/* 校园信息站 v0.1 —— 全局样式
   设计取向：中文优先的响应式排版，信息密度适中，来源与数据状态一眼可辨。
   纯 CSS，无框架、无构建步骤、无外部字体/图标请求（断网可用）。 */

:root {
  --brand: #1f59c2;
  --brand-dark: #17418f;
  --brand-soft: #eef3fd;
  --ink: #1c2230;
  --ink-2: #4a5568;
  --ink-3: #71798a;
  --line: #e3e7ef;
  --bg: #f6f7fb;
  --card: #ffffff;
  --real: #0f7b52;
  --real-bg: #e7f6ef;
  --demo: #a35b00;
  --demo-bg: #fff4e0;
  --warn: #b3261e;
  --warn-bg: #fdecea;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(20, 30, 60, .06), 0 6px 18px rgba(20, 30, 60, .05);
  --maxw: 1180px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC",
               "Noto Sans CJK SC", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 18px; }

/* ---------------------------------------------------------------- 顶部 */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 50;
}
.header-inner {
  display: flex; align-items: center; gap: 20px;
  height: 62px; max-width: var(--maxw); margin: 0 auto; padding: 0 18px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 30px; height: 30px; border-radius: 8px; flex: none;
  background: linear-gradient(135deg, var(--brand), #3f7fe0);
  color: #fff; font-size: 14px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.brand small { display: block; font-weight: 400; font-size: 12px; color: var(--ink-3); line-height: 1.2; }

.nav { display: flex; gap: 4px; margin-left: auto; flex-wrap: wrap; }
.nav a {
  padding: 7px 13px; border-radius: 8px; color: var(--ink-2);
  font-size: 14.5px; transition: background .15s, color .15s;
}
.nav a:hover { background: var(--brand-soft); color: var(--brand-dark); text-decoration: none; }
.nav a.active { background: var(--brand); color: #fff; }

.mode-chip {
  font-size: 12px; padding: 3px 9px; border-radius: 999px; white-space: nowrap;
  border: 1px solid var(--line); color: var(--ink-3);
}
.mode-chip.demo { background: var(--demo-bg); color: var(--demo); border-color: #f0d9ad; }
.mode-chip.real { background: var(--real-bg); color: var(--real); border-color: #bfe5d3; }

/* ---------------------------------------------------------------- 通用块 */
main { padding: 26px 0 60px; }

.page-head { margin-bottom: 20px; }
.page-head h1 { font-size: 25px; margin: 0 0 6px; letter-spacing: .3px; }
.page-head p { margin: 0; color: var(--ink-2); font-size: 14.5px; }

.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
}
.pad { padding: 18px 20px; }

.grid { display: grid; gap: 16px; }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }

.notice-banner {
  border-radius: var(--radius); padding: 12px 16px; font-size: 14px;
  border: 1px solid #f0d9ad; background: var(--demo-bg); color: #7a4500;
  margin-bottom: 18px;
}
.notice-banner.info { background: var(--brand-soft); border-color: #cadcfb; color: var(--brand-dark); }
.notice-banner.warn { background: var(--warn-bg); border-color: #f5c6c2; color: #8c1d18; }
.notice-banner strong { font-weight: 700; }

/* ---------------------------------------------------------------- 表单控件 */
.toolbar {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: center;
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 14px; margin-bottom: 16px; box-shadow: var(--shadow);
}
.field { display: flex; flex-direction: column; gap: 4px; }
.field label { font-size: 12.5px; color: var(--ink-3); }

input[type=text], input[type=number], input[type=search], select {
  font: inherit; font-size: 14.5px; color: var(--ink);
  padding: 8px 11px; border: 1px solid var(--line); border-radius: 9px;
  background: #fff; min-height: 38px; transition: border-color .15s, box-shadow .15s;
}
input:focus, select:focus {
  outline: none; border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(31, 89, 194, .12);
}
input[type=search] { min-width: 240px; flex: 1; }

