:root {
  --bg: #f4f8fb;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-strong: rgba(255, 255, 255, 0.88);
  --surface-soft: rgba(255, 255, 255, 0.52);
  --glass-border: rgba(255, 255, 255, 0.78);
  --glass-border-strong: rgba(255, 255, 255, 0.9);
  --text: #111827;
  --muted: #667085;
  --line: rgba(148, 163, 184, 0.22);
  --primary: #2563eb;
  --accent: #0f9f8f;
  --ink: #0f172a;
  --shadow: 0 24px 70px rgba(15, 23, 42, 0.09);
  --card-shadow: 0 16px 42px rgba(15, 23, 42, 0.07);
  --hover-shadow: 0 24px 58px rgba(15, 23, 42, 0.1);
  --dark-button: #0f172a;
  --radius: 16px;
  --radius-sm: 10px;
}

[data-theme="dark"] {
  --bg: #0c131c;
  --surface: rgba(20, 29, 42, 0.68);
  --surface-strong: rgba(29, 40, 56, 0.88);
  --surface-soft: rgba(18, 27, 39, 0.48);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-border-strong: rgba(255, 255, 255, 0.16);
  --text: #edf4fb;
  --muted: #a4b2c4;
  --line: rgba(255, 255, 255, 0.1);
  --primary: #73a7ff;
  --accent: #2dd4bf;
  --ink: #f8fbff;
  --shadow: 0 26px 78px rgba(0, 0, 0, 0.36);
  --card-shadow: 0 18px 48px rgba(0, 0, 0, 0.25);
  --hover-shadow: 0 26px 68px rgba(0, 0, 0, 0.34);
  --dark-button: rgba(255, 255, 255, 0.11);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 10% 0%, rgba(37, 99, 235, 0.1), transparent 26%),
    radial-gradient(circle at 88% 6%, rgba(15, 159, 143, 0.1), transparent 24%),
    linear-gradient(180deg, #f7fafc 0%, var(--bg) 48%, #eef5f5 100%);
  color: var(--text);
  font-family:
    Inter, "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  letter-spacing: 0;
}

[data-theme="dark"] body {
  background:
    radial-gradient(circle at 10% 0%, rgba(115, 167, 255, 0.16), transparent 28%),
    radial-gradient(circle at 88% 6%, rgba(45, 212, 191, 0.1), transparent 24%),
    linear-gradient(180deg, #0b1119 0%, var(--bg) 52%, #0a1216 100%);
}

[data-theme="dark"] .brand-mark,
[data-theme="dark"] .mini-logo {
  box-shadow: 0 14px 30px rgba(45, 212, 191, 0.12);
}

[data-theme="dark"] .logo-node.accent {
  fill: #5eead4;
}

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

main,
footer {
  width: min(1120px, calc(100% - 56px));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  margin: 0;
  padding: 14px max(28px, calc((100vw - 1120px) / 2));
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  transition:
    padding 0.18s ease,
    border-color 0.18s ease,
    border-radius 0.18s ease,
    background 0.18s ease,
    box-shadow 0.18s ease,
    backdrop-filter 0.18s ease;
}

.site-header.is-scrolled {
  padding-top: 10px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(148, 163, 184, 0.16);
  border-radius: 0;
  background:
    linear-gradient(120deg, rgba(239, 246, 255, 0.5), rgba(255, 255, 255, 0.34) 46%, rgba(236, 253, 245, 0.38)),
    rgba(255, 255, 255, 0.58);
  box-shadow:
    0 12px 30px rgba(15, 23, 42, 0.07),
    0 1px 0 rgba(255, 255, 255, 0.66) inset;
  backdrop-filter: blur(20px) saturate(165%);
  -webkit-backdrop-filter: blur(20px) saturate(165%);
}

[data-theme="dark"] .site-header {
  background: transparent;
  box-shadow: none;
}

