/* Sudoku landing: same palette and type as the app. No external requests (fonts are self-hosted). */

@font-face {
  font-family: 'Nunito Variable';
  font-style: normal;
  font-display: swap;
  font-weight: 200 1000;
  src: url(fonts/nunito-vietnamese-wght-normal.woff2) format('woff2-variations');
  unicode-range: U+0102-0103, U+0110-0111, U+0128-0129, U+0168-0169, U+01A0-01A1, U+01AF-01B0, U+0300-0301, U+0303-0304, U+0308-0309, U+0323, U+0329, U+1EA0-1EF9, U+20AB;
}
@font-face {
  font-family: 'Nunito Variable';
  font-style: normal;
  font-display: swap;
  font-weight: 200 1000;
  src: url(fonts/nunito-latin-ext-wght-normal.woff2) format('woff2-variations');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
@font-face {
  font-family: 'Nunito Variable';
  font-style: normal;
  font-display: swap;
  font-weight: 200 1000;
  src: url(fonts/nunito-latin-wght-normal.woff2) format('woff2-variations');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

:root {
  color-scheme: light;
  --page: #eef0ff;
  --card: #ffffff;
  --line: #c7d2fe;
  --soft: #e0e7ff;
  --ink: #1e1b4b;
  --accent: #4338ca;
  --primary: #7c3aed;
  --primary-dark: #5b21b6;
  --night: #312e81;
  --amber: #fef3c7;
  --amber-ink: #451a03;
  --shadow: 0 4px 0 0 var(--line);
  --radius: 1.5rem;
  --max: 68rem;
  --font: 'Nunito Variable', 'Nunito', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    color-scheme: dark;
    --page: #0e1030;
    --card: #1b1e48;
    --line: #2e3376;
    --soft: #262a63;
    --ink: #eef0ff;
    --accent: #a5b4fc;
    --primary: #8b5cf6;
    --amber: #3a2417;
    --amber-ink: #ffedd5;
  }
}

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

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

body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.6;
  font-weight: 600;
}

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

a {
  color: var(--accent);
  font-weight: 800;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 3px;
  border-radius: 0.5rem;
}

/* One language at a time. `site.js` sets <html lang>; without it the page reads as English. */
html[lang='vi'] [lang='en'],
html[lang='en'] [lang='vi'] {
  display: none !important;
}

.wrap {
  width: min(100% - 2.5rem, var(--max));
  margin-inline: auto;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0.5rem;
  background: var(--primary);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 0.75rem;
  z-index: 10;
}
.skip:focus {
  left: 0.5rem;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  background: color-mix(in srgb, var(--page) 88%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 2px solid var(--soft);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-height: 4rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 900;
  font-size: 1.35rem;
  margin-right: auto;
}

.brand img {
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 0.6rem;
}

.nav {
  display: flex;
  gap: 1.25rem;
  align-items: center;
}

.nav a {
  text-decoration: none;
  color: var(--ink);
  font-weight: 800;
}
.nav a:hover {
  color: var(--primary);
}

.lang {
  display: inline-flex;
  background: var(--soft);
  border-radius: 999px;
  padding: 0.2rem;
}

.lang button {
  font: inherit;
  font-size: 0.85rem;
  font-weight: 900;
  border: 0;
  background: transparent;
  color: var(--accent);
  border-radius: 999px;
  padding: 0.25rem 0.75rem;
  cursor: pointer;
}

html[lang='en'] .lang button[data-set-lang='en'],
html[lang='vi'] .lang button[data-set-lang='vi'] {
  background: var(--primary);
  color: #fff;
}

@media (max-width: 40rem) {
  .nav .nav-link {
    display: none;
  }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  min-height: 3.5rem;
  padding: 0.5rem 1.6rem;
  border-radius: 1.1rem;
  font: inherit;
  font-weight: 900;
  font-size: 1.1rem;
  text-decoration: none;
  color: #fff;
  background: var(--primary);
  box-shadow: 0 5px 0 0 var(--primary-dark);
  transition: transform 0.12s, box-shadow 0.12s;
}
.btn:hover {
  transform: translateY(1px);
  box-shadow: 0 4px 0 0 var(--primary-dark);
}
.btn:active {
  transform: translateY(5px);
  box-shadow: 0 0 0 0 var(--primary-dark);
}
.btn.ghost {
  background: var(--card);
  color: var(--accent);
  box-shadow: var(--shadow);
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: 3.5rem 0 4.5rem;
  background:
    radial-gradient(60rem 30rem at 85% -10%, rgb(139 92 246 / 0.22), transparent 70%),
    radial-gradient(40rem 24rem at -10% 20%, rgb(14 165 233 / 0.14), transparent 70%);
}

.hero .wrap {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: 2.5rem;
  align-items: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--card);
  border-radius: 999px;
  padding: 0.3rem 0.9rem;
  font-size: 0.9rem;
  font-weight: 900;
  color: var(--accent);
  box-shadow: var(--shadow);
}

h1,
h2,
h3 {
  line-height: 1.12;
  font-weight: 900;
  margin: 0;
  letter-spacing: -0.01em;
}

