:root {
  --bg: #191918;
  --surface: #2F2F2F;
  --text: rgba(255,255,255,0.95);
  --text-sub: rgba(255,255,255,0.6);
  --text-dim: rgba(255,255,255,0.3);
  --border: rgba(255,255,255,0.13);
  --border-light: rgba(255,255,255,0.08);
  --accent: #2383E2;
  --white: #FFFFFF;
  --danger: #EB5757;
  --success: #6FCF97;
  --warning: #F2C94C;
  --container: min(1200px, calc(100vw - 64px));
  --font: Inter, -apple-system, "system-ui", "Segoe UI", Helvetica,
    "Apple Color Emoji", Arial, sans-serif;
  --mono: SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  font-feature-settings: "lnum", "locl" 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

a, button { -webkit-tap-highlight-color: transparent; }

.container {
  width: var(--container);
  margin: 0 auto;
}

/* ─── Scroll Reveal ─── */

.js .reveal-on-scroll {
  opacity: 0;
  transform: translate3d(0, 28px, 0);
  transition:
    opacity 720ms cubic-bezier(0.2, 0.8, 0.2, 1),
    transform 720ms cubic-bezier(0.2, 0.8, 0.2, 1);
  transition-delay: calc(var(--reveal-delay, 0) * 1ms);
}

.js .reveal-on-scroll.is-visible {
  opacity: 1;
  transform: translate3d(0, 0, 0);
}

.reveal-on-scroll[data-reveal="1"] { --reveal-delay: 0; }
.reveal-on-scroll[data-reveal="2"] { --reveal-delay: 80; }
.reveal-on-scroll[data-reveal="3"] { --reveal-delay: 160; }
.reveal-on-scroll[data-reveal="4"] { --reveal-delay: 240; }
.reveal-on-scroll[data-reveal="5"] { --reveal-delay: 320; }
.reveal-on-scroll[data-reveal="6"] { --reveal-delay: 400; }

/* ─── Header ─── */

.header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(25,25,24,0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 24px;
  height: 56px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* ─── Language Switcher ─── */

.lang-switcher {
  display: flex;
  gap: 2px;
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2px;
}

.lang-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  height: 28px;
  padding: 0 8px;
  border: none;
  border-radius: 6px;
  background: transparent;
  color: var(--text-sub);
  font-family: var(--font);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: background 160ms, color 160ms;
}

.lang-btn:hover {
  color: var(--text);
  background: rgba(255,255,255,0.08);
}

.lang-btn-active {
  background: rgba(255,255,255,0.14);
  color: var(--text);
}

.logo {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.header-nav {
  display: flex;
  justify-content: center;
  gap: 24px;
  font-size: 0.9rem;
  color: var(--text-sub);
}

.header-nav a:hover {
  color: var(--text);
}

/* ─── Buttons ─── */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 8px 16px;
  border: 1px solid transparent;
  border-radius: 8px;
  font-family: var(--font);
  font-size: 16px;
  font-weight: 500;
  line-height: 1.2;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity 160ms;
}

.btn:hover { opacity: 0.85; }

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

.btn-secondary {
  background: transparent;
  border-color: rgba(255,255,255,0.2);
  color: var(--text);
}

.btn-lg {
  min-height: 52px;
  padding: 12px 28px;
  font-size: 16px;
  border-radius: 10px;
}

/* ─── Sections ─── */

section {
  padding: 100px 0;
}

.section-label {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
}

.section-title {
  font-size: 54px;
  font-weight: 700;
  line-height: 56px;
  letter-spacing: normal;
  margin-bottom: 20px;
}

.section-lead {
  color: var(--text-sub);
  font-size: 16px;
  line-height: 1.5;
  max-width: 600px;
}

/* ─── Hero ─── */

.hero {
  padding-top: 120px;
  padding-bottom: 80px;
  text-align: center;
}

.hero .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
}

.hero .section-title {
  font-size: 64px;
  line-height: 64px;
  margin-bottom: 24px;
}

.hero .section-lead {
  max-width: 560px;
  margin: 0 auto 40px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 72px;
}

/* Drop zone visual */

.drop-visual {
  position: relative;
  width: 100%;
  max-width: 680px;
}

.drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  padding: 64px 40px;
  border: 2px dashed rgba(255,255,255,0.18);
  border-radius: 16px;
  background: rgba(255,255,255,0.02);
  transition: border-color 300ms, background 300ms;
  animation: drop-pulse 3.6s ease-in-out infinite;
}

.drop-zone-icon {
  width: 56px;
  height: 56px;
  color: var(--text-sub);
}

.drop-zone-text {
  color: var(--text-sub);
  font-size: 16px;
}

.drop-zone-hint {
  color: var(--text-dim);
  font-size: 14px;
}

.drop-formats {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 4px;
}

.drop-formats span {
  padding: 4px 12px;
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: var(--mono);
  font-size: 13px;
  color: var(--text-sub);
}

