/* ===== DataX Design System — Theme Tokens ===== */
:root {
  --max-width: 1120px;
  --pad-mobile: 20px;
  --pad-desktop: 32px;
  --section-mobile: 56px;
  --section-desktop: 88px;
  --radius-card: 16px;
  --radius-btn: 14px;
  --header-h: 72px;
}

/* Light theme (default) */
:root[data-theme="light"] {
  --bg:       #FFFFFF;
  --bg2:      #F6F7F9;
  --panel:    #FFFFFF;
  --border:   #E5E7EB;
  --black:    #0F0F12;
  --text:     #2B2E34;
  --muted:    #6B7280;
  --blue:     #1FA2FF;
  --blue2:    #1C4ED8;
  --shadow:   0 8px 22px rgba(15, 15, 18, 0.08);
  --shadow-card: 0 2px 12px rgba(15, 15, 18, 0.06);
  --shadow-card-hover: 0 4px 20px rgba(15, 15, 18, 0.08);
  --btn-bg:   #0F0F12;
  --btn-hover: #1C4ED8;
  --btn-text: #FFFFFF;
  --footer-bg: #0F0F12;
  --footer-name: #FFFFFF;
  --footer-text: #9AA3B2;
  --toast-bg: #0F0F12;
  --toast-text: #FFFFFF;
  --lang-active-bg: rgba(31, 162, 255, 0.1);
  --focus-ring: 0 0 0 3px rgba(31, 162, 255, 0.15);
}

/* Dark theme (premium) */
:root[data-theme="dark"] {
  --bg:       #0B0D12;
  --bg2:      #0F1420;
  --panel:    #101827;
  --border:   rgba(255, 255, 255, 0.10);
  --black:    #F5F7FA;
  --text:     #D6D9E0;
  --muted:    #9AA3B2;
  --blue:     #45B3FF;
  --blue2:    #2D6BFF;
  --shadow:   0 10px 30px rgba(0, 0, 0, 0.35);
  --shadow-card: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.3);
  --btn-bg:   #2D6BFF;
  --btn-hover: #45B3FF;
  --btn-text: #FFFFFF;
  --footer-bg: #07090D;
  --footer-name: #F5F7FA;
  --footer-text: #9AA3B2;
  --toast-bg: #101827;
  --toast-text: #F5F7FA;
  --lang-active-bg: rgba(69, 179, 255, 0.15);
  --focus-ring: 0 0 0 2px var(--blue);
}

/* Fallback when no theme set (default light) */
:root:not([data-theme]) {
  --bg:       #FFFFFF;
  --bg2:      #F6F7F9;
  --panel:    #FFFFFF;
  --border:   #E5E7EB;
  --black:    #0F0F12;
  --text:     #2B2E34;
  --muted:    #6B7280;
  --blue:     #1FA2FF;
  --blue2:    #1C4ED8;
  --shadow:   0 8px 22px rgba(15, 15, 18, 0.08);
  --shadow-card: 0 2px 12px rgba(15, 15, 18, 0.06);
  --shadow-card-hover: 0 4px 20px rgba(15, 15, 18, 0.08);
  --btn-bg:   #0F0F12;
  --btn-hover: #1C4ED8;
  --btn-text: #FFFFFF;
  --footer-bg: #0F0F12;
  --footer-name: #FFFFFF;
  --footer-text: #9AA3B2;
  --toast-bg: #0F0F12;
  --toast-text: #FFFFFF;
  --lang-active-bg: rgba(31, 162, 255, 0.1);
  --focus-ring: 0 0 0 3px rgba(31, 162, 255, 0.15);
}

/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}

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

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* ===== Layout ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--pad-mobile);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--pad-desktop);
  }
}

.section {
  padding: var(--section-mobile) 0;
}

.section--alt {
  background: var(--bg2);
}

@media (min-width: 768px) {
  .section {
    padding: var(--section-desktop) 0;
  }
}

.section__title {
  margin: 0 0 1rem;
  font-size: 24px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--black);
}

@media (min-width: 768px) {
  .section__title {
    font-size: 32px;
  }
}

.section__text {
  margin: 0;
  font-size: 16px;
  color: var(--text);
  max-width: 72ch;
}

@media (min-width: 768px) {
  .section__text {
    font-size: 18px;
  }
}

.section__subtitle {
  margin: 0 0 2rem;
  font-size: 16px;
  color: var(--muted);
}

/* ===== Header ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.header__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--pad-mobile);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

@media (min-width: 768px) {
  .header__inner {
    padding: 0 var(--pad-desktop);
  }
}

.header__controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.logo__img {
  height: 36px;
  width: auto;
}

.logo__fallback {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--black);
}

.nav {
  display: none;
}

@media (min-width: 768px) {
  .nav {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    flex-wrap: wrap;
  }
}

.nav__link {
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  transition: color 0.2s;
}

