/* einvoice.everislabs.com — intro page + 404 (Cloudflare Pages, ADR-026). Static, no scripts.
   Brand colours follow assets/brand/icon.svg and the side panel (ADR-024). */
:root {
  color-scheme: light;
  --bg: #ffffff;
  --bg-soft: #f4f7fb;
  --fg: #0f172a;
  --muted: #475569;
  --line: #e2e8f0;
  --card: #ffffff;
  --accent: #1d4ed8;
  --accent-2: #3b82f6;
  --accent-soft: #eff6ff;
  --ok: #16a34a;
  --hero-from: #1e3a8a;
  --hero-to: #2563eb;
  --shadow: 0 1px 2px rgb(15 23 42 / 6%), 0 8px 24px rgb(15 23 42 / 8%);
  --radius: 14px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    color-scheme: dark;
    --bg: #0b1120;
    --bg-soft: #111a2e;
    --fg: #e2e8f0;
    --muted: #94a3b8;
    --line: #1e293b;
    --card: #131c31;
    --accent: #93c5fd;
    --accent-2: #60a5fa;
    --accent-soft: #172554;
    --ok: #4ade80;
    --hero-from: #0f1d4a;
    --hero-to: #1e40af;
    --shadow: 0 1px 2px rgb(0 0 0 / 30%), 0 8px 24px rgb(0 0 0 / 35%);
  }
}

* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font:
    16px/1.6 system-ui,
    -apple-system,
    'Segoe UI',
    Roboto,
    'Helvetica Neue',
    sans-serif;
  -webkit-font-smoothing: antialiased;
}
img {
  max-width: 100%;
  height: auto;
}
a {
  color: var(--accent);
}
h1,
h2,
h3 {
  line-height: 1.25;
  margin: 0;
}
.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 16px;
}
.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 16px;
  top: 8px;
  z-index: 10;
  background: var(--card);
  padding: 8px 12px;
  border-radius: 8px;
}

/* Header */
.top {
  position: sticky;
  top: 0;
  z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.top .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 60px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  color: var(--fg);
  text-decoration: none;
  white-space: nowrap;
}
.brand img {
  width: 30px;
  height: 30px;
}
/* The full store name is long; phones show only "Hóa đơn điện tử". */
.brand__sub {
  font-weight: 600;
  color: var(--muted);
}
.top nav {
  display: flex;
  gap: 20px;
  font-size: 15px;
}
.top nav a {
  color: var(--muted);
  text-decoration: none;
}
.top nav a:hover {
  color: var(--fg);
}

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--hero-from), var(--hero-to));
  color: #fff;
  overflow: hidden;
}
.hero .wrap {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: center;
  padding-top: 64px;
  padding-bottom: 64px;
}
.eyebrow {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgb(255 255 255 / 14%);
  border: 1px solid rgb(255 255 255 / 22%);
  margin-bottom: 18px;
}
.hero h1 {
  font-size: clamp(30px, 4.6vw, 46px);
  letter-spacing: -0.02em;
}
.hero .lead {
  font-size: 18px;
  color: rgb(255 255 255 / 86%);
  margin: 16px 0 28px;
  max-width: 34em;
}
.cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 20px;
}
.install {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 12px 20px 12px 14px;
  border-radius: 12px;
  background: #fff;
  color: #0f172a;
  font-weight: 700;
  text-decoration: none;
  box-shadow: 0 6px 20px rgb(0 0 0 / 22%);
  transition:
    transform 0.15s ease,
    box-shadow 0.15s ease;
}
.install:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 28px rgb(0 0 0 / 28%);
}
.install:focus-visible {
  outline: 3px solid #fde68a;
  outline-offset: 3px;
}
.install svg {
  width: 32px;
  height: 32px;
  flex: none;
}
.install small {
  display: block;
  font-size: 12px;
  font-weight: 500;
  color: #475569;
  line-height: 1.2;
}
.install span {
  line-height: 1.25;
}
.hero .cta a.ghost {
  color: #fff;
  font-weight: 600;
}
.hero .note {
  font-size: 14px;
  color: rgb(255 255 255 / 72%);
  margin: 18px 0 0;
}
.shot {
  justify-self: center;
  margin: 0;
  max-width: 360px;
}
.shot img {
  display: block;
  border-radius: 18px;
  box-shadow: 0 24px 60px rgb(0 0 0 / 35%);
}
.shot figcaption {
  font-size: 13px;
  color: rgb(255 255 255 / 70%);
  text-align: center;
  margin-top: 10px;
}

/* Sections */
section {
  padding: 72px 0;
}
section.soft {
  background: var(--bg-soft);
}
.section-head {
  max-width: 640px;
  margin-bottom: 36px;
}
.section-head h2 {
  font-size: clamp(24px, 3vw, 32px);
  letter-spacing: -0.01em;
}
.section-head p {
  color: var(--muted);
  margin: 10px 0 0;
}
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}
.card h3 {
  font-size: 17px;
  margin: 14px 0 6px;
}
.card p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
}
.ico {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: var(--accent-soft);
  color: var(--accent);
}
.ico svg {
  width: 22px;
  height: 22px;
}

/* Steps */
.steps {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  counter-reset: step;
}
.steps li {
  counter-increment: step;
  position: relative;
  padding: 22px 22px 22px 70px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 22px;
  top: 22px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--accent-2), #1d4ed8);
}
.steps strong {
  display: block;
  margin-bottom: 4px;
}
.steps span {
  color: var(--muted);
  font-size: 15px;
}

/* Privacy */
.privacy {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 40px;
  align-items: start;
}
.checks {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 12px;
}
.checks li {
  display: flex;
  gap: 12px;
  padding: 16px 18px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.checks svg {
  flex: none;
  width: 22px;
  height: 22px;
  color: var(--ok);
  margin-top: 2px;
}
.button {
  display: inline-block;
  margin-top: 20px;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--fg);
  font-weight: 600;
  text-decoration: none;
}
.button:hover {
  border-color: var(--accent-2);
}

/* FAQ */
.faq {
  max-width: 780px;
  display: grid;
  gap: 10px;
}
.faq details {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 18px;
}
.faq summary {
  cursor: pointer;
  font-weight: 600;
}
.faq details p {
  color: var(--muted);
  margin: 10px 0 2px;
}

/* English summary */
.en {
  max-width: 780px;
  color: var(--muted);
}
.en h2 {
  font-size: 20px;
  color: var(--fg);
  margin-bottom: 10px;
}

/* Footer */
footer {
  border-top: 1px solid var(--line);
  padding: 32px 0 40px;
  font-size: 14px;
  color: var(--muted);
}
footer .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px;
}
footer p {
  margin: 0;
}
footer .links {
  display: flex;
  gap: 18px;
}

/* 404 */
.notfound {
  min-height: calc(100vh - 61px);
  display: grid;
  place-items: center;
  text-align: center;
  padding: 48px 16px;
}
.notfound h1 {
  font-size: 64px;
  color: var(--accent);
}
.notfound p {
  color: var(--muted);
}

@media (max-width: 860px) {
  .brand__sub {
    display: none;
  }
  .hero .wrap,
  .privacy {
    grid-template-columns: 1fr;
  }
  .hero .wrap {
    padding-top: 44px;
    padding-bottom: 48px;
    gap: 36px;
  }
  .grid,
  .steps {
    grid-template-columns: 1fr;
  }
  section {
    padding: 52px 0;
  }
  .shot {
    max-width: 300px;
  }
}
@media (max-width: 560px) {
  .top nav a:not(.keep) {
    display: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .install {
    transition: none;
  }
}