/* ===== 学生错题管理系统 · Web 管理端设计系统（晨光蓝白） ===== */
:root {
  --bg: linear-gradient(180deg, #D9E9FA 0%, #EFF6FD 38%, #FFFFFF 100%);
  --grad: linear-gradient(135deg, #4FA3F7 0%, #2E7BE6 100%);
  --grad-soft: linear-gradient(135deg, #4FA3F7, #2E7BE6);
  --ink: #1B2A41;
  --ink-2: #54627A;
  --ink-3: #8A97A8;
  --accent: #2E7BE6;
  --accent-2: #4FA3F7;
  --tint: #E8F1FB;
  --ok: #35C77F;
  --warn: #F5A623;
  --bad: #F4736B;
  --coral: #F4736B;
  --card: #FFFFFF;
  --stroke: rgba(24, 72, 140, .10);
  --stroke-strong: rgba(24, 72, 140, .18);
  --shadow: 0 2px 12px rgba(24, 72, 140, .07);
  --shadow-lg: 0 12px 34px rgba(24, 72, 140, .14);
  --radius: 16px;
  --radius-sm: 10px;
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, -apple-system, sans-serif;
  color: var(--ink);
  background: var(--bg);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  font-size: 14px;
}
a { color: var(--accent); text-decoration: none; }
::-webkit-scrollbar { width: 9px; height: 9px; }
::-webkit-scrollbar-thumb { background: rgba(24,72,140,.18); border-radius: 9px; }
::-webkit-scrollbar-track { background: transparent; }

/* ---------- 白卡基础件 ---------- */
.glass {
  background: var(--card);
  border: 1px solid var(--stroke);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.card { padding: 18px; }
.card + .card { margin-top: 16px; }
.card-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; }
.card-title { font-size: 15px; font-weight: 600; letter-spacing: .4px; display: flex; align-items: center; gap: 8px; }
.card-title::before { content: ""; width: 4px; height: 15px; border-radius: 3px; background: var(--accent); }
.muted { color: var(--ink-3); }
.dim { color: var(--ink-2); }
.small { font-size: 12px; }
.row { display: flex; align-items: center; gap: 10px; }
.row.wrap { flex-wrap: wrap; }
.spacer { flex: 1; }
.hide { display: none !important; }

/* ---------- 布局 ---------- */
#app { position: relative; z-index: 1; min-height: 100vh; display: flex; }
.sidebar {
  width: 232px; flex: 0 0 232px; padding: 20px 14px;
  display: flex; flex-direction: column; gap: 6px;
  background: rgba(255,255,255,.72);
  backdrop-filter: blur(20px) saturate(160%);
  border-right: 1px solid var(--stroke);
  position: sticky; top: 0; height: 100vh; overflow: auto;
}
.brand { display: flex; align-items: center; gap: 10px; padding: 6px 8px 18px; }
.brand .logo {
  width: 36px; height: 36px; border-radius: 11px; display: grid; place-items: center;
  background: var(--grad); box-shadow: 0 6px 16px rgba(46,123,230,.28); font-weight: 700; color: #fff;
}
.brand b { font-size: 15px; letter-spacing: .5px; color: var(--ink); }
.brand span { display: block; font-size: 11px; color: var(--ink-3); }
.nav-item {
  display: flex; align-items: center; gap: 10px; padding: 10px 12px; border-radius: 11px;
  color: var(--ink-2); cursor: pointer; transition: .18s; font-size: 13.5px; user-select: none;
  border: 1px solid transparent;
}
.nav-item:hover { background: var(--tint); color: var(--accent); }
.nav-item.active { background: var(--tint); color: var(--accent); border-color: rgba(46,123,230,.22); font-weight: 600; }
.nav-item .ico { width: 18px; text-align: center; opacity: .95; }
.nav-item .badge { margin-left: auto; }
.nav-group { font-size: 11px; color: var(--ink-3); padding: 14px 12px 6px; letter-spacing: 1px; }

