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

html,
body {
  margin: 0;
  padding: 0;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.5;
  color: #1d1d1f;
  background: #fbfbfd;
  -webkit-tap-highlight-color: transparent;
}

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

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

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

:focus-visible {
  outline: 2px solid #0071e3;
  outline-offset: 3px;
  border-radius: 4px;
}

/* ========== Nav ========== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(251, 251, 253, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.04);
}

.nav-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 14px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.brand-icon {
  border-radius: 7px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  font-size: 14px;
  color: #1d1d1f;
  opacity: 0.85;
  transition: opacity 0.15s ease;
}

.nav-links a:hover {
  opacity: 1;
}

.lang-toggle {
  font-size: 13px;
  font-weight: 500;
  padding: 6px 12px;
  border: 1px solid rgba(0, 0, 0, 0.12);
  border-radius: 999px;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.lang-toggle:hover {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.2);
}

/* ========== Layout ========== */
main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 22px;
}

section {
  padding: 110px 0;
}

.section-title {
  font-size: clamp(34px, 4.5vw, 52px);
  font-weight: 600;
  letter-spacing: -0.02em;
  text-align: center;
  margin: 0 0 14px;
  line-height: 1.08;
}

.section-subtitle {
  text-align: center;
  font-size: clamp(17px, 1.5vw, 21px);
  color: #6e6e73;
  margin: 0 auto 64px;
  max-width: 600px;
}

/* ========== Hero ========== */
.hero {
  text-align: center;
  padding: 80px 0 80px;
}

.hero-title {
  font-size: clamp(44px, 7vw, 80px);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.05;
  margin: 0 auto 18px;
  max-width: 900px;
  background: linear-gradient(180deg, #1d1d1f 0%, #38383d 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-subtitle {
  font-size: clamp(18px, 1.7vw, 24px);
  color: #6e6e73;
  margin: 0 0 42px;
  font-weight: 400;
}

.hero-cta {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 80px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 12px 22px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 500;
  transition: transform 0.15s ease, background 0.15s ease, box-shadow 0.2s ease;
  white-space: nowrap;
}

.btn-primary {
  background: #1d1d1f;
  color: #ffffff;
}

.btn-primary:hover {
  background: #000;
  transform: translateY(-1px);
}

.btn-text {
  display: inline-flex;
  flex-direction: column;
  text-align: left;
  line-height: 1.15;
}

.btn-eyebrow {
  font-size: 10.5px;
  font-weight: 400;
  opacity: 0.7;
  letter-spacing: 0.02em;
}

.btn-main {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

/* 推荐高亮 */
.btn.is-recommended {
  box-shadow: 0 0 0 3px rgba(0, 113, 227, 0.18), 0 8px 24px rgba(0, 113, 227, 0.18);
}

/* ========== Hero mockup ========== */
.hero-mockup {
  margin: 0 auto;
  max-width: 880px;
  position: relative;
}

.mockup-img {
  width: 100%;
  height: auto;
  filter: drop-shadow(0 30px 60px rgba(0, 0, 0, 0.12))
    drop-shadow(0 8px 18px rgba(0, 0, 0, 0.08));
  border-radius: 18px;
}

/* ========== Features ========== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.feature-card {
  background: #ffffff;
  border-radius: 22px;
  padding: 36px 30px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 6px 22px rgba(0, 0, 0, 0.04);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 12px 30px rgba(0, 0, 0, 0.06);
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: linear-gradient(135deg, #f5f5f7 0%, #ebebef 100%);
  color: #1d1d1f;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
}

.feature-card h3 {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 8px;
}

.feature-card p {
  margin: 0;
  font-size: 15px;
  color: #6e6e73;
  line-height: 1.5;
}

/* ========== Downloads ========== */
.download-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  max-width: 920px;
  margin: 0 auto;
}

.dl-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 20px 22px;
  background: #ffffff;
  border-radius: 18px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 6px 22px rgba(0, 0, 0, 0.04);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.dl-card:hover:not(.dl-card-disabled) {
  transform: translateY(-2px);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 12px 30px rgba(0, 0, 0, 0.07);
}

.dl-card.is-recommended {
  box-shadow: 0 0 0 2px #0071e3, 0 12px 30px rgba(0, 113, 227, 0.18);
}

.dl-card-disabled {
  opacity: 0.55;
  cursor: not-allowed;
  pointer-events: none;
}

.dl-icon {
  width: 44px;
  height: 44px;
  flex: 0 0 44px;
  border-radius: 12px;
  background: #1d1d1f;
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
}

.dl-meta {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.dl-eyebrow {
  font-size: 11px;
  color: #6e6e73;
  letter-spacing: 0.01em;
}

.dl-platform {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-top: 2px;
}

.dl-arrow {
  color: #6e6e73;
  font-size: 18px;
  transition: transform 0.2s ease;
}

.dl-card:hover:not(.dl-card-disabled) .dl-arrow {
  transform: translateX(3px);
  color: #1d1d1f;
}

/* ========== Footer ========== */
.footer {
  border-top: 1px solid rgba(0, 0, 0, 0.06);
  padding: 36px 0;
  margin-top: 60px;
}

.footer-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: 500;
  color: #6e6e73;
}

.footer-brand img {
  border-radius: 5px;
}

.footer-copyright {
  margin: 0;
  font-size: 13px;
  color: #86868b;
}

/* ========== Responsive ========== */
@media (max-width: 920px) {
  .download-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 920px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  section {
    padding: 80px 0;
  }
  .hero {
    padding: 60px 0;
  }
  .nav-links {
    gap: 18px;
  }
}

@media (max-width: 600px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 540px) {
  .nav-links a[href="#features"],
  .nav-links a[href="#download"] {
    display: none;
  }
  .download-grid {
    grid-template-columns: 1fr;
  }
  .hero-cta {
    flex-direction: column;
    align-items: stretch;
    padding: 0 12px;
  }
  .btn {
    justify-content: center;
  }
}