.hero h1 {
  font-size: clamp(2.4rem, 5.4vw, 4rem);
  margin: 1.1rem 0 1rem;
}

.hero h1 em {
  font-style: normal;
  color: var(--primary);
}

.lead {
  font-size: 1.25rem;
  color: var(--accent);
  max-width: 34rem;
  margin: 0 0 1.75rem;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
}

.badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
  font-size: 0.95rem;
  color: var(--accent);
  font-weight: 800;
}
.badges li::before {
  content: '✓';
  color: #15803d;
  font-weight: 900;
  margin-right: 0.35rem;
}

/* ---------- Phone frame ---------- */
.phone {
  position: relative;
  width: min(100%, 17rem);
  padding: 0.55rem;
  border-radius: 2.4rem;
  background: #1e1b4b;
  box-shadow:
    0 30px 60px -20px rgb(49 46 129 / 0.45),
    0 0 0 2px rgb(255 255 255 / 0.06) inset;
}
.phone::before {
  content: '';
  position: absolute;
  top: 0.95rem;
  left: 50%;
  width: 22%;
  height: 0.28rem;
  transform: translateX(-50%);
  border-radius: 99px;
  background: rgb(255 255 255 / 0.22);
  z-index: 1;
}
.phone img {
  width: 100%;
  height: auto;
  aspect-ratio: 390 / 844;
  border-radius: 1.9rem;
  background: var(--soft);
  object-fit: cover;
  object-position: top;
}

.hero-phones {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 34rem;
}
.hero-phones .phone:nth-child(1) {
  transform: rotate(-4deg) translate(1.2rem, 1.5rem);
  z-index: 1;
}
.hero-phones .phone:nth-child(2) {
  transform: rotate(4deg) translate(-1.2rem, -0.5rem);
  margin-left: -2.2rem;
}

@media (max-width: 56rem) {
  .hero .wrap {
    grid-template-columns: 1fr;
  }
  .hero-phones {
    min-height: 0;
    padding-top: 1rem;
  }
  .hero-phones .phone {
    width: min(46%, 15rem);
  }
}

/* ---------- Sections ---------- */
section {
  padding: 4.5rem 0;
}

.section-head {
  max-width: 40rem;
  margin: 0 auto 2.75rem;
  text-align: center;
}
.section-head h2 {
  font-size: clamp(1.8rem, 3.6vw, 2.6rem);
  margin-bottom: 0.7rem;
}
.section-head p {
  margin: 0;
  color: var(--accent);
  font-size: 1.15rem;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(18.5rem, 1fr));
  gap: 1.25rem;
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 1.6rem;
  box-shadow: var(--shadow);
}
.card h3 {
  font-size: 1.25rem;
  margin: 0.9rem 0 0.4rem;
}
.card p {
  margin: 0;
  color: var(--accent);
}

.icon {
  display: grid;
  place-items: center;
  width: 3.25rem;
  height: 3.25rem;
  border-radius: 1rem;
  font-size: 1.6rem;
}
.i-green { background: #dcfce7; }
.i-sky { background: #e0f2fe; }
.i-violet { background: #ede9fe; }
.i-amber { background: #fef3c7; }
.i-rose { background: #ffe4e6; }
.i-orange { background: #ffedd5; }

/* ---------- Gallery ---------- */
.gallery-band {
  background: var(--night);
  color: #eef0ff;
}
.gallery-band .section-head p {
  color: #c7d2fe;
}

.gallery {
  display: flex;
  gap: 1.75rem;
  overflow-x: auto;
  padding: 0.5rem 1.25rem 2rem;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  scrollbar-color: #6366f1 transparent;
}
.gallery figure {
  margin: 0;
  flex: 0 0 auto;
  width: min(15.5rem, 70vw);
  scroll-snap-align: center;
  text-align: center;
}
.gallery figcaption {
  margin-top: 1rem;
  font-weight: 900;
  font-size: 1.05rem;
}
.gallery figcaption small {
  display: block;
  font-weight: 700;
  font-size: 0.9rem;
  color: #c7d2fe;
}
.gallery .phone {
  width: 100%;
  background: #0e1030;
}
/* Centre the row when it fits, without clipping its left edge when it scrolls. */
.gallery figure:first-child {
  margin-left: auto;
}
.gallery figure:last-child {
  margin-right: auto;
}

