/* FlutterLaunch — landing site
   零依赖静态样式。改主题色只需改 --brand。 */

:root {
  --brand: #2f6bff;
  --brand-dark: #1f4fd6;
  --brand-soft: #eaf0ff;

  --ink: #0f1117;
  --ink-2: #4b5163;
  --ink-3: #8a90a2;

  --bg: #ffffff;
  --bg-alt: #f7f8fa;
  --line: #e5e7eb;

  --radius: 14px;
  --maxw: 1080px;

  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* height:auto 必须显式写——否则 width/height 属性会被当成 aspect-ratio，
   图片换个比例就会被拉伸变形 */
img { max-width: 100%; height: auto; display: block; }

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- nav ---------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.nav-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  height: 62px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 650;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.logo:hover { text-decoration: none; }

.logo-mark {
  width: 26px;
  height: 26px;
  border-radius: 7px;
  background: linear-gradient(135deg, var(--brand), #7aa2ff);
  position: relative;
  flex: 0 0 auto;
}
.logo-mark::after {
  content: "";
  position: absolute;
  inset: 8px 7px;
  border-radius: 2px;
  background: #fff;
  clip-path: polygon(0 0, 100% 50%, 0 100%);
}

.nav-links {
  display: flex;
  gap: 22px;
  margin-left: auto;
  font-size: 14.5px;
}
.nav-links a { color: var(--ink-2); }
.nav-links a:hover { color: var(--ink); text-decoration: none; }

@media (max-width: 760px) {
  .nav-links { display: none; }
  /* 链接隐藏后按钮接在 logo 后面会显得挤，推到右侧 */
  .nav-inner > .btn { margin-left: auto; }
}

/* ---------- buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 44px;
  padding: 0 22px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.12s ease, background 0.15s ease, box-shadow 0.15s ease;
  white-space: nowrap;
}

.btn-primary {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 1px 2px rgba(47, 107, 255, 0.24), 0 8px 24px -12px rgba(47, 107, 255, 0.6);
}
.btn-primary:hover {
  background: var(--brand-dark);
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-ghost {
  background: #fff;
  color: var(--ink);
  border-color: var(--line);
}
.btn-ghost:hover { background: var(--bg-alt); text-decoration: none; }

.btn-sm { height: 38px; padding: 0 16px; font-size: 14px; }

/* ---------- hero ---------- */

.hero { padding: 76px 0 40px; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  color: var(--brand);
  background: var(--brand-soft);
  border-radius: 999px;
  padding: 6px 14px;
  margin-bottom: 22px;
}

.hero h1 {
  font-size: clamp(34px, 5.2vw, 56px);
  line-height: 1.12;
  letter-spacing: -0.028em;
  margin: 0 0 20px;
  font-weight: 700;
  max-width: 17em;
}

.hero p.lead {
  font-size: clamp(16px, 1.9vw, 19px);
  color: var(--ink-2);
  max-width: 40em;
  margin: 0 0 30px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin-bottom: 14px;
}

.price-tag {
  font-size: 15px;
  color: var(--ink-2);
}
.price-tag strong {
  font-size: 22px;
  color: var(--ink);
  letter-spacing: -0.02em;
}

.trust {
  font-size: 13.5px;
  color: var(--ink-3);
  font-family: var(--mono);
}

/* ---------- hero screenshots ---------- */

.phones {
  display: flex;
  gap: 26px;
  justify-content: center;
  align-items: flex-start;
  margin-top: 54px;
  padding-bottom: 10px;
}

.phone {
  width: 268px;
  border-radius: 26px;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--line);
  box-shadow:
    0 2px 4px rgba(15, 17, 23, 0.04),
    0 24px 48px -24px rgba(15, 17, 23, 0.28);
}

.phone:nth-child(2) { margin-top: 32px; }

@media (max-width: 700px) {
  .phones { gap: 14px; }
  .phone { width: 44%; border-radius: 18px; }
  .phone:nth-child(2) { margin-top: 20px; }
}

/* ---------- proof strip ---------- */

.proof {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--bg-alt);
  padding: 30px 0;
}

.proof-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  text-align: center;
}

.proof-num {
  font-size: 26px;
  font-weight: 700;
  letter-spacing: -0.02em;
  font-family: var(--mono);
}
.proof-label {
  font-size: 13px;
  color: var(--ink-3);
  margin-top: 2px;
}

@media (max-width: 700px) {
  .proof-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
}

/* ---------- sections ---------- */

section { padding: 82px 0; }
section.alt { background: var(--bg-alt); }

.sec-head { max-width: 640px; margin-bottom: 44px; }

.sec-head h2 {
  font-size: clamp(25px, 3.2vw, 34px);
  letter-spacing: -0.022em;
  line-height: 1.22;
  margin: 0 0 12px;
  font-weight: 700;
}

.sec-head p {
  color: var(--ink-2);
  font-size: 16.5px;
  margin: 0;
}

/* ---------- capability grid ---------- */

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

@media (max-width: 680px) { .cards { grid-template-columns: 1fr; } }

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 20px;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.card:hover {
  border-color: #cfd6e4;
  box-shadow: 0 10px 28px -20px rgba(15, 17, 23, 0.35);
}

.card .idx {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink-3);
  letter-spacing: 0.04em;
}

