/* 第4套：步骤时间线 · 暖橙 · 窄栏阅读 */
:root {
  --orange: #e85d04;
  --orange-d: #b44503;
  --ink: #2a2118;
  --mute: #6d6258;
  --bg: #fffaf4;
  --line: #f0d8c4;
  --dot: #ffedd5;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.8;
  font-size: 17px;
}
a { color: var(--orange-d); }
.rail { width: min(720px, calc(100% - 36px)); margin: 0 auto; }
.top {
  padding: 20px 0 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.wordmark {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--orange-d);
  font-weight: 800;
}
.wordmark svg { width: 22px; height: 22px; }
.links a {
  text-decoration: none;
  margin-left: 16px;
  font-size: 14px;
  color: var(--mute);
}
.links a.current { color: var(--orange); font-weight: 700; }
.hero { padding: 28px 0 12px; }
.hero h1 { font-size: 34px; line-height: 1.35; margin-bottom: 14px; }
.hero .intro { color: var(--mute); margin-bottom: 22px; }
.big-dl {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background: var(--orange);
  color: #fff;
  text-decoration: none;
  padding: 16px 20px;
  font-weight: 800;
  border-radius: 999px;
}
.big-dl svg { width: 20px; height: 20px; }
.jump { text-align: center; margin: 12px 0 8px; font-size: 14px; }
.sec { padding: 36px 0 8px; }
.sec h2 { font-size: 24px; margin-bottom: 14px; }
.timeline { position: relative; padding-left: 56px; }
.timeline:before {
  content: "";
  position: absolute;
  left: 19px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--line);
}
.step { position: relative; margin-bottom: 28px; }
.num {
  position: absolute;
  left: -56px;
  top: 0;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--dot);
  color: var(--orange-d);
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--orange);
}
.step h3 { font-size: 18px; margin-bottom: 6px; }
.box {
  background: #fff;
  border: 1px solid var(--line);
  padding: 16px 18px;
  border-radius: 10px;
}
.box + .box { margin-top: 12px; }
.os-list { list-style: none; }
.os-list li {
  padding: 10px 0;
  border-bottom: 1px dashed var(--line);
}
.faq > div { margin: 16px 0; }
.faq h3 { font-size: 17px; color: var(--orange-d); }
.base {
  margin-top: 48px;
  padding: 24px 0 36px;
  border-top: 3px solid var(--orange);
  font-size: 12px;
  color: var(--mute);
}
.base a { margin-right: 10px; }
@media (max-width: 640px) {
  .hero h1 { font-size: 26px; }
  .top { flex-direction: column; align-items: flex-start; gap: 10px; }
}