.main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 14px;
  padding: 12px 22px; border-bottom: 1px solid var(--stroke);
  background: rgba(255,255,255,.82);
  backdrop-filter: blur(18px) saturate(160%);
}
.topbar h1 { font-size: 17px; margin: 0; font-weight: 600; color: var(--ink); }
.crumb { color: var(--ink-3); font-size: 12.5px; }
.content { padding: 22px; width: 100%; }
.page-enter { animation: fadeUp .32s cubic-bezier(.22,.8,.3,1); }
@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 7px; justify-content: center;
  padding: 9px 15px; border-radius: 10px; cursor: pointer; font-size: 13px; font-weight: 500;
  border: 1px solid var(--stroke); background: #fff; color: var(--ink);
  transition: .18s; white-space: nowrap; user-select: none;
}
.btn:hover { background: var(--tint); border-color: rgba(46,123,230,.28); color: var(--accent); }
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--grad); border-color: transparent; box-shadow: 0 8px 18px rgba(46,123,230,.28); color: #fff; }
.btn.primary:hover { background: var(--grad); color: #fff; box-shadow: 0 10px 24px rgba(46,123,230,.36); }
.btn.ghost { background: transparent; }
.btn.ghost:hover { background: var(--tint); }
.btn.danger { color: #D6453C; border-color: rgba(244,115,107,.45); background: #fff; }
.btn.danger:hover { background: rgba(244,115,107,.12); color: #D6453C; }
.btn.sm { padding: 6px 11px; font-size: 12px; border-radius: 8px; }
.btn[disabled] { opacity: .45; pointer-events: none; }

/* ---------- 表单 ---------- */
.field { display: flex; flex-direction: column; gap: 6px; margin-bottom: 12px; }
.field label { font-size: 12.5px; color: var(--ink-2); }
.input, .select, .textarea {
  width: 100%; padding: 9px 12px; border-radius: 10px; font-size: 13.5px; color: var(--ink);
  background: #fff; border: 1px solid var(--stroke); outline: none; transition: .18s;
  font-family: inherit;
}
.input::placeholder, .textarea::placeholder { color: var(--ink-3); }
.input:focus, .select:focus, .textarea:focus { border-color: var(--accent); background: #fff; box-shadow: 0 0 0 3px rgba(46,123,230,.14); }
.textarea { min-height: 90px; resize: vertical; line-height: 1.6; }
.select option { background: #fff; color: var(--ink); }
input[type="file"] { color: var(--ink-2); font-size: 12.5px; }
.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 0 14px; }

/* ---------- 表格 ---------- */
.table-wrap { overflow: auto; border-radius: 12px; border: 1px solid var(--stroke); background: #fff; }
table.tbl { width: 100%; border-collapse: collapse; font-size: 13px; }
table.tbl th, table.tbl td { padding: 10px 12px; text-align: left; white-space: nowrap; }
table.tbl th { background: var(--tint); color: var(--ink-2); font-weight: 600; font-size: 12px; position: sticky; top: 0; }
table.tbl tr { border-bottom: 1px solid var(--stroke); }
table.tbl tbody tr:hover { background: rgba(46,123,230,.05); }
table.tbl td.wrap-cell { white-space: normal; min-width: 260px; max-width: 520px; }
table.tbl td .stem { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }

/* ---------- 徽标 / 标签 ---------- */
.badge { display: inline-flex; align-items: center; padding: 2px 9px; border-radius: 999px; font-size: 11.5px; border: 1px solid var(--stroke); background: var(--tint); color: var(--ink-2); }
.badge.ok { color: #1E9C63; border-color: rgba(53,199,127,.35); background: rgba(53,199,127,.12); }
.badge.warn { color: #C57E0C; border-color: rgba(245,166,35,.35); background: rgba(245,166,35,.13); }
.badge.bad { color: #D6453C; border-color: rgba(244,115,107,.35); background: rgba(244,115,107,.12); }
.badge.accent { color: var(--accent); border-color: rgba(46,123,230,.35); background: rgba(46,123,230,.10); }
.chip { display: inline-flex; align-items: center; gap: 5px; padding: 3px 10px; border-radius: 999px; background: #fff; border: 1px solid var(--stroke); font-size: 12px; color: var(--ink-2); cursor: pointer; transition: .15s; }
.chip:hover { border-color: rgba(46,123,230,.3); color: var(--accent); background: var(--tint); }
.chip.on { background: #fff; border: 1.5px solid var(--accent); color: var(--accent); font-weight: 600; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }

/* ---------- 统计卡（数字大屏） ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 14px; }
.stat {
  position: relative; padding: 16px 18px; border-radius: 15px; overflow: hidden;
  background: var(--card); border: 1px solid var(--stroke); box-shadow: var(--shadow);
}
.stat::after { content: ""; position: absolute; right: -26px; top: -26px; width: 84px; height: 84px; border-radius: 50%; background: radial-gradient(circle, rgba(46,123,230,.10), transparent 70%); }
.stat .k { font-size: 12.5px; color: var(--ink-3); }
.stat .v { font-size: 28px; font-weight: 700; letter-spacing: .5px; margin: 6px 0 2px; font-variant-numeric: tabular-nums; color: var(--ink); }
.stat .s { font-size: 11.5px; color: var(--ink-3); }
.stat .v small { font-size: 14px; color: var(--ink-3); font-weight: 500; margin-left: 3px; }
.stat.good .v { color: #22A567; } .stat.warn .v { color: #D98A0E; } .stat.bad .v { color: #E8544A; }

