/* Brex 风格：白底、单一 ember 强调色、Inter 负字距、12px 圆角、无阴影、发丝边框 */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap');

:root {
  --ember: #ff5900;
  --abyss: #000710;
  --carbon: #15191e;
  --ink: #000000;
  --paper: #ffffff;
  --fog: #f3f3f7;
  --mist: #b9bbc6;
  --steel: #8b8d98;
  --pewter: #6f737b;
  --graphite: #60646c;

  --font: 'Inter', ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --radius: 12px;
  --radius-tag: 6px;
  --page: 1200px;
  --read: 680px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  letter-spacing: -0.01em;
  font-feature-settings: "calt" 0, "liga" 0, "ss03", "cv01", "cv10";
}

.wrap { max-width: var(--page); margin: 0 auto; padding: 0 24px; }
main.wrap { max-width: var(--read); }

/* ---------- 顶部公告条（Carbon）---------- */
.announce {
  background: var(--carbon); color: var(--paper);
  font-size: 12px; font-weight: 500; line-height: 1.5;
  text-align: center; padding: 8px 16px;
}
.announce b { color: var(--ember); font-weight: 600; }

/* ---------- 导航 ---------- */
header.site { background: var(--paper); border-bottom: 1px solid var(--mist); }
header.site .wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; }
header.site a.logo {
  display: flex; align-items: center; gap: 8px;
  font-size: 16px; font-weight: 600; letter-spacing: -0.02em;
  color: var(--ink); text-decoration: none;
}
header.site nav a {
  font-size: 14px; font-weight: 500; color: var(--ink);
  text-decoration: none; margin-left: 24px;
}
header.site nav a:hover { color: var(--ember); }

/* ---------- 排版 ---------- */
h1 { font-size: 36px; font-weight: 600; line-height: 1.21; letter-spacing: -0.02em; margin: 48px 0 16px; }
h2 { font-size: 24px; font-weight: 600; line-height: 1.33; letter-spacing: -0.01em; margin: 48px 0 12px; }
h3 { font-size: 16px; font-weight: 600; letter-spacing: -0.01em; margin: 0 0 12px; }
p { margin: 0 0 16px; color: var(--graphite); max-width: var(--read); }
small, .small { font-size: 12px; line-height: 1.5; color: var(--pewter); }

/* 正文内联链接用 Ink + 下划线，ember 只留给 CTA */
main a { color: var(--ink); text-decoration: underline; text-underline-offset: 2px; }
main a:hover { color: var(--ember); }

/* ---------- App 头部（图标 + 名称）---------- */
.apphead { display: flex; gap: 16px; align-items: center; margin: 48px 0 16px; }
.apphead img {
  width: 64px; height: 64px; border-radius: var(--radius);
  border: 1px solid var(--mist); flex: none; background: var(--fog);
}
.apphead h1 { margin: 0; font-size: 36px; }

/* ---------- 数据条 ---------- */
.facts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 24px 0 8px; }
.facts div {
  background: var(--paper); border: 1px solid var(--mist);
  border-radius: var(--radius); padding: 24px;
}
.facts b {
  display: block; font-size: 24px; font-weight: 600;
  line-height: 1.33; letter-spacing: -0.01em;
  font-variant-numeric: tabular-nums;
}
.facts .small { display: block; margin-top: 4px; }
.facts .hot b { color: var(--ember); }

/* ---------- 步骤 ---------- */
ol.steps { padding: 0; margin: 16px 0; list-style: none; counter-reset: s; }
ol.steps li {
  counter-increment: s; position: relative;
  padding: 0 0 16px 36px; color: var(--graphite); max-width: var(--read);
}
ol.steps li::before {
  content: counter(s); position: absolute; left: 0; top: 0;
  width: 24px; height: 24px; border-radius: var(--radius-tag);
  background: var(--fog); color: var(--ink);
  font-size: 12px; font-weight: 600;
  display: grid; place-items: center;
}
ol.steps strong { color: var(--ink); font-weight: 600; }

/* ---------- 卡片 ---------- */
.card {
  background: var(--paper); border: 1px solid var(--mist);
  border-radius: var(--radius); padding: 32px; margin: 24px 0;
}
.card.offer { border-color: var(--ember); }

/* ---------- 差评原声（Fog 区块）---------- */
.voices { background: var(--fog); border-radius: var(--radius); padding: 32px; margin: 24px 0; }
.voices h2 { margin-top: 0; }
.quote { background: var(--paper); border-radius: var(--radius); padding: 24px; margin: 16px 0 0; }
.quote p { margin: 0 0 8px; color: var(--ink); font-size: 14px; line-height: 1.43; }
.quote .meta { font-size: 12px; color: var(--steel); }
.quote .stars { color: var(--ember); }

