/* MLC — static site. Không framework, không build. */

:root {
  --emerald-50:  #ecfdf5;
  --emerald-100: #d1fae5;
  --emerald-600: #059669;
  --emerald-700: #047857;
  --emerald-800: #065f46;
  --gray-50:  #f9fafb;
  --gray-200: #e5e7eb;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --wrap: 80rem;
  --nav-h: 4rem;
}

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

html {
  /* Trang chỉ có tông sáng — khai báo rõ để browser dark mode không tô nền đen */
  color-scheme: light;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: #fff;
  color: var(--gray-700);
  font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  /* chừa chỗ cho navbar fixed */
  padding-top: var(--nav-h);
}

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

a {
  color: var(--emerald-600);
}

h1,
h2,
h3 {
  color: var(--gray-900);
  line-height: 1.2;
  margin: 0;
}

.wrap {
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: 1rem;
}

@media (min-width: 640px) {
  .wrap {
    padding-inline: 1.5rem;
  }
}

/* ---------- Navbar ---------- */

.nav {
  position: fixed;
  inset: 0 0 auto;
  z-index: 20;
  background: #fff;
  box-shadow: 0 1px 2px rgb(0 0 0 / 5%);
}

.nav__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-h);
}

.nav__brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--gray-900);
  text-decoration: none;
}

.nav__brand svg {
  width: 1.5rem;
  height: 1.5rem;
  color: var(--emerald-600);
}

.nav__name b {
  color: var(--emerald-600);
  font-weight: inherit;
}

.nav__links {
  display: none;
  align-items: center;
  gap: 2rem;
}

.nav__links a:not(.btn) {
  color: var(--gray-500);
  font-size: 0.875rem;
  font-weight: 500;
  text-decoration: none;
}

.nav__links a:not(.btn):hover {
  color: var(--emerald-600);
}

/* nút hamburger: CSS-only, không cần JS */
.nav__toggle {
  display: flex;
  align-items: center;
  padding: 0.5rem;
  margin-right: -0.5rem;
  border-radius: 0.375rem;
  color: var(--gray-500);
  cursor: pointer;
}

.nav__toggle:hover {
  background: var(--gray-50);
}

.nav__toggle svg {
  width: 1.5rem;
  height: 1.5rem;
}

.nav__checkbox {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.nav__checkbox:focus-visible ~ .wrap .nav__toggle {
  outline: 2px solid var(--emerald-600);
  outline-offset: 2px;
}

.nav__mobile {
  display: none;
  border-top: 1px solid var(--gray-200);
  padding: 0.5rem;
}

.nav__checkbox:checked ~ .nav__mobile {
  display: block;
}

.nav__mobile a {
  display: block;
  padding: 0.5rem 0.75rem;
  border-radius: 0.375rem;
  color: var(--gray-900);
  font-weight: 500;
  text-decoration: none;
}

.nav__mobile a:hover {
  background: var(--gray-50);
  color: var(--emerald-600);
}

@media (min-width: 768px) {
  .nav__links {
    display: flex;
  }

  .nav__toggle,
  .nav__mobile,
  .nav__checkbox:checked ~ .nav__mobile {
    display: none;
  }
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 0.375rem;
  font-weight: 500;
  text-align: center;
  text-decoration: none;
  transition: background-color 0.2s;
}

.btn--solid {
  background: var(--emerald-600);
  color: #fff;
}

.btn--solid:hover {
  background: var(--emerald-700);
}

.btn--outline {
  background: #fff;
  color: var(--emerald-600);
  border: 1px solid var(--emerald-600);
}

.btn--outline:hover {
  background: var(--gray-50);
}

.btn--sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

.btn--onEmerald {
  background: #fff;
  color: var(--emerald-600);
}

.btn--onEmerald:hover {
  background: var(--emerald-50);
}

.btn--onEmeraldDark {
  background: var(--emerald-700);
  color: #fff;
}

.btn--onEmeraldDark:hover {
  background: var(--emerald-800);
}

/* ---------- Hero ---------- */

.hero {
  background: linear-gradient(135deg, #fff 0%, var(--emerald-100) 100%);
  padding: 3rem 0 5rem;
}

.hero__grid {
  display: grid;
  gap: 3rem;
  align-items: center;
}

.hero h1 {
  font-size: clamp(2.25rem, 6vw, 3.75rem);
  font-weight: 800;
  letter-spacing: -0.025em;
}

.hero p {
  color: var(--gray-500);
  font-size: 1.125rem;
  margin: 1.25rem 0 2rem;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.hero__media {
  position: relative;
  border-radius: 0.5rem;
  box-shadow: 0 10px 15px -3px rgb(0 0 0 / 10%);
}

.hero__media img {
  border-radius: 0.5rem;
}

@media (min-width: 1024px) {
  .hero {
    padding: 5rem 0 7rem;
  }

  .hero__grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

  .hero__media {
    max-width: 28rem;
    margin-inline: auto;
  }
}

/* ---------- Sections ---------- */

.section {
  padding: 3rem 0;
}

.section--gray {
  background: var(--gray-50);
}

.section--emerald {
  background: var(--emerald-600);
  padding: 4rem 0;
}

.section__head {
  text-align: center;
  margin-bottom: 2.5rem;
}

.section__eyebrow {
  color: var(--emerald-600);
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin: 0;
}