.nav__link:hover,
.nav__link:focus-visible {
  color: var(--blue);
}

.nav__link.active {
  color: var(--blue);
  position: relative;
}

.nav__link.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--blue);
  border-radius: 1px;
}

/* Theme toggle */
.theme {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.theme__label {
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  white-space: nowrap;
}

.theme__switcher {
  display: flex;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 2px;
  gap: 2px;
}

.theme__btn {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.6rem;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  border-radius: 8px;
  transition: color 0.2s, background 0.2s;
}

.theme__btn:hover,
.theme__btn:focus-visible {
  color: var(--blue);
}

.theme__btn:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

.theme__btn[aria-pressed="true"] {
  color: var(--blue);
  background: var(--lang-active-bg);
}

.theme__btn svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.lang-switcher {
  position: relative;
}

.lang {
  display: none;
  gap: 0.25rem;
}

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

.lang__select {
  display: block;
  padding: 0.35rem 1.75rem 0.35rem 0.6rem;
  font-size: 14px;
  font-weight: 500;
  color: var(--text);
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%236B7280' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.5rem center;
}

.lang__select:hover,
.lang__select:focus {
  border-color: var(--blue);
  outline: none;
}

@media (min-width: 768px) {
  .lang__select {
    display: none;
  }
}

.lang__btn {
  padding: 0.35rem 0.6rem;
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
  border-radius: 8px;
  transition: color 0.2s, background 0.2s;
}

.lang__btn:hover,
.lang__btn:focus-visible {
  color: var(--blue);
}

.lang__btn:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

.lang__btn[aria-pressed="true"] {
  color: var(--blue);
  background: var(--lang-active-bg);
}

/* ===== Hero ===== */
.hero {
  padding-top: calc(var(--section-mobile) + var(--header-h));
  padding-bottom: var(--section-mobile);
}

:root[data-theme="dark"] .hero {
  background: radial-gradient(800px circle at 20% 10%, rgba(69, 179, 255, 0.14), transparent 60%),
              radial-gradient(700px circle at 90% 0%, rgba(45, 107, 255, 0.10), transparent 55%),
              var(--bg);
}

@media (min-width: 768px) {
  .hero {
    padding-top: calc(var(--section-desktop) + var(--header-h));
    padding-bottom: var(--section-desktop);
  }
}

.hero__title {
  margin: 0 0 1rem;
  font-size: 34px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--black);
}

@media (min-width: 768px) {
  .hero__title {
    font-size: 48px;
  }
}

.hero__subtitle {
  margin: 0 0 1.5rem;
  font-size: 16px;
  color: var(--text);
  max-width: 58ch;
}

@media (min-width: 768px) {
  .hero__subtitle {
    font-size: 18px;
  }
}

.hero__bullets {
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.hero__bullets li {
  padding-left: 1.5rem;
  position: relative;
  font-size: 15px;
  color: var(--text);
}

.hero__bullets li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.5em;
  width: 6px;
  height: 6px;
  background: var(--blue);
  border-radius: 50%;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 1.5rem;
  font-size: 16px;
  font-weight: 600;
  border-radius: var(--radius-btn);
  transition: background 0.2s, color 0.2s, transform 0.15s;
}

.btn:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

.btn--primary {
  background: var(--btn-bg);
  color: var(--btn-text);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  background: var(--btn-hover);
}

.btn--block {
  width: 100%;
}

@media (min-width: 480px) {
  .btn--block {
    width: auto;
    min-width: 180px;
  }
}

.btn--secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.btn--secondary:hover,
.btn--secondary:focus-visible {
  background: var(--bg2);
  border-color: var(--blue);
  color: var(--blue);
}

.btn--sm {
  min-height: 40px;
  padding: 0 1rem;
  font-size: 14px;
}

/* ===== Cards ===== */
.cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-top: 2rem;
}

@media (min-width: 600px) {
  .cards {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .cards {
    grid-template-columns: repeat(4, 1fr);
  }
}

.card {
  padding: 1.5rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.2s, border-color 0.2s;
}

.card:hover {
  box-shadow: var(--shadow-card-hover);
  border-color: var(--border);
}

.card__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--blue);
  margin-bottom: 1rem;
}

.card__text {
  margin: 0;
  font-size: 15px;
  font-weight: 500;
  color: var(--text);
  line-height: 1.5;
}

/* ===== Deliverables ===== */
.deliverables {
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 600px) {
  .deliverables {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .deliverables {
    grid-template-columns: repeat(4, 1fr);
  }
}

.deliverable {
  padding: 1.25rem 1.25rem 1.25rem 1.5rem;
  border-left: 4px solid var(--blue);
  background: var(--panel);
  border-radius: 0 12px 12px 0;
  font-size: 15px;
  color: var(--text);
  box-shadow: var(--shadow-card);
}

/* ===== Elevator Pitch ===== */
.elevator {
  padding: 2rem;
  background: var(--bg2);
  border-radius: var(--radius-card);
  border: 1px solid var(--border);
}