[data-theme="dark"] .site-header.is-scrolled {
  border-bottom-color: rgba(148, 163, 184, 0.12);
  background:
    linear-gradient(120deg, rgba(37, 99, 235, 0.16), rgba(15, 23, 42, 0.48) 48%, rgba(45, 212, 191, 0.12)),
    rgba(15, 23, 42, 0.58);
  box-shadow:
    0 14px 34px rgba(0, 0, 0, 0.22),
    inset 0 1px 0 rgba(255, 255, 255, 0.07);
}

.brand,
.site-header nav,
.hero-actions,
.trust-row,
footer {
  display: flex;
  align-items: center;
}

.brand {
  gap: 10px;
  font-size: 18px;
  font-weight: 900;
}

.brand-mark,
.mini-logo {
  display: grid;
  place-items: center;
  background: transparent;
  box-shadow: 0 12px 24px rgba(37, 99, 235, 0.12);
}

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
}

.brand-mark img {
  display: block;
  width: 30px;
  height: 30px;
  object-fit: contain;
}

.brand-wordmark-wrap {
  display: inline-flex;
  align-items: center;
  color: #071747;
  font-size: 22px;
  font-weight: 950;
  line-height: 1;
  letter-spacing: 0;
}

[data-theme="dark"] .brand-wordmark-wrap {
  color: #eef6ff;
  text-shadow: 0 8px 18px rgba(110, 160, 255, 0.12);
}

.logo-glow,
.logo-link,
.logo-spark {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.logo-glow {
  stroke: rgba(255, 255, 255, 0.48);
  stroke-width: 5;
}

.logo-link {
  stroke: rgba(255, 255, 255, 0.92);
  stroke-width: 3.2;
}

.logo-node {
  fill: rgba(255, 255, 255, 0.9);
  stroke: rgba(255, 255, 255, 0.52);
  stroke-width: 1.4;
}

.logo-node.accent {
  fill: color-mix(in srgb, var(--accent) 68%, white);
}

.logo-spark {
  stroke: rgba(255, 255, 255, 0.82);
  stroke-width: 2.1;
}

.site-header nav {
  gap: 6px;
  padding: 3px;
  border: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
  border-radius: 12px;
  background: color-mix(in srgb, var(--surface-soft) 72%, transparent);
}

.site-header nav a {
  padding: 8px 11px;
  border-radius: var(--radius-sm);
  color: var(--muted);
  font-size: 13px;
  font-weight: 780;
  transition:
    transform 0.18s ease,
    background 0.18s ease,
    color 0.18s ease;
}

.site-header nav a:hover {
  background: color-mix(in srgb, var(--primary) 10%, transparent);
  color: var(--primary);
  transform: translateY(-2px);
}

.site-header nav a[href="./index.html"] {
  background: var(--primary);
  color: white;
  box-shadow: 0 10px 22px color-mix(in srgb, var(--primary) 24%, transparent);
}

.site-header nav a[href="./index.html"]:hover {
  background: color-mix(in srgb, var(--primary) 88%, var(--accent));
  color: white;
}

.theme-toggle {
  position: relative;
  display: inline-grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--text);
  cursor: pointer;
  transition:
    transform 0.18s ease,
    color 0.18s ease;
}

.theme-toggle:hover {
  transform: translateY(-2px);
  color: var(--primary);
}

[data-theme="dark"] .theme-toggle {
  background: transparent;
}

.sun-icon,
.moon-icon {
  position: absolute;
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.9;
  transition:
    opacity 0.18s ease,
    transform 0.18s ease;
}

.sun-icon {
  color: #f59e0b;
}

.moon-icon {
  color: var(--text);
  fill: color-mix(in srgb, var(--text) 8%, transparent);
}

[data-theme="light"] .sun-icon,
:root:not([data-theme]) .sun-icon {
  opacity: 0;
  transform: scale(0.7) rotate(-20deg);
}

[data-theme="light"] .moon-icon,
:root:not([data-theme]) .moon-icon {
  opacity: 1;
}

[data-theme="dark"] .sun-icon {
  opacity: 1;
}

[data-theme="dark"] .moon-icon {
  opacity: 0;
  transform: scale(0.7) rotate(20deg);
}

