:root {
  --bg: #f5f7fa;
  --card: #fff;
  --text: #1d2433;
  --muted: #6b7385;
  --line: #e5e8ef;
  --primary: #2f6fed;
  --primary-dark: #1f56c4;
  --ok: #0f8a4d;
  --ok-bg: #e9f7ef;
  --warn: #b45309;
  --warn-bg: #fff7e8;
  --danger: #b42318;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg); color: var(--text);
  font: 14.5px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
code { background: #f1f4f9; padding: 2px 6px; border-radius: 5px; font-size: 12.5px; }

/* 布局 */
.shell { display: flex; min-height: 100vh; }
.side {
  width: 216px; flex: 0 0 216px; background: #fff; border-right: 1px solid var(--line);
  display: flex; flex-direction: column; position: sticky; top: 0; height: 100vh;
}
.side-brand {
  display: flex; align-items: center; gap: 10px;
  padding: 18px 18px 16px; border-bottom: 1px solid var(--line);
}
.side-brand b { display: block; font-size: 14.5px; line-height: 1.3; }
.side-brand small { color: var(--muted); font-size: 11.5px; }
.dot {
  width: 9px; height: 9px; border-radius: 50%; background: var(--primary);
  box-shadow: 0 0 0 4px rgba(47,111,237,.14); flex: 0 0 auto;
}
.side-nav { padding: 10px 10px; flex: 1; overflow: auto; }
.side-nav a {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 12px; border-radius: 9px; color: #414a5c; font-size: 14px; margin-bottom: 2px;
}
.side-nav a:hover { background: #f4f6fa; text-decoration: none; }
.side-nav a.on { background: #eef3fe; color: var(--primary); font-weight: 600; }
.pill {
  font-style: normal; background: #ffe9e7; color: var(--danger);
  font-size: 11px; padding: 1px 7px; border-radius: 999px;
}
.side-foot {
  border-top: 1px solid var(--line); padding: 12px 18px;
  display: flex; flex-direction: column; gap: 6px; font-size: 13px;
}
.side-foot a { color: var(--muted); }

.main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.main-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 26px 16px;
}
.main-head h1 { margin: 0; font-size: 20px; letter-spacing: -.3px; }
.who { color: var(--muted); font-size: 13px; }
.main-body { padding: 0 26px 40px; }

/* 卡片/网格 */
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: 14px;
  padding: 18px 20px; margin-bottom: 16px;
}
.card h2 { margin: 0 0 14px; font-size: 15px; }
.grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-bottom: 16px; }
.stat {
  background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 16px 18px;
}
.stat b { display: block; font-size: 24px; line-height: 1.25; }
.stat span { color: var(--muted); font-size: 12.5px; }
.two { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

/* 表单 */
.field { display: block; margin-bottom: 14px; }
.field > span { display: block; font-size: 12.5px; color: var(--muted); margin-bottom: 6px; }
.field .tip { color: var(--muted); font-size: 12px; margin-top: 5px; }
textarea, input[type=text], input[type=password], input[type=number], select {
  width: 100%; padding: 9px 12px; font: inherit; color: var(--text);
  background: #fbfcfe; border: 1px solid var(--line); border-radius: 9px; outline: none;
  transition: border-color .15s, box-shadow .15s;
}
textarea { resize: vertical; line-height: 1.6; }
textarea:focus, input:focus, select:focus {
  border-color: var(--primary); background: #fff; box-shadow: 0 0 0 3px rgba(47,111,237,.12);
}
.row { display: flex; gap: 14px; }
.row > * { flex: 1; min-width: 0; }

.btn {
  appearance: none; border: 1px solid var(--line); background: #fff; color: var(--text);
  font: inherit; font-size: 13.5px; padding: 8px 15px; border-radius: 9px;
  cursor: pointer; transition: .15s; display: inline-flex; align-items: center; gap: 6px;
}
.btn:hover { background: #f8fafd; border-color: #cfd6e4; text-decoration: none; }
.btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }
.btn.primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); }
.btn.tiny { padding: 4px 10px; font-size: 12.5px; border-radius: 7px; }
.btn.tiny.link { border: none; background: none; color: var(--primary); padding: 2px 4px; }
.btn.danger { color: var(--danger); border-color: #f3c9c4; background: #fff6f5; }
.btn.disabled { color: #b9c0cd; cursor: default; }
.actions { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }

