/* 超音速浏览器官网 — 科技蓝 / 速度感，克制专业 */
:root {
  --bg: #f3f6fa;
  --bg-deep: #e7eef7;
  --surface: #ffffff;
  --ink: #0f1b2d;
  --ink-soft: #3a4a63;
  --muted: #6b7c93;
  --line: #d5e0ee;
  --accent: #1b6fe8;
  --accent-deep: #0b4fbf;
  --accent-soft: #d9e8fc;
  --sky: #8eb8f5;
  --glow: rgba(27, 111, 232, 0.22);
  --radius-sm: 8px;
  --radius-md: 14px;
  --shadow-soft: 0 20px 50px rgba(15, 31, 58, 0.12);
  --font-display: "Sora", "Noto Sans SC", sans-serif;
  --font-body: "Noto Sans SC", "Sora", sans-serif;
  --max: 1120px;
  --nav-h: 72px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  background:
    radial-gradient(1000px 520px at 12% -8%, rgba(142, 184, 245, 0.45), transparent 60%),
    radial-gradient(900px 480px at 88% 8%, rgba(27, 111, 232, 0.14), transparent 55%),
    linear-gradient(180deg, #f7f9fc 0%, var(--bg) 38%, #eef3f9 100%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.35;
  background-image:
    linear-gradient(rgba(15, 27, 45, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(15, 27, 45, 0.03) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse at 50% 20%, #000 20%, transparent 75%);
}

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

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.wrap {
  width: min(var(--max), calc(100% - 40px));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  backdrop-filter: blur(14px);
  background: rgba(247, 249, 252, 0.78);
  border-bottom: 1px solid rgba(213, 224, 238, 0.7);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.02em;
}

.brand-lockup:hover {
  text-decoration: none;
}

.brand-lockup img {
  width: 28px;
  height: 28px;
  border-radius: 7px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--ink-soft);
  font-size: 14px;
  text-decoration: none;
}

.nav-links a:hover {
  color: var(--accent-deep);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 40px;
  padding: 0 18px;
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: #fff !important;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none !important;
  transition: background 0.2s var(--ease), transform 0.2s var(--ease);
}

.nav-cta:hover {
  background: var(--accent-deep);
  transform: translateY(-1px);
}

.menu-toggle {
  display: none;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.7);
  border-radius: 8px;
  width: 42px;
  height: 42px;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: var(--ink);
}

/* —— Hero：单构图 —— */
.hero {
  position: relative;
  z-index: 1;
  min-height: calc(100vh - var(--nav-h));
  display: grid;
  align-items: center;
  overflow: hidden;
  isolation: isolate;
}

.hero-atmosphere {
  position: absolute;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(70% 55% at 70% 70%, rgba(27, 111, 232, 0.18), transparent 60%),
    radial-gradient(50% 40% at 20% 30%, rgba(142, 184, 245, 0.35), transparent 65%),
    linear-gradient(165deg, #f8fbff 0%, #eef4fb 48%, #e4edf7 100%);
}

.hero-atmosphere::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    repeating-linear-gradient(
      -18deg,
      transparent 0,
      transparent 18px,
      rgba(27, 111, 232, 0.03) 18px,
      rgba(27, 111, 232, 0.03) 19px
    );
  opacity: 0.7;
}

.hero-visual {
  position: absolute;
  left: max(0px, calc(42% - 40px));
  right: -4%;
  top: 12%;
  bottom: -6%;
  z-index: -1;
  pointer-events: none;
}

.hero-visual img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: right center;
  transform: translate3d(0, 0, 0) scale(1.02);
  opacity: 0.98;
  filter: drop-shadow(0 28px 48px rgba(15, 31, 58, 0.18));
  mask-image: linear-gradient(90deg, transparent 0%, #000 18%, #000 100%);
  animation: heroDrift 14s var(--ease) infinite alternate;
}