.hero {
  display: grid;
  gap: 44px;
  padding: 78px 0 76px;
}

.hero-copy {
  display: grid;
  justify-items: center;
  max-width: 880px;
  margin: 0 auto;
  text-align: center;
}

.eyebrow {
  margin: 0 0 16px;
  color: var(--primary);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 880px;
  margin-bottom: 22px;
  color: var(--ink);
  font-size: clamp(44px, 5.1vw, 66px);
  line-height: 1.1;
  letter-spacing: 0;
  font-weight: 900;
}

.lead {
  max-width: 720px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.85;
}

.hero-actions {
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  margin: 30px 0 22px;
}

.primary-action,
.secondary-action,
.price-grid a {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  font-weight: 850;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    background 0.18s ease;
}

.primary-action {
  padding: 0 20px;
  background: var(--primary);
  color: white;
  box-shadow: 0 16px 34px rgba(37, 99, 235, 0.22);
}

.primary-action:hover {
  transform: translateY(-3px);
  box-shadow: 0 22px 42px rgba(37, 99, 235, 0.28);
}

.secondary-action {
  padding: 0 18px;
  border: 1px solid var(--line);
  background: var(--surface-soft);
  color: var(--text);
}

.secondary-action:hover {
  transform: translateY(-3px);
  background: var(--surface-strong);
}

.trust-row {
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
}

.trust-row span {
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-soft);
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 18px;
  margin-top: 26px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.hero-stats strong {
  color: var(--ink);
  font-size: 24px;
}

.hero-stats span {
  align-self: center;
  color: var(--muted);
  font-size: 14px;
  font-weight: 750;
}

.product-preview {
  display: grid;
  grid-template-columns: 76px 1fr;
  min-height: 560px;
  overflow: hidden;
  border: 1px solid var(--glass-border-strong);
  border-radius: 22px;
  background:
    linear-gradient(145deg, var(--surface-strong), var(--surface-soft)),
    var(--surface);
  box-shadow: var(--shadow);
  backdrop-filter: blur(30px) saturate(170%);
  -webkit-backdrop-filter: blur(30px) saturate(170%);
  transition:
    transform 0.22s ease,
    box-shadow 0.22s ease;
}

.product-preview:hover {
  transform: translateY(-6px);
  box-shadow: var(--hover-shadow);
}

.preview-sidebar {
  display: grid;
  align-content: start;
  justify-items: center;
  gap: 14px;
  padding: 20px 0;
  border-right: 1px solid var(--glass-border);
  background: var(--surface-soft);
}

.mini-logo {
  width: 42px;
  height: 42px;
  border-radius: 10px;
}

.mini-logo img {
  display: block;
  width: 34px;
  height: 34px;
  object-fit: contain;
}

.rail-item {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border-radius: 10px;
  background: rgba(37, 99, 235, 0.1);
  color: var(--primary);
}

[data-theme="dark"] .rail-item {
  background: rgba(115, 167, 255, 0.12);
}

.rail-item.active {
  background: var(--primary);
  color: white;
}

.rail-item svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

.preview-main {
  display: grid;
  align-content: start;
  gap: 18px;
  padding: 30px;
}

.preview-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.preview-top span {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
}

.preview-top strong {
  font-size: 30px;
}

.preview-top i {
  display: inline-flex;
  min-width: 220px;
  min-height: 40px;
  align-items: center;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-soft);
  color: var(--muted);
  font-size: 13px;
  font-style: normal;
  font-weight: 750;
}

.favorite-strip,
.preview-grid {
  display: grid;
  gap: 12px;
}

.favorite-strip {
  grid-template-columns: repeat(3, 1fr);
  padding: 16px;
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: var(--radius);
  background:
    linear-gradient(180deg, rgba(248, 250, 252, 0.82), rgba(255, 255, 255, 0.66)),
    rgba(248, 250, 252, 0.72);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.78),
    0 16px 34px rgba(15, 23, 42, 0.045);
}