/* ---------- Levels ---------- */
.levels {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(10.5rem, 1fr));
  gap: 1rem;
}
.level {
  border-radius: 1.4rem;
  padding: 1.2rem;
  color: #fff;
  box-shadow: 0 5px 0 0 var(--edge);
  background: var(--bg);
}
.level b {
  display: grid;
  place-items: center;
  width: 2.6rem;
  height: 2.6rem;
  border-radius: 0.8rem;
  background: rgb(255 255 255 / 0.22);
  font-size: 1.4rem;
  font-weight: 900;
}
.level h3 {
  margin: 0.8rem 0 0.2rem;
  font-size: 1.2rem;
}
.level p {
  margin: 0;
  font-size: 0.95rem;
  opacity: 0.92;
  line-height: 1.4;
}
.lv1 { --bg: #15803d; --edge: #14532d; }
.lv2 { --bg: #0369a1; --edge: #0c4a6e; }
.lv3 { --bg: #6d28d9; --edge: #4c1d95; }
.lv4 { --bg: #c2410c; --edge: #7c2d12; }
.lv5 { --bg: #be123c; --edge: #881337; }

/* ---------- Split / privacy ---------- */
.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 2.5rem;
  align-items: center;
}
.split h2 {
  font-size: clamp(1.8rem, 3.4vw, 2.4rem);
  margin-bottom: 1rem;
}
.split p {
  color: var(--accent);
  font-size: 1.12rem;
}
.checks {
  list-style: none;
  padding: 0;
  margin: 1.25rem 0 0;
  display: grid;
  gap: 0.6rem;
}
.checks li {
  display: flex;
  gap: 0.7rem;
  align-items: flex-start;
}
.checks li::before {
  content: '✓';
  flex: none;
  display: grid;
  place-items: center;
  width: 1.5rem;
  height: 1.5rem;
  margin-top: 0.15rem;
  border-radius: 50%;
  background: #15803d;
  color: #fff;
  font-size: 0.85rem;
  font-weight: 900;
}
.split .phones {
  display: flex;
  justify-content: center;
}
@media (max-width: 56rem) {
  .split {
    grid-template-columns: 1fr;
  }
}

/* ---------- FAQ ---------- */
.faq {
  max-width: 46rem;
  margin: 0 auto;
  display: grid;
  gap: 0.9rem;
}
.faq details {
  background: var(--card);
  border-radius: 1.2rem;
  padding: 1rem 1.3rem;
  box-shadow: var(--shadow);
}
.faq summary {
  cursor: pointer;
  font-weight: 900;
  font-size: 1.1rem;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}
.faq summary::-webkit-details-marker {
  display: none;
}
.faq summary::after {
  content: '+';
  color: var(--primary);
  font-size: 1.5rem;
  line-height: 1;
}
.faq details[open] summary::after {
  content: '–';
}
.faq details p {
  margin: 0.7rem 0 0.2rem;
  color: var(--accent);
}

/* ---------- Final CTA ---------- */
.final {
  text-align: center;
  background: var(--night);
  color: #eef0ff;
  border-radius: 2.2rem;
  padding: 3.5rem 1.5rem;
}
.final h2 {
  font-size: clamp(1.8rem, 3.6vw, 2.6rem);
  margin-bottom: 0.7rem;
}
.final p {
  margin: 0 auto 1.8rem;
  max-width: 34rem;
  color: #c7d2fe;
  font-size: 1.15rem;
}
.final .cta {
  justify-content: center;
}
.final .btn.ghost {
  background: rgb(255 255 255 / 0.1);
  color: #fff;
  box-shadow: none;
}

/* ---------- Footer ---------- */
.site-footer {
  padding: 2.5rem 0 3rem;
  color: var(--accent);
  font-size: 0.95rem;
}
.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  align-items: center;
  justify-content: space-between;
}
.site-footer nav {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

/* ---------- Legal pages ---------- */
.legal {
  padding: 3rem 0 4rem;
}
.legal .doc {
  max-width: 48rem;
  margin: 0 auto;
  background: var(--card);
  border-radius: 2rem;
  padding: clamp(1.5rem, 4vw, 3rem);
  box-shadow: var(--shadow);
}
.legal h1 {
  font-size: clamp(2rem, 4.5vw, 2.8rem);
  margin-bottom: 0.5rem;
}
.legal .meta {
  color: var(--accent);
  font-weight: 800;
  margin: 0 0 1.5rem;
}
.legal h2 {
  font-size: 1.4rem;
  margin: 2.2rem 0 0.6rem;
}
.legal p,
.legal li {
  color: var(--ink);
  font-weight: 600;
}
.legal ul {
  padding-left: 1.3rem;
}
.legal li {
  margin: 0.35rem 0;
}
.legal .summary {
  background: var(--soft);
  border-radius: 1.2rem;
  padding: 1.1rem 1.3rem;
  margin: 1.4rem 0;
}
.legal .summary p {
  margin: 0;
}
.legal table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.98rem;
}
.legal th,
.legal td {
  text-align: left;
  vertical-align: top;
  padding: 0.65rem 0.7rem;
  border-bottom: 2px solid var(--soft);
}
.legal th {
  color: var(--accent);
  font-weight: 900;
}
@media print {
  .site-header,
  .site-footer,
  .lang {
    display: none;
  }
  body {
    background: #fff;
  }
  .legal .doc {
    box-shadow: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .btn {
    transition: none;
  }
}