@keyframes heroDrift {
  from { transform: translate3d(0, 0, 0) scale(1.02); }
  to { transform: translate3d(-1.2%, -1.4%, 0) scale(1.035); }
}

.hero-copy {
  position: relative;
  z-index: 2;
  padding: clamp(40px, 8vh, 96px) 0;
  max-width: min(540px, 46vw);
}

.hero-brand {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(42px, 7.2vw, 72px);
  line-height: 1.08;
  letter-spacing: 0.04em;
  color: var(--ink);
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.6);
}

.hero-title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(22px, 3.2vw, 34px);
  line-height: 1.3;
  color: var(--ink);
}

.hero-lead {
  margin: 0 0 28px;
  max-width: 34em;
  color: var(--ink-soft);
  font-size: clamp(15px, 1.5vw, 17px);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 0 22px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none !important;
  border: 1px solid transparent;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease), transform 0.2s var(--ease), color 0.2s var(--ease);
}

.btn-primary {
  background: linear-gradient(180deg, #2a7ef0 0%, var(--accent) 100%);
  color: #fff;
  box-shadow: 0 10px 24px var(--glow);
}

.btn-primary:hover {
  background: var(--accent-deep);
  transform: translateY(-1px);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.55);
  border-color: var(--line);
  color: var(--ink);
  backdrop-filter: blur(8px);
}

.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent-deep);
}

.btn-windows::before {
  content: "";
  width: 14px;
  height: 14px;
  background:
    linear-gradient(#fff, #fff) 0 0 / 6px 6px no-repeat,
    linear-gradient(#fff, #fff) 8px 0 / 6px 6px no-repeat,
    linear-gradient(#fff, #fff) 0 8px / 6px 6px no-repeat,
    linear-gradient(#fff, #fff) 8px 8px / 6px 6px no-repeat;
  opacity: 0.95;
}

.hero-note {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

.hero-copy.reveal {
  transition-delay: 0.05s;
}

/* —— 分区通用 —— */
.section {
  position: relative;
  z-index: 1;
  padding: clamp(64px, 10vw, 112px) 0;
}

.section-head {
  max-width: 640px;
  margin-bottom: 40px;
}

.section-kicker {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}

.section-title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(26px, 3.4vw, 36px);
  line-height: 1.25;
  letter-spacing: 0.02em;
}

.section-desc {
  margin: 0;
  color: var(--ink-soft);
  font-size: 16px;
}

.section-alt {
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.35), rgba(231, 238, 247, 0.65));
  border-block: 1px solid rgba(213, 224, 238, 0.8);
}

/* 卖点：分割节奏 + 图标层级，非卡片墙 */
.sell-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border-top: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.55), rgba(255, 255, 255, 0) 42%);
}

.sell-item {
  position: relative;
  padding: 36px 28px 36px 0;
  border-right: 1px solid var(--line);
  transition: background-color 0.35s var(--ease);
}

.sell-item + .sell-item {
  padding-left: 28px;
}

.sell-item:last-child {
  border-right: 0;
  padding-right: 0;
}

.sell-item::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), transparent 70%);
  opacity: 0;
  transition: opacity 0.35s var(--ease);
}

.sell-item + .sell-item::before {
  left: 28px;
}

.sell-item:hover::before,
.sell-item:focus-within::before {
  opacity: 1;
}

.sell-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  margin-bottom: 18px;
  border-radius: var(--radius-sm);
  color: var(--accent);
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.95), var(--accent-soft));
  border: 1px solid rgba(27, 111, 232, 0.12);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.8) inset;
  transition:
    transform 0.35s var(--ease),
    color 0.35s var(--ease),
    border-color 0.35s var(--ease),
    box-shadow 0.35s var(--ease);
}

.sell-item:hover .sell-icon,
.sell-item:focus-within .sell-icon {
  color: var(--accent-deep);
  border-color: rgba(27, 111, 232, 0.28);
  transform: translateY(-3px);
  box-shadow: 0 10px 22px rgba(27, 111, 232, 0.14);
}

