */
.band {
  padding: clamp(44px, 8vw, 88px) 0;
  background: #fff;
  border-top: 1px solid var(--line);
}

.band__grid {
  display: grid;
  gap: 32px;
}

@media (min-width: 800px) {
  .band__grid {
    grid-template-columns: 1.1fr 0.9fr;
    align-items: start;
  }
}

.h2 {
  font-size: clamp(1.5rem, 2.8vw, 2rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 0 0 1rem;
  line-height: 1.2;
  color: var(--ink);
}

.h2--light {
  color: var(--paper);
}

.prose {
  margin: 0;
  max-width: 58ch;
  line-height: 1.75;
  color: var(--ink-soft);
}

.prose--narrow {
  max-width: 52ch;
}

.band__stats {
  list-style: none;
  margin: 0;
  padding: 24px;
  border-radius: var(--r);
  background: var(--sky);
  border: 1px solid var(--line);
}

.band__stats li {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--ink);
}

.band__stats li:last-child {
  border-bottom: none;
}

.num {
  display: inline-block;
  min-width: 2ch;
  font-weight: 800;
  color: var(--accent);
}

/* Mosaic */
.mosaic {
  padding: clamp(44px, 8vw, 96px) 0;
  background: linear-gradient(180deg, var(--sky2) 0%, var(--paper) 100%);
}

.sec-head {
  margin-bottom: clamp(24px, 4vw, 40px);
}

.mosaic__grid {
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr;
}

@media (min-width: 720px) {
  .mosaic__grid {
    grid-template-columns: repeat(6, 1fr);
    grid-auto-rows: minmax(140px, auto);
    gap: 16px;
  }

  .tile--tall {
    grid-column: span 3;
    grid-row: span 2;
  }

  .tile--wide {
    grid-column: span 4;
  }

  .tile--sq {
    grid-column: span 2;
  }
}

.tile {
  position: relative;
  border-radius: var(--r);
  overflow: hidden;
  border: 1px solid var(--line);
  min-height: 220px;
  background: var(--sky2);
}

.tile__img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.55s var(--ease);
}

.tile:hover .tile__img {
  transform: scale(1.03);
}

.tile__meta {
  position: absolute;
  inset: auto 0 0;
  padding: 18px;
  background: linear-gradient(transparent, rgba(21, 50, 67, 0.88));
  color: #fff;
}

.tile__h {
  margin: 0 0 6px;
  font-size: 1.08rem;
  font-weight: 800;
}

.tile__meta p {
  margin: 0;
  font-size: 0.86rem;
  opacity: 0.92;
  line-height: 1.45;
}

/* Regions */
.regions {
  padding: clamp(44px, 8vw, 92px) 0;
  background: #fff;
}

.regions__wrap {
  display: grid;
  gap: 40px;
}

@media (min-width: 900px) {
  .regions__wrap {
    grid-template-columns: 0.95fr 1.05fr;
    align-items: end;
  }
}

.regions__fan {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

@media (min-width: 640px) {
  .regions__fan {
    flex-direction: row;
    align-items: flex-end;
    gap: 0;
    padding-bottom: 8px;
  }
}

.fan-card {
  flex: 1;
  padding: 22px 20px;
  border-radius: var(--r);
  border: 1px solid var(--line);
  box-shadow: 0 12px 32px rgba(21, 50, 67, 0.07);
  transition: transform 0.3s var(--ease);
}

.fan-card h3 {
  margin: 0 0 8px;
  font-size: 1.12rem;
  font-weight: 800;
  color: var(--ink);
}

.fan-card p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--ink-soft);
  line-height: 1.55;
}

.fan-card--north {
  background: linear-gradient(160deg, #e4f2ef, #cce5de);
}

.fan-card--central {
  background: linear-gradient(160deg, #fdf3e4, #f5e4cc);
  transform: translateY(-6px);
}

.fan-card--south {
  background: linear-gradient(160deg, #e8f0fa, #d4e4f5);
}

@media (min-width: 640px) {
  .fan-card--north {
    transform: rotate(-4deg) translateY(8px);
  }

  .fan-card--central {
    transform: translateY(-14px);
  }

  .fan-card--south {
    transform: rotate(4deg) translateY(8px);
  }

  .fan-card:hover {
    transform: translateY(-12px) scale(1.02);
    z-index: 3;
  }
}

/* Disclaimer */
.disclaimer {
  padding: clamp(36px, 6vw, 64px) 0;
  background: var(--ink);
  color: var(--paper);
}

.disclaimer .h2--light {
  color: #fff;
}

.disclaimer__box {
  padding: clamp(22px, 4vw, 32px);
  border-radius: calc(var(--r) + 4px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.06);
}

.prose-list {
  margin: 0;
  padding-left: 1.2rem;
  max-width: 65ch;
  line-height: 1.75;
  opacity: 0.92;
}

.prose-list li {
  margin-bottom: 0.75rem;
}

/* FAQ */
.faq {
  padding: clamp(44px, 8vw, 88px) 0;
  background: var(--paper);
}

.faq__list {
  max-width: 720px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq__item {
  border-radius: var(--r);
  border: 1px solid var(--line);
  background: #fff;
  padding: 0 18px;
  box-shadow: 0 8px 24px rgba(21, 50, 67, 0.05);
}

.faq__item summary {
  cursor: pointer;
  list-style: none;
  font-weight: 700;
  color: var(--ink);
  padding: 18px 28px 18px 0;
  position: relative;
}

.faq__item summary::-webkit-details-marker {
  display: none;
}

.faq__item summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 14px;
  font-size: 1.4rem;
  font-weight: 400;
  opacity: 0.45;
}

.faq__item[open] summary::after {
  content: "−";
}

.faq__item p {
  margin: 0 0 18px;
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--ink-soft);
}

.faq .inline-code {
  background: var(--sky2);
}

/* Footer */
.foot {
  padding: clamp(32px, 5vw, 52px) 0;
  background: var(--ink-soft);
  color: var(--paper);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.foot__grid {
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
  justify-content: space-between;
  align-items: flex-start;
}

.foot__eyebrow {
  color: var(--sun-soft);
  border: none;
  background: transparent;
  padding: 0;
  margin-bottom: 10px;
}

.foot__muted {
  margin: 0;
  max-width: 48ch;
  font-size: 0.88rem;
  line-height: 1.6;
  opacity: 0.75;
}

.foot__nav {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.foot__nav a {
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
}

.foot__nav a:hover {
  text-decoration: underline;
}

/* Reveal */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}