/* 表格 */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 500; font-size: 12.5px; background: #fafbfd; white-space: nowrap; }
tr:last-child td { border-bottom: none; }
td.num { white-space: nowrap; color: var(--muted); font-size: 12.5px; }
td .t { max-width: 560px; word-break: break-word; }
.ans { color: var(--ok); font-weight: 600; word-break: break-word; }

.tag {
  display: inline-block; font-size: 11.5px; padding: 1px 8px; border-radius: 999px;
  border: 1px solid transparent; white-space: nowrap;
}
.tag.single { color: #1c4bb0; background: #eef3fe; border-color: #d7e3fd; }
.tag.multiple { color: #7a3ec9; background: #f4eeff; border-color: #e3d5fb; }
.tag.judgement { color: #0d7a6f; background: #e8f8f5; border-color: #c9ece6; }
.tag.completion { color: #b45309; background: var(--warn-bg); border-color: #f3dfb8; }
.tag.shortanswer { color: #6b7385; background: #f1f4f9; border-color: #e1e6ef; }
.tag.off { color: #8a90a0; background: #f4f5f8; border-color: #e5e8ef; }

/* 提示 */
.alert { border-radius: 10px; padding: 11px 14px; font-size: 13.5px; margin-bottom: 16px; }
.alert.err { background: #fff5f4; border: 1px solid #f6d3ce; color: #a32318; }
.alert.ok { background: var(--ok-bg); border: 1px solid #cbe9d8; color: #0b6b3d; }
.alert.warn { background: var(--warn-bg); border: 1px solid #f3dfb8; color: var(--warn); }
.alert.info { background: #eef3fe; border: 1px solid #d7e3fd; color: #1c4bb0; }
.muted { color: var(--muted); }
.small { font-size: 12.5px; }

/* 分页 */
.pager { display: flex; align-items: center; gap: 12px; margin-top: 16px; }
.pager-info { color: var(--muted); font-size: 12.5px; }

/* 过滤器栏 */
.filters { display: flex; gap: 10px; align-items: flex-end; flex-wrap: wrap; }
.filters .field { margin: 0; }
.filters .field.grow { flex: 1 1 240px; }
.filters .field.mini select, .filters .field.mini input { width: auto; min-width: 110px; }

/* 空状态 */
.empty { text-align: center; color: var(--muted); padding: 34px 10px; font-size: 13.5px; }

/* 登录页 */
.login-wrap {
  min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 24px;
}
.login-card {
  width: 100%; max-width: 380px; background: #fff; border: 1px solid var(--line);
  border-radius: 16px; padding: 28px; box-shadow: 0 8px 30px rgba(23,35,60,.06);
}
.login-card h1 { font-size: 18px; margin: 0 0 4px; }
.login-card p.sub { color: var(--muted); font-size: 13px; margin: 0 0 22px; }
.login-card .btn { width: 100%; justify-content: center; }

pre.snippet {
  background: #f7f9fc; border: 1px solid var(--line); border-radius: 10px;
  padding: 12px; font-size: 12px; overflow: auto; max-height: 260px; margin: 0;
}

@media (max-width: 900px) {
  .grid { grid-template-columns: repeat(2, 1fr); }
  .two { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .shell { display: block; }
  .side {
    width: 100%; height: auto; position: sticky; top: 0; z-index: 5;
    flex-direction: row; align-items: center; overflow-x: auto; border-right: none;
    border-bottom: 1px solid var(--line);
  }
  .side-brand { display: none; }
  .side-nav { display: flex; gap: 4px; padding: 8px; flex: 0 0 auto; }
  .side-nav a { white-space: nowrap; margin: 0; }
  .side-foot { border-top: none; flex-direction: row; gap: 12px; padding: 8px 12px; }
  .main-head { padding: 16px 16px 12px; }
  .main-body { padding: 0 16px 30px; }
  td .t { max-width: 220px; }
}