/* desktop: graphite + green, stacked chrome + CSS window mock */
:root {
  --ink: #212121;
  --wa: #25D366;
  --fog: #F5F5F5;
  --mid: #424242;
  --teal: #00A884;
  --card: #ffffff;
}

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

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--fog);
  color: var(--ink);
  line-height: 1.7;
}

a { color: var(--teal); text-decoration: none; }
a:hover { color: var(--wa); }

.bar {
  background: var(--ink);
  color: #fff;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 18px 20px 0;
}

.brand {
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.04em;
}

.menu {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0;
  margin-top: 14px;
}

.menu a {
  color: #e0e0e0;
  padding: 10px 14px;
  border-bottom: 3px solid transparent;
  font-size: 0.92rem;
}

.menu a:hover { border-bottom-color: var(--wa); color: #fff; }

.hero-band {
  background: linear-gradient(180deg, var(--ink) 0 42%, var(--fog) 42% 100%);
  padding: 36px 20px 20px;
}

.hero {
  max-width: 760px;
  margin: 0 auto 28px;
  color: #fafafa;
}

.hero h1 {
  font-size: clamp(1.65rem, 3vw, 2.2rem);
  line-height: 1.3;
  margin-bottom: 16px;
}

.hero p { margin-bottom: 12px; color: #eeeeee; }

.when { color: #9e9e9e !important; font-size: 0.88rem; }

.mock {
  max-width: 920px;
  margin: 0 auto;
  background: #2b2b2b;
  border-radius: 10px 10px 0 0;
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
  overflow: hidden;
}

.mock-chrome {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  background: #1a1a1a;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #616161;
}

.dot:nth-child(1) { background: #e57373; }
.dot:nth-child(2) { background: #ffd54f; }
.dot:nth-child(3) { background: var(--wa); }

.mock-url {
  flex: 1;
  height: 12px;
  margin-left: 12px;
  background: #333;
  border-radius: 6px;
}

.mock-cols {
  display: grid;
  grid-template-columns: 22% 1fr 20%;
  min-height: 220px;
  background: #111;
}

.mock-list { background: #1e1e1e; padding: 14px 12px; display: grid; gap: 10px; align-content: start; }
.mock-chat { background: #121d16; padding: 18px 16px; display: flex; flex-direction: column; gap: 12px; }
.mock-profile { background: #242424; padding: 18px 12px; display: grid; gap: 10px; justify-items: center; align-content: start; }

.sk {
  display: block;
  height: 10px;
  width: 70%;
  background: #3a3a3a;
  border-radius: 4px;
}

.sk-lg { width: 90%; }
.sk-mid { width: 50%; }

.bubble {
  display: block;
  height: 28px;
  width: 58%;
  border-radius: 8px;
  background: #2e4736;
}

.bubble.right { align-self: flex-end; background: #1f5c3a; width: 46%; }
.bubble.short { width: 34%; }

.avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: #3d3d3d;
}

main { max-width: 980px; margin: 0 auto 56px; padding: 8px 20px 0; }

.block { padding: 28px 0 12px; }

.block h2, .pair h2, .cover-card h2 {
  font-size: 1.4rem;
  margin-bottom: 12px;
  color: var(--ink);
}

.block p, .pair > p, .cover-card p { margin-bottom: 12px; }

.feat {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 18px 0 22px;
}

.feat li {
  background: var(--card);
  padding: 16px;
  border-top: 4px solid var(--wa);
  box-shadow: 0 1px 0 #e0e0e0;
}

.feat svg { color: var(--teal); margin-bottom: 8px; }

.sheet { overflow-x: auto; }

table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  font-size: 0.94rem;
}

caption {
  text-align: left;
  font-weight: 700;
  margin-bottom: 8px;
}

th, td { border: 1px solid #e0e0e0; padding: 10px 12px; text-align: left; }
th { background: var(--ink); color: #fff; }
tr:nth-child(even) td { background: #f0f7f3; }

.pair { padding: 20px 0 8px; }

.pair-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin-top: 8px;
}

.screen-card {
  background: var(--ink);
  color: #f5f5f5;
  padding: 22px 20px 18px;
}

.screen-card h3 { color: var(--wa); margin: 10px 0 8px; }
.screen-card p { color: #eeeeee; }
.screen-card svg { color: var(--wa); }

.tint { background: #fff; padding: 24px 22px; margin: 12px 0; }

.track {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-top: 16px;
}

.track li {
  background: var(--fog);
  padding: 14px 12px 12px;
  border-bottom: 4px solid var(--teal);
}

.track b {
  display: inline-block;
  width: 28px;
  height: 28px;
  background: var(--wa);
  color: var(--ink);
  text-align: center;
  line-height: 28px;
  margin-bottom: 8px;
}

.cover-card {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 16px;
  background: #e8f5e9;
  border-left: 8px solid var(--teal);
  padding: 22px 20px;
  margin: 18px 0;
}

.cover-icon svg { color: var(--teal); }

.faq { margin-top: 8px; }

.faq > div {
  background: #fff;
  margin-bottom: 10px;
  padding: 14px 16px;
  border-left: 4px solid var(--wa);
}

.faq dt { font-weight: 700; margin-bottom: 6px; }

.foot {
  background: var(--ink);
  color: #bdbdbd;
  text-align: center;
  padding: 28px 18px 36px;
  font-size: 0.9rem;
}

.foot p { margin-bottom: 8px; }

@media (max-width: 800px) {
  .mock-cols { grid-template-columns: 1fr 1.2fr; }
  .mock-profile { display: none; }
  .feat, .pair-grid, .track { grid-template-columns: 1fr; }
  .cover-card { grid-template-columns: 1fr; }
}