@keyframes drop-pulse {
  0%, 100% {
    border-color: rgba(255,255,255,0.18);
    background: rgba(255,255,255,0.02);
  }
  50% {
    border-color: rgba(35,131,226,0.4);
    background: rgba(35,131,226,0.03);
  }
}

/* ─── Cards ─── */

.card {
  background: var(--surface);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 28px;
  transition: border-color 200ms;
}

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

.card-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: rgba(35,131,226,0.12);
  color: var(--accent);
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 20px;
}

.card-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: rgba(255,255,255,0.06);
  margin-bottom: 20px;
  color: var(--text-sub);
}

.card-icon svg {
  width: 22px;
  height: 22px;
}

.card h3 {
  font-size: 22px;
  font-weight: 700;
  line-height: 28px;
  margin-bottom: 10px;
}

.card p {
  color: var(--text-sub);
  font-size: 15px;
  line-height: 1.6;
}

/* ─── Modes Section ─── */

.modes-section {
  border-top: 1px solid var(--border);
}

.mode-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 48px;
}

/* ─── Options Section ─── */

.options-section {
  border-top: 1px solid var(--border);
}

.option-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 48px;
}

/* ─── How-to Section ─── */

.howto-section {
  border-top: 1px solid var(--border);
  text-align: center;
}

.howto-section .section-lead {
  margin: 0 auto 56px;
}

.howto-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  max-width: 800px;
  margin: 0 auto;
}

.howto-step {
  text-align: center;
  padding: 28px 20px;
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  color: var(--text-sub);
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 18px;
}

.howto-step h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 8px;
}

.howto-step p {
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.6;
}

.step-connector {
  display: none;
}

/* ─── Formats Section ─── */

.formats-section {
  border-top: 1px solid var(--border);
  text-align: center;
}

.formats-section .section-lead {
  margin: 0 auto 40px;
}

.format-chips {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

.format-chip {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 10px 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-family: var(--mono);
  font-size: 16px;
  color: var(--text);
  letter-spacing: 0.01em;
  transition: border-color 200ms, background 200ms;
}

.format-chip:hover {
  border-color: var(--accent);
  background: rgba(35,131,226,0.08);
}

/* ─── Download Section ─── */

.download-section {
  border-top: 1px solid var(--border);
  text-align: center;
}

.download-section .section-lead {
  margin: 0 auto 40px;
}

.download-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}

.download-actions .btn {
  min-width: 220px;
}

/* ─── FAQ Section ─── */

.faq-section {
  border-top: 1px solid var(--border);
}

.faq-list {
  display: grid;
  gap: 8px;
  margin-top: 48px;
  max-width: 760px;
}

.faq-item {
  border: 1px solid var(--border-light);
  border-radius: 10px;
  background: var(--surface);
  overflow: hidden;
}

.faq-item summary {
  padding: 18px 24px;
  cursor: pointer;
  list-style: none;
  font-weight: 500;
  font-size: 15px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

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

.faq-item summary::after {
  content: "+";
  flex-shrink: 0;
  font-size: 20px;
  font-weight: 400;
  color: var(--text-sub);
  transition: transform 200ms;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item p {
  padding: 0 24px 18px;
  color: var(--text-sub);
  font-size: 15px;
  line-height: 1.6;
}

/* ─── Footer ─── */

.footer {
  padding: 32px 0 48px;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.footer-brand {
  font-weight: 700;
  font-size: 1rem;
}

.footer-brand span {
  display: block;
  color: var(--text-sub);
  font-size: 0.8rem;
  font-weight: 400;
  margin-top: 4px;
}

.footer-links {
  display: flex;
  gap: 20px;
  color: var(--text-sub);
  font-size: 0.88rem;
}

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

/* ─── Responsive ─── */

@media (max-width: 1024px) {
  .section-title {
    font-size: 40px;
    line-height: 44px;
  }

  .hero .section-title {
    font-size: 48px;
    line-height: 50px;
  }
}

@media (max-width: 768px) {
  :root {
    --container: min(100vw - 32px, 1200px);
  }

  section {
    padding: 72px 0;
  }

  .hero {
    padding-top: 88px;
  }

  .header-inner {
    grid-template-columns: auto 1fr;
    gap: 16px;
  }

  .header-nav {
    justify-content: flex-end;
    gap: 16px;
    font-size: 0.82rem;
  }

  .header-actions {
    gap: 10px;
  }

  .header-cta {
    display: none;
  }

  .lang-btn {
    min-width: 30px;
    padding: 0 6px;
    font-size: 11px;
  }

  .section-title {
    font-size: 32px;
    line-height: 36px;
  }

  .hero .section-title {
    font-size: 36px;
    line-height: 40px;
  }

  .mode-grid {
    grid-template-columns: 1fr;
  }

  .option-grid {
    grid-template-columns: 1fr;
  }

  .howto-steps {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .download-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .download-actions .btn {
    min-width: 0;
    width: 100%;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
    width: 100%;
    max-width: 360px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
  }

  .drop-zone {
    padding: 48px 24px;
  }

  .faq-list {
    max-width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}