.sell-index {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
}

.sell-item h3 {
  margin: 0 0 12px;
  font-size: 21px;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.3;
}

.sell-item p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.7;
  max-width: 28em;
}

/* 功能：单向分区，左右交替，无卡片 */
.feature-list {
  display: grid;
  gap: 48px;
}

.feature-row {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 40px;
  align-items: center;
  padding-block: 12px;
  border-bottom: 1px solid var(--line);
}

.feature-row:last-child {
  border-bottom: 0;
}

.feature-row.reverse .feature-copy {
  order: 2;
}

.feature-row.reverse .feature-art {
  order: 1;
}

.feature-copy h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 24px;
}

.feature-copy p {
  margin: 0;
  color: var(--ink-soft);
  max-width: 36em;
}

.feature-art {
  min-height: 200px;
  border-radius: var(--radius-md);
  background:
    radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.75), transparent 45%),
    linear-gradient(135deg, #dce8f8 0%, #c5d8f2 45%, #aec8ea 100%);
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.55);
}

.feature-art::before {
  content: "";
  position: absolute;
  inset: 18% 12%;
  border: 1.5px solid rgba(255, 255, 255, 0.85);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.28);
}

.feature-art[data-art="tabs"]::after {
  content: "";
  position: absolute;
  left: 18%;
  top: 28%;
  width: 64%;
  height: 10px;
  border-radius: 999px;
  background: rgba(27, 111, 232, 0.35);
  box-shadow: 0 22px 0 rgba(15, 27, 45, 0.08), 0 44px 0 rgba(15, 27, 45, 0.06);
}

.feature-art[data-art="privacy"]::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 72px;
  height: 72px;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  border: 3px solid rgba(27, 111, 232, 0.45);
  box-shadow: inset 0 0 0 12px rgba(255, 255, 255, 0.35);
}

.feature-art[data-art="tools"]::after {
  content: "";
  position: absolute;
  inset: 28% 20%;
  background:
    linear-gradient(90deg, rgba(27, 111, 232, 0.35) 0 28%, transparent 28% 36%, rgba(15, 27, 45, 0.12) 36% 100%),
    linear-gradient(180deg, transparent 0 40%, rgba(255, 255, 255, 0.5) 40% 42%, transparent 42%);
  border-radius: 8px;
}

/* 下载 */
.download {
  text-align: center;
}

.download .section-head {
  margin-inline: auto;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 8px;
  text-align: left;
}

.download-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  min-height: 100%;
  padding: 28px 24px 30px;
  border-radius: 18px;
  border: 1px solid var(--line);
  background:
    radial-gradient(420px 140px at 12% 0%, rgba(27, 111, 232, 0.12), transparent 70%),
    rgba(255, 255, 255, 0.58);
}

.download-card.is-soon {
  background:
    radial-gradient(420px 140px at 12% 0%, rgba(107, 124, 147, 0.1), transparent 70%),
    rgba(255, 255, 255, 0.5);
}

.download-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  margin-bottom: 16px;
  border-radius: 12px;
  color: var(--accent);
  background: rgba(27, 111, 232, 0.1);
}

.download-icon-android {
  color: #3ddc84;
  background: rgba(61, 220, 132, 0.12);
}

.download-icon-apple {
  color: var(--ink);
  background: rgba(15, 27, 45, 0.08);
}

.download-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 22px;
}

.download-card > p {
  margin: 0 0 22px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.6;
  flex: 1;
}

.download-card .btn {
  width: 100%;
}

.btn-icon {
  flex-shrink: 0;
}

.btn-soon {
  background: rgba(255, 255, 255, 0.72);
  border-color: var(--line);
  color: var(--ink-soft);
  cursor: pointer;
  box-shadow: none;
}

.btn-soon:hover,
.btn-soon:focus-visible {
  border-color: rgba(27, 111, 232, 0.45);
  color: var(--accent-deep);
  transform: none;
}