.card h3 {
  font-size: 16.5px;
  margin: 6px 0 8px;
  letter-spacing: -0.01em;
  font-weight: 650;
}

.card p {
  font-size: 14px;
  color: var(--ink-2);
  margin: 0;
  line-height: 1.6;
}

/* ---------- feature split ---------- */

.feature {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 64px;
  align-items: center;
}

/* 代码块做视觉主体时，两栏等宽 */
.feature.code { grid-template-columns: 1fr 1fr; gap: 48px; }

@media (max-width: 820px) {
  .feature, .feature.code { grid-template-columns: 1fr; gap: 32px; }
}

.feature-text h2 {
  font-size: clamp(24px, 3vw, 32px);
  letter-spacing: -0.022em;
  margin: 0 0 14px;
  line-height: 1.24;
}

.feature-text p {
  color: var(--ink-2);
  font-size: 16px;
  margin: 0 0 16px;
}

.feature-text ul {
  margin: 0;
  padding-left: 0;
  list-style: none;
}

.feature-text li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 10px;
  font-size: 15px;
  color: var(--ink-2);
}

.feature-text li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 9px;
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--brand);
  opacity: 0.85;
}

.feature-media img {
  border-radius: 22px;
  border: 1px solid var(--line);
  box-shadow: 0 24px 48px -28px rgba(15, 17, 23, 0.35);
}

/* ---------- code block ---------- */

pre {
  background: #0f1117;
  color: #e6e9f0;
  border-radius: 12px;
  padding: 18px 20px;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.75;
  margin: 0 0 18px;
}

pre .c { color: #7a8090; }
pre .g { color: #3ecf8e; }
pre .y { color: #ffc65c; }
pre .r { color: #ff6b6f; }

/* ---------- gallery ---------- */

.gallery {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

@media (max-width: 900px) { .gallery { grid-template-columns: repeat(2, 1fr); } }

.gallery figure { margin: 0; }

.gallery img {
  border-radius: 18px;
  border: 1px solid var(--line);
  box-shadow: 0 18px 36px -26px rgba(15, 17, 23, 0.4);
}

.gallery figcaption {
  font-size: 13px;
  color: var(--ink-3);
  margin-top: 10px;
  text-align: center;
}

/* ---------- pricing ---------- */

.pricing {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  max-width: 760px;
}

@media (max-width: 700px) { .pricing { grid-template-columns: 1fr; } }

.plan {
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 28px 26px;
  background: #fff;
  display: flex;
  flex-direction: column;
}

.plan.featured {
  border-color: var(--brand);
  box-shadow: 0 18px 44px -28px rgba(47, 107, 255, 0.65);
}

.plan .tag {
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--brand);
  margin-bottom: 8px;
}

.plan .amount {
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
}
.plan .amount span {
  font-size: 15px;
  font-weight: 500;
  color: var(--ink-3);
  letter-spacing: 0;
}

.plan .desc {
  font-size: 14.5px;
  color: var(--ink-2);
  margin: 10px 0 20px;
  flex: 1;
}

/* 首发价标记：把低价说成「限时」而不是「就值这点」。
   做成色块而不是胶囊——胶囊里换行会显得挤。 */
.launch-note {
  display: block;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--brand);
  background: var(--brand-soft);
  border-radius: 8px;
  padding: 8px 10px;
  margin-top: 12px;
  line-height: 1.45;
}

.plan ul {
  list-style: none;
  padding: 0;
  margin: 0 0 24px;
  font-size: 14.5px;
  color: var(--ink-2);
}
.plan li {
  padding-left: 22px;
  position: relative;
  margin-bottom: 8px;
}
.plan li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 8px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--brand);
}

/* ---------- faq ---------- */

.faq { max-width: 780px; }

.faq details {
  border-bottom: 1px solid var(--line);
  padding: 18px 0;
}
.faq details:first-child { border-top: 1px solid var(--line); }

.faq summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 16px;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 16px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  color: var(--ink-3);
  font-weight: 400;
  font-size: 20px;
  line-height: 1;
}
.faq details[open] summary::after { content: "–"; }

.faq p {
  color: var(--ink-2);
  font-size: 15px;
  margin: 12px 0 0;
  max-width: 62ch;
}

/* ---------- footer ---------- */

footer {
  border-top: 1px solid var(--line);
  background: var(--bg-alt);
  padding: 44px 0 56px;
  font-size: 14px;
  color: var(--ink-3);
}

.foot-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  justify-content: space-between;
  align-items: flex-start;
}

.foot-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}
.foot-links a { color: var(--ink-2); }

/* ---------- legal pages ---------- */

.legal {
  max-width: 760px;
  margin: 0 auto;
  padding: 56px 24px 96px;
}

.legal h1 {
  font-size: 34px;
  letter-spacing: -0.024em;
  margin: 0 0 8px;
}

.legal .updated {
  color: var(--ink-3);
  font-size: 14px;
  margin-bottom: 36px;
}

.legal h2 {
  font-size: 20px;
  margin: 40px 0 12px;
  letter-spacing: -0.015em;
}

.legal p, .legal li {
  color: var(--ink-2);
  font-size: 15.5px;
}

.legal ul { padding-left: 22px; }
.legal li { margin-bottom: 8px; }

.legal .back {
  display: inline-block;
  margin-bottom: 28px;
  font-size: 14px;
}