.btn {
  font: inherit; font-size: 14.5px; cursor: pointer;
  padding: 9px 17px; border-radius: 9px; border: 1px solid var(--brand);
  background: var(--brand); color: #fff; transition: background .15s, opacity .15s;
}
.btn:hover { background: var(--brand-dark); }
.btn.ghost { background: #fff; color: var(--ink-2); border-color: var(--line); }
.btn.ghost:hover { background: var(--bg); color: var(--ink); }
.btn.ghost.on { background: var(--brand-soft); color: var(--brand-dark); border-color: #b9cdf5; }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.small { padding: 6px 12px; font-size: 13.5px; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip {
  font-size: 13px; padding: 5px 11px; border-radius: 999px; cursor: pointer;
  border: 1px solid var(--line); background: #fff; color: var(--ink-2); user-select: none;
}
.chip:hover { border-color: #b9cdf5; color: var(--brand-dark); }
.chip.on { background: var(--brand); border-color: var(--brand); color: #fff; }
.chip .n { opacity: .7; font-size: 12px; margin-left: 3px; }

/* ---------------------------------------------------------------- 标签 */
.tag {
  display: inline-block; font-size: 12px; padding: 2px 8px; border-radius: 6px;
  background: var(--brand-soft); color: var(--brand-dark); white-space: nowrap;
}
.tag.cat { background: #eef0f5; color: var(--ink-2); }
.tag.real { background: var(--real-bg); color: var(--real); }
.tag.demo { background: var(--demo-bg); color: var(--demo); border: 1px solid #f0d9ad; }
.tag.deadline { background: var(--warn-bg); color: var(--warn); }
.tag.outline { background: transparent; border: 1px solid var(--line); color: var(--ink-3); }

.meta { color: var(--ink-3); font-size: 13px; display: flex; flex-wrap: wrap; gap: 4px 14px; }
.meta b { font-weight: 600; color: var(--ink-2); }

/* ---------------------------------------------------------------- 通知卡片 */
.list { display: grid; gap: 12px; }
.ncard {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px; box-shadow: var(--shadow);
  display: grid; gap: 9px; transition: border-color .15s, transform .15s;
}
.ncard:hover { border-color: #b9cdf5; transform: translateY(-1px); }
.ncard h3 { margin: 0; font-size: 17px; line-height: 1.5; font-weight: 600; }
.ncard h3 a { color: var(--ink); }
.ncard h3 a:hover { color: var(--brand); text-decoration: none; }
.ncard .summary { margin: 0; color: var(--ink-2); font-size: 14.3px; line-height: 1.75; }
.ncard .row { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.ncard .foot { display: flex; flex-wrap: wrap; gap: 6px 14px; align-items: center; font-size: 13px; color: var(--ink-3); }
.ncard .foot .spacer { flex: 1; }
.ncard.demo { border-left: 3px solid #e8b667; }

/* ---------------------------------------------------------------- 分页 */
.pager { display: flex; gap: 8px; align-items: center; justify-content: center; margin-top: 22px; flex-wrap: wrap; }
.pager .info { color: var(--ink-3); font-size: 14px; margin: 0 8px; }
.pager button {
  font: inherit; font-size: 14px; cursor: pointer; padding: 7px 13px;
  border: 1px solid var(--line); background: #fff; border-radius: 8px; color: var(--ink-2);
}
.pager button:hover:not(:disabled) { border-color: #b9cdf5; color: var(--brand-dark); }
.pager button:disabled { opacity: .45; cursor: not-allowed; }

/* ---------------------------------------------------------------- 空状态 */
.empty {
  text-align: center; padding: 54px 24px; color: var(--ink-2);
  background: var(--card); border: 1px dashed var(--line); border-radius: var(--radius);
}
.empty .icon { font-size: 34px; line-height: 1; margin-bottom: 10px; opacity: .55; }
.empty h3 { margin: 0 0 8px; font-size: 17px; color: var(--ink); }
.empty p { margin: 0 auto 6px; font-size: 14.3px; max-width: 520px; }
.empty .hint { font-size: 13px; color: var(--ink-3); }