.favorite-strip article,
.preview-grid article {
  border: 1px solid rgba(148, 163, 184, 0.24);
  border-radius: var(--radius);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(248, 250, 252, 0.9)),
    #ffffff;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.92),
    0 14px 30px rgba(15, 23, 42, 0.065);
}

.favorite-strip article {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 58px;
  padding: 10px;
}

.favorite-strip b,
.preview-grid b {
  display: grid;
  place-items: center;
  border-radius: var(--radius-sm);
  background: var(--tone, var(--primary));
  color: white;
  font-size: 13px;
  font-style: normal;
  font-weight: 900;
}

.favorite-strip b {
  width: 32px;
  height: 32px;
}

.favorite-strip span {
  font-weight: 850;
}

.preview-grid {
  grid-template-columns: repeat(2, 1fr);
}

.preview-grid article {
  display: grid;
  gap: 8px;
  min-height: 146px;
  padding: 18px;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.92),
    0 16px 36px rgba(15, 23, 42, 0.075),
    0 1px 2px rgba(15, 23, 42, 0.035);
}

.preview-grid b {
  width: 42px;
  height: 42px;
  background: var(--tone);
}

.app-icon.chatgpt {
  background: #10a37f;
}

.app-icon.notion {
  background: #111827;
}

.app-icon.github {
  background: #24292f;
  font-size: 11px;
}

.app-icon.bilibili {
  background: #00aeec;
  font-size: 20px;
}

.app-icon.figma {
  overflow: hidden;
  background:
    radial-gradient(circle at 34% 28%, #f24e1e 0 18%, transparent 19%),
    radial-gradient(circle at 66% 28%, #ff7262 0 18%, transparent 19%),
    radial-gradient(circle at 34% 52%, #a259ff 0 18%, transparent 19%),
    radial-gradient(circle at 66% 52%, #1abcfe 0 18%, transparent 19%),
    radial-gradient(circle at 34% 76%, #0acf83 0 18%, transparent 19%),
    #ffffff;
}

[data-theme="dark"] .app-icon.notion,
[data-theme="dark"] .app-icon.github {
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.12);
}

.app-icon.figma em {
  display: none;
}

.preview-grid strong {
  font-size: 18px;
}

.preview-grid span {
  color: var(--muted);
  font-size: 14px;
}

[data-theme="dark"] .favorite-strip {
  border-color: var(--glass-border);
  background: var(--surface-soft);
  box-shadow: none;
}

[data-theme="dark"] .favorite-strip article,
[data-theme="dark"] .preview-grid article {
  border-color: var(--glass-border);
  background: var(--surface-strong);
  box-shadow: var(--card-shadow);
}

.section {
  padding: 86px 0;
}

.intro {
  max-width: 880px;
  margin: 0 auto;
  text-align: center;
}

.section-head {
  max-width: 760px;
  margin: 0 auto 32px;
  text-align: center;
}

.section h2 {
  max-width: 780px;
  margin: 0 auto 16px;
  color: var(--ink);
  font-size: clamp(34px, 4vw, 52px);
  line-height: 1.08;
}

.section p {
  color: var(--muted);
  font-size: 17px;
  line-height: 1.75;
}

.feature-grid,
.price-grid,
.policy-grid {
  display: grid;
  gap: 16px;
}

.feature-grid {
  grid-template-columns: repeat(3, 1fr);
}

.feature-grid article,
.price-grid article,
.policy-grid article,
.final-cta {
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--card-shadow);
  backdrop-filter: blur(24px) saturate(170%);
  -webkit-backdrop-filter: blur(24px) saturate(170%);
}

.feature-grid article {
  min-height: 230px;
  padding: 26px;
  transition:
    transform 0.18s ease,
    border-color 0.18s ease,
    box-shadow 0.18s ease;
}

.feature-grid article:hover,
.price-grid article:hover,
.policy-grid article:hover {
  transform: translateY(-5px);
  border-color: color-mix(in srgb, var(--primary) 34%, var(--glass-border));
  box-shadow: var(--hover-shadow);
}

