:root {
  --primary: #2b4fd8;
  --primary-dark: #1f3cb0;
  --text: #17191e;
  --muted: #5f6573;
  --line: #d5d8df;
  --bg: #f3f4f6;
  --card: #ffffff;
  --dark: #141a2e;
  --error: #c62828;
  --ok: #1b7f3b;
}
* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: var(--text);
  background: var(--card);
}
a {
  color: var(--primary);
  text-decoration: none;
}
h1,
h2,
h3 {
  margin: 0 0 12px;
  line-height: 1.3;
}
.wrap {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 16px;
}
.row {
  display: flex;
  align-items: center;
  gap: 16px;
}
.between {
  justify-content: space-between;
  flex-wrap: wrap;
}
.muted {
  color: var(--muted);
}
.small {
  font-size: 13px;
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 42px;
  padding: 0 20px;
  border-radius: 6px;
  border: 1px solid var(--primary);
  background: var(--primary);
  color: #fff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
}
.btn:hover {
  background: var(--primary-dark);
}
.btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}
.btn.ghost {
  background: #fff;
  color: var(--primary);
}
.btn.ghost:hover {
  background: #eef2ff;
}
.btn.small {
  height: 34px;
  padding: 0 14px;
}
.btn.block {
  width: 100%;
}
.link {
  background: none;
  border: 0;
  padding: 0;
  color: var(--primary);
  font: inherit;
  cursor: pointer;
}

.top {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid var(--line);
}
.top .row {
  height: 60px;
  justify-content: space-between;
}
.brand {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
}
.top nav {
  display: flex;
  align-items: center;
  gap: 20px;
}
.top nav a:not(.btn),
.top nav .link {
  color: var(--muted);
}

.hero {
  background: linear-gradient(160deg, var(--dark) 0%, #24305a 100%);
  color: #fff;
  padding: 64px 0;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: center;
}
.hero h1 {
  font-size: 40px;
}
.hero .lead {
  color: #c9d1e8;
  font-size: 17px;
  max-width: 520px;
}
.hero .muted {
  color: #9aa5c4;
}
.actions {
  display: flex;
  gap: 12px;
  margin: 24px 0 16px;
  flex-wrap: wrap;
}

.card {
  background: var(--card);
  color: var(--text);
  border-radius: 10px;
  padding: 28px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}
.card .muted {
  color: var(--muted);
}
.card label {
  display: block;
  margin-bottom: 14px;
}
.card label > span {
  display: block;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 4px;
}
.card input:not([type="checkbox"]) {
  width: 100%;
  height: 42px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  font: inherit;
}
.card input:focus {
  outline: 2px solid var(--primary);
  outline-offset: -1px;
}
.inline {
  display: flex;
  gap: 8px;
}
.check {
  display: flex !important;
  gap: 8px;
  align-items: flex-start;
}
.check > span {
  display: inline !important;
  font-size: 13px;
  color: var(--muted);
  margin: 0 !important;
}
.check input {
  margin-top: 4px;
}
.message {
  min-height: 22px;
  margin-bottom: 8px;
  font-size: 14px;
}
.message.error {
  color: var(--error);
}
.message.ok {
  color: var(--ok);
}
.message.info {
  color: var(--muted);
}

.features {
  padding: 64px 0;
  background: var(--bg);
}
.features h2 {
  text-align: center;
  margin-bottom: 32px;
}
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.grid article {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
}
.grid h3 {
  font-size: 17px;
}
.grid p {
  margin: 0;
  color: var(--muted);
}

.download {
  padding: 48px 0;
}
.download p {
  max-width: 640px;
}
.download-actions {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
}

.foot {
  border-top: 1px solid var(--line);
  padding: 20px 0;
  font-size: 13px;
  color: var(--muted);
}

dialog {
  width: min(680px, calc(100% - 32px));
  max-height: 80vh;
  border: 0;
  border-radius: 10px;
  padding: 0;
}
dialog::backdrop {
  background: rgba(0, 0, 0, 0.45);
}
.dialog-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--line);
}
.dialog-head h2 {
  margin: 0;
  font-size: 18px;
}
.dialog-body {
  padding: 20px;
  overflow: auto;
  max-height: calc(80vh - 60px);
  white-space: pre-wrap;
}
.dialog-body img {
  display: block;
  margin: 0 auto 12px;
  width: 200px;
  height: 200px;
  object-fit: contain;
}

@media (max-width: 860px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .hero h1 {
    font-size: 30px;
  }
  .grid {
    grid-template-columns: 1fr;
  }
  .top nav a:not(.btn) {
    display: none;
  }
}