.elevator__title {
  margin: 0 0 1rem;
  font-size: 20px;
  font-weight: 600;
  line-height: 1.3;
  color: var(--black);
}

.elevator__text {
  margin: 0;
  font-size: 16px;
  color: var(--text);
  line-height: 1.6;
}

@media (min-width: 768px) {
  .elevator__text {
    font-size: 18px;
  }
}

/* ===== Steps (Process) ===== */
.section__intro {
  margin: 0 0 1.5rem;
  font-size: 16px;
  color: var(--muted);
}

.steps {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.step {
  position: relative;
  padding-left: 3rem;
  padding-bottom: 1rem;
  font-size: 16px;
  color: var(--text);
  line-height: 1.5;
}

.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  color: var(--blue);
  background: var(--lang-active-bg);
  border-radius: 50%;
}

/* ===== Cards variants ===== */
.cards--3 {
  grid-template-columns: 1fr;
}

@media (min-width: 600px) {
  .cards--3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .cards--3 {
    grid-template-columns: repeat(3, 1fr);
  }
}

.cards--4 {
  grid-template-columns: 1fr;
}

@media (min-width: 600px) {
  .cards--4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .cards--4 {
    grid-template-columns: repeat(4, 1fr);
  }
}

.card__heading {
  margin: 0 0 0.5rem;
  font-size: 18px;
  font-weight: 600;
  color: var(--black);
}

.card--compact {
  display: flex;
  align-items: center;
  min-height: 80px;
}

.card--compact .card__text {
  margin: 0;
}

/* ===== Package cards ===== */
.card--package {
  display: flex;
  flex-direction: column;
  min-height: 280px;
}

.card--package .card__heading {
  margin-top: 0;
}

.card--package .card__text {
  flex: 1;
  margin-bottom: 1rem;
}

.card__bullets {
  margin: 0 0 1.25rem;
  padding: 0 0 0 1.25rem;
  list-style: none;
  font-size: 14px;
  color: var(--text);
  line-height: 1.6;
}

.card__bullets li {
  position: relative;
  margin-bottom: 0.35rem;
}

.card__bullets li::before {
  content: '•';
  position: absolute;
  left: -1rem;
  color: var(--blue);
}

.card--package .btn {
  align-self: flex-start;
}

.card--recommended {
  position: relative;
  border-color: var(--blue);
  box-shadow: var(--shadow-card);
}

.card__badge {
  position: absolute;
  top: -1px;
  right: 1rem;
  padding: 0.25rem 0.6rem;
  font-size: 12px;
  font-weight: 600;
  color: var(--blue);
  background: var(--lang-active-bg);
  border-radius: 0 0 8px 8px;
}

/* ===== Receive bullets ===== */
.receive__bullets {
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.receive__bullets li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.5rem;
  font-size: 15px;
  color: var(--text);
}

.receive__bullets li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--blue);
}

/* ===== FAQ ===== */
.faq {
  margin: 2rem 0 0;
  padding: 0;
}

.faq__item {
  margin-bottom: 1.25rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}

.faq__item:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.faq__q {
  margin: 0 0 0.5rem;
  font-size: 16px;
  font-weight: 600;
  color: var(--black);
}

.faq__a {
  margin: 0;
  font-size: 15px;
  color: var(--text);
  line-height: 1.5;
}

/* ===== Contact block ===== */
.section--contact .section__title {
  margin-bottom: 1.5rem;
}

.contact-block {
  max-width: 480px;
}

.contact-block__row {
  margin: 0 0 1.25rem;
  font-size: 16px;
}

.contact-block__label {
  font-size: 14px;
  font-weight: 500;
  color: var(--muted);
}

.contact-block__value {
  color: var(--text);
}

.contact-block__link {
  color: var(--blue);
  font-weight: 500;
}

.contact-block__link:hover,
.contact-block__link:focus-visible {
  color: var(--blue2);
  text-decoration: underline;
}

.contact-block .btn {
  margin-top: 0.5rem;
}

/* ===== Footer ===== */
.footer {
  padding: 2rem 0;
  background: var(--footer-bg);
  color: var(--footer-text);
}

.footer__inner {
  text-align: center;
}

.footer__name {
  margin: 0 0 0.5rem;
  font-size: 18px;
  font-weight: 600;
  color: var(--footer-name);
}

.footer__contacts {
  margin: 0 0 0.5rem;
  font-size: 14px;
}

.footer__copy {
  margin: 0;
  font-size: 13px;
  color: var(--footer-text);
}

/* ===== Footer links ===== */
.footer a {
  color: var(--footer-text);
}

.footer a:hover {
  color: var(--footer-name);
}

/* ===== Responsive tweaks ===== */
@media (max-width: 600px) {
  .theme__label {
    display: none;
  }
}

@media (max-width: 360px) {
  .header__inner {
    padding: 0 16px;
  }
  .container {
    padding: 0 16px;
  }
  .hero__title {
    font-size: 28px;
  }
}