/* ---------- 进度条 ---------- */
.bar { height: 8px; border-radius: 999px; background: var(--tint); overflow: hidden; }
.bar > i { display: block; height: 100%; border-radius: 999px; background: var(--grad); transition: width .6s cubic-bezier(.22,.8,.3,1); }
.bar.ok > i { background: linear-gradient(90deg, #35C77F, #1FA46A); }
.bar.bad > i { background: linear-gradient(90deg, #F4736B, #D6453C); }

/* ---------- 弹窗 ---------- */
.mask { position: fixed; inset: 0; z-index: 60; background: rgba(17,38,72,.42); backdrop-filter: blur(4px); display: grid; place-items: center; padding: 20px; animation: fade .2s; }
@keyframes fade { from { opacity: 0 } to { opacity: 1 } }
.dialog { width: min(880px, 96vw); max-height: 90vh; overflow: auto; background: var(--card); border: 1px solid var(--stroke); border-radius: var(--radius); box-shadow: var(--shadow-lg); animation: pop .26s cubic-bezier(.22,1.1,.35,1); }
.dialog.narrow { width: min(520px, 96vw); }
.dialog.wide { width: min(1180px, 98vw); }
@keyframes pop { from { opacity: 0; transform: translateY(14px) scale(.98) } to { opacity: 1; transform: none } }
.dialog-head { display: flex; align-items: center; gap: 12px; padding: 16px 20px; border-bottom: 1px solid var(--stroke); position: sticky; top: 0; background: rgba(255,255,255,.92); backdrop-filter: blur(14px); z-index: 2; }
.dialog-head h3 { margin: 0; font-size: 15.5px; color: var(--ink); }
.dialog-body { padding: 18px 20px; }
.dialog-foot { display: flex; justify-content: flex-end; gap: 10px; padding: 14px 20px; border-top: 1px solid var(--stroke); position: sticky; bottom: 0; background: rgba(255,255,255,.92); backdrop-filter: blur(14px); }

/* ---------- Toast ---------- */
#toasts { position: fixed; right: 20px; bottom: 20px; z-index: 90; display: flex; flex-direction: column; gap: 10px; }
.toast { padding: 12px 16px; border-radius: 12px; min-width: 220px; font-size: 13px; animation: slideIn .28s; border: 1px solid var(--stroke); background: #fff; color: var(--ink); box-shadow: var(--shadow-lg); }
.toast.ok { border-color: rgba(53,199,127,.45); } .toast.err { border-color: rgba(244,115,107,.45); } .toast.info { border-color: rgba(46,123,230,.4); }
@keyframes slideIn { from { opacity: 0; transform: translateX(24px) } to { opacity: 1; transform: none } }

/* ---------- 图表 ---------- */
.chart { width: 100%; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 8px; font-size: 12px; color: var(--ink-2); }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 5px; vertical-align: -1px; }
.empty { text-align: center; padding: 46px 12px; color: var(--ink-3); }
.empty .big { font-size: 34px; opacity: .5; }
.spinner { width: 26px; height: 26px; border-radius: 50%; border: 3px solid var(--tint); border-top-color: var(--accent); animation: spin .8s linear infinite; margin: 40px auto; }
@keyframes spin { to { transform: rotate(360deg) } }

/* ---------- 登录页 ---------- */
.login-wrap { min-height: 100vh; display: grid; place-items: center; padding: 24px; position: relative; z-index: 1; }
.login-box { width: min(940px, 96vw); display: grid; grid-template-columns: 1.05fr .95fr; overflow: hidden; background: var(--card); border: 1px solid var(--stroke); border-radius: var(--radius); box-shadow: var(--shadow-lg); }
.login-hero { padding: 40px 36px; background: var(--grad); position: relative; color: #fff; }
.login-hero h2 { margin: 0 0 8px; font-size: 26px; color: #fff; }
.login-hero p { color: rgba(255,255,255,.9); line-height: 1.9; font-size: 13.5px; margin: 0 0 22px; }
.hero-list { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 12px; }
.hero-list li { display: flex; gap: 10px; font-size: 13px; color: rgba(255,255,255,.88); }
.hero-list b { color: #fff; font-weight: 600; }
.login-form { padding: 40px 36px; background: #fff; }
@media (max-width: 820px) { .login-box { grid-template-columns: 1fr; } .login-hero { display: none; } }

@media (max-width: 900px) {
  .sidebar { position: fixed; left: 0; top: 0; z-index: 40; transform: translateX(-100%); transition: .25s; background: #fff; }
  .sidebar.open { transform: none; }
  .content { padding: 14px; }
}