/* ---------------------------------------------------------------- 统计卡 */
.stat { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); }
.stat .k { font-size: 13px; color: var(--ink-3); }
.stat .v { font-size: 30px; font-weight: 700; letter-spacing: .5px; line-height: 1.25; }
.stat .s { font-size: 12.5px; color: var(--ink-3); }

.bar { height: 7px; border-radius: 999px; background: #edf0f6; overflow: hidden; margin-top: 8px; }
.bar > i { display: block; height: 100%; background: linear-gradient(90deg, var(--brand), #5c95ea); }

/* ---------------------------------------------------------------- 详情 */
.detail-grid { display: grid; grid-template-columns: minmax(0, 1fr) 320px; gap: 18px; align-items: start; }
.article h1 { font-size: 24px; line-height: 1.45; margin: 0 0 12px; }
.article .body { margin-top: 18px; }
.article .body pre {
  white-space: pre-wrap; word-break: break-word; font-family: inherit;
  font-size: 15.4px; line-height: 1.95; color: var(--ink);
  background: #fbfcfe; border: 1px solid var(--line); border-radius: 10px;
  padding: 18px 20px; margin: 0; max-height: none;
}
.srcbox { font-size: 13.5px; }
.srcbox dt { color: var(--ink-3); font-size: 12.5px; margin-top: 11px; }
.srcbox dd { margin: 2px 0 0; word-break: break-all; }
.srcbox dd.url { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 12.3px; }

/* ---------------------------------------------------------------- 实验页 */
.lab-grid { display: grid; grid-template-columns: 320px minmax(0, 1fr); gap: 18px; align-items: start; }
.kv { display: grid; grid-template-columns: auto 1fr; gap: 4px 14px; font-size: 14px; }
.kv dt { color: var(--ink-3); }
.kv dd { margin: 0; font-weight: 600; font-variant-numeric: tabular-nums; }
.chart { width: 100%; height: auto; display: block; }
.chart .axis { stroke: #d7dde8; stroke-width: 1; }
.chart .grid-line { stroke: #eef1f7; stroke-width: 1; }
.chart .lbl { font-size: 11px; fill: var(--ink-3); }
.chart .line-q { fill: none; stroke: #1f59c2; stroke-width: 2.4; }
.chart .line-r { fill: none; stroke: #d97706; stroke-width: 2.4; }
.chart .dot { fill: #d97706; }
.slider { width: 100%; }

/* ---------------------------------------------------------------- 表格 */
table.tbl { width: 100%; border-collapse: collapse; font-size: 14px; }
table.tbl th, table.tbl td { text-align: left; padding: 9px 11px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.tbl th { color: var(--ink-3); font-weight: 600; font-size: 13px; background: #fafbfe; }
table.tbl tr:last-child td { border-bottom: none; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 12.5px; }

.skeleton { color: var(--ink-3); padding: 30px; text-align: center; }

/* ---------------------------------------------------------------- 页脚 */
.site-footer {
  border-top: 1px solid var(--line); background: var(--card);
  padding: 22px 0; color: var(--ink-3); font-size: 13px;
}
.site-footer .wrap { display: grid; gap: 6px; }
.site-footer b { color: var(--ink-2); }

/* ---------------------------------------------------------------- 响应式 */
@media (max-width: 980px) {
  .grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .grid.cols-3 { grid-template-columns: repeat(2, 1fr); }
  .detail-grid, .lab-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  html, body { font-size: 15.5px; }
  .header-inner { height: auto; flex-wrap: wrap; padding: 10px 18px; gap: 10px; }
  .nav { margin-left: 0; width: 100%; order: 3; }
  .grid.cols-4, .grid.cols-3, .grid.cols-2 { grid-template-columns: 1fr; }
  input[type=search] { min-width: 100%; }
  .page-head h1 { font-size: 21px; }
  .stat .v { font-size: 25px; }
  .toolbar { padding: 12px; }
}

/* Four platform entry points, including the math modelling library. */
.quick-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
.header-inner{height:auto;min-height:80px;flex-wrap:wrap;padding-top:12px;padding-bottom:12px}
.nav{flex-wrap:wrap}
@media(max-width:700px){.quick-grid{grid-template-columns:1fr}}