:root {
  --bg: #16181c;
  --bg-deep: #0f1114;
  --panel: #1e2126;
  --panel-hi: #262a31;
  --line: #2a2e35;
  --fg: #e8eaed;
  --fg-dim: #9aa0a6;
  --accent: #76b900;
  --accent-dark: #5d9400;
  --radius: 6px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  color: var(--fg);
  font: 15px/1.6 "Segoe UI", -apple-system, "PingFang SC", "Microsoft YaHei",
    sans-serif;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

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

.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
}

.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 62px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.mark {
  width: 20px;
  height: 20px;
  border: 3px solid var(--accent);
  border-radius: 50%;
}

.btn {
  height: 36px;
  padding: 0 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel-hi);
  color: var(--fg-dim);
  font: inherit;
  line-height: 36px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s;
}

.btn:hover {
  border-color: #3a4048;
  background: var(--panel-hi);
  color: var(--fg);
  text-decoration: none;
}

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

.hero {
  padding: 100px 0 90px;
  text-align: center;
}

.hero h1 {
  margin: 0 0 14px;
  font-size: 52px;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.lead {
  margin: 0 0 34px;
  color: var(--fg-dim);
  font-size: 19px;
}

.actions {
  display: flex;
  gap: 14px;
  justify-content: center;
}

.btn-primary,
.btn-secondary {
  height: 48px;
  padding: 0 32px;
  border-radius: var(--radius);
  font: inherit;
  font-size: 16px;
  font-weight: 600;
  line-height: 48px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s;
}

.btn-primary {
  border: none;
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-dark);
  text-decoration: none;
}

.btn-secondary {
  border: 1px solid var(--line);
  background: var(--panel-hi);
  color: var(--fg);
}

.btn-secondary:hover {
  border-color: #3a4048;
  background: var(--panel-hi);
  color: var(--fg);
  text-decoration: none;
}

/* --------------------------------- intro ---------------------------------- */

.intro {
  padding: 0 0 70px;
}

.intro .container {
  max-width: 780px;
}

.intro p {
  margin: 0 0 22px;
  color: var(--fg-dim);
  font-size: 16px;
  line-height: 1.8;
}

.scenario-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.scenario-list li {
  position: relative;
  padding: 8px 0 8px 20px;
  color: var(--fg-dim);
  font-size: 15px;
}

.scenario-list li::before {
  position: absolute;
  left: 0;
  color: var(--accent);
  content: "—";
}

/* ---------------------------------- tools --------------------------------- */

.tools {
  padding: 60px 0 70px;
  border-top: 1px solid var(--line);
  background: var(--bg-deep);
}

.tools h2 {
  margin: 0 0 30px;
  font-size: 32px;
  font-weight: 700;
  text-align: center;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.tool {
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.tool h3 {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 16px;
  font-weight: 600;
}

.tool p {
  margin: 0;
  color: var(--fg-dim);
  font-size: 14px;
  line-height: 1.6;
}

/* -------------------------------- features -------------------------------- */

.features {
  padding: 70px 0;
  border-top: 1px solid var(--line);
  background: var(--bg);
}

.features .container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 40px;
}

.feature h3 {
  margin: 0 0 10px;
  font-size: 19px;
  font-weight: 600;
}

.feature p {
  margin: 0;
  color: var(--fg-dim);
  font-size: 15px;
  line-height: 1.7;
}

/* --------------------------------- safety --------------------------------- */

.safety {
  padding: 70px 0;
  border-top: 1px solid var(--line);
  background: var(--bg-deep);
}

.safety h2 {
  margin: 0 0 26px;
  font-size: 32px;
  font-weight: 700;
  text-align: center;
}

.safety-list {
  max-width: 640px;
  margin: 0 auto;
  padding: 0;
  list-style: none;
}

.safety-list li {
  position: relative;
  padding: 12px 0 12px 26px;
  border-bottom: 1px solid var(--line);
  color: var(--fg-dim);
  font-size: 15px;
}

.safety-list li:last-child {
  border-bottom: none;
}

/* 用 CSS 画的小方块作为项目符号,避免引入任何符号字体/emoji */
.safety-list li::before {
  position: absolute;
  top: 20px;
  left: 0;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background: var(--accent);
  content: "";
}

code {
  padding: 2px 6px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--panel-hi);
  color: var(--fg);
  font-family: "SF Mono", "Consolas", monospace;
  font-size: 13px;
}

/* ------------------------------- shortcuts -------------------------------- */

.shortcuts {
  padding: 70px 0;
  border-top: 1px solid var(--line);
  background: var(--bg);
}

.group-title {
  margin: 34px 0 14px;
  color: var(--fg-dim);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.group-title:first-of-type {
  margin-top: 0;
}

.shortcut-note {
  margin: 34px 0 0;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--fg-dim);
  font-size: 14px;
  line-height: 1.9;
}

.shortcuts h2 {
  margin: 0 0 30px;
  font-size: 32px;
  font-weight: 700;
  text-align: center;
}

.shortcut-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.shortcut-item {
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 14px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.shortcut-item kbd {
  flex: 0 0 auto;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--panel-hi);
  color: var(--accent);
  font-family: "SF Mono", "Consolas", monospace;
  font-size: 13px;
  font-weight: 600;
  white-space: nowrap;
}

.shortcut-item span {
  color: var(--fg-dim);
  font-size: 14px;
}

/* -------------------------------- download -------------------------------- */

.download {
  padding: 70px 0;
  border-top: 1px solid var(--line);
  background: var(--bg-deep);
  text-align: center;
}

.download h2 {
  margin: 0 0 16px;
  font-size: 32px;
  font-weight: 700;
}

.download p {
  margin: 0 0 22px;
  color: var(--fg-dim);
  font-size: 16px;
}

.platform-list {
  max-width: 520px;
  margin: 0 auto;
  padding: 0;
  list-style: none;
  text-align: left;
}

.platform-list li {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  color: var(--fg-dim);
  font-size: 15px;
}

.platform-list li:last-child {
  border-bottom: none;
}

.platform-list strong {
  color: var(--fg);
}

.download-note {
  max-width: 520px;
  margin: 22px auto 0;
  color: var(--fg-dim);
  font-size: 14px;
}

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

footer {
  padding: 40px 0;
  border-top: 1px solid var(--line);
  background: var(--panel);
  color: var(--fg-dim);
  font-size: 13px;
  text-align: center;
}

footer p {
  margin: 6px 0;
}

footer p:first-child {
  color: var(--fg);
}

/* ------------------------------- responsive ------------------------------- */

@media (max-width: 768px) {
  .hero h1 {
    font-size: 38px;
  }

  .lead {
    font-size: 17px;
  }

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

  .btn-primary,
  .btn-secondary {
    width: 100%;
    max-width: 280px;
  }

  .features .container {
    grid-template-columns: 1fr;
    gap: 32px;
  }

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

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

  .tools h2,
  .safety h2,
  .shortcuts h2,
  .download h2 {
    font-size: 26px;
  }
}