:root {
  --bg-1: #eef3f8;
  --bg-2: #e4ebf4;
  --ink: #152033;
  --text: #1c2b3d;
  --muted: #607285;
  --accent: #c62828;
  --accent-hover: #b71c1c;
  --accent-soft: rgba(198, 40, 40, 0.1);
  --tech: #0f766e;
  --tech-soft: rgba(15, 118, 110, 0.12);
  --border: rgba(28, 52, 78, 0.12);
  --surface: rgba(255, 255, 255, 0.82);
  --shadow: 0 18px 48px rgba(21, 40, 70, 0.1);
  --font-display: 'Sora', 'Source Sans 3', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Source Sans 3', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --radius: 14px;
  /* 随视口变宽：约 1366→~1200，1920→~1600，2K→~1760 */
  --page-pad: clamp(16px, 3vw, 40px);
  --page-max: min(92vw, 1680px);
  --hero-max: min(78vw, 1320px);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  font-family: var(--font-body);
  color: var(--text);
  background:
    radial-gradient(1200px 520px at 12% -10%, rgba(198, 40, 40, 0.12), transparent 55%),
    radial-gradient(900px 480px at 92% 8%, rgba(15, 118, 110, 0.1), transparent 50%),
    linear-gradient(180deg, var(--bg-1) 0%, var(--bg-2) 100%);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

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

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

.bg-glow,
.bg-grid {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}

.bg-grid {
  opacity: 0.35;
  background-image:
    linear-gradient(rgba(28, 52, 78, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(28, 52, 78, 0.05) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(180deg, #000 0%, transparent 78%);
}

.top,
main,
.foot {
  position: relative;
  z-index: 1;
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: min(100%, var(--page-max));
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 20px var(--page-pad) 0;
}

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

.brand img {
  border-radius: 10px;
  box-shadow: 0 8px 20px rgba(21, 40, 70, 0.12);
}

.brand em {
  display: block;
  font-family: var(--font-display);
  font-style: normal;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: lowercase;
  color: var(--accent);
}

.brand strong {
  display: block;
  font-size: 14px;
  font-weight: 650;
  color: var(--ink);
}

.top-nav {
  display: flex;
  gap: 8px;
}

.top-nav a {
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
}

.top-nav a:hover {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.55);
}

.hero {
  width: min(100%, var(--hero-max));
  max-width: var(--hero-max);
  margin: 0 auto;
  padding: clamp(48px, 7vh, 88px) var(--page-pad) 56px;
  text-align: left;
  animation: rise 0.55s ease both;
}

.brand-hero {
  font-family: var(--font-display);
  font-size: clamp(42px, 8vw, 72px);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 0.95;
  color: var(--ink);
  margin-bottom: 18px;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(26px, 3.2vw, 44px);
  font-weight: 650;
  letter-spacing: -0.03em;
  line-height: 1.2;
  color: var(--ink);
  max-width: 18em;
  margin-bottom: 14px;
}

.hero-lead {
  max-width: 42em;
  font-size: clamp(15px, 1.15vw, 18px);
  color: var(--muted);
  margin-bottom: 28px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 14px;
  animation: rise 0.65s 0.08s ease both;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 18px;
  border-radius: 12px;
  font-size: 15px;
  font-weight: 650;
  border: 1px solid transparent;
  transition: transform 0.15s ease, background 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn-win {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 10px 24px rgba(198, 40, 40, 0.28);
}

.btn-win:hover {
  background: var(--accent-hover);
}

.btn-mac {
  background: #122033;
  color: #fff;
  box-shadow: 0 10px 24px rgba(18, 32, 51, 0.22);
}

.btn-mac:hover {
  background: #0c1622;
}

.btn-block {
  width: 100%;
}

.hero-version {
  margin-top: 10px;
  font-size: 14px;
  font-weight: 600;
  color: var(--tech);
}

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

.platform-meta {
  margin: 0 0 12px;
  font-size: 13px;
  color: var(--muted);
}

.btn.is-disabled,
.btn[aria-disabled='true'] {
  opacity: 0.45;
  pointer-events: none;
  cursor: not-allowed;
}

.section {
  width: min(100%, var(--page-max));
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 28px var(--page-pad) 48px;
}

.section-head {
  margin-bottom: 22px;
  max-width: 48em;
}

.section-head h2 {
  font-family: var(--font-display);
  font-size: clamp(22px, 3vw, 28px);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--ink);
  margin-bottom: 8px;
}

.section-head p {
  color: var(--muted);
  font-size: 15px;
}

.feature-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(14px, 1.2vw, 22px);
}

.feature-list article {
  padding: 20px 18px;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
  backdrop-filter: blur(8px);
  box-shadow: var(--shadow);
  animation: rise 0.5s ease both;
}

.feature-list article:nth-child(2) {
  animation-delay: 0.06s;
}

.feature-list article:nth-child(3) {
  animation-delay: 0.12s;
}

.feature-list h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 8px;
}

.feature-list p {
  font-size: 14px;
  color: var(--muted);
}

.platform-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(14px, 1.2vw, 22px);
}

.platform-card {
  padding: 22px 20px;
  border-radius: var(--radius);
  background: #fff;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.platform-card header {
  margin-bottom: 10px;
}

.plat-badge {
  display: inline-block;
  margin-bottom: 10px;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
}

.plat-badge.win {
  background: var(--accent-soft);
  color: var(--accent);
}

.plat-badge.mac {
  background: var(--tech-soft);
  color: var(--tech);
}

.platform-card h3 {
  font-size: 18px;
  color: var(--ink);
}

.platform-card > p {
  margin: 8px 0 18px;
  font-size: 14px;
  color: var(--muted);
}

.foot {
  width: min(100%, var(--page-max));
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 28px var(--page-pad) 40px;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
  font-size: 13px;
}

.foot-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 600;
}

.foot-brand img {
  border-radius: 8px;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 1100px) {
  :root {
    --page-max: min(94vw, 1080px);
    --hero-max: min(90vw, 880px);
  }
}

@media (max-width: 860px) {
  :root {
    --page-max: 100%;
    --hero-max: 100%;
  }

  .feature-list,
  .platform-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 48px;
  }

  .top-nav a:last-child {
    background: var(--accent);
    color: #fff;
  }
}

@media (max-width: 560px) {
  .top-nav a:first-child {
    display: none;
  }

  .hero-cta {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}