:root {
  --bg: #0f1115;
  --card: #171a21;
  --card-2: #1d212b;
  --border: #2a2f3a;
  --text: #e8eaf0;
  --muted: #9aa1af;
  --accent: #25f4ee;      /* 青色主色（呼应平台色但不侵权使用） */
  --accent-2: #fe2c55;    /* 品红强调色 */
  --ok: #34d399;
  --warn: #fbbf24;
  --bad: #f87171;
  --radius: 12px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* ===== 导航 ===== */
header.site {
  border-bottom: 1px solid var(--border);
  background: rgba(15,17,21,.9);
  backdrop-filter: blur(8px);
  position: sticky; top: 0; z-index: 10;
}
header.site .container { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.logo { font-weight: 700; font-size: 17px; color: var(--text); text-decoration: none; }
.logo span { color: var(--accent); }
nav.top a { color: var(--muted); text-decoration: none; margin-left: 18px; font-size: 14px; }
nav.top a:hover, nav.top a.active { color: var(--text); }

/* ===== Hero ===== */
.hero { padding: 56px 0 32px; text-align: center; }
.hero h1 { font-size: clamp(26px, 4vw, 40px); line-height: 1.2; }
.hero h1 em { font-style: normal; color: var(--accent); }
.hero p.sub { color: var(--muted); max-width: 640px; margin: 14px auto 0; font-size: 16px; }

/* ===== 卡片与布局 ===== */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}
.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  align-items: start;
}
@media (max-width: 860px) { .calc-grid { grid-template-columns: 1fr; } }

h2.section { font-size: 22px; margin: 48px 0 18px; }
h3 { font-size: 16px; margin-bottom: 12px; color: var(--text); }

/* ===== 表单 ===== */
.field { margin-bottom: 12px; }
.field label {
  display: flex; justify-content: space-between; align-items: baseline;
  font-size: 13px; color: var(--muted); margin-bottom: 5px;
}
.field label .hint { font-size: 11px; color: #6b7280; }
.field input, .field select {
  width: 100%;
  background: var(--card-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 9px 11px;
  font-size: 15px;
  outline: none;
}
.field input:focus, .field select:focus { border-color: var(--accent); }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
fieldset { border: none; margin-bottom: 8px; }
legend {
  font-size: 12px; text-transform: uppercase; letter-spacing: .08em;
  color: var(--accent); margin-bottom: 10px; font-weight: 600;
}

/* ===== 结果区 ===== */
.results .big {
  display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 16px;
}
.result-box {
  background: var(--card-2); border: 1px solid var(--border);
  border-radius: 10px; padding: 14px;
}
.result-box .k { font-size: 12px; color: var(--muted); }
.result-box .v { font-size: 26px; font-weight: 700; margin-top: 2px; font-variant-numeric: tabular-nums; }
.result-box .v.ok { color: var(--ok); }
.result-box .v.bad { color: var(--bad); }
.result-box .v.warn { color: var(--warn); }

table.breakdown { width: 100%; border-collapse: collapse; font-size: 14px; }
table.breakdown td { padding: 7px 4px; border-bottom: 1px solid var(--border); }
table.breakdown td:last-child { text-align: right; font-variant-numeric: tabular-nums; }
table.breakdown tr.total td { font-weight: 700; border-bottom: none; padding-top: 10px; }

.reverse { margin-top: 16px; border-top: 1px dashed var(--border); padding-top: 14px; }
.reverse .out { font-size: 15px; margin-top: 8px; }
.reverse .out b { color: var(--accent); font-size: 20px; }

/* ===== 文章 ===== */
.article { max-width: 760px; margin: 40px auto; }
.article h1 { font-size: 30px; margin-bottom: 8px; }
.article .meta { color: var(--muted); font-size: 13px; margin-bottom: 28px; }
.article h2 { font-size: 21px; margin: 34px 0 12px; }
.article h3 { font-size: 17px; margin: 24px 0 10px; }
.article p, .article li { color: #c9cdd6; font-size: 15.5px; }
.article p { margin-bottom: 14px; }
.article ul, .article ol { padding-left: 22px; margin-bottom: 14px; }
.article table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 14px; }
.article th, .article td { border: 1px solid var(--border); padding: 8px 10px; text-align: left; }
.article th { background: var(--card-2); }
.article a { color: var(--accent); text-decoration: none; }
.article a:hover { text-decoration: underline; }

.callout {
  border-left: 3px solid var(--accent);
  background: var(--card-2);
  padding: 12px 16px;
  border-radius: 0 8px 8px 0;
  margin: 18px 0;
  font-size: 14px;
  color: #c9cdd6;
}
.callout.warn { border-color: var(--warn); }

/* ===== FAQ ===== */
details {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 10px; padding: 14px 18px; margin-bottom: 10px;
}
details summary { cursor: pointer; font-weight: 600; font-size: 15px; }
details p { margin-top: 10px; color: var(--muted); font-size: 14.5px; }

/* ===== 页脚 ===== */
footer.site {
  border-top: 1px solid var(--border);
  margin-top: 64px; padding: 28px 0; color: var(--muted); font-size: 13px;
}
footer.site .container { display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; }
footer.site a { color: var(--muted); text-decoration: none; margin-left: 14px; }
footer.site a:hover { color: var(--text); }

.btn {
  display: inline-block; background: var(--accent-2); color: #fff;
  padding: 10px 20px; border-radius: 8px; text-decoration: none;
  font-weight: 600; font-size: 15px;
}
.btn:hover { filter: brightness(1.1); }

.note { font-size: 12px; color: #6b7280; margin-top: 10px; }