.feature-icon {
  display: inline-grid;
  width: 46px;
  height: 34px;
  place-items: center;
  margin-bottom: 28px;
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--primary) 12%, var(--surface-strong));
  color: var(--primary);
  font-size: 13px;
  font-weight: 900;
}

.feature-grid h3 {
  margin-bottom: 10px;
  font-size: 22px;
}

.price-grid {
  grid-template-columns: repeat(3, 1fr);
}

.price-grid article {
  display: grid;
  gap: 18px;
  min-height: 350px;
  padding: 28px;
  transition:
    transform 0.18s ease,
    border-color 0.18s ease,
    box-shadow 0.18s ease;
}

.price-grid article.featured {
  border-color: color-mix(in srgb, var(--primary) 42%, var(--glass-border));
  background:
    linear-gradient(145deg, color-mix(in srgb, var(--primary) 10%, var(--surface-strong)), var(--surface)),
    var(--surface-strong);
}

.price-grid h3 {
  margin: 0;
  font-size: 38px;
}

.price-grid h3 span {
  color: var(--muted);
  font-size: 16px;
}

.price-grid ul {
  display: grid;
  gap: 10px;
  min-height: 116px;
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
}

.price-grid a {
  background: var(--dark-button);
  color: white;
}

.price-grid .featured a {
  background: var(--primary);
}

.price-grid a:hover {
  transform: translateY(-3px);
}

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

.policy-grid article {
  padding: 30px;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease;
}

.policy-grid h2 {
  font-size: 32px;
  text-align: left;
}

.legal-main {
  display: grid;
  gap: 22px;
  max-width: 860px;
  padding: 78px 0 42px;
}

.legal-hero {
  padding: 18px 0 10px;
}

.legal-hero h1 {
  max-width: 760px;
  margin-bottom: 16px;
  font-size: clamp(42px, 5vw, 62px);
}

.legal-card {
  display: grid;
  gap: 18px;
  padding: 34px;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--card-shadow);
  backdrop-filter: blur(24px) saturate(170%);
  -webkit-backdrop-filter: blur(24px) saturate(170%);
}

.legal-card h2 {
  margin: 16px 0 0;
  color: var(--ink);
  font-size: 24px;
}

.legal-card p,
.legal-card li {
  color: var(--muted);
  font-size: 16px;
  line-height: 1.85;
}

.legal-card ul {
  display: grid;
  gap: 8px;
  margin: 0;
  padding-left: 20px;
}

.legal-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 8px;
}

.final-cta {
  display: grid;
  justify-items: center;
  margin: 68px 0 34px;
  padding: 72px 24px;
  text-align: center;
}

.final-cta h2 {
  max-width: 760px;
  margin-bottom: 24px;
  font-size: clamp(38px, 5vw, 62px);
  line-height: 1.04;
}

footer {
  justify-content: center;
  gap: 16px;
  padding: 28px 0 42px;
  color: var(--muted);
  font-size: 14px;
}

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

@media (max-width: 980px) {
  main,
  footer {
    width: min(100% - 28px, 720px);
  }

  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding-right: 14px;
    padding-left: 14px;
  }

  .site-header nav {
    flex-wrap: wrap;
  }

  .feature-grid,
  .price-grid,
  .policy-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 56px;
  }

  .product-preview {
    grid-template-columns: 56px 1fr;
    min-height: 480px;
  }

  .preview-main {
    padding: 18px;
  }

  .preview-top {
    align-items: flex-start;
    flex-direction: column;
  }

  .favorite-strip,
  .preview-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  h1 {
    max-width: 360px;
    font-size: 42px;
  }

  .hero-actions,
  .primary-action,
  .secondary-action {
    width: 100%;
  }

  .hero-stats {
    align-items: center;
    flex-direction: column;
  }

  .product-preview {
    grid-template-columns: 1fr;
  }

  .preview-sidebar {
    display: none;
  }
}