/* ---------- 表单 ---------- */
label { display: block; font-size: 14px; font-weight: 600; color: var(--ink); margin: 24px 0 8px; }
select, input[type=text], input[type=date], textarea {
  width: 100%; padding: 12px 16px;
  font-family: var(--font); font-size: 14px; letter-spacing: -0.01em;
  color: var(--ink); background: var(--paper);
  border: 1px solid var(--mist); border-radius: var(--radius);
}
::placeholder { color: var(--steel); }
select:focus, input:focus, textarea:focus { outline: 2px solid var(--ember); outline-offset: -1px; }
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

button {
  font-family: var(--font); font-size: 16px; font-weight: 600; letter-spacing: -0.01em;
  cursor: pointer; padding: 12px 24px;
  border: none; border-radius: var(--radius);
  background: var(--ember); color: var(--paper);
}
button:hover { filter: brightness(1.08); }
button:disabled { opacity: .4; cursor: not-allowed; filter: none; }
button.ghost {
  background: transparent; color: var(--ink);
  border: 1px solid var(--mist); font-size: 14px; font-weight: 500;
}
button.ghost:hover { border-color: var(--ink); filter: none; }

/* ---------- 生成结果 ---------- */
.out { margin-top: 24px; }
.out .reason {
  background: var(--fog); border-radius: var(--radius);
  padding: 16px; font-size: 14px; color: var(--graphite); margin-bottom: 16px;
}
.out .reason b { display: block; color: var(--ink); font-weight: 600; margin-top: 4px; }
pre.letter {
  white-space: pre-wrap; word-wrap: break-word; margin: 0;
  background: var(--fog); border-radius: var(--radius); padding: 24px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px; line-height: 1.6; letter-spacing: 0; color: var(--ink);
}
.actions { display: flex; gap: 8px; margin-top: 16px; flex-wrap: wrap; }

ul.pack { list-style: none; padding: 0; margin: 16px 0; }
ul.pack li {
  position: relative; padding-left: 24px; margin-bottom: 8px;
  font-size: 14px; line-height: 1.43; color: var(--graphite);
}
ul.pack li::before { content: '→'; position: absolute; left: 0; color: var(--ember); }
ul.pack strong { color: var(--ink); font-weight: 600; }

label.confirm {
  display: flex; gap: 12px; align-items: flex-start;
  font-size: 14px; font-weight: 400; line-height: 1.43;
  color: var(--graphite); margin: 24px 0 0; cursor: pointer;
}
label.confirm input { margin: 2px 0 0; flex: none; accent-color: var(--ember); }

/* ---------- App 列表 ---------- */
.applist { list-style: none; padding: 0; margin: 16px 0; }
.applist li { border-bottom: 1px solid var(--mist); }
.applist li:last-child { border-bottom: none; }
.applist a {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 0; text-decoration: none; color: var(--ink);
  font-size: 14px; font-weight: 500;
}
.applist a:hover { color: var(--ember); }
.applist img {
  width: 32px; height: 32px; border-radius: var(--radius-tag);
  border: 1px solid var(--mist); flex: none; background: var(--fog);
}
.applist .nm { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.applist .n {
  font-size: 12px; font-weight: 500; color: var(--pewter);
  font-variant-numeric: tabular-nums; white-space: nowrap;
}

/* ---------- FAQ ---------- */
details { border-top: 1px solid var(--mist); padding: 16px 0; }
details:last-of-type { border-bottom: 1px solid var(--mist); }
details summary { cursor: pointer; font-size: 16px; font-weight: 600; letter-spacing: -0.01em; }
details summary::marker { color: var(--steel); }
details p { margin: 12px 0 0; font-size: 14px; line-height: 1.43; }

/* ---------- 深色页脚 ---------- */
footer.site { background: var(--abyss); color: var(--paper); margin-top: 80px; padding: 48px 0; }
footer.site .wrap { max-width: var(--page); }
footer.site .mark {
  display: flex; align-items: center; gap: 8px;
  font-size: 16px; font-weight: 600; letter-spacing: -0.02em; margin-bottom: 24px;
}
footer.site p { color: var(--mist); font-size: 14px; line-height: 1.43; max-width: 640px; }
footer.site a { color: var(--paper); text-decoration: underline; text-underline-offset: 2px; }

@media (max-width: 640px) {
  h1, .apphead h1 { font-size: 28px; }
  h2 { font-size: 20px; }
  .facts { grid-template-columns: 1fr; gap: 8px; }
  .row { grid-template-columns: 1fr; }
  .card, .voices { padding: 24px; }
  .apphead img { width: 48px; height: 48px; }
}