.section__title {
  font-size: clamp(1.875rem, 4vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  margin: 0.5rem 0 0;
}

.section__lead {
  color: var(--gray-500);
  font-size: 1.25rem;
  max-width: 42rem;
  margin: 1rem auto 0;
}

/* ---------- Stats ---------- */

.stats {
  display: grid;
  gap: 2rem;
  grid-template-columns: 1fr;
}

.stat {
  text-align: center;
}

.stat__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 4rem;
  height: 4rem;
  margin: 0 auto;
  border-radius: 50%;
  background: var(--emerald-100);
  color: var(--emerald-600);
}

.stat__icon svg {
  width: 1.5rem;
  height: 1.5rem;
}

/* .stat p đứng sau và specificity cao hơn -> phải qualify bằng .stat */
.stat .stat__num {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--gray-900);
  margin: 1.25rem 0 0;
}

.stat p {
  color: var(--gray-500);
  font-size: 0.875rem;
  margin: 0.5rem 0 0;
}

@media (min-width: 640px) {
  .stats {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .stats {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* ---------- Feature cards ---------- */

.features {
  display: grid;
  gap: 2rem;
  grid-template-columns: 1fr;
}

.feature {
  background: #fff;
  padding: 2rem;
  border-radius: 0.75rem;
  box-shadow: 0 4px 6px -1px rgb(0 0 0 / 10%);
  transition: transform 0.3s, box-shadow 0.3s;
}

.feature:hover {
  transform: translateY(-5px);
  box-shadow: 0 20px 25px -5px rgb(0 0 0 / 10%);
}

.feature__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 3rem;
  height: 3rem;
  border-radius: 0.375rem;
  background: var(--emerald-100);
  color: var(--emerald-600);
}

.feature__icon svg {
  width: 1.25rem;
  height: 1.25rem;
}

.feature h3 {
  font-size: 1.125rem;
  font-weight: 500;
  margin: 1.5rem 0 0;
}

.feature p {
  color: var(--gray-500);
  margin: 0.5rem 0 0;
}

@media (min-width: 768px) {
  .features {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ---------- Vision ---------- */

.vision {
  display: grid;
  gap: 2rem;
  align-items: center;
}

.vision h2 {
  color: #fff;
  font-size: clamp(1.875rem, 4vw, 2.25rem);
  font-weight: 800;
}

.vision p {
  color: var(--emerald-100);
  font-size: 1.125rem;
  margin: 0.75rem 0 0;
}

.vision__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

@media (min-width: 1024px) {
  .vision {
    grid-template-columns: 1fr 1fr;
  }
}

/* ---------- Footer ---------- */

.footer {
  background: #fff;
  border-top: 1px solid var(--gray-200);
  padding: 3rem 0;
  /* navbar fixed che mất khi nhảy tới #contact */
  scroll-margin-top: var(--nav-h);
}

.footer__grid {
  display: grid;
  gap: 2.5rem;
}

.footer h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gray-800);
  margin-bottom: 1.5rem;
}

.contact {
  display: grid;
  gap: 1.5rem;
}

.contact__item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.contact__icon {
  flex-shrink: 0;
  display: flex;
  padding: 0.75rem;
  border-radius: 50%;
  background: var(--emerald-50);
  color: var(--emerald-600);
}

.contact__icon svg {
  width: 1.25rem;
  height: 1.25rem;
}

.contact h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--gray-800);
  margin: 0;
}

.contact p,
.contact a {
  margin: 0;
  color: var(--gray-600);
}

.contact a {
  color: var(--emerald-600);
}

.footer__legal h3 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--emerald-600);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.footer__legal ul {
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.footer__legal a {
  color: var(--gray-500);
  text-decoration: none;
}

.footer__legal a:hover {
  color: var(--emerald-600);
}

.footer__bottom {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--gray-200);
  color: var(--gray-500);
}

.footer__bottom p {
  margin: 0;
}

@media (min-width: 640px) {
  .contact {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 768px) {
  .footer__grid {
    grid-template-columns: 2fr 1fr;
  }
}

/* ---------- Trang văn bản (Privacy / EULA) ---------- */

.page {
  padding: 3rem 0 5rem;
}

.page .wrap {
  max-width: 56rem;
}

.page h1 {
  font-size: clamp(1.875rem, 5vw, 2.25rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 3rem;
}

.card {
  background: #fff;
  border: 1px solid var(--gray-200);
  border-radius: 0.75rem;
  box-shadow: 0 4px 6px -1px rgb(0 0 0 / 6%);
  padding: 2rem;
  margin-bottom: 2rem;
  scroll-margin-top: var(--nav-h);
}

.card h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 1.5rem 0 0.75rem;
}

.card p {
  margin: 0 0 1rem;
}

.card p:last-child {
  margin-bottom: 0;
}

.card ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.5rem;
}

.card ul.bullets {
  list-style: disc;
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.card a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

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

.card a svg {
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
}

.callout {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background: var(--emerald-50);
  border-radius: 0.5rem;
  padding: 1rem;
}

.callout svg {
  width: 1.25rem;
  height: 1.25rem;
  color: var(--emerald-600);
  flex-shrink: 0;
}

.callout strong {
  color: var(--gray-800);
  font-weight: 500;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}