.btn-soon:active {
  transform: none;
}

.download-toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  z-index: 60;
  margin: 0;
  padding: 12px 18px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(15, 27, 45, 0.92);
  color: #fff;
  font-size: 14px;
  font-weight: 500;
  box-shadow: 0 12px 32px rgba(15, 31, 58, 0.22);
  transform: translateX(-50%) translateY(12px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
}

.download-toast.is-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.download-toast[hidden] {
  display: block;
}

/* 页脚 */
.site-footer {
  position: relative;
  z-index: 1;
  padding: 40px 0 48px;
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(231, 238, 247, 0.5), #e4ecf6);
}

.footer-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 24px;
  align-items: flex-start;
}

.footer-brand {
  display: flex;
  gap: 12px;
  align-items: center;
}

.footer-brand img {
  width: 36px;
  height: 36px;
  border-radius: 9px;
}

.footer-brand strong {
  display: block;
  font-family: var(--font-display);
  font-size: 15px;
}

.footer-brand span {
  color: var(--muted);
  font-size: 13px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 22px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links a {
  color: var(--ink-soft);
  font-size: 14px;
}

.footer-copy {
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid rgba(213, 224, 238, 0.9);
  color: var(--muted);
  font-size: 13px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  justify-content: space-between;
  align-items: center;
}

.footer-beian {
  color: var(--muted);
  text-decoration: none !important;
}

.footer-beian:hover {
  color: var(--accent-deep);
  text-decoration: underline !important;
}

/* 法律页 */
.legal-page {
  position: relative;
  z-index: 1;
  padding: 48px 0 80px;
}

.legal-page article {
  max-width: 760px;
}

.legal-page h1 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 32px;
}

.legal-page .meta {
  color: var(--muted);
  font-size: 13px;
  margin-bottom: 28px;
}

.legal-page h2 {
  margin: 28px 0 8px;
  font-size: 18px;
}

.legal-page p,
.legal-page li {
  color: var(--ink-soft);
  font-size: 15px;
}

/* 动效尊重减少动态偏好 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-visual img { animation: none; }
  .sell-icon,
  .sell-item::before {
    transition: none;
  }
  .sell-item:hover .sell-icon,
  .sell-item:focus-within .sell-icon {
    transform: none;
  }
}

@media (max-width: 900px) {
  .download-grid {
    grid-template-columns: 1fr;
  }

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

  .sell-item,
  .sell-item + .sell-item {
    border-right: 0;
    border-bottom: 1px solid var(--line);
    padding: 28px 0;
  }

  .sell-item + .sell-item::before {
    left: 0;
  }

  .sell-item:last-child {
    border-bottom: 0;
  }

  .feature-row,
  .feature-row.reverse .feature-copy,
  .feature-row.reverse .feature-art {
    grid-template-columns: 1fr;
    order: initial;
  }

  .feature-row.reverse .feature-copy,
  .feature-row.reverse .feature-art {
    order: initial;
  }

  .hero-visual {
    height: 55vh;
    opacity: 0.85;
  }
}

@media (max-width: 720px) {
  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 20px 16px;
    background: rgba(247, 249, 252, 0.96);
    border-bottom: 1px solid var(--line);
  }

  .nav-links.is-open {
    display: flex;
  }

  .nav-links li {
    border-top: 1px solid rgba(213, 224, 238, 0.7);
  }

  .nav-links a,
  .nav-links .nav-cta {
    display: block;
    width: 100%;
    padding: 14px 0;
    text-align: left;
  }

  .nav-links .nav-cta {
    text-align: center;
    margin-top: 8px;
  }

  .menu-toggle {
    display: inline-block;
  }

  .hero {
    min-height: auto;
  }

  .hero-copy {
    padding-top: 40px;
    padding-bottom: 280px;
  }

  .hero-visual {
    height: 42vh;
  }

  .footer-copy {
    flex-direction: column;
    align-items: flex-start;
  }

  .download-card {
    padding: 24px 20px 26px;
  }
}