/* GPA tools — 单文件样式，无外部依赖（站点 CSP 为 style-src 'self'，禁止内联样式） */
:root {
  --ink: #16202b;
  --muted: #5b6b7c;
  --line: #dde3ea;
  --bg: #f6f8fa;
  --card: #ffffff;
  --brand: #1d5fd0;
  --brand-dark: #17479c;
  --ok: #0f7b5f;
  --warn: #a3561a;
  --radius: 10px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
}

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: 880px; margin: 0 auto; padding: 0 18px; }

/* 顶部 */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 56px;
  flex-wrap: wrap;
}
.brand {
  font-weight: 700;
  font-size: 17px;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.brand span { color: var(--brand); }
.site-nav { display: flex; gap: 14px; flex-wrap: wrap; font-size: 14px; }
.site-nav a { color: var(--muted); }
.site-nav a:hover { color: var(--brand); }

/* 主体 */
main { padding: 26px 0 40px; }
h1 {
  font-size: 30px;
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin: 6px 0 10px;
}
h2 {
  font-size: 21px;
  line-height: 1.35;
  margin: 34px 0 10px;
  letter-spacing: -0.01em;
}
h3 { font-size: 17px; margin: 22px 0 8px; }
p, li { color: var(--ink); }
.lede { font-size: 17px; color: var(--muted); margin: 0 0 22px; }

.breadcrumbs { font-size: 13px; color: var(--muted); margin: 0 0 4px; }
.breadcrumbs ol { list-style: none; display: flex; gap: 6px; padding: 0; margin: 0; flex-wrap: wrap; }
.breadcrumbs li + li::before { content: "/"; margin-right: 6px; color: #b9c3ce; }

/* 工具卡片 */
.tool {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  margin: 18px 0 8px;
}
.tool-rows { display: grid; gap: 8px; }

.row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 92px 76px 104px 34px;
  gap: 8px;
  align-items: center;
}
.row.is-simple { grid-template-columns: minmax(0, 1fr) 92px 76px 34px; }

.row input, .row select, .field input, .field select {
  width: 100%;
  padding: 8px 9px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: #fff;
  color: var(--ink);
  font: inherit;
  font-size: 15px;
  min-height: 38px;
}
.row input:focus, .row select:focus, .field input:focus, .field select:focus {
  outline: 2px solid rgba(29, 95, 208, 0.35);
  outline-offset: 1px;
  border-color: var(--brand);
}

.head {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  font-weight: 600;
}

.btn {
  font: inherit;
  font-size: 15px;
  border-radius: 7px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  padding: 9px 14px;
  cursor: pointer;
  min-height: 38px;
}
.btn:hover { border-color: #c3ccd6; background: #fbfcfd; }
.btn-primary {
  background: var(--brand);
  border-color: var(--brand);
  color: #fff;
  font-weight: 600;
}
.btn-primary:hover { background: var(--brand-dark); border-color: var(--brand-dark); }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 14px; }
.btn-icon {
  padding: 0;
  width: 34px;
  min-height: 34px;
  line-height: 1;
  color: var(--muted);
  font-size: 18px;
}
.btn-icon:hover { color: #b3261e; border-color: #e3b6b2; }

.fields { display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
.field label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 4px; }

/* 结果 */
.result {
  margin-top: 16px;
  padding: 14px 16px;
  border-radius: var(--radius);
  background: #eef4ff;
  border: 1px solid #d3e0f8;
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-wrap: wrap;
}
.result-label { font-size: 14px; color: var(--muted); font-weight: 600; }
.result-value {
  font-size: 30px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--brand-dark);
  font-variant-numeric: tabular-nums;
}
.result-note { font-size: 14px; color: var(--muted); flex-basis: 100%; }
.result[hidden] { display: none; }
.result.is-warn { background: #fdf3e8; border-color: #f0d6b8; }
.result.is-warn .result-value { color: var(--warn); }
.result.is-ok .result-value { color: var(--ok); }

/* 表格 */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0 6px;
  font-size: 15px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); }
th { background: #f0f3f7; font-size: 13px; text-transform: uppercase; letter-spacing: 0.03em; color: var(--muted); }
tr:last-child td { border-bottom: none; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

/* 说明块 */
.callout {
  border-left: 3px solid var(--brand);
  background: #f2f6fd;
  padding: 12px 14px;
  border-radius: 0 8px 8px 0;
  margin: 16px 0;
  font-size: 15px;
}
.callout p:first-child { margin-top: 0; }
.callout p:last-child { margin-bottom: 0; }

details.faq {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 10px 0;
}
details.faq summary { cursor: pointer; font-weight: 600; }
details.faq p { color: var(--muted); margin: 8px 0 2px; }

.related { margin: 30px 0 0; padding: 16px 18px; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); }
.related h2 { margin: 0 0 8px; font-size: 16px; }
.related ul { margin: 0; padding-left: 18px; columns: 2; column-gap: 24px; }
.related li { margin: 3px 0; }

code, .formula {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 14px;
  background: #eef1f5;
  padding: 2px 6px;
  border-radius: 5px;
}
.formula { display: block; padding: 10px 12px; margin: 10px 0; overflow-x: auto; }

/* 首页全站索引 */
.index { margin-top: 34px; }
.index h2 { margin-top: 0; }
.index-group { border-top: 1px solid var(--line); margin-top: 14px; padding-top: 12px; }
.index-group h3 {
  margin: 0 0 6px;
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.index-group ul { margin: 0; padding-left: 18px; columns: 2; column-gap: 24px; }
.index-group li { margin: 3px 0; }

/* 页脚 */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--card);
  padding: 18px 0 26px;
  font-size: 13px;
  color: var(--muted);
}
.site-footer p { color: var(--muted); margin: 4px 0; }

@media (max-width: 640px) {
  h1 { font-size: 24px; }
  .row, .row.is-simple {
    grid-template-columns: minmax(0, 1fr) 76px 64px 30px;
    grid-template-areas: "name grade credits del";
  }
  .row .type-select { grid-column: 1 / -1; }
  .related ul { columns: 1; }
  .result-value { font-size: 26px; }
}