:root {
  --mint: #E6F4F1;
  --ink: #2C3333;
  --accent: #1B7A6E;
  --accent-deep: #0E3D37;
  --card: #ffffff;
  --line: #c5ddd8;
  --muted: #5b6666;
  --radius: 22px;
}

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

html {
  scroll-behavior: auto;
}

body {
  background: var(--mint);
  color: var(--ink);
  font-family: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.8;
}

img,
svg {
  display: block;
}

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

a:hover {
  text-decoration: underline;
}

.shell {
  width: min(1080px, calc(100% - 48px));
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 18px;
  z-index: 20;
  padding-top: 6px;
}

.topbar-card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: 0 10px 28px rgba(14, 61, 55, 0.12);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 14px 22px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 700;
  white-space: nowrap;
}

.logo:hover {
  text-decoration: none;
}

.logo svg {
  width: 28px;
  height: 28px;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px 14px;
}

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

.hero {
  background: var(--mint);
  padding: 56px 0 28px;
}

.hero h1 {
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.35;
  margin-bottom: 18px;
  max-width: 18em;
}

.hero p {
  max-width: 42em;
  font-size: 18px;
}

.device-board {
  padding: 8px 0 36px;
}

.device-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.device-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: 0 8px 20px rgba(14, 61, 55, 0.08);
}

.device-card h3 {
  font-size: 18px;
  margin: 12px 0 8px;
}

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

.tag {
  display: inline-block;
  background: #d8efe9;
  color: var(--accent);
  border-radius: 999px;
  padding: 2px 10px;
  font-size: 12px;
  font-weight: 600;
}

.block {
  padding: 8px 0 48px;
}

.block h2 {
  font-size: 26px;
  line-height: 1.4;
  margin-bottom: 16px;
}

.block p {
  margin-bottom: 14px;
  max-width: 46em;
}

.feat-stack {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 22px;
}

.feat {
  display: flex;
  align-items: flex-start;
  gap: 18px;
  background: var(--card);
  border-radius: var(--radius);
  padding: 20px 22px;
  box-shadow: 0 6px 16px rgba(14, 61, 55, 0.06);
}

.feat-icon {
  flex: 0 0 48px;
  width: 48px;
  height: 48px;
  border-radius: 16px;
  background: #d8efe9;
  display: grid;
  place-items: center;
}

.feat h3 {
  font-size: 18px;
  margin-bottom: 6px;
}

.feat p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
}

.step-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: 24px 0 8px;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--card);
  box-shadow: 0 6px 16px rgba(14, 61, 55, 0.06);
}

.step {
  padding: 22px 16px;
  border-right: 1px solid var(--line);
  min-height: 150px;
}

.step:last-child {
  border-right: 0;
}

.step b {
  display: block;
  color: var(--accent);
  font-size: 13px;
  margin-bottom: 8px;
}

.step p {
  margin: 0;
  font-size: 15px;
}

.table-wrap {
  margin-top: 20px;
  background: var(--card);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 6px 16px rgba(14, 61, 55, 0.06);
}

table {
  width: 100%;
  border-collapse: collapse;
}

th,
td {
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

th {
  background: #d8efe9;
  font-size: 14px;
}

tr:last-child td {
  border-bottom: 0;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 18px;
}

details {
  background: var(--card);
  border-radius: var(--radius);
  padding: 4px 20px 4px;
  box-shadow: 0 6px 16px rgba(14, 61, 55, 0.06);
}

summary {
  cursor: pointer;
  font-weight: 700;
  padding: 16px 0;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

details p {
  padding-bottom: 16px;
  color: var(--muted);
}

.site-footer {
  background: var(--accent-deep);
  color: #d7ece7;
  padding: 40px 0 48px;
  margin-top: 20px;
}

.site-footer p {
  margin-bottom: 10px;
  max-width: 46em;
}

@media (max-width: 900px) {
  .device-grid,
  .step-bar {
    grid-template-columns: 1fr;
  }

  .step {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .topbar-card {
    flex-direction: column;
    align-items: flex-start;
  }

  .nav {
    justify-content: flex-start;
  }
}